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);
286 sg_set_page(&sg[i], pg, 0, offset);
287 remainder_of_page = PAGE_CACHE_SIZE - offset;
288 if (size >= remainder_of_page) {
290 sg[i].length = remainder_of_page;
291 addr += remainder_of_page;
292 size -= remainder_of_page;
307 * encrypt_scatterlist
308 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
309 * @dest_sg: Destination of encrypted data
310 * @src_sg: Data to be encrypted
311 * @size: Length of data to be encrypted
312 * @iv: iv to use during encryption
314 * Returns the number of bytes encrypted; negative value on error
316 static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
317 struct scatterlist *dest_sg,
318 struct scatterlist *src_sg, int size,
321 struct blkcipher_desc desc = {
322 .tfm = crypt_stat->tfm,
324 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
328 BUG_ON(!crypt_stat || !crypt_stat->tfm
329 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
330 if (unlikely(ecryptfs_verbosity > 0)) {
331 ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n",
332 crypt_stat->key_size);
333 ecryptfs_dump_hex(crypt_stat->key,
334 crypt_stat->key_size);
336 /* Consider doing this once, when the file is opened */
337 mutex_lock(&crypt_stat->cs_tfm_mutex);
338 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
339 crypt_stat->key_size);
341 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
343 mutex_unlock(&crypt_stat->cs_tfm_mutex);
347 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
348 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
349 mutex_unlock(&crypt_stat->cs_tfm_mutex);
355 * ecryptfs_lower_offset_for_extent
357 * Convert an eCryptfs page index into a lower byte offset
359 void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
360 struct ecryptfs_crypt_stat *crypt_stat)
362 (*offset) = ((crypt_stat->extent_size
363 * crypt_stat->num_header_extents_at_front)
364 + (crypt_stat->extent_size * extent_num));
368 * ecryptfs_encrypt_extent
369 * @enc_extent_page: Allocated page into which to encrypt the data in
371 * @crypt_stat: crypt_stat containing cryptographic context for the
372 * encryption operation
373 * @page: Page containing plaintext data extent to encrypt
374 * @extent_offset: Page extent offset for use in generating IV
376 * Encrypts one extent of data.
378 * Return zero on success; non-zero otherwise
380 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
381 struct ecryptfs_crypt_stat *crypt_stat,
383 unsigned long extent_offset)
386 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
389 extent_base = (((loff_t)page->index)
390 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
391 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
392 (extent_base + extent_offset));
394 ecryptfs_printk(KERN_ERR, "Error attempting to "
395 "derive IV for extent [0x%.16x]; "
396 "rc = [%d]\n", (extent_base + extent_offset),
400 if (unlikely(ecryptfs_verbosity > 0)) {
401 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
403 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
404 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
406 ecryptfs_dump_hex((char *)
408 + (extent_offset * crypt_stat->extent_size)),
411 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
413 * crypt_stat->extent_size),
414 crypt_stat->extent_size, extent_iv);
416 printk(KERN_ERR "%s: Error attempting to encrypt page with "
417 "page->index = [%ld], extent_offset = [%ld]; "
418 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
423 if (unlikely(ecryptfs_verbosity > 0)) {
424 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
425 "rc = [%d]\n", (extent_base + extent_offset),
427 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
429 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
436 * ecryptfs_encrypt_page
437 * @page: Page mapped from the eCryptfs inode for the file; contains
438 * decrypted content that needs to be encrypted (to a temporary
439 * page; not in place) and written out to the lower file
441 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
442 * that eCryptfs pages may straddle the lower pages -- for instance,
443 * if the file was created on a machine with an 8K page size
444 * (resulting in an 8K header), and then the file is copied onto a
445 * host with a 32K page size, then when reading page 0 of the eCryptfs
446 * file, 24K of page 0 of the lower file will be read and decrypted,
447 * and then 8K of page 1 of the lower file will be read and decrypted.
