2 * eCryptfs: Linux filesystem encryption layer
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2007 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
27 #include <linux/mount.h>
28 #include <linux/pagemap.h>
29 #include <linux/random.h>
30 #include <linux/compiler.h>
31 #include <linux/key.h>
32 #include <linux/namei.h>
33 #include <linux/crypto.h>
34 #include <linux/file.h>
35 #include <linux/scatterlist.h>
36 #include "ecryptfs_kernel.h"
39 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
40 struct page *dst_page, int dst_offset,
41 struct page *src_page, int src_offset, int size,
44 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
45 struct page *dst_page, int dst_offset,
46 struct page *src_page, int src_offset, int size,
51 * @dst: Buffer to take hex character representation of contents of
52 * src; must be at least of size (src_size * 2)
53 * @src: Buffer to be converted to a hex string respresentation
54 * @src_size: number of bytes to convert
56 void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
60 for (x = 0; x < src_size; x++)
61 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
66 * @dst: Buffer to take the bytes from src hex; must be at least of
68 * @src: Buffer to be converted from a hex string respresentation to raw value
69 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
71 void ecryptfs_from_hex(char *dst, char *src, int dst_size)
76 for (x = 0; x < dst_size; x++) {
78 tmp[1] = src[x * 2 + 1];
79 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
84 * ecryptfs_calculate_md5 - calculates the md5 of @src
85 * @dst: Pointer to 16 bytes of allocated memory
86 * @crypt_stat: Pointer to crypt_stat struct for the current inode
87 * @src: Data to be md5'd
88 * @len: Length of @src
90 * Uses the allocated crypto context that crypt_stat references to
91 * generate the MD5 sum of the contents of src.
93 static int ecryptfs_calculate_md5(char *dst,
94 struct ecryptfs_crypt_stat *crypt_stat,
97 struct scatterlist sg;
98 struct hash_desc desc = {
99 .tfm = crypt_stat->hash_tfm,
100 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
104 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
105 sg_init_one(&sg, (u8 *)src, len);
107 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
109 if (IS_ERR(desc.tfm)) {
110 rc = PTR_ERR(desc.tfm);
111 ecryptfs_printk(KERN_ERR, "Error attempting to "
112 "allocate crypto context; rc = [%d]\n",
116 crypt_stat->hash_tfm = desc.tfm;
118 crypto_hash_init(&desc);
119 crypto_hash_update(&desc, &sg, len);
120 crypto_hash_final(&desc, dst);
121 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
126 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
128 char *chaining_modifier)
130 int cipher_name_len = strlen(cipher_name);
131 int chaining_modifier_len = strlen(chaining_modifier);
132 int algified_name_len;
135 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
136 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
137 if (!(*algified_name)) {
141 snprintf((*algified_name), algified_name_len, "%s(%s)",
142 chaining_modifier, cipher_name);
150 * @iv: destination for the derived iv vale
151 * @crypt_stat: Pointer to crypt_stat struct for the current inode
152 * @offset: Offset of the extent whose IV we are to derive
154 * Generate the initialization vector from the given root IV and page
157 * Returns zero on success; non-zero on error.
159 static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
163 char dst[MD5_DIGEST_SIZE];
164 char src[ECRYPTFS_MAX_IV_BYTES + 16];
166 if (unlikely(ecryptfs_verbosity > 0)) {
167 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
168 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
170 /* TODO: It is probably secure to just cast the least
171 * significant bits of the root IV into an unsigned long and
172 * add the offset to that rather than go through all this
173 * hashing business. -Halcrow */
174 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
175 memset((src + crypt_stat->iv_bytes), 0, 16);
176 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
177 if (unlikely(ecryptfs_verbosity > 0)) {
178 ecryptfs_printk(KERN_DEBUG, "source:\n");
179 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
181 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
182 (crypt_stat->iv_bytes + 16));
184 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
185 "MD5 while generating IV for a page\n");
188 memcpy(iv, dst, crypt_stat->iv_bytes);
189 if (unlikely(ecryptfs_verbosity > 0)) {
190 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
191 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
198 * ecryptfs_init_crypt_stat
199 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
201 * Initialize the crypt_stat structure.
204 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
206 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
207 INIT_LIST_HEAD(&crypt_stat->keysig_list);
208 mutex_init(&crypt_stat->keysig_list_mutex);
209 mutex_init(&crypt_stat->cs_mutex);
210 mutex_init(&crypt_stat->cs_tfm_mutex);
211 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
212 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
216 * ecryptfs_destroy_crypt_stat
217 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
219 * Releases all memory associated with a crypt_stat struct.
