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 rc = crypto_hash_init(&desc);
121 "%s: Error initializing crypto hash; rc = [%d]\n",
125 rc = crypto_hash_update(&desc, &sg, len);
128 "%s: Error updating crypto hash; rc = [%d]\n",
132 rc = crypto_hash_final(&desc, dst);
135 "%s: Error finalizing crypto hash; rc = [%d]\n",
140 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
144 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
146 char *chaining_modifier)
148 int cipher_name_len = strlen(cipher_name);
149 int chaining_modifier_len = strlen(chaining_modifier);
150 int algified_name_len;
153 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
154 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
155 if (!(*algified_name)) {
159 snprintf((*algified_name), algified_name_len, "%s(%s)",
160 chaining_modifier, cipher_name);
168 * @iv: destination for the derived iv vale
169 * @crypt_stat: Pointer to crypt_stat struct for the current inode
170 * @offset: Offset of the extent whose IV we are to derive
172 * Generate the initialization vector from the given root IV and page
175 * Returns zero on success; non-zero on error.
177 static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
181 char dst[MD5_DIGEST_SIZE];
182 char src[ECRYPTFS_MAX_IV_BYTES + 16];
184 if (unlikely(ecryptfs_verbosity > 0)) {
185 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
186 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
188 /* TODO: It is probably secure to just cast the least
189 * significant bits of the root IV into an unsigned long and
190 * add the offset to that rather than go through all this
191 * hashing business. -Halcrow */
192 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
193 memset((src + crypt_stat->iv_bytes), 0, 16);
194 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
195 if (unlikely(ecryptfs_verbosity > 0)) {
196 ecryptfs_printk(KERN_DEBUG, "source:\n");
197 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
199 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
200 (crypt_stat->iv_bytes + 16));
202 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
203 "MD5 while generating IV for a page\n");
206 memcpy(iv, dst, crypt_stat->iv_bytes);
207 if (unlikely(ecryptfs_verbosity > 0)) {
208 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
209 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
216 * ecryptfs_init_crypt_stat
217 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
219 * Initialize the crypt_stat structure.
222 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
224 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
225 INIT_LIST_HEAD(&crypt_stat->keysig_list);
226 mutex_init(&crypt_stat->keysig_list_mutex);
227 mutex_init(&crypt_stat->cs_mutex);
228 mutex_init(&crypt_stat->cs_tfm_mutex);
229 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
230 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
234 * ecryptfs_destroy_crypt_stat
235 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
237 * Releases all memory associated with a crypt_stat struct.
239 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
241 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
244 crypto_free_blkcipher(crypt_stat->tfm);
245 if (crypt_stat->hash_tfm)
246 crypto_free_hash(crypt_stat->hash_tfm);
247 mutex_lock(&crypt_stat->keysig_list_mutex);
248 list_for_each_entry_safe(key_sig, key_sig_tmp,
249 &crypt_stat->keysig_list, crypt_stat_list) {
250 list_del(&key_sig->crypt_stat_list);
251 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
253 mutex_unlock(&crypt_stat->keysig_list_mutex);
254 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
257 void ecryptfs_destroy_mount_crypt_stat(
258 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
260 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
262 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
264 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
265 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
266 &mount_crypt_stat->global_auth_tok_list,
267 mount_crypt_stat_list) {
268 list_del(&auth_tok->mount_crypt_stat_list);
269 mount_crypt_stat->num_global_auth_toks--;
270 if (auth_tok->global_auth_tok_key
271 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
272 key_put(auth_tok->global_auth_tok_key);
273 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
275 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
276 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
280 * virt_to_scatterlist
281 * @addr: Virtual address
282 * @size: Size of data; should be an even multiple of the block size
283 * @sg: Pointer to scatterlist array; set to NULL to obtain only
284 * the number of scatterlist structs required in array
285 * @sg_size: Max array size
287 * Fills in a scatterlist array with page references for a passed
290 * Returns the number of scatterlist structs in array used
292 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
298 int remainder_of_page;
300 sg_init_table(sg, sg_size);
302 while (size > 0 && i < sg_size) {
303 pg = virt_to_page(addr);
304 offset = offset_in_page(addr);
306 sg_set_page(&sg[i], pg, 0, offset);
307 remainder_of_page = PAGE_CACHE_SIZE - offset;
308 if (size >= remainder_of_page) {
310 sg[i].length = remainder_of_page;
311 addr += remainder_of_page;
312 size -= remainder_of_page;
327 * encrypt_scatterlist
328 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
329 * @dest_sg: Destination of encrypted data
330 * @src_sg: Data to be encrypted
331 * @size: Length of data to be encrypted
332 * @iv: iv to use during encryption
334 * Returns the number of bytes encrypted; negative value on error
336 static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
337 struct scatterlist *dest_sg,
338 struct scatterlist *src_sg, int size,
341 struct blkcipher_desc desc = {
342 .tfm = crypt_stat->tfm,
344 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
348 BUG_ON(!crypt_stat || !crypt_stat->tfm
349 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
350 if (unlikely(ecryptfs_verbosity > 0)) {
351 ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n",
352 crypt_stat->key_size);
353 ecryptfs_dump_hex(crypt_stat->key,
354 crypt_stat->key_size);
356 /* Consider doing this once, when the file is opened */
357 mutex_lock(&crypt_stat->cs_tfm_mutex);
358 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
359 crypt_stat->key_size);
361 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
363 mutex_unlock(&crypt_stat->cs_tfm_mutex);
367 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
368 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
369 mutex_unlock(&crypt_stat->cs_tfm_mutex);
375 * ecryptfs_lower_offset_for_extent
377 * Convert an eCryptfs page index into a lower byte offset
379 static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
380 struct ecryptfs_crypt_stat *crypt_stat)
382 (*offset) = (crypt_stat->num_header_bytes_at_front
383 + (crypt_stat->extent_size * extent_num));
387 * ecryptfs_encrypt_extent
388 * @enc_extent_page: Allocated page into which to encrypt the data in
390 * @crypt_stat: crypt_stat containing cryptographic context for the
391 * encryption operation
392 * @page: Page containing plaintext data extent to encrypt
393 * @extent_offset: Page extent offset for use in generating IV
395 * Encrypts one extent of data.
