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 extent whose 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, "%lld", 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_lower_offset_for_extent
359 * Convert an eCryptfs page index into a lower byte offset
361 void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
362 struct ecryptfs_crypt_stat *crypt_stat)
364 (*offset) = ((crypt_stat->extent_size
365 * crypt_stat->num_header_extents_at_front)
366 + (crypt_stat->extent_size * extent_num));
370 * ecryptfs_encrypt_extent
371 * @enc_extent_page: Allocated page into which to encrypt the data in
373 * @crypt_stat: crypt_stat containing cryptographic context for the
374 * encryption operation
375 * @page: Page containing plaintext data extent to encrypt
376 * @extent_offset: Page extent offset for use in generating IV
378 * Encrypts one extent of data.
380 * Return zero on success; non-zero otherwise
382 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
383 struct ecryptfs_crypt_stat *crypt_stat,
385 unsigned long extent_offset)
388 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
391 extent_base = (((loff_t)page->index)
392 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
393 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
394 (extent_base + extent_offset));
396 ecryptfs_printk(KERN_ERR, "Error attempting to "
397 "derive IV for extent [0x%.16x]; "
398 "rc = [%d]\n", (extent_base + extent_offset),
402 if (unlikely(ecryptfs_verbosity > 0)) {
403 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
405 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
406 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
408 ecryptfs_dump_hex((char *)
410 + (extent_offset * crypt_stat->extent_size)),
413 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
415 * crypt_stat->extent_size),
416 crypt_stat->extent_size, extent_iv);
418 printk(KERN_ERR "%s: Error attempting to encrypt page with "
419 "page->index = [%ld], extent_offset = [%ld]; "
420 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
425 if (unlikely(ecryptfs_verbosity > 0)) {
426 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
427 "rc = [%d]\n", (extent_base + extent_offset),
429 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
431 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
438 * ecryptfs_encrypt_page
439 * @page: Page mapped from the eCryptfs inode for the file; contains
440 * decrypted content that needs to be encrypted (to a temporary
441 * page; not in place) and written out to the lower file
443 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
444 * that eCryptfs pages may straddle the lower pages -- for instance,
445 * if the file was created on a machine with an 8K page size
446 * (resulting in an 8K header), and then the file is copied onto a
447 * host with a 32K page size, then when reading page 0 of the eCryptfs
448 * file, 24K of page 0 of the lower file will be read and decrypted,
449 * and then 8K of page 1 of the lower file will be read and decrypted.
451 * Returns zero on success; negative on error
453 int ecryptfs_encrypt_page(struct page *page)
455 struct inode *ecryptfs_inode;
456 struct ecryptfs_crypt_stat *crypt_stat;
457 char *enc_extent_virt = NULL;
458 struct page *enc_extent_page;
459 loff_t extent_offset;
462 ecryptfs_inode = page->mapping->host;
464 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
465 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
466 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
469 printk(KERN_ERR "%s: Error attempting to copy "
470 "page at index [%ld]\n", __FUNCTION__,
474 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
475 if (!enc_extent_virt) {
477 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
478 "encrypted extent\n");
481 enc_extent_page = virt_to_page(enc_extent_virt);
482 for (extent_offset = 0;
483 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
487 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
490 printk(KERN_ERR "%s: Error encrypting extent; "
491 "rc = [%d]\n", __FUNCTION__, rc);
494 ecryptfs_lower_offset_for_extent(
495 &offset, ((((loff_t)page->index)
497 / crypt_stat->extent_size))
498 + extent_offset), crypt_stat);
499 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
500 offset, crypt_stat->extent_size);
502 ecryptfs_printk(KERN_ERR, "Error attempting "
503 "to write lower page; rc = [%d]"
510 kfree(enc_extent_virt);
514 static int ecryptfs_decrypt_extent(struct page *page,
515 struct ecryptfs_crypt_stat *crypt_stat,
516 struct page *enc_extent_page,
517 unsigned long extent_offset)
520 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
523 extent_base = (((loff_t)page->index)
524 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
525 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
526 (extent_base + extent_offset));
528 ecryptfs_printk(KERN_ERR, "Error attempting to "
529 "derive IV for extent [0x%.16x]; "
530 "rc = [%d]\n", (extent_base + extent_offset),
534 if (unlikely(ecryptfs_verbosity > 0)) {
535 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
537 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
538 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
540 ecryptfs_dump_hex((char *)
541 (page_address(enc_extent_page)
542 + (extent_offset * crypt_stat->extent_size)),
545 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
547 * crypt_stat->extent_size),
549 crypt_stat->extent_size, extent_iv);
551 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
552 "page->index = [%ld], extent_offset = [%ld]; "
553 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
558 if (unlikely(ecryptfs_verbosity > 0)) {
559 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
560 "rc = [%d]\n", (extent_base + extent_offset),
562 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
564 ecryptfs_dump_hex((char *)(page_address(page)
566 * crypt_stat->extent_size)), 8);
573 * ecryptfs_decrypt_page
574 * @page: Page mapped from the eCryptfs inode for the file; data read
575 * and decrypted from the lower file will be written into this
578 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
579 * that eCryptfs pages may straddle the lower pages -- for instance,
580 * if the file was created on a machine with an 8K page size
581 * (resulting in an 8K header), and then the file is copied onto a
582 * host with a 32K page size, then when reading page 0 of the eCryptfs
583 * file, 24K of page 0 of the lower file will be read and decrypted,
584 * and then 8K of page 1 of the lower file will be read and decrypted.