449 * Returns zero on success; negative on error
451 int ecryptfs_encrypt_page(struct page *page)
453 struct inode *ecryptfs_inode;
454 struct ecryptfs_crypt_stat *crypt_stat;
455 char *enc_extent_virt = NULL;
456 struct page *enc_extent_page;
457 loff_t extent_offset;
460 ecryptfs_inode = page->mapping->host;
462 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
463 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
464 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
467 printk(KERN_ERR "%s: Error attempting to copy "
468 "page at index [%ld]\n", __FUNCTION__,
472 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
473 if (!enc_extent_virt) {
475 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
476 "encrypted extent\n");
479 enc_extent_page = virt_to_page(enc_extent_virt);
480 for (extent_offset = 0;
481 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
485 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
488 printk(KERN_ERR "%s: Error encrypting extent; "
489 "rc = [%d]\n", __FUNCTION__, rc);
492 ecryptfs_lower_offset_for_extent(
493 &offset, ((((loff_t)page->index)
495 / crypt_stat->extent_size))
496 + extent_offset), crypt_stat);
497 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
498 offset, crypt_stat->extent_size);
500 ecryptfs_printk(KERN_ERR, "Error attempting "
501 "to write lower page; rc = [%d]"
508 kfree(enc_extent_virt);
512 static int ecryptfs_decrypt_extent(struct page *page,
513 struct ecryptfs_crypt_stat *crypt_stat,
514 struct page *enc_extent_page,
515 unsigned long extent_offset)
518 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
521 extent_base = (((loff_t)page->index)
522 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
523 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
524 (extent_base + extent_offset));
526 ecryptfs_printk(KERN_ERR, "Error attempting to "
527 "derive IV for extent [0x%.16x]; "
528 "rc = [%d]\n", (extent_base + extent_offset),
532 if (unlikely(ecryptfs_verbosity > 0)) {
533 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
535 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
536 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
538 ecryptfs_dump_hex((char *)
539 (page_address(enc_extent_page)
540 + (extent_offset * crypt_stat->extent_size)),
543 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
545 * crypt_stat->extent_size),
547 crypt_stat->extent_size, extent_iv);
549 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
550 "page->index = [%ld], extent_offset = [%ld]; "
551 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
556 if (unlikely(ecryptfs_verbosity > 0)) {
557 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
558 "rc = [%d]\n", (extent_base + extent_offset),
560 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
562 ecryptfs_dump_hex((char *)(page_address(page)
564 * crypt_stat->extent_size)), 8);
571 * ecryptfs_decrypt_page
572 * @page: Page mapped from the eCryptfs inode for the file; data read
573 * and decrypted from the lower file will be written into this
576 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
577 * that eCryptfs pages may straddle the lower pages -- for instance,
578 * if the file was created on a machine with an 8K page size
579 * (resulting in an 8K header), and then the file is copied onto a
580 * host with a 32K page size, then when reading page 0 of the eCryptfs
581 * file, 24K of page 0 of the lower file will be read and decrypted,
582 * and then 8K of page 1 of the lower file will be read and decrypted.
584 * Returns zero on success; negative on error
586 int ecryptfs_decrypt_page(struct page *page)
588 struct inode *ecryptfs_inode;
589 struct ecryptfs_crypt_stat *crypt_stat;
590 char *enc_extent_virt = NULL;
591 struct page *enc_extent_page;
592 unsigned long extent_offset;
595 ecryptfs_inode = page->mapping->host;
597 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
598 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
599 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
603 printk(KERN_ERR "%s: Error attempting to copy "
604 "page at index [%ld]\n", __FUNCTION__,
608 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
609 if (!enc_extent_virt) {
611 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
612 "encrypted extent\n");
615 enc_extent_page = virt_to_page(enc_extent_virt);
616 for (extent_offset = 0;
617 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
621 ecryptfs_lower_offset_for_extent(
622 &offset, ((page->index * (PAGE_CACHE_SIZE
623 / crypt_stat->extent_size))
624 + extent_offset), crypt_stat);
625 rc = ecryptfs_read_lower(enc_extent_virt, offset,
626 crypt_stat->extent_size,
629 ecryptfs_printk(KERN_ERR, "Error attempting "
630 "to read lower page; rc = [%d]"
634 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
637 printk(KERN_ERR "%s: Error encrypting extent; "
638 "rc = [%d]\n", __FUNCTION__, rc);
644 kfree(enc_extent_virt);
649 * decrypt_scatterlist
650 * @crypt_stat: Cryptographic context