397 * Return zero on success; non-zero otherwise
399 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
400 struct ecryptfs_crypt_stat *crypt_stat,
402 unsigned long extent_offset)
405 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
408 extent_base = (((loff_t)page->index)
409 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
410 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
411 (extent_base + extent_offset));
413 ecryptfs_printk(KERN_ERR, "Error attempting to "
414 "derive IV for extent [0x%.16x]; "
415 "rc = [%d]\n", (extent_base + extent_offset),
419 if (unlikely(ecryptfs_verbosity > 0)) {
420 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
422 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
423 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
425 ecryptfs_dump_hex((char *)
427 + (extent_offset * crypt_stat->extent_size)),
430 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
432 * crypt_stat->extent_size),
433 crypt_stat->extent_size, extent_iv);
435 printk(KERN_ERR "%s: Error attempting to encrypt page with "
436 "page->index = [%ld], extent_offset = [%ld]; "
437 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
442 if (unlikely(ecryptfs_verbosity > 0)) {
443 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
444 "rc = [%d]\n", (extent_base + extent_offset),
446 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
448 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
455 * ecryptfs_encrypt_page
456 * @page: Page mapped from the eCryptfs inode for the file; contains
457 * decrypted content that needs to be encrypted (to a temporary
458 * page; not in place) and written out to the lower file
460 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
461 * that eCryptfs pages may straddle the lower pages -- for instance,
462 * if the file was created on a machine with an 8K page size
463 * (resulting in an 8K header), and then the file is copied onto a
464 * host with a 32K page size, then when reading page 0 of the eCryptfs
465 * file, 24K of page 0 of the lower file will be read and decrypted,
466 * and then 8K of page 1 of the lower file will be read and decrypted.
468 * Returns zero on success; negative on error
470 int ecryptfs_encrypt_page(struct page *page)
472 struct inode *ecryptfs_inode;
473 struct ecryptfs_crypt_stat *crypt_stat;
474 char *enc_extent_virt = NULL;
475 struct page *enc_extent_page;
476 loff_t extent_offset;
479 ecryptfs_inode = page->mapping->host;
481 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
482 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
483 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
486 printk(KERN_ERR "%s: Error attempting to copy "
487 "page at index [%ld]\n", __FUNCTION__,
491 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
492 if (!enc_extent_virt) {
494 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
495 "encrypted extent\n");
498 enc_extent_page = virt_to_page(enc_extent_virt);
499 for (extent_offset = 0;
500 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
504 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
507 printk(KERN_ERR "%s: Error encrypting extent; "
508 "rc = [%d]\n", __FUNCTION__, rc);
511 ecryptfs_lower_offset_for_extent(
512 &offset, ((((loff_t)page->index)
514 / crypt_stat->extent_size))
515 + extent_offset), crypt_stat);
516 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
517 offset, crypt_stat->extent_size);
519 ecryptfs_printk(KERN_ERR, "Error attempting "
520 "to write lower page; rc = [%d]"
526 kfree(enc_extent_virt);
530 static int ecryptfs_decrypt_extent(struct page *page,
531 struct ecryptfs_crypt_stat *crypt_stat,
532 struct page *enc_extent_page,
533 unsigned long extent_offset)
536 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
539 extent_base = (((loff_t)page->index)
540 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
541 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
542 (extent_base + extent_offset));
544 ecryptfs_printk(KERN_ERR, "Error attempting to "
545 "derive IV for extent [0x%.16x]; "
546 "rc = [%d]\n", (extent_base + extent_offset),
550 if (unlikely(ecryptfs_verbosity > 0)) {
551 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
553 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
554 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
556 ecryptfs_dump_hex((char *)
557 (page_address(enc_extent_page)
558 + (extent_offset * crypt_stat->extent_size)),
561 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
563 * crypt_stat->extent_size),
565 crypt_stat->extent_size, extent_iv);
567 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
568 "page->index = [%ld], extent_offset = [%ld]; "
569 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
574 if (unlikely(ecryptfs_verbosity > 0)) {
575 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
576 "rc = [%d]\n", (extent_base + extent_offset),
578 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
580 ecryptfs_dump_hex((char *)(page_address(page)
582 * crypt_stat->extent_size)), 8);
589 * ecryptfs_decrypt_page
590 * @page: Page mapped from the eCryptfs inode for the file; data read
591 * and decrypted from the lower file will be written into this
594 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
595 * that eCryptfs pages may straddle the lower pages -- for instance,
596 * if the file was created on a machine with an 8K page size
597 * (resulting in an 8K header), and then the file is copied onto a
598 * host with a 32K page size, then when reading page 0 of the eCryptfs
599 * file, 24K of page 0 of the lower file will be read and decrypted,
600 * and then 8K of page 1 of the lower file will be read and decrypted.
