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 "ecryptfs_kernel.h"
39 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
40 struct page *dst_page, int dst_offset,
41 struct page *src_page, int src_offset, int size,
44 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
45 struct page *dst_page, int dst_offset,
46 struct page *src_page, int src_offset, int size,
51 * @dst: Buffer to take hex character representation of contents of
52 * src; must be at least of size (src_size * 2)
53 * @src: Buffer to be converted to a hex string respresentation
54 * @src_size: number of bytes to convert
56 void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
60 for (x = 0; x < src_size; x++)
61 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
66 * @dst: Buffer to take the bytes from src hex; must be at least of
68 * @src: Buffer to be converted from a hex string respresentation to raw value
69 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
71 void ecryptfs_from_hex(char *dst, char *src, int dst_size)
76 for (x = 0; x < dst_size; x++) {
78 tmp[1] = src[x * 2 + 1];
79 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
84 * ecryptfs_calculate_md5 - calculates the md5 of @src
85 * @dst: Pointer to 16 bytes of allocated memory
86 * @crypt_stat: Pointer to crypt_stat struct for the current inode
87 * @src: Data to be md5'd
88 * @len: Length of @src
90 * Uses the allocated crypto context that crypt_stat references to
91 * generate the MD5 sum of the contents of src.
93 static int ecryptfs_calculate_md5(char *dst,
94 struct ecryptfs_crypt_stat *crypt_stat,
97 struct scatterlist sg;
98 struct hash_desc desc = {
99 .tfm = crypt_stat->hash_tfm,
100 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
104 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
105 sg_init_one(&sg, (u8 *)src, len);
107 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
109 if (IS_ERR(desc.tfm)) {
110 rc = PTR_ERR(desc.tfm);
111 ecryptfs_printk(KERN_ERR, "Error attempting to "
112 "allocate crypto context; rc = [%d]\n",
116 crypt_stat->hash_tfm = desc.tfm;
118 crypto_hash_init(&desc);
119 crypto_hash_update(&desc, &sg, len);
120 crypto_hash_final(&desc, dst);
121 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
126 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
128 char *chaining_modifier)
130 int cipher_name_len = strlen(cipher_name);
131 int chaining_modifier_len = strlen(chaining_modifier);
132 int algified_name_len;
135 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
136 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
137 if (!(*algified_name)) {
141 snprintf((*algified_name), algified_name_len, "%s(%s)",
142 chaining_modifier, cipher_name);
150 * @iv: destination for the derived iv vale
151 * @crypt_stat: Pointer to crypt_stat struct for the current inode
152 * @offset: Offset of the page whose's iv we are to derive
154 * Generate the initialization vector from the given root IV and page
157 * Returns zero on success; non-zero on error.
159 static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
163 char dst[MD5_DIGEST_SIZE];
164 char src[ECRYPTFS_MAX_IV_BYTES + 16];
166 if (unlikely(ecryptfs_verbosity > 0)) {
167 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
168 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
170 /* TODO: It is probably secure to just cast the least
171 * significant bits of the root IV into an unsigned long and
172 * add the offset to that rather than go through all this
173 * hashing business. -Halcrow */
174 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
175 memset((src + crypt_stat->iv_bytes), 0, 16);
176 snprintf((src + crypt_stat->iv_bytes), 16, "%ld", offset);
177 if (unlikely(ecryptfs_verbosity > 0)) {
178 ecryptfs_printk(KERN_DEBUG, "source:\n");
179 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
181 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
182 (crypt_stat->iv_bytes + 16));
184 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
185 "MD5 while generating IV for a page\n");
188 memcpy(iv, dst, crypt_stat->iv_bytes);
189 if (unlikely(ecryptfs_verbosity > 0)) {
190 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
191 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
198 * ecryptfs_init_crypt_stat
199 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
201 * Initialize the crypt_stat structure.
204 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
206 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
207 INIT_LIST_HEAD(&crypt_stat->keysig_list);
208 mutex_init(&crypt_stat->keysig_list_mutex);
209 mutex_init(&crypt_stat->cs_mutex);
210 mutex_init(&crypt_stat->cs_tfm_mutex);
211 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
212 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
216 * ecryptfs_destroy_crypt_stat
217 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
219 * Releases all memory associated with a crypt_stat struct.