651 * @dest_sg: The destination scatterlist to decrypt into
652 * @src_sg: The source scatterlist to decrypt from
653 * @size: The number of bytes to decrypt
654 * @iv: The initialization vector to use for the decryption
656 * Returns the number of bytes decrypted; negative value on error
658 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
659 struct scatterlist *dest_sg,
660 struct scatterlist *src_sg, int size,
663 struct blkcipher_desc desc = {
664 .tfm = crypt_stat->tfm,
666 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
670 /* Consider doing this once, when the file is opened */
671 mutex_lock(&crypt_stat->cs_tfm_mutex);
672 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
673 crypt_stat->key_size);
675 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
677 mutex_unlock(&crypt_stat->cs_tfm_mutex);
681 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
682 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
683 mutex_unlock(&crypt_stat->cs_tfm_mutex);
685 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
695 * ecryptfs_encrypt_page_offset
696 * @crypt_stat: The cryptographic context
697 * @dst_page: The page to encrypt into
698 * @dst_offset: The offset in the page to encrypt into
699 * @src_page: The page to encrypt from
700 * @src_offset: The offset in the page to encrypt from
701 * @size: The number of bytes to encrypt
702 * @iv: The initialization vector to use for the encryption
704 * Returns the number of bytes encrypted
707 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
708 struct page *dst_page, int dst_offset,
709 struct page *src_page, int src_offset, int size,
712 struct scatterlist src_sg, dst_sg;
714 sg_init_table(&src_sg, 1);
715 sg_init_table(&dst_sg, 1);
717 sg_set_page(&src_sg, src_page, size, src_offset);
718 sg_set_page(&dst_sg, dst_page, size, dst_offset);
719 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
723 * ecryptfs_decrypt_page_offset
724 * @crypt_stat: The cryptographic context
725 * @dst_page: The page to decrypt into
726 * @dst_offset: The offset in the page to decrypt into
727 * @src_page: The page to decrypt from
728 * @src_offset: The offset in the page to decrypt from
729 * @size: The number of bytes to decrypt
730 * @iv: The initialization vector to use for the decryption
732 * Returns the number of bytes decrypted
735 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
736 struct page *dst_page, int dst_offset,
737 struct page *src_page, int src_offset, int size,
740 struct scatterlist src_sg, dst_sg;
742 sg_init_table(&src_sg, 1);
743 sg_set_page(&src_sg, src_page, size, src_offset);
745 sg_init_table(&dst_sg, 1);
746 sg_set_page(&dst_sg, dst_page, size, dst_offset);
748 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
751 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
754 * ecryptfs_init_crypt_ctx
755 * @crypt_stat: Uninitilized crypt stats structure
757 * Initialize the crypto context.
759 * TODO: Performance: Keep a cache of initialized cipher contexts;
760 * only init if needed
762 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
767 if (!crypt_stat->cipher) {
768 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
771 ecryptfs_printk(KERN_DEBUG,
772 "Initializing cipher [%s]; strlen = [%d]; "
773 "key_size_bits = [%d]\n",
774 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
775 crypt_stat->key_size << 3);
776 if (crypt_stat->tfm) {
780 mutex_lock(&crypt_stat->cs_tfm_mutex);
781 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
782 crypt_stat->cipher, "cbc");
785 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
787 kfree(full_alg_name);
788 if (IS_ERR(crypt_stat->tfm)) {
789 rc = PTR_ERR(crypt_stat->tfm);
790 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
791 "Error initializing cipher [%s]\n",
793 mutex_unlock(&crypt_stat->cs_tfm_mutex);
796 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
797 mutex_unlock(&crypt_stat->cs_tfm_mutex);
803 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
807 crypt_stat->extent_mask = 0xFFFFFFFF;
808 crypt_stat->extent_shift = 0;
809 if (crypt_stat->extent_size == 0)
811 extent_size_tmp = crypt_stat->extent_size;
812 while ((extent_size_tmp & 0x01) == 0) {
813 extent_size_tmp >>= 1;
814 crypt_stat->extent_mask <<= 1;
815 crypt_stat->extent_shift++;
819 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
821 /* Default values; may be overwritten as we are parsing the
823 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
824 set_extent_mask_and_shift(crypt_stat);
825 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
826 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
827 crypt_stat->num_header_extents_at_front = 0;
829 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
830 crypt_stat->num_header_extents_at_front =
831 (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
832 / crypt_stat->extent_size);
834 crypt_stat->num_header_extents_at_front =
835 (PAGE_CACHE_SIZE / crypt_stat->extent_size);
840 * ecryptfs_compute_root_iv
843 * On error, sets the root IV to all 0's.