221 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
223 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
226 crypto_free_blkcipher(crypt_stat->tfm);
227 if (crypt_stat->hash_tfm)
228 crypto_free_hash(crypt_stat->hash_tfm);
229 mutex_lock(&crypt_stat->keysig_list_mutex);
230 list_for_each_entry_safe(key_sig, key_sig_tmp,
231 &crypt_stat->keysig_list, crypt_stat_list) {
232 list_del(&key_sig->crypt_stat_list);
233 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
235 mutex_unlock(&crypt_stat->keysig_list_mutex);
236 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
239 void ecryptfs_destroy_mount_crypt_stat(
240 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
242 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
244 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
246 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
247 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
248 &mount_crypt_stat->global_auth_tok_list,
249 mount_crypt_stat_list) {
250 list_del(&auth_tok->mount_crypt_stat_list);
251 mount_crypt_stat->num_global_auth_toks--;
252 if (auth_tok->global_auth_tok_key
253 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
254 key_put(auth_tok->global_auth_tok_key);
255 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
257 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
258 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
262 * virt_to_scatterlist
263 * @addr: Virtual address
264 * @size: Size of data; should be an even multiple of the block size
265 * @sg: Pointer to scatterlist array; set to NULL to obtain only
266 * the number of scatterlist structs required in array
267 * @sg_size: Max array size
269 * Fills in a scatterlist array with page references for a passed
272 * Returns the number of scatterlist structs in array used
274 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
280 int remainder_of_page;
282 while (size > 0 && i < sg_size) {
283 pg = virt_to_page(addr);
284 offset = offset_in_page(addr);
287 sg[i].offset = offset;
289 remainder_of_page = PAGE_CACHE_SIZE - offset;
290 if (size >= remainder_of_page) {
292 sg[i].length = remainder_of_page;
293 addr += remainder_of_page;
294 size -= remainder_of_page;
309 * encrypt_scatterlist
310 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
311 * @dest_sg: Destination of encrypted data
312 * @src_sg: Data to be encrypted
313 * @size: Length of data to be encrypted
314 * @iv: iv to use during encryption
316 * Returns the number of bytes encrypted; negative value on error
318 static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
319 struct scatterlist *dest_sg,
320 struct scatterlist *src_sg, int size,
323 struct blkcipher_desc desc = {
324 .tfm = crypt_stat->tfm,
326 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
330 BUG_ON(!crypt_stat || !crypt_stat->tfm
331 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
332 if (unlikely(ecryptfs_verbosity > 0)) {
333 ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n",
334 crypt_stat->key_size);
335 ecryptfs_dump_hex(crypt_stat->key,
336 crypt_stat->key_size);
338 /* Consider doing this once, when the file is opened */
339 mutex_lock(&crypt_stat->cs_tfm_mutex);
340 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
341 crypt_stat->key_size);
343 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
345 mutex_unlock(&crypt_stat->cs_tfm_mutex);
349 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
350 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
351 mutex_unlock(&crypt_stat->cs_tfm_mutex);
357 ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx,
359 struct ecryptfs_crypt_stat *crypt_stat,
360 unsigned long extent_num)
362 unsigned long lower_extent_num;
363 int extents_occupied_by_headers_at_front;
364 int bytes_occupied_by_headers_at_front;
366 int extents_per_page;
368 bytes_occupied_by_headers_at_front =
369 (crypt_stat->extent_size
370 * crypt_stat->num_header_extents_at_front);
371 extents_occupied_by_headers_at_front =
372 ( bytes_occupied_by_headers_at_front
373 / crypt_stat->extent_size );
374 lower_extent_num = extents_occupied_by_headers_at_front + extent_num;
375 extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size;
376 (*lower_page_idx) = lower_extent_num / extents_per_page;
377 extent_offset = lower_extent_num % extents_per_page;
378 (*byte_offset) = extent_offset * crypt_stat->extent_size;
379 ecryptfs_printk(KERN_DEBUG, " * crypt_stat->extent_size = "
380 "[%d]\n", crypt_stat->extent_size);
381 ecryptfs_printk(KERN_DEBUG, " * crypt_stat->"
382 "num_header_extents_at_front = [%d]\n",
383 crypt_stat->num_header_extents_at_front);
384 ecryptfs_printk(KERN_DEBUG, " * extents_occupied_by_headers_at_"
385 "front = [%d]\n", extents_occupied_by_headers_at_front);
386 ecryptfs_printk(KERN_DEBUG, " * lower_extent_num = [0x%.16x]\n",
388 ecryptfs_printk(KERN_DEBUG, " * extents_per_page = [%d]\n",
390 ecryptfs_printk(KERN_DEBUG, " * (*lower_page_idx) = [0x%.16x]\n",
392 ecryptfs_printk(KERN_DEBUG, " * extent_offset = [%d]\n",
394 ecryptfs_printk(KERN_DEBUG, " * (*byte_offset) = [%d]\n",
398 static int ecryptfs_write_out_page(struct ecryptfs_page_crypt_context *ctx,
399 struct page *lower_page,
400 struct inode *lower_inode,
401 int byte_offset_in_page, int bytes_to_write)
405 if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) {
406 rc = ecryptfs_commit_lower_page(lower_page, lower_inode,
407 ctx->param.lower_file,
411 ecryptfs_printk(KERN_ERR, "Error calling lower "
412 "commit; rc = [%d]\n", rc);
416 rc = ecryptfs_writepage_and_release_lower_page(lower_page,
420 ecryptfs_printk(KERN_ERR, "Error calling lower "
421 "writepage(); rc = [%d]\n", rc);
429 static int ecryptfs_read_in_page(struct ecryptfs_page_crypt_context *ctx,
430 struct page **lower_page,
431 struct inode *lower_inode,
432 unsigned long lower_page_idx,
433 int byte_offset_in_page)
437 if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) {
438 /* TODO: Limit this to only the data extents that are
440 rc = ecryptfs_get_lower_page(lower_page, lower_inode,
441 ctx->param.lower_file,
445 - byte_offset_in_page));
448 KERN_ERR, "Error attempting to grab, map, "
449 "and prepare_write lower page with index "
450 "[0x%.16x]; rc = [%d]\n", lower_page_idx, rc);
454 *lower_page = grab_cache_page(lower_inode->i_mapping,
456 if (!(*lower_page)) {
459 KERN_ERR, "Error attempting to grab and map "
460 "lower page with index [0x%.16x]; rc = [%d]\n",
470 * ecryptfs_lower_offset_for_extent
472 * Convert an eCryptfs page index into a lower byte offset
474 void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
475 struct ecryptfs_crypt_stat *crypt_stat)
477 (*offset) = ((crypt_stat->extent_size
478 * crypt_stat->num_header_extents_at_front)
479 + (crypt_stat->extent_size * extent_num));
483 * ecryptfs_encrypt_extent
484 * @enc_extent_page: Allocated page into which to encrypt the data in
486 * @crypt_stat: crypt_stat containing cryptographic context for the
487 * encryption operation
488 * @page: Page containing plaintext data extent to encrypt
489 * @extent_offset: Page extent offset for use in generating IV
491 * Encrypts one extent of data.