602 * Returns zero on success; negative on error
604 int ecryptfs_decrypt_page(struct page *page)
606 struct inode *ecryptfs_inode;
607 struct ecryptfs_crypt_stat *crypt_stat;
608 char *enc_extent_virt = NULL;
609 struct page *enc_extent_page;
610 unsigned long extent_offset;
613 ecryptfs_inode = page->mapping->host;
615 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
616 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
617 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
621 printk(KERN_ERR "%s: Error attempting to copy "
622 "page at index [%ld]\n", __FUNCTION__,
626 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
627 if (!enc_extent_virt) {
629 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
630 "encrypted extent\n");
633 enc_extent_page = virt_to_page(enc_extent_virt);
634 for (extent_offset = 0;
635 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
639 ecryptfs_lower_offset_for_extent(
640 &offset, ((page->index * (PAGE_CACHE_SIZE
641 / crypt_stat->extent_size))
642 + extent_offset), crypt_stat);
643 rc = ecryptfs_read_lower(enc_extent_virt, offset,
644 crypt_stat->extent_size,
647 ecryptfs_printk(KERN_ERR, "Error attempting "
648 "to read lower page; rc = [%d]"
652 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
655 printk(KERN_ERR "%s: Error encrypting extent; "
656 "rc = [%d]\n", __FUNCTION__, rc);
661 kfree(enc_extent_virt);
666 * decrypt_scatterlist
667 * @crypt_stat: Cryptographic context
668 * @dest_sg: The destination scatterlist to decrypt into
669 * @src_sg: The source scatterlist to decrypt from
670 * @size: The number of bytes to decrypt
671 * @iv: The initialization vector to use for the decryption
673 * Returns the number of bytes decrypted; negative value on error
675 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
676 struct scatterlist *dest_sg,
677 struct scatterlist *src_sg, int size,
680 struct blkcipher_desc desc = {
681 .tfm = crypt_stat->tfm,
683 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
687 /* Consider doing this once, when the file is opened */
688 mutex_lock(&crypt_stat->cs_tfm_mutex);
689 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
690 crypt_stat->key_size);
692 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
694 mutex_unlock(&crypt_stat->cs_tfm_mutex);
698 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
699 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
700 mutex_unlock(&crypt_stat->cs_tfm_mutex);
702 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
712 * ecryptfs_encrypt_page_offset
713 * @crypt_stat: The cryptographic context
714 * @dst_page: The page to encrypt into
715 * @dst_offset: The offset in the page to encrypt into
716 * @src_page: The page to encrypt from
717 * @src_offset: The offset in the page to encrypt from
718 * @size: The number of bytes to encrypt
719 * @iv: The initialization vector to use for the encryption
721 * Returns the number of bytes encrypted
724 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
725 struct page *dst_page, int dst_offset,
726 struct page *src_page, int src_offset, int size,
729 struct scatterlist src_sg, dst_sg;
731 sg_init_table(&src_sg, 1);
732 sg_init_table(&dst_sg, 1);
734 sg_set_page(&src_sg, src_page, size, src_offset);
735 sg_set_page(&dst_sg, dst_page, size, dst_offset);
736 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
740 * ecryptfs_decrypt_page_offset
741 * @crypt_stat: The cryptographic context
742 * @dst_page: The page to decrypt into
743 * @dst_offset: The offset in the page to decrypt into
744 * @src_page: The page to decrypt from
745 * @src_offset: The offset in the page to decrypt from
746 * @size: The number of bytes to decrypt
747 * @iv: The initialization vector to use for the decryption
749 * Returns the number of bytes decrypted
752 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
753 struct page *dst_page, int dst_offset,
754 struct page *src_page, int src_offset, int size,
757 struct scatterlist src_sg, dst_sg;
759 sg_init_table(&src_sg, 1);
760 sg_set_page(&src_sg, src_page, size, src_offset);
762 sg_init_table(&dst_sg, 1);
763 sg_set_page(&dst_sg, dst_page, size, dst_offset);
765 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
768 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
771 * ecryptfs_init_crypt_ctx
772 * @crypt_stat: Uninitilized crypt stats structure
774 * Initialize the crypto context.