586 * Returns zero on success; negative on error
588 int ecryptfs_decrypt_page(struct page *page)
590 struct inode *ecryptfs_inode;
591 struct ecryptfs_crypt_stat *crypt_stat;
592 char *enc_extent_virt = NULL;
593 struct page *enc_extent_page;
594 unsigned long extent_offset;
597 ecryptfs_inode = page->mapping->host;
599 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
600 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
601 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
605 printk(KERN_ERR "%s: Error attempting to copy "
606 "page at index [%ld]\n", __FUNCTION__,
608 goto out_clear_uptodate;
610 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
611 if (!enc_extent_virt) {
613 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
614 "encrypted extent\n");
615 goto out_clear_uptodate;
617 enc_extent_page = virt_to_page(enc_extent_virt);
618 for (extent_offset = 0;
619 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
623 ecryptfs_lower_offset_for_extent(
624 &offset, ((page->index * (PAGE_CACHE_SIZE
625 / crypt_stat->extent_size))
626 + extent_offset), crypt_stat);
627 rc = ecryptfs_read_lower(enc_extent_virt, offset,
628 crypt_stat->extent_size,
631 ecryptfs_printk(KERN_ERR, "Error attempting "
632 "to read lower page; rc = [%d]"
634 goto out_clear_uptodate;
636 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
639 printk(KERN_ERR "%s: Error encrypting extent; "
640 "rc = [%d]\n", __FUNCTION__, rc);
641 goto out_clear_uptodate;
645 SetPageUptodate(page);
648 ClearPageUptodate(page);
650 kfree(enc_extent_virt);
655 * decrypt_scatterlist
656 * @crypt_stat: Cryptographic context
657 * @dest_sg: The destination scatterlist to decrypt into
658 * @src_sg: The source scatterlist to decrypt from
659 * @size: The number of bytes to decrypt
660 * @iv: The initialization vector to use for the decryption
662 * Returns the number of bytes decrypted; negative value on error
664 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
665 struct scatterlist *dest_sg,
666 struct scatterlist *src_sg, int size,
669 struct blkcipher_desc desc = {
670 .tfm = crypt_stat->tfm,
672 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
676 /* Consider doing this once, when the file is opened */
677 mutex_lock(&crypt_stat->cs_tfm_mutex);
678 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
679 crypt_stat->key_size);
681 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
683 mutex_unlock(&crypt_stat->cs_tfm_mutex);
687 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
688 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
689 mutex_unlock(&crypt_stat->cs_tfm_mutex);
691 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
701 * ecryptfs_encrypt_page_offset
702 * @crypt_stat: The cryptographic context
703 * @dst_page: The page to encrypt into
704 * @dst_offset: The offset in the page to encrypt into
705 * @src_page: The page to encrypt from
706 * @src_offset: The offset in the page to encrypt from
707 * @size: The number of bytes to encrypt
708 * @iv: The initialization vector to use for the encryption
710 * Returns the number of bytes encrypted
713 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
714 struct page *dst_page, int dst_offset,
715 struct page *src_page, int src_offset, int size,
718 struct scatterlist src_sg, dst_sg;
720 src_sg.page = src_page;
721 src_sg.offset = src_offset;
722 src_sg.length = size;
723 dst_sg.page = dst_page;
724 dst_sg.offset = dst_offset;
725 dst_sg.length = size;
726 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
730 * ecryptfs_decrypt_page_offset
731 * @crypt_stat: The cryptographic context
732 * @dst_page: The page to decrypt into
733 * @dst_offset: The offset in the page to decrypt into
734 * @src_page: The page to decrypt from
735 * @src_offset: The offset in the page to decrypt from
736 * @size: The number of bytes to decrypt
737 * @iv: The initialization vector to use for the decryption
739 * Returns the number of bytes decrypted
742 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
743 struct page *dst_page, int dst_offset,
744 struct page *src_page, int src_offset, int size,
747 struct scatterlist src_sg, dst_sg;
749 src_sg.page = src_page;
750 src_sg.offset = src_offset;
751 src_sg.length = size;
752 dst_sg.page = dst_page;
753 dst_sg.offset = dst_offset;
754 dst_sg.length = size;
755 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
758 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
761 * ecryptfs_init_crypt_ctx
762 * @crypt_stat: Uninitilized crypt stats structure
764 * Initialize the crypto context.