845 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
848 char dst[MD5_DIGEST_SIZE];
850 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
851 BUG_ON(crypt_stat->iv_bytes <= 0);
852 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
854 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
855 "cannot generate root IV\n");
858 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
859 crypt_stat->key_size);
861 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
862 "MD5 while generating root IV\n");
865 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
868 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
869 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
874 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
876 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
877 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
878 ecryptfs_compute_root_iv(crypt_stat);
879 if (unlikely(ecryptfs_verbosity > 0)) {
880 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
881 ecryptfs_dump_hex(crypt_stat->key,
882 crypt_stat->key_size);
887 * ecryptfs_copy_mount_wide_flags_to_inode_flags
888 * @crypt_stat: The inode's cryptographic context
889 * @mount_crypt_stat: The mount point's cryptographic context
891 * This function propagates the mount-wide flags to individual inode
894 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
895 struct ecryptfs_crypt_stat *crypt_stat,
896 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
898 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
899 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
900 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
901 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
904 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
905 struct ecryptfs_crypt_stat *crypt_stat,
906 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
908 struct ecryptfs_global_auth_tok *global_auth_tok;
911 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
912 list_for_each_entry(global_auth_tok,
913 &mount_crypt_stat->global_auth_tok_list,
914 mount_crypt_stat_list) {
915 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
917 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
919 &mount_crypt_stat->global_auth_tok_list_mutex);
923 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
929 * ecryptfs_set_default_crypt_stat_vals
930 * @crypt_stat: The inode's cryptographic context
931 * @mount_crypt_stat: The mount point's cryptographic context
933 * Default values in the event that policy does not override them.
935 static void ecryptfs_set_default_crypt_stat_vals(
936 struct ecryptfs_crypt_stat *crypt_stat,
937 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
939 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
941 ecryptfs_set_default_sizes(crypt_stat);
942 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
943 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
944 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
945 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
946 crypt_stat->mount_crypt_stat = mount_crypt_stat;
950 * ecryptfs_new_file_context
951 * @ecryptfs_dentry: The eCryptfs dentry
953 * If the crypto context for the file has not yet been established,
954 * this is where we do that. Establishing a new crypto context
955 * involves the following decisions:
956 * - What cipher to use?
957 * - What set of authentication tokens to use?
958 * Here we just worry about getting enough information into the
959 * authentication tokens so that we know that they are available.
960 * We associate the available authentication tokens with the new file
961 * via the set of signatures in the crypt_stat struct. Later, when
962 * the headers are actually written out, we may again defer to
963 * userspace to perform the encryption of the session key; for the
964 * foreseeable future, this will be the case with public key packets.
966 * Returns zero on success; non-zero otherwise
968 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
970 struct ecryptfs_crypt_stat *crypt_stat =
971 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
972 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
973 &ecryptfs_superblock_to_private(
974 ecryptfs_dentry->d_sb)->mount_crypt_stat;
978 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
979 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
980 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
982 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
985 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
986 "to the inode key sigs; rc = [%d]\n", rc);
990 strlen(mount_crypt_stat->global_default_cipher_name);
991 memcpy(crypt_stat->cipher,
992 mount_crypt_stat->global_default_cipher_name,
994 crypt_stat->cipher[cipher_name_len] = '\0';
995 crypt_stat->key_size =
996 mount_crypt_stat->global_default_cipher_key_size;
997 ecryptfs_generate_new_key(crypt_stat);
998 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1000 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1001 "context for cipher [%s]: rc = [%d]\n",
1002 crypt_stat->cipher, rc);
1008 * contains_ecryptfs_marker - check for the ecryptfs marker
1009 * @data: The data block in which to check
1011 * Returns one if marker found; zero if not found
1013 static int contains_ecryptfs_marker(char *data)
1017 memcpy(&m_1, data, 4);
1018 m_1 = be32_to_cpu(m_1);
1019 memcpy(&m_2, (data + 4), 4);
1020 m_2 = be32_to_cpu(m_2);
1021 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1023 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1024 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1025 MAGIC_ECRYPTFS_MARKER);