221 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
223 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
226 crypto_free_blkcipher(crypt_stat->tfm);
227 if (crypt_stat->hash_tfm)
228 crypto_free_hash(crypt_stat->hash_tfm);
229 mutex_lock(&crypt_stat->keysig_list_mutex);
230 list_for_each_entry_safe(key_sig, key_sig_tmp,
231 &crypt_stat->keysig_list, crypt_stat_list) {
232 list_del(&key_sig->crypt_stat_list);
233 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
235 mutex_unlock(&crypt_stat->keysig_list_mutex);
236 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
239 void ecryptfs_destroy_mount_crypt_stat(
240 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
242 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
244 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
246 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
247 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
248 &mount_crypt_stat->global_auth_tok_list,
249 mount_crypt_stat_list) {
250 list_del(&auth_tok->mount_crypt_stat_list);
251 mount_crypt_stat->num_global_auth_toks--;
252 if (auth_tok->global_auth_tok_key
253 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
254 key_put(auth_tok->global_auth_tok_key);
255 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
257 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
258 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
262 * virt_to_scatterlist
263 * @addr: Virtual address
264 * @size: Size of data; should be an even multiple of the block size
265 * @sg: Pointer to scatterlist array; set to NULL to obtain only
266 * the number of scatterlist structs required in array
267 * @sg_size: Max array size
269 * Fills in a scatterlist array with page references for a passed
272 * Returns the number of scatterlist structs in array used
274 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
280 int remainder_of_page;
282 while (size > 0 && i < sg_size) {
283 pg = virt_to_page(addr);
284 offset = offset_in_page(addr);
287 sg[i].offset = offset;
289 remainder_of_page = PAGE_CACHE_SIZE - offset;
290 if (size >= remainder_of_page) {
292 sg[i].length = remainder_of_page;
293 addr += remainder_of_page;
294 size -= remainder_of_page;
309 * encrypt_scatterlist
310 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
311 * @dest_sg: Destination of encrypted data
312 * @src_sg: Data to be encrypted
313 * @size: Length of data to be encrypted
314 * @iv: iv to use during encryption
316 * Returns the number of bytes encrypted; negative value on error
318 static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
319 struct scatterlist *dest_sg,
320 struct scatterlist *src_sg, int size,
323 struct blkcipher_desc desc = {
324 .tfm = crypt_stat->tfm,
326 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
330 BUG_ON(!crypt_stat || !crypt_stat->tfm
331 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
332 if (unlikely(ecryptfs_verbosity > 0)) {
333 ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n",
334 crypt_stat->key_size);
335 ecryptfs_dump_hex(crypt_stat->key,
336 crypt_stat->key_size);
338 /* Consider doing this once, when the file is opened */
339 mutex_lock(&crypt_stat->cs_tfm_mutex);
340 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
341 crypt_stat->key_size);
343 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
345 mutex_unlock(&crypt_stat->cs_tfm_mutex);
349 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
350 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
351 mutex_unlock(&crypt_stat->cs_tfm_mutex);
357 ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx,
359 struct ecryptfs_crypt_stat *crypt_stat,
360 unsigned long extent_num)
362 unsigned long lower_extent_num;
363 int extents_occupied_by_headers_at_front;
364 int bytes_occupied_by_headers_at_front;
366 int extents_per_page;
368 bytes_occupied_by_headers_at_front =
369 (crypt_stat->extent_size
370 * crypt_stat->num_header_extents_at_front);
371 extents_occupied_by_headers_at_front =
372 ( bytes_occupied_by_headers_at_front
373 / crypt_stat->extent_size );
374 lower_extent_num = extents_occupied_by_headers_at_front + extent_num;
375 extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size;
376 (*lower_page_idx) = lower_extent_num / extents_per_page;
377 extent_offset = lower_extent_num % extents_per_page;
378 (*byte_offset) = extent_offset * crypt_stat->extent_size;
379 ecryptfs_printk(KERN_DEBUG, " * crypt_stat->extent_size = "
380 "[%d]\n", crypt_stat->extent_size);
381 ecryptfs_printk(KERN_DEBUG, " * crypt_stat->"
382 "num_header_extents_at_front = [%d]\n",
383 crypt_stat->num_header_extents_at_front);
384 ecryptfs_printk(KERN_DEBUG, " * extents_occupied_by_headers_at_"
385 "front = [%d]\n", extents_occupied_by_headers_at_front);
386 ecryptfs_printk(KERN_DEBUG, " * lower_extent_num = [0x%.16x]\n",
388 ecryptfs_printk(KERN_DEBUG, " * extents_per_page = [%d]\n",
390 ecryptfs_printk(KERN_DEBUG, " * (*lower_page_idx) = [0x%.16x]\n",
392 ecryptfs_printk(KERN_DEBUG, " * extent_offset = [%d]\n",
394 ecryptfs_printk(KERN_DEBUG, " * (*byte_offset) = [%d]\n",
398 static int ecryptfs_write_out_page(struct ecryptfs_page_crypt_context *ctx,
399 struct page *lower_page,
400 struct inode *lower_inode,
401 int byte_offset_in_page, int bytes_to_write)
405 if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) {
406 rc = ecryptfs_commit_lower_page(lower_page, lower_inode,
407 ctx->param.lower_file,
411 ecryptfs_printk(KERN_ERR, "Error calling lower "
412 "commit; rc = [%d]\n", rc);
416 rc = ecryptfs_writepage_and_release_lower_page(lower_page,
420 ecryptfs_printk(KERN_ERR, "Error calling lower "
421 "writepage(); rc = [%d]\n", rc);
429 static int ecryptfs_read_in_page(struct ecryptfs_page_crypt_context *ctx,
430 struct page **lower_page,
431 struct inode *lower_inode,
432 unsigned long lower_page_idx,
433 int byte_offset_in_page)
437 if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) {
438 /* TODO: Limit this to only the data extents that are
440 rc = ecryptfs_get_lower_page(lower_page, lower_inode,
441 ctx->param.lower_file,
445 - byte_offset_in_page));
448 KERN_ERR, "Error attempting to grab, map, "
449 "and prepare_write lower page with index "
450 "[0x%.16x]; rc = [%d]\n", lower_page_idx, rc);
454 *lower_page = grab_cache_page(lower_inode->i_mapping,
456 if (!(*lower_page)) {
459 KERN_ERR, "Error attempting to grab and map "
460 "lower page with index [0x%.16x]; rc = [%d]\n",
470 * ecryptfs_lower_offset_for_extent
472 * Convert an eCryptfs page index into a lower byte offset
474 void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
475 struct ecryptfs_crypt_stat *crypt_stat)
477 (*offset) = ((crypt_stat->extent_size
478 * crypt_stat->num_header_extents_at_front)
479 + (crypt_stat->extent_size * extent_num));
483 * ecryptfs_encrypt_extent
484 * @enc_extent_page: Allocated page into which to encrypt the data in
486 * @crypt_stat: crypt_stat containing cryptographic context for the
487 * encryption operation
488 * @page: Page containing plaintext data extent to encrypt
489 * @extent_offset: Page extent offset for use in generating IV
491 * Encrypts one extent of data.