766 * TODO: Performance: Keep a cache of initialized cipher contexts;
767 * only init if needed
769 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
774 if (!crypt_stat->cipher) {
775 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
778 ecryptfs_printk(KERN_DEBUG,
779 "Initializing cipher [%s]; strlen = [%d]; "
780 "key_size_bits = [%d]\n",
781 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
782 crypt_stat->key_size << 3);
783 if (crypt_stat->tfm) {
787 mutex_lock(&crypt_stat->cs_tfm_mutex);
788 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
789 crypt_stat->cipher, "cbc");
792 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
794 kfree(full_alg_name);
795 if (IS_ERR(crypt_stat->tfm)) {
796 rc = PTR_ERR(crypt_stat->tfm);
797 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
798 "Error initializing cipher [%s]\n",
800 mutex_unlock(&crypt_stat->cs_tfm_mutex);
803 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
804 mutex_unlock(&crypt_stat->cs_tfm_mutex);
810 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
814 crypt_stat->extent_mask = 0xFFFFFFFF;
815 crypt_stat->extent_shift = 0;
816 if (crypt_stat->extent_size == 0)
818 extent_size_tmp = crypt_stat->extent_size;
819 while ((extent_size_tmp & 0x01) == 0) {
820 extent_size_tmp >>= 1;
821 crypt_stat->extent_mask <<= 1;
822 crypt_stat->extent_shift++;
826 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
828 /* Default values; may be overwritten as we are parsing the
830 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
831 set_extent_mask_and_shift(crypt_stat);
832 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
833 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
834 crypt_stat->num_header_extents_at_front = 0;
836 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
837 crypt_stat->num_header_extents_at_front =
838 (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
839 / crypt_stat->extent_size);
841 crypt_stat->num_header_extents_at_front =
842 (PAGE_CACHE_SIZE / crypt_stat->extent_size);
847 * ecryptfs_compute_root_iv
850 * On error, sets the root IV to all 0's.
852 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
855 char dst[MD5_DIGEST_SIZE];
857 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
858 BUG_ON(crypt_stat->iv_bytes <= 0);
859 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
861 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
862 "cannot generate root IV\n");
865 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
866 crypt_stat->key_size);
868 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
869 "MD5 while generating root IV\n");
872 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
875 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
876 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
881 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
883 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
884 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
885 ecryptfs_compute_root_iv(crypt_stat);
886 if (unlikely(ecryptfs_verbosity > 0)) {
887 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
888 ecryptfs_dump_hex(crypt_stat->key,
889 crypt_stat->key_size);
894 * ecryptfs_copy_mount_wide_flags_to_inode_flags
895 * @crypt_stat: The inode's cryptographic context
896 * @mount_crypt_stat: The mount point's cryptographic context
898 * This function propagates the mount-wide flags to individual inode
901 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
902 struct ecryptfs_crypt_stat *crypt_stat,
903 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
905 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
906 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
907 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
908 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
911 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
912 struct ecryptfs_crypt_stat *crypt_stat,
913 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
915 struct ecryptfs_global_auth_tok *global_auth_tok;
918 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
919 list_for_each_entry(global_auth_tok,
920 &mount_crypt_stat->global_auth_tok_list,
921 mount_crypt_stat_list) {
922 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
924 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
926 &mount_crypt_stat->global_auth_tok_list_mutex);
930 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
936 * ecryptfs_set_default_crypt_stat_vals
937 * @crypt_stat: The inode's cryptographic context
938 * @mount_crypt_stat: The mount point's cryptographic context
940 * Default values in the event that policy does not override them.