1026 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1027 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1031 struct ecryptfs_flag_map_elem {
1036 /* Add support for additional flags by adding elements here. */
1037 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1038 {0x00000001, ECRYPTFS_ENABLE_HMAC},
1039 {0x00000002, ECRYPTFS_ENCRYPTED},
1040 {0x00000004, ECRYPTFS_METADATA_IN_XATTR}
1044 * ecryptfs_process_flags
1045 * @crypt_stat: The cryptographic context
1046 * @page_virt: Source data to be parsed
1047 * @bytes_read: Updated with the number of bytes read
1049 * Returns zero on success; non-zero if the flag set is invalid
1051 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1052 char *page_virt, int *bytes_read)
1058 memcpy(&flags, page_virt, 4);
1059 flags = be32_to_cpu(flags);
1060 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1061 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1062 if (flags & ecryptfs_flag_map[i].file_flag) {
1063 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1065 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1066 /* Version is in top 8 bits of the 32-bit flag vector */
1067 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1073 * write_ecryptfs_marker
1074 * @page_virt: The pointer to in a page to begin writing the marker
1075 * @written: Number of bytes written
1077 * Marker = 0x3c81b7f5
1079 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1083 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1084 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1085 m_1 = cpu_to_be32(m_1);
1086 memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1087 m_2 = cpu_to_be32(m_2);
1088 memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2,
1089 (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1090 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1094 write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1100 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1101 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1102 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1103 flags |= ecryptfs_flag_map[i].file_flag;
1104 /* Version is in top 8 bits of the 32-bit flag vector */
1105 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1106 flags = cpu_to_be32(flags);
1107 memcpy(page_virt, &flags, 4);
1111 struct ecryptfs_cipher_code_str_map_elem {
1112 char cipher_str[16];
1116 /* Add support for additional ciphers by adding elements here. The
1117 * cipher_code is whatever OpenPGP applicatoins use to identify the
1118 * ciphers. List in order of probability. */
1119 static struct ecryptfs_cipher_code_str_map_elem
1120 ecryptfs_cipher_code_str_map[] = {
1121 {"aes",RFC2440_CIPHER_AES_128 },
1122 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1123 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1124 {"cast5", RFC2440_CIPHER_CAST_5},
1125 {"twofish", RFC2440_CIPHER_TWOFISH},
1126 {"cast6", RFC2440_CIPHER_CAST_6},
1127 {"aes", RFC2440_CIPHER_AES_192},
1128 {"aes", RFC2440_CIPHER_AES_256}
1132 * ecryptfs_code_for_cipher_string
1133 * @crypt_stat: The cryptographic context
1135 * Returns zero on no match, or the cipher code on match
1137 u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat)
1141 struct ecryptfs_cipher_code_str_map_elem *map =
1142 ecryptfs_cipher_code_str_map;
1144 if (strcmp(crypt_stat->cipher, "aes") == 0) {
1145 switch (crypt_stat->key_size) {
1147 code = RFC2440_CIPHER_AES_128;
1150 code = RFC2440_CIPHER_AES_192;
1153 code = RFC2440_CIPHER_AES_256;
1156 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1157 if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){
1158 code = map[i].cipher_code;
1166 * ecryptfs_cipher_code_to_string
1167 * @str: Destination to write out the cipher name
1168 * @cipher_code: The code to convert to cipher name string
1170 * Returns zero on success
1172 int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
1178 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1179 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1180 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1181 if (str[0] == '\0') {
1182 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1183 "[%d]\n", cipher_code);
1189 int ecryptfs_read_and_validate_header_region(char *data,
1190 struct inode *ecryptfs_inode)
1192 struct ecryptfs_crypt_stat *crypt_stat =
1193 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
1196 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1199 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
1203 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
1205 ecryptfs_printk(KERN_DEBUG, "Valid marker not found\n");
1212 ecryptfs_write_header_metadata(char *virt,
1213 struct ecryptfs_crypt_stat *crypt_stat,
1216 u32 header_extent_size;
1217 u16 num_header_extents_at_front;
1219 header_extent_size = (u32)crypt_stat->extent_size;
1220 num_header_extents_at_front =
1221 (u16)crypt_stat->num_header_extents_at_front;
1222 header_extent_size = cpu_to_be32(header_extent_size);
1223 memcpy(virt, &header_extent_size, 4);
1225 num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front);
1226 memcpy(virt, &num_header_extents_at_front, 2);
1230 struct kmem_cache *ecryptfs_header_cache_0;
1231 struct kmem_cache *ecryptfs_header_cache_1;
1232 struct kmem_cache *ecryptfs_header_cache_2;
1235 * ecryptfs_write_headers_virt
1236 * @page_virt: The virtual address to write the headers to
1237 * @size: Set to the number of bytes written by this function
1238 * @crypt_stat: The cryptographic context