493 * Return zero on success; non-zero otherwise
495 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
496 struct ecryptfs_crypt_stat *crypt_stat,
498 unsigned long extent_offset)
501 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
504 extent_base = (((loff_t)page->index)
505 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
506 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
507 (extent_base + extent_offset));
509 ecryptfs_printk(KERN_ERR, "Error attempting to "
510 "derive IV for extent [0x%.16x]; "
511 "rc = [%d]\n", (extent_base + extent_offset),
515 if (unlikely(ecryptfs_verbosity > 0)) {
516 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
518 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
519 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
521 ecryptfs_dump_hex((char *)
523 + (extent_offset * crypt_stat->extent_size)),
526 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
528 * crypt_stat->extent_size),
529 crypt_stat->extent_size, extent_iv);
531 printk(KERN_ERR "%s: Error attempting to encrypt page with "
532 "page->index = [%ld], extent_offset = [%ld]; "
533 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
538 if (unlikely(ecryptfs_verbosity > 0)) {
539 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
540 "rc = [%d]\n", (extent_base + extent_offset),
542 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
544 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
551 * ecryptfs_encrypt_page
552 * @page: Page mapped from the eCryptfs inode for the file; contains
553 * decrypted content that needs to be encrypted (to a temporary
554 * page; not in place) and written out to the lower file
556 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
557 * that eCryptfs pages may straddle the lower pages -- for instance,
558 * if the file was created on a machine with an 8K page size
559 * (resulting in an 8K header), and then the file is copied onto a
560 * host with a 32K page size, then when reading page 0 of the eCryptfs
561 * file, 24K of page 0 of the lower file will be read and decrypted,
562 * and then 8K of page 1 of the lower file will be read and decrypted.
564 * Returns zero on success; negative on error
566 int ecryptfs_encrypt_page(struct page *page)
568 struct inode *ecryptfs_inode;
569 struct ecryptfs_crypt_stat *crypt_stat;
570 char *enc_extent_virt = NULL;
571 struct page *enc_extent_page;
572 loff_t extent_offset;
575 ecryptfs_inode = page->mapping->host;
577 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
578 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
579 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
582 printk(KERN_ERR "%s: Error attempting to copy "
583 "page at index [%ld]\n", __FUNCTION__,
587 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
588 if (!enc_extent_virt) {
590 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
591 "encrypted extent\n");
594 enc_extent_page = virt_to_page(enc_extent_virt);
595 for (extent_offset = 0;
596 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
600 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
603 printk(KERN_ERR "%s: Error encrypting extent; "
604 "rc = [%d]\n", __FUNCTION__, rc);
607 ecryptfs_lower_offset_for_extent(
608 &offset, ((((loff_t)page->index)
610 / crypt_stat->extent_size))
611 + extent_offset), crypt_stat);
612 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
613 offset, crypt_stat->extent_size);
615 ecryptfs_printk(KERN_ERR, "Error attempting "
616 "to write lower page; rc = [%d]"
623 kfree(enc_extent_virt);
627 static int ecryptfs_decrypt_extent(struct page *page,
628 struct ecryptfs_crypt_stat *crypt_stat,
629 struct page *enc_extent_page,
630 unsigned long extent_offset)
633 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
636 extent_base = (((loff_t)page->index)
637 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
638 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
639 (extent_base + extent_offset));
641 ecryptfs_printk(KERN_ERR, "Error attempting to "
642 "derive IV for extent [0x%.16x]; "
643 "rc = [%d]\n", (extent_base + extent_offset),
647 if (unlikely(ecryptfs_verbosity > 0)) {
648 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
650 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
651 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
653 ecryptfs_dump_hex((char *)
654 (page_address(enc_extent_page)
655 + (extent_offset * crypt_stat->extent_size)),
658 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
660 * crypt_stat->extent_size),
662 crypt_stat->extent_size, extent_iv);
664 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
665 "page->index = [%ld], extent_offset = [%ld]; "
666 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
671 if (unlikely(ecryptfs_verbosity > 0)) {
672 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
673 "rc = [%d]\n", (extent_base + extent_offset),
675 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
677 ecryptfs_dump_hex((char *)(page_address(page)
679 * crypt_stat->extent_size)), 8);
686 * ecryptfs_decrypt_page
687 * @page: Page mapped from the eCryptfs inode for the file; data read
688 * and decrypted from the lower file will be written into this
691 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
692 * that eCryptfs pages may straddle the lower pages -- for instance,
693 * if the file was created on a machine with an 8K page size
694 * (resulting in an 8K header), and then the file is copied onto a
695 * host with a 32K page size, then when reading page 0 of the eCryptfs
696 * file, 24K of page 0 of the lower file will be read and decrypted,
697 * and then 8K of page 1 of the lower file will be read and decrypted.