776 * TODO: Performance: Keep a cache of initialized cipher contexts;
777 * only init if needed
779 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
784 if (!crypt_stat->cipher) {
785 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
788 ecryptfs_printk(KERN_DEBUG,
789 "Initializing cipher [%s]; strlen = [%d]; "
790 "key_size_bits = [%d]\n",
791 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
792 crypt_stat->key_size << 3);
793 if (crypt_stat->tfm) {
797 mutex_lock(&crypt_stat->cs_tfm_mutex);
798 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
799 crypt_stat->cipher, "cbc");
802 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
804 kfree(full_alg_name);
805 if (IS_ERR(crypt_stat->tfm)) {
806 rc = PTR_ERR(crypt_stat->tfm);
807 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
808 "Error initializing cipher [%s]\n",
812 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
815 mutex_unlock(&crypt_stat->cs_tfm_mutex);
820 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
824 crypt_stat->extent_mask = 0xFFFFFFFF;
825 crypt_stat->extent_shift = 0;
826 if (crypt_stat->extent_size == 0)
828 extent_size_tmp = crypt_stat->extent_size;
829 while ((extent_size_tmp & 0x01) == 0) {
830 extent_size_tmp >>= 1;
831 crypt_stat->extent_mask <<= 1;
832 crypt_stat->extent_shift++;
836 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
838 /* Default values; may be overwritten as we are parsing the
840 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
841 set_extent_mask_and_shift(crypt_stat);
842 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
843 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
844 crypt_stat->num_header_bytes_at_front = 0;
846 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
847 crypt_stat->num_header_bytes_at_front =
848 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
850 crypt_stat->num_header_bytes_at_front = PAGE_CACHE_SIZE;
855 * ecryptfs_compute_root_iv
858 * On error, sets the root IV to all 0's.
860 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
863 char dst[MD5_DIGEST_SIZE];
865 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
866 BUG_ON(crypt_stat->iv_bytes <= 0);
867 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
869 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
870 "cannot generate root IV\n");
873 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
874 crypt_stat->key_size);
876 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
877 "MD5 while generating root IV\n");
880 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
883 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
884 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
889 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
891 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
892 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
893 ecryptfs_compute_root_iv(crypt_stat);
894 if (unlikely(ecryptfs_verbosity > 0)) {
895 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
896 ecryptfs_dump_hex(crypt_stat->key,
897 crypt_stat->key_size);
902 * ecryptfs_copy_mount_wide_flags_to_inode_flags
903 * @crypt_stat: The inode's cryptographic context
904 * @mount_crypt_stat: The mount point's cryptographic context
906 * This function propagates the mount-wide flags to individual inode
909 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
910 struct ecryptfs_crypt_stat *crypt_stat,
911 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
913 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
914 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
915 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
916 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
919 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
920 struct ecryptfs_crypt_stat *crypt_stat,
921 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
923 struct ecryptfs_global_auth_tok *global_auth_tok;
926 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
927 list_for_each_entry(global_auth_tok,
928 &mount_crypt_stat->global_auth_tok_list,
929 mount_crypt_stat_list) {
930 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
932 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
934 &mount_crypt_stat->global_auth_tok_list_mutex);
938 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
944 * ecryptfs_set_default_crypt_stat_vals
945 * @crypt_stat: The inode's cryptographic context
946 * @mount_crypt_stat: The mount point's cryptographic context
948 * Default values in the event that policy does not override them.
950 static void ecryptfs_set_default_crypt_stat_vals(
951 struct ecryptfs_crypt_stat *crypt_stat,
952 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
954 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
956 ecryptfs_set_default_sizes(crypt_stat);
957 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
958 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
959 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
960 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
961 crypt_stat->mount_crypt_stat = mount_crypt_stat;
965 * ecryptfs_new_file_context
966 * @ecryptfs_dentry: The eCryptfs dentry
968 * If the crypto context for the file has not yet been established,
969 * this is where we do that. Establishing a new crypto context
970 * involves the following decisions:
971 * - What cipher to use?
972 * - What set of authentication tokens to use?
973 * Here we just worry about getting enough information into the
974 * authentication tokens so that we know that they are available.
975 * We associate the available authentication tokens with the new file
976 * via the set of signatures in the crypt_stat struct. Later, when
977 * the headers are actually written out, we may again defer to
978 * userspace to perform the encryption of the session key; for the
979 * foreseeable future, this will be the case with public key packets.