493 * Return zero on success; non-zero otherwise
495 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
496 struct ecryptfs_crypt_stat *crypt_stat,
498 unsigned long extent_offset)
500 unsigned long extent_base;
501 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
504 extent_base = (page->index
505 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
506 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
507 (extent_base + extent_offset));
509 ecryptfs_printk(KERN_ERR, "Error attempting to "
510 "derive IV for extent [0x%.16x]; "
511 "rc = [%d]\n", (extent_base + extent_offset),
515 if (unlikely(ecryptfs_verbosity > 0)) {
516 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
518 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
519 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
521 ecryptfs_dump_hex((char *)
523 + (extent_offset * crypt_stat->extent_size)),
526 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
528 * crypt_stat->extent_size),
529 crypt_stat->extent_size, extent_iv);
531 printk(KERN_ERR "%s: Error attempting to encrypt page with "
532 "page->index = [%ld], extent_offset = [%ld]; "
533 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
538 if (unlikely(ecryptfs_verbosity > 0)) {
539 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
540 "rc = [%d]\n", (extent_base + extent_offset),
542 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
544 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
551 * ecryptfs_encrypt_page
552 * @page: Page mapped from the eCryptfs inode for the file; contains
553 * decrypted content that needs to be encrypted (to a temporary
554 * page; not in place) and written out to the lower file
556 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
557 * that eCryptfs pages may straddle the lower pages -- for instance,
558 * if the file was created on a machine with an 8K page size
559 * (resulting in an 8K header), and then the file is copied onto a
560 * host with a 32K page size, then when reading page 0 of the eCryptfs
561 * file, 24K of page 0 of the lower file will be read and decrypted,
562 * and then 8K of page 1 of the lower file will be read and decrypted.
564 * Returns zero on success; negative on error
566 int ecryptfs_encrypt_page(struct page *page)
568 struct inode *ecryptfs_inode;
569 struct ecryptfs_crypt_stat *crypt_stat;
570 char *enc_extent_virt = NULL;
571 struct page *enc_extent_page;
572 loff_t extent_offset;
575 ecryptfs_inode = page->mapping->host;
577 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
578 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
579 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
582 printk(KERN_ERR "%s: Error attempting to copy "
583 "page at index [%ld]\n", __FUNCTION__,
587 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
588 if (!enc_extent_virt) {
590 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
591 "encrypted extent\n");
594 enc_extent_page = virt_to_page(enc_extent_virt);
595 for (extent_offset = 0;
596 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
600 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
603 printk(KERN_ERR "%s: Error encrypting extent; "
604 "rc = [%d]\n", __FUNCTION__, rc);
607 ecryptfs_lower_offset_for_extent(
608 &offset, ((page->index * (PAGE_CACHE_SIZE
609 / crypt_stat->extent_size))
610 + extent_offset), crypt_stat);
611 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
612 offset, crypt_stat->extent_size);
614 ecryptfs_printk(KERN_ERR, "Error attempting "
615 "to write lower page; rc = [%d]"
622 kfree(enc_extent_virt);
626 static int ecryptfs_decrypt_extent(struct page *page,
627 struct ecryptfs_crypt_stat *crypt_stat,
628 struct page *enc_extent_page,
629 unsigned long extent_offset)
631 unsigned long extent_base;
632 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
635 extent_base = (page->index
636 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
637 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
638 (extent_base + extent_offset));
640 ecryptfs_printk(KERN_ERR, "Error attempting to "
641 "derive IV for extent [0x%.16x]; "
642 "rc = [%d]\n", (extent_base + extent_offset),
646 if (unlikely(ecryptfs_verbosity > 0)) {
647 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
649 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
650 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
652 ecryptfs_dump_hex((char *)
653 (page_address(enc_extent_page)
654 + (extent_offset * crypt_stat->extent_size)),
657 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
659 * crypt_stat->extent_size),
661 crypt_stat->extent_size, extent_iv);
663 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
664 "page->index = [%ld], extent_offset = [%ld]; "
665 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
670 if (unlikely(ecryptfs_verbosity > 0)) {
671 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
672 "rc = [%d]\n", (extent_base + extent_offset),
674 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
676 ecryptfs_dump_hex((char *)(page_address(page)
678 * crypt_stat->extent_size)), 8);
685 * ecryptfs_decrypt_page
686 * @page: Page mapped from the eCryptfs inode for the file; data read
687 * and decrypted from the lower file will be written into this
690 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
691 * that eCryptfs pages may straddle the lower pages -- for instance,
692 * if the file was created on a machine with an 8K page size
693 * (resulting in an 8K header), and then the file is copied onto a
694 * host with a 32K page size, then when reading page 0 of the eCryptfs
695 * file, 24K of page 0 of the lower file will be read and decrypted,
696 * and then 8K of page 1 of the lower file will be read and decrypted.