699 * Returns zero on success; negative on error
701 int ecryptfs_decrypt_page(struct page *page)
703 struct inode *ecryptfs_inode;
704 struct ecryptfs_crypt_stat *crypt_stat;
705 char *enc_extent_virt = NULL;
706 struct page *enc_extent_page;
707 unsigned long extent_offset;
710 ecryptfs_inode = page->mapping->host;
712 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
713 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
714 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
718 printk(KERN_ERR "%s: Error attempting to copy "
719 "page at index [%ld]\n", __FUNCTION__,
721 goto out_clear_uptodate;
723 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
724 if (!enc_extent_virt) {
726 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
727 "encrypted extent\n");
728 goto out_clear_uptodate;
730 enc_extent_page = virt_to_page(enc_extent_virt);
731 for (extent_offset = 0;
732 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
736 ecryptfs_lower_offset_for_extent(
737 &offset, ((page->index * (PAGE_CACHE_SIZE
738 / crypt_stat->extent_size))
739 + extent_offset), crypt_stat);
740 rc = ecryptfs_read_lower(enc_extent_virt, offset,
741 crypt_stat->extent_size,
744 ecryptfs_printk(KERN_ERR, "Error attempting "
745 "to read lower page; rc = [%d]"
747 goto out_clear_uptodate;
749 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
752 printk(KERN_ERR "%s: Error encrypting extent; "
753 "rc = [%d]\n", __FUNCTION__, rc);
754 goto out_clear_uptodate;
758 SetPageUptodate(page);
761 ClearPageUptodate(page);
763 kfree(enc_extent_virt);
768 * decrypt_scatterlist
769 * @crypt_stat: Cryptographic context
770 * @dest_sg: The destination scatterlist to decrypt into
771 * @src_sg: The source scatterlist to decrypt from
772 * @size: The number of bytes to decrypt
773 * @iv: The initialization vector to use for the decryption
775 * Returns the number of bytes decrypted; negative value on error
777 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
778 struct scatterlist *dest_sg,
779 struct scatterlist *src_sg, int size,
782 struct blkcipher_desc desc = {
783 .tfm = crypt_stat->tfm,
785 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
789 /* Consider doing this once, when the file is opened */
790 mutex_lock(&crypt_stat->cs_tfm_mutex);
791 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
792 crypt_stat->key_size);
794 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
796 mutex_unlock(&crypt_stat->cs_tfm_mutex);
800 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
801 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
802 mutex_unlock(&crypt_stat->cs_tfm_mutex);
804 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
814 * ecryptfs_encrypt_page_offset
815 * @crypt_stat: The cryptographic context
816 * @dst_page: The page to encrypt into
817 * @dst_offset: The offset in the page to encrypt into
818 * @src_page: The page to encrypt from
819 * @src_offset: The offset in the page to encrypt from
820 * @size: The number of bytes to encrypt
821 * @iv: The initialization vector to use for the encryption
823 * Returns the number of bytes encrypted
826 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
827 struct page *dst_page, int dst_offset,
828 struct page *src_page, int src_offset, int size,
831 struct scatterlist src_sg, dst_sg;
833 src_sg.page = src_page;
834 src_sg.offset = src_offset;
835 src_sg.length = size;
836 dst_sg.page = dst_page;
837 dst_sg.offset = dst_offset;
838 dst_sg.length = size;
839 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
843 * ecryptfs_decrypt_page_offset
844 * @crypt_stat: The cryptographic context
845 * @dst_page: The page to decrypt into
846 * @dst_offset: The offset in the page to decrypt into
847 * @src_page: The page to decrypt from
848 * @src_offset: The offset in the page to decrypt from
849 * @size: The number of bytes to decrypt
850 * @iv: The initialization vector to use for the decryption
852 * Returns the number of bytes decrypted
855 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
856 struct page *dst_page, int dst_offset,
857 struct page *src_page, int src_offset, int size,
860 struct scatterlist src_sg, dst_sg;
862 src_sg.page = src_page;
863 src_sg.offset = src_offset;
864 src_sg.length = size;
865 dst_sg.page = dst_page;
866 dst_sg.offset = dst_offset;
867 dst_sg.length = size;
868 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
871 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
874 * ecryptfs_init_crypt_ctx
875 * @crypt_stat: Uninitilized crypt stats structure
877 * Initialize the crypto context.
879 * TODO: Performance: Keep a cache of initialized cipher contexts;
880 * only init if needed
882 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
887 if (!crypt_stat->cipher) {
888 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
891 ecryptfs_printk(KERN_DEBUG,
892 "Initializing cipher [%s]; strlen = [%d]; "
893 "key_size_bits = [%d]\n",
894 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
895 crypt_stat->key_size << 3);
896 if (crypt_stat->tfm) {
900 mutex_lock(&crypt_stat->cs_tfm_mutex);
901 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
902 crypt_stat->cipher, "cbc");
905 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
907 kfree(full_alg_name);
908 if (IS_ERR(crypt_stat->tfm)) {
909 rc = PTR_ERR(crypt_stat->tfm);
910 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
911 "Error initializing cipher [%s]\n",
913 mutex_unlock(&crypt_stat->cs_tfm_mutex);
916 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
917 mutex_unlock(&crypt_stat->cs_tfm_mutex);
923 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
927 crypt_stat->extent_mask = 0xFFFFFFFF;
928 crypt_stat->extent_shift = 0;
929 if (crypt_stat->extent_size == 0)
931 extent_size_tmp = crypt_stat->extent_size;
932 while ((extent_size_tmp & 0x01) == 0) {
933 extent_size_tmp >>= 1;
934 crypt_stat->extent_mask <<= 1;
935 crypt_stat->extent_shift++;
939 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
941 /* Default values; may be overwritten as we are parsing the
943 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
944 set_extent_mask_and_shift(crypt_stat);
945 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
946 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
947 crypt_stat->num_header_extents_at_front = 0;
949 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
950 crypt_stat->num_header_extents_at_front =
951 (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
952 / crypt_stat->extent_size);
954 crypt_stat->num_header_extents_at_front =
955 (PAGE_CACHE_SIZE / crypt_stat->extent_size);
960 * ecryptfs_compute_root_iv
963 * On error, sets the root IV to all 0's.