981 * Returns zero on success; non-zero otherwise
983 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
985 struct ecryptfs_crypt_stat *crypt_stat =
986 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
987 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
988 &ecryptfs_superblock_to_private(
989 ecryptfs_dentry->d_sb)->mount_crypt_stat;
993 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
994 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
995 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
997 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1000 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1001 "to the inode key sigs; rc = [%d]\n", rc);
1005 strlen(mount_crypt_stat->global_default_cipher_name);
1006 memcpy(crypt_stat->cipher,
1007 mount_crypt_stat->global_default_cipher_name,
1009 crypt_stat->cipher[cipher_name_len] = '\0';
1010 crypt_stat->key_size =
1011 mount_crypt_stat->global_default_cipher_key_size;
1012 ecryptfs_generate_new_key(crypt_stat);
1013 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1015 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1016 "context for cipher [%s]: rc = [%d]\n",
1017 crypt_stat->cipher, rc);
1023 * contains_ecryptfs_marker - check for the ecryptfs marker
1024 * @data: The data block in which to check
1026 * Returns one if marker found; zero if not found
1028 static int contains_ecryptfs_marker(char *data)
1032 memcpy(&m_1, data, 4);
1033 m_1 = be32_to_cpu(m_1);
1034 memcpy(&m_2, (data + 4), 4);
1035 m_2 = be32_to_cpu(m_2);
1036 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1038 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1039 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1040 MAGIC_ECRYPTFS_MARKER);
1041 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1042 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1046 struct ecryptfs_flag_map_elem {
1051 /* Add support for additional flags by adding elements here. */
1052 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1053 {0x00000001, ECRYPTFS_ENABLE_HMAC},
1054 {0x00000002, ECRYPTFS_ENCRYPTED},
1055 {0x00000004, ECRYPTFS_METADATA_IN_XATTR}
1059 * ecryptfs_process_flags
1060 * @crypt_stat: The cryptographic context
1061 * @page_virt: Source data to be parsed
1062 * @bytes_read: Updated with the number of bytes read
1064 * Returns zero on success; non-zero if the flag set is invalid
1066 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1067 char *page_virt, int *bytes_read)
1073 memcpy(&flags, page_virt, 4);
1074 flags = be32_to_cpu(flags);
1075 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1076 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1077 if (flags & ecryptfs_flag_map[i].file_flag) {
1078 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1080 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1081 /* Version is in top 8 bits of the 32-bit flag vector */
1082 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1088 * write_ecryptfs_marker
1089 * @page_virt: The pointer to in a page to begin writing the marker
1090 * @written: Number of bytes written
1092 * Marker = 0x3c81b7f5
1094 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1098 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1099 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1100 m_1 = cpu_to_be32(m_1);
1101 memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1102 m_2 = cpu_to_be32(m_2);
1103 memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2,
1104 (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1105 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1109 write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1115 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1116 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1117 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1118 flags |= ecryptfs_flag_map[i].file_flag;
1119 /* Version is in top 8 bits of the 32-bit flag vector */
1120 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1121 flags = cpu_to_be32(flags);
1122 memcpy(page_virt, &flags, 4);
1126 struct ecryptfs_cipher_code_str_map_elem {
1127 char cipher_str[16];
1131 /* Add support for additional ciphers by adding elements here. The
1132 * cipher_code is whatever OpenPGP applicatoins use to identify the
1133 * ciphers. List in order of probability. */
1134 static struct ecryptfs_cipher_code_str_map_elem
1135 ecryptfs_cipher_code_str_map[] = {
1136 {"aes",RFC2440_CIPHER_AES_128 },
1137 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1138 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1139 {"cast5", RFC2440_CIPHER_CAST_5},
1140 {"twofish", RFC2440_CIPHER_TWOFISH},
1141 {"cast6", RFC2440_CIPHER_CAST_6},
1142 {"aes", RFC2440_CIPHER_AES_192},
1143 {"aes", RFC2440_CIPHER_AES_256}
1147 * ecryptfs_code_for_cipher_string
1148 * @crypt_stat: The cryptographic context
1150 * Returns zero on no match, or the cipher code on match
1152 u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat)
1156 struct ecryptfs_cipher_code_str_map_elem *map =
1157 ecryptfs_cipher_code_str_map;
1159 if (strcmp(crypt_stat->cipher, "aes") == 0) {
1160 switch (crypt_stat->key_size) {
1162 code = RFC2440_CIPHER_AES_128;
1165 code = RFC2440_CIPHER_AES_192;
1168 code = RFC2440_CIPHER_AES_256;
1171 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1172 if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){
1173 code = map[i].cipher_code;
1181 * ecryptfs_cipher_code_to_string
1182 * @str: Destination to write out the cipher name
1183 * @cipher_code: The code to convert to cipher name string
1185 * Returns zero on success
1187 int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
1193 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1194 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1195 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1196 if (str[0] == '\0') {
1197 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1198 "[%d]\n", cipher_code);
1204 int ecryptfs_read_and_validate_header_region(char *data,
1205 struct inode *ecryptfs_inode)
1207 struct ecryptfs_crypt_stat *crypt_stat =
1208 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