942 static void ecryptfs_set_default_crypt_stat_vals(
943 struct ecryptfs_crypt_stat *crypt_stat,
944 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
946 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
948 ecryptfs_set_default_sizes(crypt_stat);
949 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
950 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
951 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
952 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
953 crypt_stat->mount_crypt_stat = mount_crypt_stat;
957 * ecryptfs_new_file_context
958 * @ecryptfs_dentry: The eCryptfs dentry
960 * If the crypto context for the file has not yet been established,
961 * this is where we do that. Establishing a new crypto context
962 * involves the following decisions:
963 * - What cipher to use?
964 * - What set of authentication tokens to use?
965 * Here we just worry about getting enough information into the
966 * authentication tokens so that we know that they are available.
967 * We associate the available authentication tokens with the new file
968 * via the set of signatures in the crypt_stat struct. Later, when
969 * the headers are actually written out, we may again defer to
970 * userspace to perform the encryption of the session key; for the
971 * foreseeable future, this will be the case with public key packets.
973 * Returns zero on success; non-zero otherwise
975 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
977 struct ecryptfs_crypt_stat *crypt_stat =
978 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
979 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
980 &ecryptfs_superblock_to_private(
981 ecryptfs_dentry->d_sb)->mount_crypt_stat;
985 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
986 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
987 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
989 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
992 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
993 "to the inode key sigs; rc = [%d]\n", rc);
997 strlen(mount_crypt_stat->global_default_cipher_name);
998 memcpy(crypt_stat->cipher,
999 mount_crypt_stat->global_default_cipher_name,
1001 crypt_stat->cipher[cipher_name_len] = '\0';
1002 crypt_stat->key_size =
1003 mount_crypt_stat->global_default_cipher_key_size;
1004 ecryptfs_generate_new_key(crypt_stat);
1005 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1007 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1008 "context for cipher [%s]: rc = [%d]\n",
1009 crypt_stat->cipher, rc);
1015 * contains_ecryptfs_marker - check for the ecryptfs marker
1016 * @data: The data block in which to check
1018 * Returns one if marker found; zero if not found
1020 static int contains_ecryptfs_marker(char *data)
1024 memcpy(&m_1, data, 4);
1025 m_1 = be32_to_cpu(m_1);
1026 memcpy(&m_2, (data + 4), 4);
1027 m_2 = be32_to_cpu(m_2);
1028 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1030 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1031 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1032 MAGIC_ECRYPTFS_MARKER);
1033 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1034 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1038 struct ecryptfs_flag_map_elem {
1043 /* Add support for additional flags by adding elements here. */
1044 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1045 {0x00000001, ECRYPTFS_ENABLE_HMAC},
1046 {0x00000002, ECRYPTFS_ENCRYPTED},
1047 {0x00000004, ECRYPTFS_METADATA_IN_XATTR}
1051 * ecryptfs_process_flags
1052 * @crypt_stat: The cryptographic context
1053 * @page_virt: Source data to be parsed
1054 * @bytes_read: Updated with the number of bytes read
1056 * Returns zero on success; non-zero if the flag set is invalid
1058 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1059 char *page_virt, int *bytes_read)
1065 memcpy(&flags, page_virt, 4);
1066 flags = be32_to_cpu(flags);
1067 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1068 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1069 if (flags & ecryptfs_flag_map[i].file_flag) {
1070 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1072 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1073 /* Version is in top 8 bits of the 32-bit flag vector */
1074 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1080 * write_ecryptfs_marker
1081 * @page_virt: The pointer to in a page to begin writing the marker
1082 * @written: Number of bytes written
1084 * Marker = 0x3c81b7f5
1086 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1090 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1091 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1092 m_1 = cpu_to_be32(m_1);
1093 memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1094 m_2 = cpu_to_be32(m_2);