698 * Returns zero on success; negative on error
700 int ecryptfs_decrypt_page(struct page *page)
702 struct inode *ecryptfs_inode;
703 struct ecryptfs_crypt_stat *crypt_stat;
704 char *enc_extent_virt = NULL;
705 struct page *enc_extent_page;
706 unsigned long extent_offset;
709 ecryptfs_inode = page->mapping->host;
711 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
712 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
713 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
717 printk(KERN_ERR "%s: Error attempting to copy "
718 "page at index [%ld]\n", __FUNCTION__,
720 goto out_clear_uptodate;
722 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
723 if (!enc_extent_virt) {
725 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
726 "encrypted extent\n");
727 goto out_clear_uptodate;
729 enc_extent_page = virt_to_page(enc_extent_virt);
730 for (extent_offset = 0;
731 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
735 ecryptfs_lower_offset_for_extent(
736 &offset, ((page->index * (PAGE_CACHE_SIZE
737 / crypt_stat->extent_size))
738 + extent_offset), crypt_stat);
739 rc = ecryptfs_read_lower(enc_extent_virt, offset,
740 crypt_stat->extent_size,
743 ecryptfs_printk(KERN_ERR, "Error attempting "
744 "to read lower page; rc = [%d]"
746 goto out_clear_uptodate;
748 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
751 printk(KERN_ERR "%s: Error encrypting extent; "
752 "rc = [%d]\n", __FUNCTION__, rc);
753 goto out_clear_uptodate;
757 SetPageUptodate(page);
760 ClearPageUptodate(page);
762 kfree(enc_extent_virt);
767 * decrypt_scatterlist
768 * @crypt_stat: Cryptographic context
769 * @dest_sg: The destination scatterlist to decrypt into
770 * @src_sg: The source scatterlist to decrypt from
771 * @size: The number of bytes to decrypt
772 * @iv: The initialization vector to use for the decryption
774 * Returns the number of bytes decrypted; negative value on error
776 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
777 struct scatterlist *dest_sg,
778 struct scatterlist *src_sg, int size,
781 struct blkcipher_desc desc = {
782 .tfm = crypt_stat->tfm,
784 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
788 /* Consider doing this once, when the file is opened */
789 mutex_lock(&crypt_stat->cs_tfm_mutex);
790 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
791 crypt_stat->key_size);
793 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
795 mutex_unlock(&crypt_stat->cs_tfm_mutex);
799 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
800 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
801 mutex_unlock(&crypt_stat->cs_tfm_mutex);
803 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
813 * ecryptfs_encrypt_page_offset
814 * @crypt_stat: The cryptographic context
815 * @dst_page: The page to encrypt into
816 * @dst_offset: The offset in the page to encrypt into
817 * @src_page: The page to encrypt from
818 * @src_offset: The offset in the page to encrypt from
819 * @size: The number of bytes to encrypt
820 * @iv: The initialization vector to use for the encryption
822 * Returns the number of bytes encrypted
825 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
826 struct page *dst_page, int dst_offset,
827 struct page *src_page, int src_offset, int size,
830 struct scatterlist src_sg, dst_sg;
832 src_sg.page = src_page;
833 src_sg.offset = src_offset;
834 src_sg.length = size;
835 dst_sg.page = dst_page;
836 dst_sg.offset = dst_offset;
837 dst_sg.length = size;
838 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
842 * ecryptfs_decrypt_page_offset
843 * @crypt_stat: The cryptographic context
844 * @dst_page: The page to decrypt into
845 * @dst_offset: The offset in the page to decrypt into
846 * @src_page: The page to decrypt from
847 * @src_offset: The offset in the page to decrypt from
848 * @size: The number of bytes to decrypt
849 * @iv: The initialization vector to use for the decryption
851 * Returns the number of bytes decrypted
854 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
855 struct page *dst_page, int dst_offset,
856 struct page *src_page, int src_offset, int size,
859 struct scatterlist src_sg, dst_sg;
861 src_sg.page = src_page;
862 src_sg.offset = src_offset;
863 src_sg.length = size;
864 dst_sg.page = dst_page;
865 dst_sg.offset = dst_offset;
866 dst_sg.length = size;
867 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
870 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
873 * ecryptfs_init_crypt_ctx
874 * @crypt_stat: Uninitilized crypt stats structure
876 * Initialize the crypto context.
878 * TODO: Performance: Keep a cache of initialized cipher contexts;
879 * only init if needed
881 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
886 if (!crypt_stat->cipher) {
887 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
890 ecryptfs_printk(KERN_DEBUG,
891 "Initializing cipher [%s]; strlen = [%d]; "
892 "key_size_bits = [%d]\n",
893 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
894 crypt_stat->key_size << 3);
895 if (crypt_stat->tfm) {
899 mutex_lock(&crypt_stat->cs_tfm_mutex);
900 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
901 crypt_stat->cipher, "cbc");
904 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
906 kfree(full_alg_name);
907 if (IS_ERR(crypt_stat->tfm)) {
908 rc = PTR_ERR(crypt_stat->tfm);
909 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
910 "Error initializing cipher [%s]\n",
912 mutex_unlock(&crypt_stat->cs_tfm_mutex);
915 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
916 mutex_unlock(&crypt_stat->cs_tfm_mutex);
922 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
926 crypt_stat->extent_mask = 0xFFFFFFFF;
927 crypt_stat->extent_shift = 0;
928 if (crypt_stat->extent_size == 0)
930 extent_size_tmp = crypt_stat->extent_size;
931 while ((extent_size_tmp & 0x01) == 0) {
932 extent_size_tmp >>= 1;
933 crypt_stat->extent_mask <<= 1;
934 crypt_stat->extent_shift++;
938 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
940 /* Default values; may be overwritten as we are parsing the
942 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
943 set_extent_mask_and_shift(crypt_stat);
944 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
945 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
946 crypt_stat->num_header_extents_at_front = 0;
948 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
949 crypt_stat->num_header_extents_at_front =
950 (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
951 / crypt_stat->extent_size);
953 crypt_stat->num_header_extents_at_front =
954 (PAGE_CACHE_SIZE / crypt_stat->extent_size);
959 * ecryptfs_compute_root_iv
962 * On error, sets the root IV to all 0's.