1211 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1214 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
1218 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
1220 ecryptfs_printk(KERN_DEBUG, "Valid marker not found\n");
1227 ecryptfs_write_header_metadata(char *virt,
1228 struct ecryptfs_crypt_stat *crypt_stat,
1231 u32 header_extent_size;
1232 u16 num_header_extents_at_front;
1234 header_extent_size = (u32)crypt_stat->extent_size;
1235 num_header_extents_at_front =
1236 (u16)(crypt_stat->num_header_bytes_at_front
1237 / crypt_stat->extent_size);
1238 header_extent_size = cpu_to_be32(header_extent_size);
1239 memcpy(virt, &header_extent_size, 4);
1241 num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front);
1242 memcpy(virt, &num_header_extents_at_front, 2);
1246 struct kmem_cache *ecryptfs_header_cache_0;
1247 struct kmem_cache *ecryptfs_header_cache_1;
1248 struct kmem_cache *ecryptfs_header_cache_2;
1251 * ecryptfs_write_headers_virt
1252 * @page_virt: The virtual address to write the headers to
1253 * @size: Set to the number of bytes written by this function
1254 * @crypt_stat: The cryptographic context
1255 * @ecryptfs_dentry: The eCryptfs dentry
1260 * Octets 0-7: Unencrypted file size (big-endian)
1261 * Octets 8-15: eCryptfs special marker
1262 * Octets 16-19: Flags
1263 * Octet 16: File format version number (between 0 and 255)
1264 * Octets 17-18: Reserved
1265 * Octet 19: Bit 1 (lsb): Reserved
1267 * Bits 3-8: Reserved
1268 * Octets 20-23: Header extent size (big-endian)
1269 * Octets 24-25: Number of header extents at front of file
1271 * Octet 26: Begin RFC 2440 authentication token packet set
1273 * Lower data (CBC encrypted)
1275 * Lower data (CBC encrypted)
1278 * Returns zero on success
1280 static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
1281 struct ecryptfs_crypt_stat *crypt_stat,
1282 struct dentry *ecryptfs_dentry)
1288 offset = ECRYPTFS_FILE_SIZE_BYTES;
1289 write_ecryptfs_marker((page_virt + offset), &written);
1291 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1293 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1296 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1297 ecryptfs_dentry, &written,
1298 PAGE_CACHE_SIZE - offset);
1300 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1301 "set; rc = [%d]\n", rc);
1310 ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
1311 struct dentry *ecryptfs_dentry,
1316 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
1317 0, crypt_stat->num_header_bytes_at_front);
1319 printk(KERN_ERR "%s: Error attempting to write header "
1320 "information to lower file; rc = [%d]\n", __FUNCTION__,
1326 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1327 struct ecryptfs_crypt_stat *crypt_stat,
1328 char *page_virt, size_t size)
1332 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1338 * ecryptfs_write_metadata
1339 * @ecryptfs_dentry: The eCryptfs dentry
1341 * Write the file headers out. This will likely involve a userspace
1342 * callout, in which the session key is encrypted with one or more
1343 * public keys and/or the passphrase necessary to do the encryption is
1344 * retrieved via a prompt. Exactly what happens at this point should
1345 * be policy-dependent.
1347 * Returns zero on success; non-zero on error
1349 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
1351 struct ecryptfs_crypt_stat *crypt_stat =
1352 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1357 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1358 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1359 printk(KERN_ERR "Key is invalid; bailing out\n");
1364 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1369 /* Released in this function */
1370 virt = kzalloc(crypt_stat->num_header_bytes_at_front, GFP_KERNEL);
1372 printk(KERN_ERR "%s: Out of memory\n", __FUNCTION__);
1376 rc = ecryptfs_write_headers_virt(virt, &size, crypt_stat,
1379 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1383 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1384 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
1385 crypt_stat, virt, size);
1387 rc = ecryptfs_write_metadata_to_contents(crypt_stat,
1388 ecryptfs_dentry, virt);
1390 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1391 "rc = [%d]\n", __FUNCTION__, rc);
1395 memset(virt, 0, crypt_stat->num_header_bytes_at_front);
1401 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1402 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1403 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1404 char *virt, int *bytes_read,
1405 int validate_header_size)
1408 u32 header_extent_size;
1409 u16 num_header_extents_at_front;
1411 memcpy(&header_extent_size, virt, sizeof(u32));
1412 header_extent_size = be32_to_cpu(header_extent_size);
1413 virt += sizeof(u32);
1414 memcpy(&num_header_extents_at_front, virt, sizeof(u16));
1415 num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
1416 crypt_stat->num_header_bytes_at_front =
1417 (((size_t)num_header_extents_at_front
1418 * (size_t)header_extent_size));
1419 (*bytes_read) = (sizeof(u32) + sizeof(u16));
1420 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1421 && (crypt_stat->num_header_bytes_at_front
1422 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1424 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1425 crypt_stat->num_header_bytes_at_front);
1431 * set_default_header_data
1432 * @crypt_stat: The cryptographic context
1434 * For version 0 file format; this function is only for backwards
1435 * compatibility for files created with the prior versions of
1438 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1440 crypt_stat->num_header_bytes_at_front =
1441 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1445 * ecryptfs_read_headers_virt
1446 * @page_virt: The virtual address into which to read the headers
1447 * @crypt_stat: The cryptographic context
1448 * @ecryptfs_dentry: The eCryptfs dentry
1449 * @validate_header_size: Whether to validate the header size while reading
1451 * Read/parse the header data. The header format is detailed in the
1452 * comment block for the ecryptfs_write_headers_virt() function.