1095 memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2,
1096 (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1097 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1101 write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1107 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1108 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1109 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1110 flags |= ecryptfs_flag_map[i].file_flag;
1111 /* Version is in top 8 bits of the 32-bit flag vector */
1112 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1113 flags = cpu_to_be32(flags);
1114 memcpy(page_virt, &flags, 4);
1118 struct ecryptfs_cipher_code_str_map_elem {
1119 char cipher_str[16];
1123 /* Add support for additional ciphers by adding elements here. The
1124 * cipher_code is whatever OpenPGP applicatoins use to identify the
1125 * ciphers. List in order of probability. */
1126 static struct ecryptfs_cipher_code_str_map_elem
1127 ecryptfs_cipher_code_str_map[] = {
1128 {"aes",RFC2440_CIPHER_AES_128 },
1129 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1130 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1131 {"cast5", RFC2440_CIPHER_CAST_5},
1132 {"twofish", RFC2440_CIPHER_TWOFISH},
1133 {"cast6", RFC2440_CIPHER_CAST_6},
1134 {"aes", RFC2440_CIPHER_AES_192},
1135 {"aes", RFC2440_CIPHER_AES_256}
1139 * ecryptfs_code_for_cipher_string
1140 * @crypt_stat: The cryptographic context
1142 * Returns zero on no match, or the cipher code on match
1144 u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat)
1148 struct ecryptfs_cipher_code_str_map_elem *map =
1149 ecryptfs_cipher_code_str_map;
1151 if (strcmp(crypt_stat->cipher, "aes") == 0) {
1152 switch (crypt_stat->key_size) {
1154 code = RFC2440_CIPHER_AES_128;
1157 code = RFC2440_CIPHER_AES_192;
1160 code = RFC2440_CIPHER_AES_256;
1163 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1164 if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){
1165 code = map[i].cipher_code;
1173 * ecryptfs_cipher_code_to_string
1174 * @str: Destination to write out the cipher name
1175 * @cipher_code: The code to convert to cipher name string
1177 * Returns zero on success
1179 int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
1185 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1186 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1187 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1188 if (str[0] == '\0') {
1189 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1190 "[%d]\n", cipher_code);
1196 int ecryptfs_read_and_validate_header_region(char *data,
1197 struct inode *ecryptfs_inode)
1199 struct ecryptfs_crypt_stat *crypt_stat =
1200 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
1203 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1206 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
1210 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
1212 ecryptfs_printk(KERN_DEBUG, "Valid marker not found\n");
1219 ecryptfs_write_header_metadata(char *virt,
1220 struct ecryptfs_crypt_stat *crypt_stat,
1223 u32 header_extent_size;
1224 u16 num_header_extents_at_front;
1226 header_extent_size = (u32)crypt_stat->extent_size;
1227 num_header_extents_at_front =
1228 (u16)crypt_stat->num_header_extents_at_front;
1229 header_extent_size = cpu_to_be32(header_extent_size);
1230 memcpy(virt, &header_extent_size, 4);
1232 num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front);
1233 memcpy(virt, &num_header_extents_at_front, 2);
1237 struct kmem_cache *ecryptfs_header_cache_0;
1238 struct kmem_cache *ecryptfs_header_cache_1;
1239 struct kmem_cache *ecryptfs_header_cache_2;
1242 * ecryptfs_write_headers_virt
1243 * @page_virt: The virtual address to write the headers to
1244 * @size: Set to the number of bytes written by this function
1245 * @crypt_stat: The cryptographic context
1246 * @ecryptfs_dentry: The eCryptfs dentry
1251 * Octets 0-7: Unencrypted file size (big-endian)
1252 * Octets 8-15: eCryptfs special marker
1253 * Octets 16-19: Flags
1254 * Octet 16: File format version number (between 0 and 255)
1255 * Octets 17-18: Reserved
1256 * Octet 19: Bit 1 (lsb): Reserved
1258 * Bits 3-8: Reserved
1259 * Octets 20-23: Header extent size (big-endian)
1260 * Octets 24-25: Number of header extents at front of file
1262 * Octet 26: Begin RFC 2440 authentication token packet set
1264 * Lower data (CBC encrypted)
1266 * Lower data (CBC encrypted)
1269 * Returns zero on success
1271 static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
1272 struct ecryptfs_crypt_stat *crypt_stat,
1273 struct dentry *ecryptfs_dentry)
1279 offset = ECRYPTFS_FILE_SIZE_BYTES;
1280 write_ecryptfs_marker((page_virt + offset), &written);