965 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
968 char dst[MD5_DIGEST_SIZE];
970 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
971 BUG_ON(crypt_stat->iv_bytes <= 0);
972 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
974 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
975 "cannot generate root IV\n");
978 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
979 crypt_stat->key_size);
981 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
982 "MD5 while generating root IV\n");
985 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
988 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
989 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
994 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
996 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
997 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
998 ecryptfs_compute_root_iv(crypt_stat);
999 if (unlikely(ecryptfs_verbosity > 0)) {
1000 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
1001 ecryptfs_dump_hex(crypt_stat->key,
1002 crypt_stat->key_size);
1007 * ecryptfs_copy_mount_wide_flags_to_inode_flags
1008 * @crypt_stat: The inode's cryptographic context
1009 * @mount_crypt_stat: The mount point's cryptographic context
1011 * This function propagates the mount-wide flags to individual inode
1014 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
1015 struct ecryptfs_crypt_stat *crypt_stat,
1016 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1018 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
1019 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1020 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
1021 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
1024 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
1025 struct ecryptfs_crypt_stat *crypt_stat,
1026 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1028 struct ecryptfs_global_auth_tok *global_auth_tok;
1031 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
1032 list_for_each_entry(global_auth_tok,
1033 &mount_crypt_stat->global_auth_tok_list,
1034 mount_crypt_stat_list) {
1035 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
1037 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
1039 &mount_crypt_stat->global_auth_tok_list_mutex);
1043 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
1049 * ecryptfs_set_default_crypt_stat_vals
1050 * @crypt_stat: The inode's cryptographic context
1051 * @mount_crypt_stat: The mount point's cryptographic context
1053 * Default values in the event that policy does not override them.
1055 static void ecryptfs_set_default_crypt_stat_vals(
1056 struct ecryptfs_crypt_stat *crypt_stat,
1057 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1059 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1061 ecryptfs_set_default_sizes(crypt_stat);
1062 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
1063 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
1064 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
1065 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
1066 crypt_stat->mount_crypt_stat = mount_crypt_stat;
1070 * ecryptfs_new_file_context
1071 * @ecryptfs_dentry: The eCryptfs dentry
1073 * If the crypto context for the file has not yet been established,
1074 * this is where we do that. Establishing a new crypto context
1075 * involves the following decisions:
1076 * - What cipher to use?
1077 * - What set of authentication tokens to use?
1078 * Here we just worry about getting enough information into the
1079 * authentication tokens so that we know that they are available.
1080 * We associate the available authentication tokens with the new file
1081 * via the set of signatures in the crypt_stat struct. Later, when
1082 * the headers are actually written out, we may again defer to
1083 * userspace to perform the encryption of the session key; for the
1084 * foreseeable future, this will be the case with public key packets.
1086 * Returns zero on success; non-zero otherwise
1088 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
1090 struct ecryptfs_crypt_stat *crypt_stat =
1091 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1092 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1093 &ecryptfs_superblock_to_private(
1094 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1095 int cipher_name_len;
1098 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
1099 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
1100 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1102 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1105 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1106 "to the inode key sigs; rc = [%d]\n", rc);
1110 strlen(mount_crypt_stat->global_default_cipher_name);
1111 memcpy(crypt_stat->cipher,
1112 mount_crypt_stat->global_default_cipher_name,
1114 crypt_stat->cipher[cipher_name_len] = '\0';
1115 crypt_stat->key_size =
1116 mount_crypt_stat->global_default_cipher_key_size;
1117 ecryptfs_generate_new_key(crypt_stat);
1118 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1120 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1121 "context for cipher [%s]: rc = [%d]\n",
1122 crypt_stat->cipher, rc);
1128 * contains_ecryptfs_marker - check for the ecryptfs marker
1129 * @data: The data block in which to check
1131 * Returns one if marker found; zero if not found
1133 static int contains_ecryptfs_marker(char *data)
1137 memcpy(&m_1, data, 4);
1138 m_1 = be32_to_cpu(m_1);
1139 memcpy(&m_2, (data + 4), 4);
1140 m_2 = be32_to_cpu(m_2);
1141 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1143 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1144 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1145 MAGIC_ECRYPTFS_MARKER);
1146 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1147 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1151 struct ecryptfs_flag_map_elem {
1156 /* Add support for additional flags by adding elements here. */
1157 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1158 {0x00000001, ECRYPTFS_ENABLE_HMAC},
1159 {0x00000002, ECRYPTFS_ENCRYPTED},
1160 {0x00000004, ECRYPTFS_METADATA_IN_XATTR}
1164 * ecryptfs_process_flags
1165 * @crypt_stat: The cryptographic context
1166 * @page_virt: Source data to be parsed
1167 * @bytes_read: Updated with the number of bytes read
1169 * Returns zero on success; non-zero if the flag set is invalid
1171 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1172 char *page_virt, int *bytes_read)
1178 memcpy(&flags, page_virt, 4);
1179 flags = be32_to_cpu(flags);
1180 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1181 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1182 if (flags & ecryptfs_flag_map[i].file_flag) {
1183 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1185 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1186 /* Version is in top 8 bits of the 32-bit flag vector */
1187 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1193 * write_ecryptfs_marker
1194 * @page_virt: The pointer to in a page to begin writing the marker
1195 * @written: Number of bytes written
1197 * Marker = 0x3c81b7f5
1199 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1203 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1204 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1205 m_1 = cpu_to_be32(m_1);