964 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
967 char dst[MD5_DIGEST_SIZE];
969 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
970 BUG_ON(crypt_stat->iv_bytes <= 0);
971 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
973 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
974 "cannot generate root IV\n");
977 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
978 crypt_stat->key_size);
980 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
981 "MD5 while generating root IV\n");
984 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
987 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
988 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
993 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
995 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
996 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
997 ecryptfs_compute_root_iv(crypt_stat);
998 if (unlikely(ecryptfs_verbosity > 0)) {
999 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
1000 ecryptfs_dump_hex(crypt_stat->key,
1001 crypt_stat->key_size);
1006 * ecryptfs_copy_mount_wide_flags_to_inode_flags
1007 * @crypt_stat: The inode's cryptographic context
1008 * @mount_crypt_stat: The mount point's cryptographic context
1010 * This function propagates the mount-wide flags to individual inode
1013 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
1014 struct ecryptfs_crypt_stat *crypt_stat,
1015 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1017 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
1018 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1019 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
1020 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
1023 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
1024 struct ecryptfs_crypt_stat *crypt_stat,
1025 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1027 struct ecryptfs_global_auth_tok *global_auth_tok;
1030 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
1031 list_for_each_entry(global_auth_tok,
1032 &mount_crypt_stat->global_auth_tok_list,
1033 mount_crypt_stat_list) {
1034 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
1036 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
1038 &mount_crypt_stat->global_auth_tok_list_mutex);
1042 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
1048 * ecryptfs_set_default_crypt_stat_vals
1049 * @crypt_stat: The inode's cryptographic context
1050 * @mount_crypt_stat: The mount point's cryptographic context
1052 * Default values in the event that policy does not override them.
1054 static void ecryptfs_set_default_crypt_stat_vals(
1055 struct ecryptfs_crypt_stat *crypt_stat,
1056 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1058 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1060 ecryptfs_set_default_sizes(crypt_stat);
1061 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
1062 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
1063 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
1064 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
1065 crypt_stat->mount_crypt_stat = mount_crypt_stat;
1069 * ecryptfs_new_file_context
1070 * @ecryptfs_dentry: The eCryptfs dentry
1072 * If the crypto context for the file has not yet been established,
1073 * this is where we do that. Establishing a new crypto context
1074 * involves the following decisions:
1075 * - What cipher to use?
1076 * - What set of authentication tokens to use?
1077 * Here we just worry about getting enough information into the
1078 * authentication tokens so that we know that they are available.
1079 * We associate the available authentication tokens with the new file
1080 * via the set of signatures in the crypt_stat struct. Later, when
1081 * the headers are actually written out, we may again defer to
1082 * userspace to perform the encryption of the session key; for the
1083 * foreseeable future, this will be the case with public key packets.
1085 * Returns zero on success; non-zero otherwise
1087 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
1089 struct ecryptfs_crypt_stat *crypt_stat =
1090 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1091 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1092 &ecryptfs_superblock_to_private(
1093 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1094 int cipher_name_len;
1097 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
1098 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
1099 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1101 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1104 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1105 "to the inode key sigs; rc = [%d]\n", rc);
1109 strlen(mount_crypt_stat->global_default_cipher_name);
1110 memcpy(crypt_stat->cipher,
1111 mount_crypt_stat->global_default_cipher_name,
1113 crypt_stat->cipher[cipher_name_len] = '\0';
1114 crypt_stat->key_size =
1115 mount_crypt_stat->global_default_cipher_key_size;
1116 ecryptfs_generate_new_key(crypt_stat);
1117 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1119 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1120 "context for cipher [%s]: rc = [%d]\n",
1121 crypt_stat->cipher, rc);
1127 * contains_ecryptfs_marker - check for the ecryptfs marker
1128 * @data: The data block in which to check
1130 * Returns one if marker found; zero if not found
1132 static int contains_ecryptfs_marker(char *data)
1136 memcpy(&m_1, data, 4);
1137 m_1 = be32_to_cpu(m_1);
1138 memcpy(&m_2, (data + 4), 4);
1139 m_2 = be32_to_cpu(m_2);
1140 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1142 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1143 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1144 MAGIC_ECRYPTFS_MARKER);
1145 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1146 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1150 struct ecryptfs_flag_map_elem {
1155 /* Add support for additional flags by adding elements here. */
1156 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1157 {0x00000001, ECRYPTFS_ENABLE_HMAC},
1158 {0x00000002, ECRYPTFS_ENCRYPTED},
1159 {0x00000004, ECRYPTFS_METADATA_IN_XATTR}
1163 * ecryptfs_process_flags
1164 * @crypt_stat: The cryptographic context
1165 * @page_virt: Source data to be parsed
1166 * @bytes_read: Updated with the number of bytes read
1168 * Returns zero on success; non-zero if the flag set is invalid
1170 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1171 char *page_virt, int *bytes_read)
1177 memcpy(&flags, page_virt, 4);
1178 flags = be32_to_cpu(flags);
1179 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1180 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1181 if (flags & ecryptfs_flag_map[i].file_flag) {
1182 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1184 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1185 /* Version is in top 8 bits of the 32-bit flag vector */
1186 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1192 * write_ecryptfs_marker
1193 * @page_virt: The pointer to in a page to begin writing the marker
1194 * @written: Number of bytes written
1196 * Marker = 0x3c81b7f5
1198 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1202 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1203 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1204 m_1 = cpu_to_be32(m_1);