1282 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1284 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1287 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1288 ecryptfs_dentry, &written,
1289 PAGE_CACHE_SIZE - offset);
1291 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1292 "set; rc = [%d]\n", rc);
1301 ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
1302 struct dentry *ecryptfs_dentry,
1305 int current_header_page;
1309 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, page_virt,
1310 0, PAGE_CACHE_SIZE);
1312 printk(KERN_ERR "%s: Error attempting to write header "
1313 "information to lower file; rc = [%d]\n", __FUNCTION__,
1317 header_pages = ((crypt_stat->extent_size
1318 * crypt_stat->num_header_extents_at_front)
1320 memset(page_virt, 0, PAGE_CACHE_SIZE);
1321 current_header_page = 1;
1322 while (current_header_page < header_pages) {
1325 offset = (((loff_t)current_header_page) << PAGE_CACHE_SHIFT);
1326 if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode,
1328 PAGE_CACHE_SIZE))) {
1329 printk(KERN_ERR "%s: Error attempting to write header "
1330 "information to lower file; rc = [%d]\n",
1334 current_header_page++;
1341 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1342 struct ecryptfs_crypt_stat *crypt_stat,
1343 char *page_virt, size_t size)
1347 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1353 * ecryptfs_write_metadata
1354 * @ecryptfs_dentry: The eCryptfs dentry
1356 * Write the file headers out. This will likely involve a userspace
1357 * callout, in which the session key is encrypted with one or more
1358 * public keys and/or the passphrase necessary to do the encryption is
1359 * retrieved via a prompt. Exactly what happens at this point should
1360 * be policy-dependent.
1362 * TODO: Support header information spanning multiple pages
1364 * Returns zero on success; non-zero on error
1366 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
1368 struct ecryptfs_crypt_stat *crypt_stat =
1369 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1374 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1375 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1376 printk(KERN_ERR "Key is invalid; bailing out\n");
1382 ecryptfs_printk(KERN_WARNING,
1383 "Called with crypt_stat->encrypted == 0\n");
1386 /* Released in this function */
1387 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER);
1389 ecryptfs_printk(KERN_ERR, "Out of memory\n");
1393 rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat,
1396 ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n");
1397 memset(page_virt, 0, PAGE_CACHE_SIZE);
1400 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1401 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
1402 crypt_stat, page_virt,
1405 rc = ecryptfs_write_metadata_to_contents(crypt_stat,
1409 printk(KERN_ERR "Error writing metadata out to lower file; "
1414 kmem_cache_free(ecryptfs_header_cache_0, page_virt);
1419 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1420 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1421 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1422 char *virt, int *bytes_read,
1423 int validate_header_size)
1426 u32 header_extent_size;
1427 u16 num_header_extents_at_front;
1429 memcpy(&header_extent_size, virt, sizeof(u32));
1430 header_extent_size = be32_to_cpu(header_extent_size);
1431 virt += sizeof(u32);
1432 memcpy(&num_header_extents_at_front, virt, sizeof(u16));
1433 num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
1434 crypt_stat->num_header_extents_at_front =
1435 (int)num_header_extents_at_front;
1436 (*bytes_read) = (sizeof(u32) + sizeof(u16));
1437 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1438 && ((crypt_stat->extent_size
1439 * crypt_stat->num_header_extents_at_front)
1440 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1442 printk(KERN_WARNING "Invalid number of header extents: [%zd]\n",
1443 crypt_stat->num_header_extents_at_front);
1449 * set_default_header_data
1450 * @crypt_stat: The cryptographic context
1452 * For version 0 file format; this function is only for backwards
1453 * compatibility for files created with the prior versions of
1456 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1458 crypt_stat->num_header_extents_at_front = 2;
1462 * ecryptfs_read_headers_virt
1463 * @page_virt: The virtual address into which to read the headers
1464 * @crypt_stat: The cryptographic context
1465 * @ecryptfs_dentry: The eCryptfs dentry
1466 * @validate_header_size: Whether to validate the header size while reading
1468 * Read/parse the header data. The header format is detailed in the
1469 * comment block for the ecryptfs_write_headers_virt() function.