1454 * Returns zero on success
1456 static int ecryptfs_read_headers_virt(char *page_virt,
1457 struct ecryptfs_crypt_stat *crypt_stat,
1458 struct dentry *ecryptfs_dentry,
1459 int validate_header_size)
1465 ecryptfs_set_default_sizes(crypt_stat);
1466 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1467 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1468 offset = ECRYPTFS_FILE_SIZE_BYTES;
1469 rc = contains_ecryptfs_marker(page_virt + offset);
1474 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1475 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1478 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1481 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1482 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1483 "file version [%d] is supported by this "
1484 "version of eCryptfs\n",
1485 crypt_stat->file_version,
1486 ECRYPTFS_SUPPORTED_FILE_VERSION);
1490 offset += bytes_read;
1491 if (crypt_stat->file_version >= 1) {
1492 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1493 &bytes_read, validate_header_size);
1495 ecryptfs_printk(KERN_WARNING, "Error reading header "
1496 "metadata; rc = [%d]\n", rc);
1498 offset += bytes_read;
1500 set_default_header_data(crypt_stat);
1501 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1508 * ecryptfs_read_xattr_region
1509 * @page_virt: The vitual address into which to read the xattr data
1510 * @ecryptfs_inode: The eCryptfs inode
1512 * Attempts to read the crypto metadata from the extended attribute
1513 * region of the lower file.
1515 * Returns zero on success; non-zero on error
1517 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1519 struct dentry *lower_dentry =
1520 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1524 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1525 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1527 printk(KERN_ERR "Error attempting to read the [%s] "
1528 "xattr from the lower file; return value = [%zd]\n",
1529 ECRYPTFS_XATTR_NAME, size);
1537 int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1538 struct dentry *ecryptfs_dentry)
1542 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
1545 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1546 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1547 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1555 * ecryptfs_read_metadata
1557 * Common entry point for reading file metadata. From here, we could
1558 * retrieve the header information from the header region of the file,
1559 * the xattr region of the file, or some other repostory that is
1560 * stored separately from the file itself. The current implementation
1561 * supports retrieving the metadata information from the file contents
1562 * and from the xattr region.
1564 * Returns zero if valid headers found and parsed; non-zero otherwise
1566 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1569 char *page_virt = NULL;
1570 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1571 struct ecryptfs_crypt_stat *crypt_stat =
1572 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1573 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1574 &ecryptfs_superblock_to_private(
1575 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1577 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1579 /* Read the first page from the underlying file */
1580 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
1583 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1587 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1590 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1592 ECRYPTFS_VALIDATE_HEADER_SIZE);
1594 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1596 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1597 "file header region or xattr region\n");
1601 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1603 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1605 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1606 "file xattr region either\n");
1609 if (crypt_stat->mount_crypt_stat->flags
1610 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1611 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1613 printk(KERN_WARNING "Attempt to access file with "
1614 "crypto metadata only in the extended attribute "
1615 "region, but eCryptfs was mounted without "
1616 "xattr support enabled. eCryptfs will not treat "
1617 "this like an encrypted file.\n");
1623 memset(page_virt, 0, PAGE_CACHE_SIZE);
1624 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1630 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1631 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1632 * @name: The plaintext name
1633 * @length: The length of the plaintext
1634 * @encoded_name: The encypted name
1636 * Encrypts and encodes a filename into something that constitutes a
1637 * valid filename for a filesystem, with printable characters.
1639 * We assume that we have a properly initialized crypto context,
1640 * pointed to by crypt_stat->tfm.
1642 * TODO: Implement filename decoding and decryption here, in place of
1643 * memcpy. We are keeping the framework around for now to (1)
1644 * facilitate testing of the components needed to implement filename
1645 * encryption and (2) to provide a code base from which other
1646 * developers in the community can easily implement this feature.