1205 memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1206 m_2 = cpu_to_be32(m_2);
1207 memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2,
1208 (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1209 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1213 write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1219 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1220 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1221 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1222 flags |= ecryptfs_flag_map[i].file_flag;
1223 /* Version is in top 8 bits of the 32-bit flag vector */
1224 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1225 flags = cpu_to_be32(flags);
1226 memcpy(page_virt, &flags, 4);
1230 struct ecryptfs_cipher_code_str_map_elem {
1231 char cipher_str[16];
1235 /* Add support for additional ciphers by adding elements here. The
1236 * cipher_code is whatever OpenPGP applicatoins use to identify the
1237 * ciphers. List in order of probability. */
1238 static struct ecryptfs_cipher_code_str_map_elem
1239 ecryptfs_cipher_code_str_map[] = {
1240 {"aes",RFC2440_CIPHER_AES_128 },
1241 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1242 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1243 {"cast5", RFC2440_CIPHER_CAST_5},
1244 {"twofish", RFC2440_CIPHER_TWOFISH},
1245 {"cast6", RFC2440_CIPHER_CAST_6},
1246 {"aes", RFC2440_CIPHER_AES_192},
1247 {"aes", RFC2440_CIPHER_AES_256}
1251 * ecryptfs_code_for_cipher_string
1252 * @crypt_stat: The cryptographic context
1254 * Returns zero on no match, or the cipher code on match
1256 u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat)
1260 struct ecryptfs_cipher_code_str_map_elem *map =
1261 ecryptfs_cipher_code_str_map;
1263 if (strcmp(crypt_stat->cipher, "aes") == 0) {
1264 switch (crypt_stat->key_size) {
1266 code = RFC2440_CIPHER_AES_128;
1269 code = RFC2440_CIPHER_AES_192;
1272 code = RFC2440_CIPHER_AES_256;
1275 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1276 if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){
1277 code = map[i].cipher_code;
1285 * ecryptfs_cipher_code_to_string
1286 * @str: Destination to write out the cipher name
1287 * @cipher_code: The code to convert to cipher name string
1289 * Returns zero on success
1291 int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
1297 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1298 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1299 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1300 if (str[0] == '\0') {
1301 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1302 "[%d]\n", cipher_code);
1309 * ecryptfs_read_header_region
1310 * @data: The virtual address to write header region data into
1311 * @dentry: The lower dentry
1312 * @mnt: The lower VFS mount
1314 * Returns zero on success; non-zero otherwise
1316 static int ecryptfs_read_header_region(char *data, struct dentry *dentry,
1317 struct vfsmount *mnt)
1319 struct file *lower_file;
1323 rc = ecryptfs_open_lower_file(&lower_file, dentry, mnt, O_RDONLY);
1326 "Error opening lower_file to read header region\n");
1329 lower_file->f_pos = 0;
1332 rc = lower_file->f_op->read(lower_file, (char __user *)data,
1333 ECRYPTFS_DEFAULT_EXTENT_SIZE, &lower_file->f_pos);
1335 rc = ecryptfs_close_lower_file(lower_file);
1337 printk(KERN_ERR "Error closing lower_file\n");
1345 int ecryptfs_read_and_validate_header_region(char *data,
1346 struct inode *ecryptfs_inode)
1348 struct ecryptfs_crypt_stat *crypt_stat =
1349 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
1352 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1355 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
1359 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
1361 ecryptfs_printk(KERN_DEBUG, "Valid marker not found\n");
1368 ecryptfs_write_header_metadata(char *virt,
1369 struct ecryptfs_crypt_stat *crypt_stat,
1372 u32 header_extent_size;
1373 u16 num_header_extents_at_front;
1375 header_extent_size = (u32)crypt_stat->extent_size;
1376 num_header_extents_at_front =
1377 (u16)crypt_stat->num_header_extents_at_front;
1378 header_extent_size = cpu_to_be32(header_extent_size);
1379 memcpy(virt, &header_extent_size, 4);
1381 num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front);
1382 memcpy(virt, &num_header_extents_at_front, 2);
1386 struct kmem_cache *ecryptfs_header_cache_0;
1387 struct kmem_cache *ecryptfs_header_cache_1;
1388 struct kmem_cache *ecryptfs_header_cache_2;
1391 * ecryptfs_write_headers_virt
1392 * @page_virt: The virtual address to write the headers to
1393 * @size: Set to the number of bytes written by this function
1394 * @crypt_stat: The cryptographic context
1395 * @ecryptfs_dentry: The eCryptfs dentry
1400 * Octets 0-7: Unencrypted file size (big-endian)
1401 * Octets 8-15: eCryptfs special marker
1402 * Octets 16-19: Flags
1403 * Octet 16: File format version number (between 0 and 255)
1404 * Octets 17-18: Reserved
1405 * Octet 19: Bit 1 (lsb): Reserved
1407 * Bits 3-8: Reserved
1408 * Octets 20-23: Header extent size (big-endian)
1409 * Octets 24-25: Number of header extents at front of file
1411 * Octet 26: Begin RFC 2440 authentication token packet set
1413 * Lower data (CBC encrypted)
1415 * Lower data (CBC encrypted)
1418 * Returns zero on success
1420 static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
1421 struct ecryptfs_crypt_stat *crypt_stat,
1422 struct dentry *ecryptfs_dentry)
1428 offset = ECRYPTFS_FILE_SIZE_BYTES;
1429 write_ecryptfs_marker((page_virt + offset), &written);
1431 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1433 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1436 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1437 ecryptfs_dentry, &written,
1438 PAGE_CACHE_SIZE - offset);
1440 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1441 "set; rc = [%d]\n", rc);
1450 ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
1451 struct dentry *ecryptfs_dentry,
1454 int current_header_page;
1458 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, page_virt,
1459 0, PAGE_CACHE_SIZE);
1461 printk(KERN_ERR "%s: Error attempting to write header "
1462 "information to lower file; rc = [%d]\n", __FUNCTION__,
1466 header_pages = ((crypt_stat->extent_size
1467 * crypt_stat->num_header_extents_at_front)
1469 memset(page_virt, 0, PAGE_CACHE_SIZE);
1470 current_header_page = 1;
1471 while (current_header_page < header_pages) {
1474 offset = (current_header_page << PAGE_CACHE_SHIFT);
1475 if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode,
1477 PAGE_CACHE_SIZE))) {
1478 printk(KERN_ERR "%s: Error attempting to write header "
1479 "information to lower file; rc = [%d]\n",
1483 current_header_page++;
1490 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1491 struct ecryptfs_crypt_stat *crypt_stat,
1492 char *page_virt, size_t size)
1496 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1502 * ecryptfs_write_metadata
1503 * @ecryptfs_dentry: The eCryptfs dentry
1505 * Write the file headers out. This will likely involve a userspace
1506 * callout, in which the session key is encrypted with one or more
1507 * public keys and/or the passphrase necessary to do the encryption is
1508 * retrieved via a prompt. Exactly what happens at this point should
1509 * be policy-dependent.