1471 * Returns zero on success
1473 static int ecryptfs_read_headers_virt(char *page_virt,
1474 struct ecryptfs_crypt_stat *crypt_stat,
1475 struct dentry *ecryptfs_dentry,
1476 int validate_header_size)
1482 ecryptfs_set_default_sizes(crypt_stat);
1483 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1484 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1485 offset = ECRYPTFS_FILE_SIZE_BYTES;
1486 rc = contains_ecryptfs_marker(page_virt + offset);
1491 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1492 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1495 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1498 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1499 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1500 "file version [%d] is supported by this "
1501 "version of eCryptfs\n",
1502 crypt_stat->file_version,
1503 ECRYPTFS_SUPPORTED_FILE_VERSION);
1507 offset += bytes_read;
1508 if (crypt_stat->file_version >= 1) {
1509 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1510 &bytes_read, validate_header_size);
1512 ecryptfs_printk(KERN_WARNING, "Error reading header "
1513 "metadata; rc = [%d]\n", rc);
1515 offset += bytes_read;
1517 set_default_header_data(crypt_stat);
1518 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1525 * ecryptfs_read_xattr_region
1526 * @page_virt: The vitual address into which to read the xattr data
1527 * @ecryptfs_inode: The eCryptfs inode
1529 * Attempts to read the crypto metadata from the extended attribute
1530 * region of the lower file.
1532 * Returns zero on success; non-zero on error
1534 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1536 struct dentry *lower_dentry =
1537 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1541 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1542 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1544 printk(KERN_ERR "Error attempting to read the [%s] "
1545 "xattr from the lower file; return value = [%zd]\n",
1546 ECRYPTFS_XATTR_NAME, size);
1554 int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1555 struct dentry *ecryptfs_dentry)
1559 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
1562 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1563 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1564 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1572 * ecryptfs_read_metadata
1574 * Common entry point for reading file metadata. From here, we could
1575 * retrieve the header information from the header region of the file,
1576 * the xattr region of the file, or some other repostory that is
1577 * stored separately from the file itself. The current implementation
1578 * supports retrieving the metadata information from the file contents
1579 * and from the xattr region.
1581 * Returns zero if valid headers found and parsed; non-zero otherwise
1583 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1586 char *page_virt = NULL;
1587 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1588 struct ecryptfs_crypt_stat *crypt_stat =
1589 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1590 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1591 &ecryptfs_superblock_to_private(
1592 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1594 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1596 /* Read the first page from the underlying file */
1597 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
1600 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1604 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1607 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1609 ECRYPTFS_VALIDATE_HEADER_SIZE);
1611 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1613 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1614 "file header region or xattr region\n");
1618 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1620 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1622 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1623 "file xattr region either\n");
1626 if (crypt_stat->mount_crypt_stat->flags
1627 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1628 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1630 printk(KERN_WARNING "Attempt to access file with "
1631 "crypto metadata only in the extended attribute "
1632 "region, but eCryptfs was mounted without "
1633 "xattr support enabled. eCryptfs will not treat "
1634 "this like an encrypted file.\n");
1640 memset(page_virt, 0, PAGE_CACHE_SIZE);
1641 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1647 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1648 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1649 * @name: The plaintext name
1650 * @length: The length of the plaintext
1651 * @encoded_name: The encypted name
1653 * Encrypts and encodes a filename into something that constitutes a
1654 * valid filename for a filesystem, with printable characters.
1656 * We assume that we have a properly initialized crypto context,
1657 * pointed to by crypt_stat->tfm.
1659 * TODO: Implement filename decoding and decryption here, in place of
1660 * memcpy. We are keeping the framework around for now to (1)
1661 * facilitate testing of the components needed to implement filename
1662 * encryption and (2) to provide a code base from which other
1663 * developers in the community can easily implement this feature.
1665 * Returns the length of encoded filename; negative if error
1668 ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1669 const char *name, int length, char **encoded_name)
1673 (*encoded_name) = kmalloc(length + 2, GFP_KERNEL);
1674 if (!(*encoded_name)) {
1678 /* TODO: Filename encryption is a scheduled feature for a
1679 * future version of eCryptfs. This function is here only for
1680 * the purpose of providing a framework for other developers
1681 * to easily implement filename encryption. Hint: Replace this
1682 * memcpy() with a call to encrypt and encode the
1683 * filename, the set the length accordingly. */
1684 memcpy((void *)(*encoded_name), (void *)name, length);
1685 (*encoded_name)[length] = '\0';
1692 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1693 * @crypt_stat: The crypt_stat struct associated with the file
1694 * @name: The filename in cipher text
1695 * @length: The length of the cipher text name
1696 * @decrypted_name: The plaintext name
1698 * Decodes and decrypts the filename.