1206 memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1207 m_2 = cpu_to_be32(m_2);
1208 memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2,
1209 (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1210 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1214 write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1220 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1221 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1222 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1223 flags |= ecryptfs_flag_map[i].file_flag;
1224 /* Version is in top 8 bits of the 32-bit flag vector */
1225 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1226 flags = cpu_to_be32(flags);
1227 memcpy(page_virt, &flags, 4);
1231 struct ecryptfs_cipher_code_str_map_elem {
1232 char cipher_str[16];
1236 /* Add support for additional ciphers by adding elements here. The
1237 * cipher_code is whatever OpenPGP applicatoins use to identify the
1238 * ciphers. List in order of probability. */
1239 static struct ecryptfs_cipher_code_str_map_elem
1240 ecryptfs_cipher_code_str_map[] = {
1241 {"aes",RFC2440_CIPHER_AES_128 },
1242 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1243 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1244 {"cast5", RFC2440_CIPHER_CAST_5},
1245 {"twofish", RFC2440_CIPHER_TWOFISH},
1246 {"cast6", RFC2440_CIPHER_CAST_6},
1247 {"aes", RFC2440_CIPHER_AES_192},
1248 {"aes", RFC2440_CIPHER_AES_256}
1252 * ecryptfs_code_for_cipher_string
1253 * @crypt_stat: The cryptographic context
1255 * Returns zero on no match, or the cipher code on match
1257 u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat)
1261 struct ecryptfs_cipher_code_str_map_elem *map =
1262 ecryptfs_cipher_code_str_map;
1264 if (strcmp(crypt_stat->cipher, "aes") == 0) {
1265 switch (crypt_stat->key_size) {
1267 code = RFC2440_CIPHER_AES_128;
1270 code = RFC2440_CIPHER_AES_192;
1273 code = RFC2440_CIPHER_AES_256;
1276 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1277 if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){
1278 code = map[i].cipher_code;
1286 * ecryptfs_cipher_code_to_string
1287 * @str: Destination to write out the cipher name
1288 * @cipher_code: The code to convert to cipher name string
1290 * Returns zero on success
1292 int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
1298 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1299 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1300 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1301 if (str[0] == '\0') {
1302 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1303 "[%d]\n", cipher_code);
1310 * ecryptfs_read_header_region
1311 * @data: The virtual address to write header region data into
1312 * @dentry: The lower dentry
1313 * @mnt: The lower VFS mount
1315 * Returns zero on success; non-zero otherwise
1317 static int ecryptfs_read_header_region(char *data, struct dentry *dentry,
1318 struct vfsmount *mnt)
1320 struct file *lower_file;
1324 rc = ecryptfs_open_lower_file(&lower_file, dentry, mnt, O_RDONLY);
1327 "Error opening lower_file to read header region\n");
1330 lower_file->f_pos = 0;
1333 rc = lower_file->f_op->read(lower_file, (char __user *)data,
1334 ECRYPTFS_DEFAULT_EXTENT_SIZE, &lower_file->f_pos);
1336 rc = ecryptfs_close_lower_file(lower_file);
1338 printk(KERN_ERR "Error closing lower_file\n");
1346 int ecryptfs_read_and_validate_header_region(char *data,
1347 struct inode *ecryptfs_inode)
1349 struct ecryptfs_crypt_stat *crypt_stat =
1350 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
1353 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1356 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
1360 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
1362 ecryptfs_printk(KERN_DEBUG, "Valid marker not found\n");
1369 ecryptfs_write_header_metadata(char *virt,
1370 struct ecryptfs_crypt_stat *crypt_stat,
1373 u32 header_extent_size;
1374 u16 num_header_extents_at_front;
1376 header_extent_size = (u32)crypt_stat->extent_size;
1377 num_header_extents_at_front =
1378 (u16)crypt_stat->num_header_extents_at_front;
1379 header_extent_size = cpu_to_be32(header_extent_size);
1380 memcpy(virt, &header_extent_size, 4);
1382 num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front);
1383 memcpy(virt, &num_header_extents_at_front, 2);
1387 struct kmem_cache *ecryptfs_header_cache_0;
1388 struct kmem_cache *ecryptfs_header_cache_1;
1389 struct kmem_cache *ecryptfs_header_cache_2;
1392 * ecryptfs_write_headers_virt
1393 * @page_virt: The virtual address to write the headers to
1394 * @size: Set to the number of bytes written by this function
1395 * @crypt_stat: The cryptographic context
1396 * @ecryptfs_dentry: The eCryptfs dentry
1401 * Octets 0-7: Unencrypted file size (big-endian)
1402 * Octets 8-15: eCryptfs special marker
1403 * Octets 16-19: Flags
1404 * Octet 16: File format version number (between 0 and 255)
1405 * Octets 17-18: Reserved
1406 * Octet 19: Bit 1 (lsb): Reserved
1408 * Bits 3-8: Reserved
1409 * Octets 20-23: Header extent size (big-endian)
1410 * Octets 24-25: Number of header extents at front of file
1412 * Octet 26: Begin RFC 2440 authentication token packet set
1414 * Lower data (CBC encrypted)
1416 * Lower data (CBC encrypted)
1419 * Returns zero on success
1421 static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
1422 struct ecryptfs_crypt_stat *crypt_stat,
1423 struct dentry *ecryptfs_dentry)
1429 offset = ECRYPTFS_FILE_SIZE_BYTES;
1430 write_ecryptfs_marker((page_virt + offset), &written);
1432 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1434 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1437 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1438 ecryptfs_dentry, &written,
1439 PAGE_CACHE_SIZE - offset);
1441 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1442 "set; rc = [%d]\n", rc);
1451 ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
1452 struct dentry *ecryptfs_dentry,
1455 int current_header_page;
1459 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, page_virt,
1460 0, PAGE_CACHE_SIZE);
1462 printk(KERN_ERR "%s: Error attempting to write header "
1463 "information to lower file; rc = [%d]\n", __FUNCTION__,
1467 header_pages = ((crypt_stat->extent_size
1468 * crypt_stat->num_header_extents_at_front)
1470 memset(page_virt, 0, PAGE_CACHE_SIZE);
1471 current_header_page = 1;
1472 while (current_header_page < header_pages) {
1475 offset = (((loff_t)current_header_page) << PAGE_CACHE_SHIFT);
1476 if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode,
1478 PAGE_CACHE_SIZE))) {
1479 printk(KERN_ERR "%s: Error attempting to write header "
1480 "information to lower file; rc = [%d]\n",
1484 current_header_page++;
1491 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1492 struct ecryptfs_crypt_stat *crypt_stat,
1493 char *page_virt, size_t size)
1497 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1503 * ecryptfs_write_metadata
1504 * @ecryptfs_dentry: The eCryptfs dentry
1506 * Write the file headers out. This will likely involve a userspace
1507 * callout, in which the session key is encrypted with one or more
1508 * public keys and/or the passphrase necessary to do the encryption is
1509 * retrieved via a prompt. Exactly what happens at this point should
1510 * be policy-dependent.