1511 * TODO: Support header information spanning multiple pages
1513 * Returns zero on success; non-zero on error
1515 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
1517 struct ecryptfs_crypt_stat *crypt_stat =
1518 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1523 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1524 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1525 printk(KERN_ERR "Key is invalid; bailing out\n");
1531 ecryptfs_printk(KERN_WARNING,
1532 "Called with crypt_stat->encrypted == 0\n");
1535 /* Released in this function */
1536 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER);
1538 ecryptfs_printk(KERN_ERR, "Out of memory\n");
1542 rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat,
1545 ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n");
1546 memset(page_virt, 0, PAGE_CACHE_SIZE);
1549 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1550 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
1551 crypt_stat, page_virt,
1554 rc = ecryptfs_write_metadata_to_contents(crypt_stat,
1558 printk(KERN_ERR "Error writing metadata out to lower file; "
1563 kmem_cache_free(ecryptfs_header_cache_0, page_virt);
1568 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1569 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1570 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1571 char *virt, int *bytes_read,
1572 int validate_header_size)
1575 u32 header_extent_size;
1576 u16 num_header_extents_at_front;
1578 memcpy(&header_extent_size, virt, 4);
1579 header_extent_size = be32_to_cpu(header_extent_size);
1581 memcpy(&num_header_extents_at_front, virt, 2);
1582 num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
1583 crypt_stat->num_header_extents_at_front =
1584 (int)num_header_extents_at_front;
1585 (*bytes_read) = (sizeof(u32) + sizeof(u16));
1586 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1587 && ((crypt_stat->extent_size
1588 * crypt_stat->num_header_extents_at_front)
1589 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1591 printk(KERN_WARNING "Invalid number of header extents: [%zd]\n",
1592 crypt_stat->num_header_extents_at_front);
1598 * set_default_header_data
1599 * @crypt_stat: The cryptographic context
1601 * For version 0 file format; this function is only for backwards
1602 * compatibility for files created with the prior versions of
1605 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1607 crypt_stat->num_header_extents_at_front = 2;
1611 * ecryptfs_read_headers_virt
1612 * @page_virt: The virtual address into which to read the headers
1613 * @crypt_stat: The cryptographic context
1614 * @ecryptfs_dentry: The eCryptfs dentry
1615 * @validate_header_size: Whether to validate the header size while reading
1617 * Read/parse the header data. The header format is detailed in the
1618 * comment block for the ecryptfs_write_headers_virt() function.
1620 * Returns zero on success
1622 static int ecryptfs_read_headers_virt(char *page_virt,
1623 struct ecryptfs_crypt_stat *crypt_stat,
1624 struct dentry *ecryptfs_dentry,
1625 int validate_header_size)
1631 ecryptfs_set_default_sizes(crypt_stat);
1632 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1633 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1634 offset = ECRYPTFS_FILE_SIZE_BYTES;
1635 rc = contains_ecryptfs_marker(page_virt + offset);
1640 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1641 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1644 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1647 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1648 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1649 "file version [%d] is supported by this "
1650 "version of eCryptfs\n",
1651 crypt_stat->file_version,
1652 ECRYPTFS_SUPPORTED_FILE_VERSION);
1656 offset += bytes_read;
1657 if (crypt_stat->file_version >= 1) {
1658 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1659 &bytes_read, validate_header_size);
1661 ecryptfs_printk(KERN_WARNING, "Error reading header "
1662 "metadata; rc = [%d]\n", rc);
1664 offset += bytes_read;
1666 set_default_header_data(crypt_stat);
1667 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1674 * ecryptfs_read_xattr_region
1675 * @page_virt: The vitual address into which to read the xattr data
1676 * @ecryptfs_dentry: The eCryptfs dentry
1678 * Attempts to read the crypto metadata from the extended attribute
1679 * region of the lower file.
1681 * Returns zero on success; non-zero on error
1683 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1685 struct dentry *lower_dentry =
1686 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1690 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1691 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1693 printk(KERN_ERR "Error attempting to read the [%s] "
1694 "xattr from the lower file; return value = [%zd]\n",
1695 ECRYPTFS_XATTR_NAME, size);
1703 int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1704 struct dentry *ecryptfs_dentry)
1708 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
1711 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1712 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1713 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1721 * ecryptfs_read_metadata
1723 * Common entry point for reading file metadata. From here, we could
1724 * retrieve the header information from the header region of the file,
1725 * the xattr region of the file, or some other repostory that is
1726 * stored separately from the file itself. The current implementation
1727 * supports retrieving the metadata information from the file contents
1728 * and from the xattr region.
1730 * Returns zero if valid headers found and parsed; non-zero otherwise
1732 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1735 char *page_virt = NULL;
1736 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1737 struct ecryptfs_crypt_stat *crypt_stat =
1738 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1739 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1740 &ecryptfs_superblock_to_private(
1741 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1743 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1745 /* Read the first page from the underlying file */
1746 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
1749 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1753 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1756 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1758 ECRYPTFS_VALIDATE_HEADER_SIZE);
1760 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1762 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1763 "file header region or xattr region\n");
1767 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1769 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1771 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1772 "file xattr region either\n");
1775 if (crypt_stat->mount_crypt_stat->flags
1776 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1777 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1779 printk(KERN_WARNING "Attempt to access file with "
1780 "crypto metadata only in the extended attribute "
1781 "region, but eCryptfs was mounted without "
1782 "xattr support enabled. eCryptfs will not treat "
1783 "this like an encrypted file.\n");
1789 memset(page_virt, 0, PAGE_CACHE_SIZE);
1790 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1796 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1797 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1798 * @name: The plaintext name
1799 * @length: The length of the plaintext
1800 * @encoded_name: The encypted name
1802 * Encrypts and encodes a filename into something that constitutes a
1803 * valid filename for a filesystem, with printable characters.