1648 * Returns the length of encoded filename; negative if error
1651 ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1652 const char *name, int length, char **encoded_name)
1656 (*encoded_name) = kmalloc(length + 2, GFP_KERNEL);
1657 if (!(*encoded_name)) {
1661 /* TODO: Filename encryption is a scheduled feature for a
1662 * future version of eCryptfs. This function is here only for
1663 * the purpose of providing a framework for other developers
1664 * to easily implement filename encryption. Hint: Replace this
1665 * memcpy() with a call to encrypt and encode the
1666 * filename, the set the length accordingly. */
1667 memcpy((void *)(*encoded_name), (void *)name, length);
1668 (*encoded_name)[length] = '\0';
1675 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1676 * @crypt_stat: The crypt_stat struct associated with the file
1677 * @name: The filename in cipher text
1678 * @length: The length of the cipher text name
1679 * @decrypted_name: The plaintext name
1681 * Decodes and decrypts the filename.
1683 * We assume that we have a properly initialized crypto context,
1684 * pointed to by crypt_stat->tfm.
1686 * TODO: Implement filename decoding and decryption here, in place of
1687 * memcpy. We are keeping the framework around for now to (1)
1688 * facilitate testing of the components needed to implement filename
1689 * encryption and (2) to provide a code base from which other
1690 * developers in the community can easily implement this feature.
1692 * Returns the length of decoded filename; negative if error
1695 ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1696 const char *name, int length, char **decrypted_name)
1700 (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL);
1701 if (!(*decrypted_name)) {
1705 /* TODO: Filename encryption is a scheduled feature for a
1706 * future version of eCryptfs. This function is here only for
1707 * the purpose of providing a framework for other developers
1708 * to easily implement filename encryption. Hint: Replace this
1709 * memcpy() with a call to decode and decrypt the
1710 * filename, the set the length accordingly. */
1711 memcpy((void *)(*decrypted_name), (void *)name, length);
1712 (*decrypted_name)[length + 1] = '\0'; /* Only for convenience
1713 * in printing out the
1722 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1723 * @key_tfm: Crypto context for key material, set by this function
1724 * @cipher_name: Name of the cipher
1725 * @key_size: Size of the key in bytes
1727 * Returns zero on success. Any crypto_tfm structs allocated here
1728 * should be released by other functions, such as on a superblock put
1729 * event, regardless of whether this function succeeds for fails.
1732 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1733 char *cipher_name, size_t *key_size)
1735 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1736 char *full_alg_name;
1740 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1742 printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum "
1743 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1746 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1750 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1751 kfree(full_alg_name);
1752 if (IS_ERR(*key_tfm)) {
1753 rc = PTR_ERR(*key_tfm);
1754 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1755 "[%s]; rc = [%d]\n", cipher_name, rc);
1758 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1759 if (*key_size == 0) {
1760 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1762 *key_size = alg->max_keysize;
1764 get_random_bytes(dummy_key, *key_size);
1765 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1767 printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
1768 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
1776 struct kmem_cache *ecryptfs_key_tfm_cache;
1777 static struct list_head key_tfm_list;
1778 static struct mutex key_tfm_list_mutex;
1780 int ecryptfs_init_crypto(void)
1782 mutex_init(&key_tfm_list_mutex);
1783 INIT_LIST_HEAD(&key_tfm_list);
1787 int ecryptfs_destroy_crypto(void)
1789 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1791 mutex_lock(&key_tfm_list_mutex);
1792 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1794 list_del(&key_tfm->key_tfm_list);
1795 if (key_tfm->key_tfm)
1796 crypto_free_blkcipher(key_tfm->key_tfm);
1797 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1799 mutex_unlock(&key_tfm_list_mutex);
1804 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1807 struct ecryptfs_key_tfm *tmp_tfm;
1810 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1811 if (key_tfm != NULL)
1812 (*key_tfm) = tmp_tfm;
1815 printk(KERN_ERR "Error attempting to allocate from "
1816 "ecryptfs_key_tfm_cache\n");
1819 mutex_init(&tmp_tfm->key_tfm_mutex);
1820 strncpy(tmp_tfm->cipher_name, cipher_name,
1821 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1822 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1823 tmp_tfm->key_size = key_size;
1824 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1825 tmp_tfm->cipher_name,
1826 &tmp_tfm->key_size);
1828 printk(KERN_ERR "Error attempting to initialize key TFM "
1829 "cipher with name = [%s]; rc = [%d]\n",
1830 tmp_tfm->cipher_name, rc);
1831 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1832 if (key_tfm != NULL)
1836 mutex_lock(&key_tfm_list_mutex);
1837 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1838 mutex_unlock(&key_tfm_list_mutex);
1843 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1844 struct mutex **tfm_mutex,
1847 struct ecryptfs_key_tfm *key_tfm;
1851 (*tfm_mutex) = NULL;
1852 mutex_lock(&key_tfm_list_mutex);
1853 list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) {
1854 if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
1855 (*tfm) = key_tfm->key_tfm;
1856 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1857 mutex_unlock(&key_tfm_list_mutex);
1861 mutex_unlock(&key_tfm_list_mutex);
1862 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1864 printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
1868 (*tfm) = key_tfm->key_tfm;
1869 (*tfm_mutex) = &key_tfm->key_tfm_mutex;