1700 * We assume that we have a properly initialized crypto context,
1701 * pointed to by crypt_stat->tfm.
1703 * TODO: Implement filename decoding and decryption here, in place of
1704 * memcpy. We are keeping the framework around for now to (1)
1705 * facilitate testing of the components needed to implement filename
1706 * encryption and (2) to provide a code base from which other
1707 * developers in the community can easily implement this feature.
1709 * Returns the length of decoded filename; negative if error
1712 ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1713 const char *name, int length, char **decrypted_name)
1717 (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL);
1718 if (!(*decrypted_name)) {
1722 /* TODO: Filename encryption is a scheduled feature for a
1723 * future version of eCryptfs. This function is here only for
1724 * the purpose of providing a framework for other developers
1725 * to easily implement filename encryption. Hint: Replace this
1726 * memcpy() with a call to decode and decrypt the
1727 * filename, the set the length accordingly. */
1728 memcpy((void *)(*decrypted_name), (void *)name, length);
1729 (*decrypted_name)[length + 1] = '\0'; /* Only for convenience
1730 * in printing out the
1739 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1740 * @key_tfm: Crypto context for key material, set by this function
1741 * @cipher_name: Name of the cipher
1742 * @key_size: Size of the key in bytes
1744 * Returns zero on success. Any crypto_tfm structs allocated here
1745 * should be released by other functions, such as on a superblock put
1746 * event, regardless of whether this function succeeds for fails.
1749 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1750 char *cipher_name, size_t *key_size)
1752 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1753 char *full_alg_name;
1757 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1759 printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum "
1760 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1763 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1767 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1768 kfree(full_alg_name);
1769 if (IS_ERR(*key_tfm)) {
1770 rc = PTR_ERR(*key_tfm);
1771 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1772 "[%s]; rc = [%d]\n", cipher_name, rc);
1775 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1776 if (*key_size == 0) {
1777 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1779 *key_size = alg->max_keysize;
1781 get_random_bytes(dummy_key, *key_size);
1782 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1784 printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
1785 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
1793 struct kmem_cache *ecryptfs_key_tfm_cache;
1794 struct list_head key_tfm_list;
1795 struct mutex key_tfm_list_mutex;
1797 int ecryptfs_init_crypto(void)
1799 mutex_init(&key_tfm_list_mutex);
1800 INIT_LIST_HEAD(&key_tfm_list);
1804 int ecryptfs_destroy_crypto(void)
1806 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1808 mutex_lock(&key_tfm_list_mutex);
1809 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1811 list_del(&key_tfm->key_tfm_list);
1812 if (key_tfm->key_tfm)
1813 crypto_free_blkcipher(key_tfm->key_tfm);
1814 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1816 mutex_unlock(&key_tfm_list_mutex);
1821 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1824 struct ecryptfs_key_tfm *tmp_tfm;
1827 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1828 if (key_tfm != NULL)
1829 (*key_tfm) = tmp_tfm;
1832 printk(KERN_ERR "Error attempting to allocate from "
1833 "ecryptfs_key_tfm_cache\n");
1836 mutex_init(&tmp_tfm->key_tfm_mutex);
1837 strncpy(tmp_tfm->cipher_name, cipher_name,
1838 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1839 tmp_tfm->key_size = key_size;
1840 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1841 tmp_tfm->cipher_name,
1842 &tmp_tfm->key_size);
1844 printk(KERN_ERR "Error attempting to initialize key TFM "
1845 "cipher with name = [%s]; rc = [%d]\n",
1846 tmp_tfm->cipher_name, rc);
1847 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1848 if (key_tfm != NULL)
1852 mutex_lock(&key_tfm_list_mutex);
1853 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1854 mutex_unlock(&key_tfm_list_mutex);
1859 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1860 struct mutex **tfm_mutex,
1863 struct ecryptfs_key_tfm *key_tfm;
1867 (*tfm_mutex) = NULL;
1868 mutex_lock(&key_tfm_list_mutex);
1869 list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) {
1870 if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
1871 (*tfm) = key_tfm->key_tfm;
1872 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1873 mutex_unlock(&key_tfm_list_mutex);
1877 mutex_unlock(&key_tfm_list_mutex);
1878 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1880 printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
1884 (*tfm) = key_tfm->key_tfm;
1885 (*tfm_mutex) = &key_tfm->key_tfm_mutex;