1805 * We assume that we have a properly initialized crypto context,
1806 * pointed to by crypt_stat->tfm.
1808 * TODO: Implement filename decoding and decryption here, in place of
1809 * memcpy. We are keeping the framework around for now to (1)
1810 * facilitate testing of the components needed to implement filename
1811 * encryption and (2) to provide a code base from which other
1812 * developers in the community can easily implement this feature.
1814 * Returns the length of encoded filename; negative if error
1817 ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1818 const char *name, int length, char **encoded_name)
1822 (*encoded_name) = kmalloc(length + 2, GFP_KERNEL);
1823 if (!(*encoded_name)) {
1827 /* TODO: Filename encryption is a scheduled feature for a
1828 * future version of eCryptfs. This function is here only for
1829 * the purpose of providing a framework for other developers
1830 * to easily implement filename encryption. Hint: Replace this
1831 * memcpy() with a call to encrypt and encode the
1832 * filename, the set the length accordingly. */
1833 memcpy((void *)(*encoded_name), (void *)name, length);
1834 (*encoded_name)[length] = '\0';
1841 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1842 * @crypt_stat: The crypt_stat struct associated with the file
1843 * @name: The filename in cipher text
1844 * @length: The length of the cipher text name
1845 * @decrypted_name: The plaintext name
1847 * Decodes and decrypts the filename.
1849 * We assume that we have a properly initialized crypto context,
1850 * pointed to by crypt_stat->tfm.
1852 * TODO: Implement filename decoding and decryption here, in place of
1853 * memcpy. We are keeping the framework around for now to (1)
1854 * facilitate testing of the components needed to implement filename
1855 * encryption and (2) to provide a code base from which other
1856 * developers in the community can easily implement this feature.
1858 * Returns the length of decoded filename; negative if error
1861 ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1862 const char *name, int length, char **decrypted_name)
1866 (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL);
1867 if (!(*decrypted_name)) {
1871 /* TODO: Filename encryption is a scheduled feature for a
1872 * future version of eCryptfs. This function is here only for
1873 * the purpose of providing a framework for other developers
1874 * to easily implement filename encryption. Hint: Replace this
1875 * memcpy() with a call to decode and decrypt the
1876 * filename, the set the length accordingly. */
1877 memcpy((void *)(*decrypted_name), (void *)name, length);
1878 (*decrypted_name)[length + 1] = '\0'; /* Only for convenience
1879 * in printing out the
1888 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1889 * @key_tfm: Crypto context for key material, set by this function
1890 * @cipher_name: Name of the cipher
1891 * @key_size: Size of the key in bytes
1893 * Returns zero on success. Any crypto_tfm structs allocated here
1894 * should be released by other functions, such as on a superblock put
1895 * event, regardless of whether this function succeeds for fails.
1898 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1899 char *cipher_name, size_t *key_size)
1901 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1902 char *full_alg_name;
1906 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1908 printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum "
1909 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1912 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1916 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1917 kfree(full_alg_name);
1918 if (IS_ERR(*key_tfm)) {
1919 rc = PTR_ERR(*key_tfm);
1920 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1921 "[%s]; rc = [%d]\n", cipher_name, rc);
1924 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1925 if (*key_size == 0) {
1926 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1928 *key_size = alg->max_keysize;
1930 get_random_bytes(dummy_key, *key_size);
1931 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1933 printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
1934 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
1942 struct kmem_cache *ecryptfs_key_tfm_cache;
1943 struct list_head key_tfm_list;
1944 struct mutex key_tfm_list_mutex;
1946 int ecryptfs_init_crypto(void)
1948 mutex_init(&key_tfm_list_mutex);
1949 INIT_LIST_HEAD(&key_tfm_list);
1953 int ecryptfs_destroy_crypto(void)
1955 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1957 mutex_lock(&key_tfm_list_mutex);
1958 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1960 list_del(&key_tfm->key_tfm_list);
1961 if (key_tfm->key_tfm)
1962 crypto_free_blkcipher(key_tfm->key_tfm);
1963 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1965 mutex_unlock(&key_tfm_list_mutex);
1970 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1973 struct ecryptfs_key_tfm *tmp_tfm;
1976 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1977 if (key_tfm != NULL)
1978 (*key_tfm) = tmp_tfm;
1981 printk(KERN_ERR "Error attempting to allocate from "
1982 "ecryptfs_key_tfm_cache\n");
1985 mutex_init(&tmp_tfm->key_tfm_mutex);
1986 strncpy(tmp_tfm->cipher_name, cipher_name,
1987 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1988 tmp_tfm->key_size = key_size;
1989 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1990 tmp_tfm->cipher_name,
1991 &tmp_tfm->key_size);
1993 printk(KERN_ERR "Error attempting to initialize key TFM "
1994 "cipher with name = [%s]; rc = [%d]\n",
1995 tmp_tfm->cipher_name, rc);
1996 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1997 if (key_tfm != NULL)
2001 mutex_lock(&key_tfm_list_mutex);
2002 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
2003 mutex_unlock(&key_tfm_list_mutex);
2008 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
2009 struct mutex **tfm_mutex,
2012 struct ecryptfs_key_tfm *key_tfm;
2016 (*tfm_mutex) = NULL;
2017 mutex_lock(&key_tfm_list_mutex);
2018 list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) {
2019 if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
2020 (*tfm) = key_tfm->key_tfm;
2021 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
2022 mutex_unlock(&key_tfm_list_mutex);
2026 mutex_unlock(&key_tfm_list_mutex);
2027 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
2029 printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
2033 (*tfm) = key_tfm->key_tfm;
2034 (*tfm_mutex) = &key_tfm->key_tfm_mutex;