1239 * @ecryptfs_dentry: The eCryptfs dentry
1244 * Octets 0-7: Unencrypted file size (big-endian)
1245 * Octets 8-15: eCryptfs special marker
1246 * Octets 16-19: Flags
1247 * Octet 16: File format version number (between 0 and 255)
1248 * Octets 17-18: Reserved
1249 * Octet 19: Bit 1 (lsb): Reserved
1251 * Bits 3-8: Reserved
1252 * Octets 20-23: Header extent size (big-endian)
1253 * Octets 24-25: Number of header extents at front of file
1255 * Octet 26: Begin RFC 2440 authentication token packet set
1257 * Lower data (CBC encrypted)
1259 * Lower data (CBC encrypted)
1262 * Returns zero on success
1264 static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
1265 struct ecryptfs_crypt_stat *crypt_stat,
1266 struct dentry *ecryptfs_dentry)
1272 offset = ECRYPTFS_FILE_SIZE_BYTES;
1273 write_ecryptfs_marker((page_virt + offset), &written);
1275 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1277 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1280 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1281 ecryptfs_dentry, &written,
1282 PAGE_CACHE_SIZE - offset);
1284 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1285 "set; rc = [%d]\n", rc);
1294 ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
1295 struct dentry *ecryptfs_dentry,
1298 int current_header_page;
1302 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, page_virt,
1303 0, PAGE_CACHE_SIZE);
1305 printk(KERN_ERR "%s: Error attempting to write header "
1306 "information to lower file; rc = [%d]\n", __FUNCTION__,
1310 header_pages = ((crypt_stat->extent_size
1311 * crypt_stat->num_header_extents_at_front)
1313 memset(page_virt, 0, PAGE_CACHE_SIZE);
1314 current_header_page = 1;
1315 while (current_header_page < header_pages) {
1318 offset = (((loff_t)current_header_page) << PAGE_CACHE_SHIFT);
1319 if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode,
1321 PAGE_CACHE_SIZE))) {
1322 printk(KERN_ERR "%s: Error attempting to write header "
1323 "information to lower file; rc = [%d]\n",
1327 current_header_page++;
1334 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1335 struct ecryptfs_crypt_stat *crypt_stat,
1336 char *page_virt, size_t size)
1340 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1346 * ecryptfs_write_metadata
1347 * @ecryptfs_dentry: The eCryptfs dentry
1349 * Write the file headers out. This will likely involve a userspace
1350 * callout, in which the session key is encrypted with one or more
1351 * public keys and/or the passphrase necessary to do the encryption is
1352 * retrieved via a prompt. Exactly what happens at this point should
1353 * be policy-dependent.
1355 * TODO: Support header information spanning multiple pages
1357 * Returns zero on success; non-zero on error
1359 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
1361 struct ecryptfs_crypt_stat *crypt_stat =
1362 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1367 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1368 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1369 printk(KERN_ERR "Key is invalid; bailing out\n");
1375 ecryptfs_printk(KERN_WARNING,
1376 "Called with crypt_stat->encrypted == 0\n");
1379 /* Released in this function */
1380 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER);
1382 ecryptfs_printk(KERN_ERR, "Out of memory\n");
1386 rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat,
1389 ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n");
1390 memset(page_virt, 0, PAGE_CACHE_SIZE);
1393 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1394 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
1395 crypt_stat, page_virt,
1398 rc = ecryptfs_write_metadata_to_contents(crypt_stat,
1402 printk(KERN_ERR "Error writing metadata out to lower file; "
1407 kmem_cache_free(ecryptfs_header_cache_0, page_virt);
1412 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1413 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1414 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1415 char *virt, int *bytes_read,
1416 int validate_header_size)
1419 u32 header_extent_size;
1420 u16 num_header_extents_at_front;
1422 memcpy(&header_extent_size, virt, sizeof(u32));
1423 header_extent_size = be32_to_cpu(header_extent_size);
1424 virt += sizeof(u32);
1425 memcpy(&num_header_extents_at_front, virt, sizeof(u16));
1426 num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
1427 crypt_stat->num_header_extents_at_front =
1428 (int)num_header_extents_at_front;
1429 (*bytes_read) = (sizeof(u32) + sizeof(u16));
1430 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1431 && ((crypt_stat->extent_size
1432 * crypt_stat->num_header_extents_at_front)
1433 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1435 printk(KERN_WARNING "Invalid number of header extents: [%zd]\n",
1436 crypt_stat->num_header_extents_at_front);
1442 * set_default_header_data
1443 * @crypt_stat: The cryptographic context
1445 * For version 0 file format; this function is only for backwards
1446 * compatibility for files created with the prior versions of
1449 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1451 crypt_stat->num_header_extents_at_front = 2;
1455 * ecryptfs_read_headers_virt
1456 * @page_virt: The virtual address into which to read the headers
1457 * @crypt_stat: The cryptographic context
1458 * @ecryptfs_dentry: The eCryptfs dentry
1459 * @validate_header_size: Whether to validate the header size while reading
1461 * Read/parse the header data. The header format is detailed in the
1462 * comment block for the ecryptfs_write_headers_virt() function.