1512 * TODO: Support header information spanning multiple pages
1514 * Returns zero on success; non-zero on error
1516 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
1518 struct ecryptfs_crypt_stat *crypt_stat =
1519 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1524 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1525 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1526 printk(KERN_ERR "Key is invalid; bailing out\n");
1532 ecryptfs_printk(KERN_WARNING,
1533 "Called with crypt_stat->encrypted == 0\n");
1536 /* Released in this function */
1537 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER);
1539 ecryptfs_printk(KERN_ERR, "Out of memory\n");
1543 rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat,
1546 ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n");
1547 memset(page_virt, 0, PAGE_CACHE_SIZE);
1550 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1551 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
1552 crypt_stat, page_virt,
1555 rc = ecryptfs_write_metadata_to_contents(crypt_stat,
1559 printk(KERN_ERR "Error writing metadata out to lower file; "
1564 kmem_cache_free(ecryptfs_header_cache_0, page_virt);
1569 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1570 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1571 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1572 char *virt, int *bytes_read,
1573 int validate_header_size)
1576 u32 header_extent_size;
1577 u16 num_header_extents_at_front;
1579 memcpy(&header_extent_size, virt, 4);
1580 header_extent_size = be32_to_cpu(header_extent_size);
1582 memcpy(&num_header_extents_at_front, virt, 2);
1583 num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
1584 crypt_stat->num_header_extents_at_front =
1585 (int)num_header_extents_at_front;
1586 (*bytes_read) = (sizeof(u32) + sizeof(u16));
1587 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1588 && ((crypt_stat->extent_size
1589 * crypt_stat->num_header_extents_at_front)
1590 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1592 printk(KERN_WARNING "Invalid number of header extents: [%zd]\n",
1593 crypt_stat->num_header_extents_at_front);
1599 * set_default_header_data
1600 * @crypt_stat: The cryptographic context
1602 * For version 0 file format; this function is only for backwards
1603 * compatibility for files created with the prior versions of
1606 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1608 crypt_stat->num_header_extents_at_front = 2;
1612 * ecryptfs_read_headers_virt
1613 * @page_virt: The virtual address into which to read the headers
1614 * @crypt_stat: The cryptographic context
1615 * @ecryptfs_dentry: The eCryptfs dentry
1616 * @validate_header_size: Whether to validate the header size while reading
1618 * Read/parse the header data. The header format is detailed in the
1619 * comment block for the ecryptfs_write_headers_virt() function.
1621 * Returns zero on success
1623 static int ecryptfs_read_headers_virt(char *page_virt,
1624 struct ecryptfs_crypt_stat *crypt_stat,
1625 struct dentry *ecryptfs_dentry,
1626 int validate_header_size)
1632 ecryptfs_set_default_sizes(crypt_stat);
1633 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1634 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1635 offset = ECRYPTFS_FILE_SIZE_BYTES;
1636 rc = contains_ecryptfs_marker(page_virt + offset);
1641 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1642 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1645 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1648 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1649 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1650 "file version [%d] is supported by this "
1651 "version of eCryptfs\n",
1652 crypt_stat->file_version,
1653 ECRYPTFS_SUPPORTED_FILE_VERSION);
1657 offset += bytes_read;
1658 if (crypt_stat->file_version >= 1) {
1659 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1660 &bytes_read, validate_header_size);
1662 ecryptfs_printk(KERN_WARNING, "Error reading header "
1663 "metadata; rc = [%d]\n", rc);
1665 offset += bytes_read;
1667 set_default_header_data(crypt_stat);
1668 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1675 * ecryptfs_read_xattr_region
1676 * @page_virt: The vitual address into which to read the xattr data
1677 * @ecryptfs_inode: The eCryptfs inode
1679 * Attempts to read the crypto metadata from the extended attribute
1680 * region of the lower file.
1682 * Returns zero on success; non-zero on error
1684 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1686 struct dentry *lower_dentry =
1687 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1691 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1692 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1694 printk(KERN_ERR "Error attempting to read the [%s] "
1695 "xattr from the lower file; return value = [%zd]\n",
1696 ECRYPTFS_XATTR_NAME, size);
1704 int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1705 struct dentry *ecryptfs_dentry)
1709 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
1712 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1713 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1714 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1722 * ecryptfs_read_metadata
1724 * Common entry point for reading file metadata. From here, we could
1725 * retrieve the header information from the header region of the file,
1726 * the xattr region of the file, or some other repostory that is
1727 * stored separately from the file itself. The current implementation
1728 * supports retrieving the metadata information from the file contents
1729 * and from the xattr region.
1731 * Returns zero if valid headers found and parsed; non-zero otherwise
1733 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1736 char *page_virt = NULL;
1737 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1738 struct ecryptfs_crypt_stat *crypt_stat =
1739 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1740 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1741 &ecryptfs_superblock_to_private(
1742 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1744 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1746 /* Read the first page from the underlying file */
1747 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
1750 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1754 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1757 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1759 ECRYPTFS_VALIDATE_HEADER_SIZE);
1761 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1763 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1764 "file header region or xattr region\n");
1768 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1770 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1772 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1773 "file xattr region either\n");
1776 if (crypt_stat->mount_crypt_stat->flags
1777 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1778 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1780 printk(KERN_WARNING "Attempt to access file with "
1781 "crypto metadata only in the extended attribute "
1782 "region, but eCryptfs was mounted without "
1783 "xattr support enabled. eCryptfs will not treat "
1784 "this like an encrypted file.\n");
1790 memset(page_virt, 0, PAGE_CACHE_SIZE);
1791 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1797 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1798 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1799 * @name: The plaintext name
1800 * @length: The length of the plaintext
1801 * @encoded_name: The encypted name
1803 * Encrypts and encodes a filename into something that constitutes a
1804 * valid filename for a filesystem, with printable characters.