1464 * Returns zero on success
1466 static int ecryptfs_read_headers_virt(char *page_virt,
1467 struct ecryptfs_crypt_stat *crypt_stat,
1468 struct dentry *ecryptfs_dentry,
1469 int validate_header_size)
1475 ecryptfs_set_default_sizes(crypt_stat);
1476 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1477 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1478 offset = ECRYPTFS_FILE_SIZE_BYTES;
1479 rc = contains_ecryptfs_marker(page_virt + offset);
1484 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1485 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1488 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1491 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1492 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1493 "file version [%d] is supported by this "
1494 "version of eCryptfs\n",
1495 crypt_stat->file_version,
1496 ECRYPTFS_SUPPORTED_FILE_VERSION);
1500 offset += bytes_read;
1501 if (crypt_stat->file_version >= 1) {
1502 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1503 &bytes_read, validate_header_size);
1505 ecryptfs_printk(KERN_WARNING, "Error reading header "
1506 "metadata; rc = [%d]\n", rc);
1508 offset += bytes_read;
1510 set_default_header_data(crypt_stat);
1511 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1518 * ecryptfs_read_xattr_region
1519 * @page_virt: The vitual address into which to read the xattr data
1520 * @ecryptfs_inode: The eCryptfs inode
1522 * Attempts to read the crypto metadata from the extended attribute
1523 * region of the lower file.
1525 * Returns zero on success; non-zero on error
1527 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1529 struct dentry *lower_dentry =
1530 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1534 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1535 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1537 printk(KERN_ERR "Error attempting to read the [%s] "
1538 "xattr from the lower file; return value = [%zd]\n",
1539 ECRYPTFS_XATTR_NAME, size);
1547 int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1548 struct dentry *ecryptfs_dentry)
1552 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
1555 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1556 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1557 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1565 * ecryptfs_read_metadata
1567 * Common entry point for reading file metadata. From here, we could
1568 * retrieve the header information from the header region of the file,
1569 * the xattr region of the file, or some other repostory that is
1570 * stored separately from the file itself. The current implementation
1571 * supports retrieving the metadata information from the file contents
1572 * and from the xattr region.
1574 * Returns zero if valid headers found and parsed; non-zero otherwise
1576 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1579 char *page_virt = NULL;
1580 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1581 struct ecryptfs_crypt_stat *crypt_stat =
1582 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1583 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1584 &ecryptfs_superblock_to_private(
1585 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1587 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1589 /* Read the first page from the underlying file */
1590 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
1593 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1597 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1600 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1602 ECRYPTFS_VALIDATE_HEADER_SIZE);
1604 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1606 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1607 "file header region or xattr region\n");
1611 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1613 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1615 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1616 "file xattr region either\n");
1619 if (crypt_stat->mount_crypt_stat->flags
1620 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1621 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1623 printk(KERN_WARNING "Attempt to access file with "
1624 "crypto metadata only in the extended attribute "
1625 "region, but eCryptfs was mounted without "
1626 "xattr support enabled. eCryptfs will not treat "
1627 "this like an encrypted file.\n");
1633 memset(page_virt, 0, PAGE_CACHE_SIZE);
1634 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1640 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1641 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1642 * @name: The plaintext name
1643 * @length: The length of the plaintext
1644 * @encoded_name: The encypted name
1646 * Encrypts and encodes a filename into something that constitutes a
1647 * valid filename for a filesystem, with printable characters.
1649 * We assume that we have a properly initialized crypto context,
1650 * pointed to by crypt_stat->tfm.
1652 * TODO: Implement filename decoding and decryption here, in place of
1653 * memcpy. We are keeping the framework around for now to (1)
1654 * facilitate testing of the components needed to implement filename
1655 * encryption and (2) to provide a code base from which other
1656 * developers in the community can easily implement this feature.
1658 * Returns the length of encoded filename; negative if error
1661 ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1662 const char *name, int length, char **encoded_name)
1666 (*encoded_name) = kmalloc(length + 2, GFP_KERNEL);
1667 if (!(*encoded_name)) {
1671 /* TODO: Filename encryption is a scheduled feature for a
1672 * future version of eCryptfs. This function is here only for
1673 * the purpose of providing a framework for other developers
1674 * to easily implement filename encryption. Hint: Replace this
1675 * memcpy() with a call to encrypt and encode the
1676 * filename, the set the length accordingly. */
1677 memcpy((void *)(*encoded_name), (void *)name, length);
1678 (*encoded_name)[length] = '\0';
1685 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1686 * @crypt_stat: The crypt_stat struct associated with the file
1687 * @name: The filename in cipher text
1688 * @length: The length of the cipher text name
1689 * @decrypted_name: The plaintext name
1691 * Decodes and decrypts the filename.
1693 * We assume that we have a properly initialized crypto context,
1694 * pointed to by crypt_stat->tfm.
1696 * TODO: Implement filename decoding and decryption here, in place of
1697 * memcpy. We are keeping the framework around for now to (1)
1698 * facilitate testing of the components needed to implement filename
1699 * encryption and (2) to provide a code base from which other
1700 * developers in the community can easily implement this feature.
1702 * Returns the length of decoded filename; negative if error
1705 ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1706 const char *name, int length, char **decrypted_name)
1710 (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL);
1711 if (!(*decrypted_name)) {
1715 /* TODO: Filename encryption is a scheduled feature for a
1716 * future version of eCryptfs. This function is here only for
1717 * the purpose of providing a framework for other developers
1718 * to easily implement filename encryption. Hint: Replace this
1719 * memcpy() with a call to decode and decrypt the
1720 * filename, the set the length accordingly. */
1721 memcpy((void *)(*decrypted_name), (void *)name, length);
1722 (*decrypted_name)[length + 1] = '\0'; /* Only for convenience
1723 * in printing out the
1732 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1733 * @key_tfm: Crypto context for key material, set by this function
1734 * @cipher_name: Name of the cipher
1735 * @key_size: Size of the key in bytes
1737 * Returns zero on success. Any crypto_tfm structs allocated here
1738 * should be released by other functions, such as on a superblock put
1739 * event, regardless of whether this function succeeds for fails.
1742 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1743 char *cipher_name, size_t *key_size)
1745 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1746 char *full_alg_name;
1750 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1752 printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum "
1753 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1756 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1760 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1761 kfree(full_alg_name);
1762 if (IS_ERR(*key_tfm)) {
1763 rc = PTR_ERR(*key_tfm);
1764 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1765 "[%s]; rc = [%d]\n", cipher_name, rc);
1768 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1769 if (*key_size == 0) {
1770 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1772 *key_size = alg->max_keysize;
1774 get_random_bytes(dummy_key, *key_size);
1775 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1777 printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
1778 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
1786 struct kmem_cache *ecryptfs_key_tfm_cache;
1787 struct list_head key_tfm_list;
1788 struct mutex key_tfm_list_mutex;
1790 int ecryptfs_init_crypto(void)
1792 mutex_init(&key_tfm_list_mutex);
1793 INIT_LIST_HEAD(&key_tfm_list);
1797 int ecryptfs_destroy_crypto(void)
1799 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1801 mutex_lock(&key_tfm_list_mutex);
1802 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1804 list_del(&key_tfm->key_tfm_list);
1805 if (key_tfm->key_tfm)
1806 crypto_free_blkcipher(key_tfm->key_tfm);
1807 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1809 mutex_unlock(&key_tfm_list_mutex);
1814 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1817 struct ecryptfs_key_tfm *tmp_tfm;
1820 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1821 if (key_tfm != NULL)
1822 (*key_tfm) = tmp_tfm;
1825 printk(KERN_ERR "Error attempting to allocate from "
1826 "ecryptfs_key_tfm_cache\n");
1829 mutex_init(&tmp_tfm->key_tfm_mutex);
1830 strncpy(tmp_tfm->cipher_name, cipher_name,
1831 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1832 tmp_tfm->key_size = key_size;
1833 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1834 tmp_tfm->cipher_name,
1835 &tmp_tfm->key_size);
1837 printk(KERN_ERR "Error attempting to initialize key TFM "
1838 "cipher with name = [%s]; rc = [%d]\n",
1839 tmp_tfm->cipher_name, rc);
1840 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1841 if (key_tfm != NULL)
1845 mutex_lock(&key_tfm_list_mutex);
1846 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1847 mutex_unlock(&key_tfm_list_mutex);
1852 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1853 struct mutex **tfm_mutex,
1856 struct ecryptfs_key_tfm *key_tfm;
1860 (*tfm_mutex) = NULL;
1861 mutex_lock(&key_tfm_list_mutex);
1862 list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) {
1863 if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
1864 (*tfm) = key_tfm->key_tfm;
1865 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1866 mutex_unlock(&key_tfm_list_mutex);
1870 mutex_unlock(&key_tfm_list_mutex);
1871 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1873 printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
1877 (*tfm) = key_tfm->key_tfm;
1878 (*tfm_mutex) = &key_tfm->key_tfm_mutex;