1806 * We assume that we have a properly initialized crypto context,
1807 * pointed to by crypt_stat->tfm.
1809 * TODO: Implement filename decoding and decryption here, in place of
1810 * memcpy. We are keeping the framework around for now to (1)
1811 * facilitate testing of the components needed to implement filename
1812 * encryption and (2) to provide a code base from which other
1813 * developers in the community can easily implement this feature.
1815 * Returns the length of encoded filename; negative if error
1818 ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1819 const char *name, int length, char **encoded_name)
1823 (*encoded_name) = kmalloc(length + 2, GFP_KERNEL);
1824 if (!(*encoded_name)) {
1828 /* TODO: Filename encryption is a scheduled feature for a
1829 * future version of eCryptfs. This function is here only for
1830 * the purpose of providing a framework for other developers
1831 * to easily implement filename encryption. Hint: Replace this
1832 * memcpy() with a call to encrypt and encode the
1833 * filename, the set the length accordingly. */
1834 memcpy((void *)(*encoded_name), (void *)name, length);
1835 (*encoded_name)[length] = '\0';
1842 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1843 * @crypt_stat: The crypt_stat struct associated with the file
1844 * @name: The filename in cipher text
1845 * @length: The length of the cipher text name
1846 * @decrypted_name: The plaintext name
1848 * Decodes and decrypts the filename.
1850 * We assume that we have a properly initialized crypto context,
1851 * pointed to by crypt_stat->tfm.
1853 * TODO: Implement filename decoding and decryption here, in place of
1854 * memcpy. We are keeping the framework around for now to (1)
1855 * facilitate testing of the components needed to implement filename
1856 * encryption and (2) to provide a code base from which other
1857 * developers in the community can easily implement this feature.
1859 * Returns the length of decoded filename; negative if error
1862 ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1863 const char *name, int length, char **decrypted_name)
1867 (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL);
1868 if (!(*decrypted_name)) {
1872 /* TODO: Filename encryption is a scheduled feature for a
1873 * future version of eCryptfs. This function is here only for
1874 * the purpose of providing a framework for other developers
1875 * to easily implement filename encryption. Hint: Replace this
1876 * memcpy() with a call to decode and decrypt the
1877 * filename, the set the length accordingly. */
1878 memcpy((void *)(*decrypted_name), (void *)name, length);
1879 (*decrypted_name)[length + 1] = '\0'; /* Only for convenience
1880 * in printing out the
1889 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1890 * @key_tfm: Crypto context for key material, set by this function
1891 * @cipher_name: Name of the cipher
1892 * @key_size: Size of the key in bytes
1894 * Returns zero on success. Any crypto_tfm structs allocated here
1895 * should be released by other functions, such as on a superblock put
1896 * event, regardless of whether this function succeeds for fails.
1899 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1900 char *cipher_name, size_t *key_size)
1902 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1903 char *full_alg_name;
1907 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1909 printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum "
1910 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1913 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1917 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1918 kfree(full_alg_name);
1919 if (IS_ERR(*key_tfm)) {
1920 rc = PTR_ERR(*key_tfm);
1921 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1922 "[%s]; rc = [%d]\n", cipher_name, rc);
1925 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1926 if (*key_size == 0) {
1927 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1929 *key_size = alg->max_keysize;
1931 get_random_bytes(dummy_key, *key_size);
1932 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1934 printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
1935 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
1943 struct kmem_cache *ecryptfs_key_tfm_cache;
1944 struct list_head key_tfm_list;
1945 struct mutex key_tfm_list_mutex;
1947 int ecryptfs_init_crypto(void)
1949 mutex_init(&key_tfm_list_mutex);
1950 INIT_LIST_HEAD(&key_tfm_list);
1954 int ecryptfs_destroy_crypto(void)
1956 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1958 mutex_lock(&key_tfm_list_mutex);
1959 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1961 list_del(&key_tfm->key_tfm_list);
1962 if (key_tfm->key_tfm)
1963 crypto_free_blkcipher(key_tfm->key_tfm);
1964 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1966 mutex_unlock(&key_tfm_list_mutex);
1971 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1974 struct ecryptfs_key_tfm *tmp_tfm;
1977 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1978 if (key_tfm != NULL)
1979 (*key_tfm) = tmp_tfm;
1982 printk(KERN_ERR "Error attempting to allocate from "
1983 "ecryptfs_key_tfm_cache\n");
1986 mutex_init(&tmp_tfm->key_tfm_mutex);
1987 strncpy(tmp_tfm->cipher_name, cipher_name,
1988 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1989 tmp_tfm->key_size = key_size;
1990 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1991 tmp_tfm->cipher_name,
1992 &tmp_tfm->key_size);
1994 printk(KERN_ERR "Error attempting to initialize key TFM "
1995 "cipher with name = [%s]; rc = [%d]\n",
1996 tmp_tfm->cipher_name, rc);
1997 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1998 if (key_tfm != NULL)
2002 mutex_lock(&key_tfm_list_mutex);
2003 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
2004 mutex_unlock(&key_tfm_list_mutex);
2009 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
2010 struct mutex **tfm_mutex,
2013 struct ecryptfs_key_tfm *key_tfm;
2017 (*tfm_mutex) = NULL;
2018 mutex_lock(&key_tfm_list_mutex);
2019 list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) {
2020 if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
2021 (*tfm) = key_tfm->key_tfm;
2022 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
2023 mutex_unlock(&key_tfm_list_mutex);
2027 mutex_unlock(&key_tfm_list_mutex);
2028 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
2030 printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
2034 (*tfm) = key_tfm->key_tfm;
2035 (*tfm_mutex) = &key_tfm->key_tfm_mutex;