blob: 8e9b36df78818f8ea9bfa456cb906490e302bdf2 [file] [log] [blame]
Michael Halcrow237fead2006-10-04 02:16:22 -07001/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08006 * Copyright (C) 2004-2007 International Business Machines Corp.
Michael Halcrow237fead2006-10-04 02:16:22 -07007 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
9 *
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.
14 *
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.
19 *
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
23 * 02111-1307, USA.
24 */
25
26#include <linux/fs.h>
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"
37
38static int
39ecryptfs_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,
42 unsigned char *iv);
43static int
44ecryptfs_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,
47 unsigned char *iv);
48
49/**
50 * ecryptfs_to_hex
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
55 */
56void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
57{
58 int x;
59
60 for (x = 0; x < src_size; x++)
61 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
62}
63
64/**
65 * ecryptfs_from_hex
66 * @dst: Buffer to take the bytes from src hex; must be at least of
67 * size (src_size / 2)
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
70 */
71void ecryptfs_from_hex(char *dst, char *src, int dst_size)
72{
73 int x;
74 char tmp[3] = { 0, };
75
76 for (x = 0; x < dst_size; x++) {
77 tmp[0] = src[x * 2];
78 tmp[1] = src[x * 2 + 1];
79 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
80 }
81}
82
83/**
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
89 *
90 * Uses the allocated crypto context that crypt_stat references to
91 * generate the MD5 sum of the contents of src.
92 */
93static int ecryptfs_calculate_md5(char *dst,
94 struct ecryptfs_crypt_stat *crypt_stat,
95 char *src, int len)
96{
Michael Halcrow237fead2006-10-04 02:16:22 -070097 struct scatterlist sg;
Michael Halcrow565d9722006-10-30 22:07:17 -080098 struct hash_desc desc = {
99 .tfm = crypt_stat->hash_tfm,
100 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
101 };
102 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700103
Michael Halcrow565d9722006-10-30 22:07:17 -0800104 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700105 sg_init_one(&sg, (u8 *)src, len);
Michael Halcrow565d9722006-10-30 22:07:17 -0800106 if (!desc.tfm) {
107 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
108 CRYPTO_ALG_ASYNC);
109 if (IS_ERR(desc.tfm)) {
110 rc = PTR_ERR(desc.tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700111 ecryptfs_printk(KERN_ERR, "Error attempting to "
Michael Halcrow565d9722006-10-30 22:07:17 -0800112 "allocate crypto context; rc = [%d]\n",
113 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700114 goto out;
115 }
Michael Halcrow565d9722006-10-30 22:07:17 -0800116 crypt_stat->hash_tfm = desc.tfm;
Michael Halcrow237fead2006-10-04 02:16:22 -0700117 }
Michael Halcrow565d9722006-10-30 22:07:17 -0800118 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);
Michael Halcrow237fead2006-10-04 02:16:22 -0700122out:
123 return rc;
124}
125
Michael Halcrowcd9d67d2007-10-16 01:28:04 -0700126static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
127 char *cipher_name,
128 char *chaining_modifier)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800129{
130 int cipher_name_len = strlen(cipher_name);
131 int chaining_modifier_len = strlen(chaining_modifier);
132 int algified_name_len;
133 int rc;
134
135 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
136 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
Michael Halcrow7bd473f2006-11-02 22:06:56 -0800137 if (!(*algified_name)) {
Michael Halcrow8bba0662006-10-30 22:07:18 -0800138 rc = -ENOMEM;
139 goto out;
140 }
141 snprintf((*algified_name), algified_name_len, "%s(%s)",
142 chaining_modifier, cipher_name);
143 rc = 0;
144out:
145 return rc;
146}
147
Michael Halcrow237fead2006-10-04 02:16:22 -0700148/**
149 * ecryptfs_derive_iv
150 * @iv: destination for the derived iv vale
151 * @crypt_stat: Pointer to crypt_stat struct for the current inode
152 * @offset: Offset of the page whose's iv we are to derive
153 *
154 * Generate the initialization vector from the given root IV and page
155 * offset.
156 *
157 * Returns zero on success; non-zero on error.
158 */
159static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
160 pgoff_t offset)
161{
162 int rc = 0;
163 char dst[MD5_DIGEST_SIZE];
164 char src[ECRYPTFS_MAX_IV_BYTES + 16];
165
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);
169 }
170 /* TODO: It is probably secure to just cast the least
171 * significant bits of the root IV into an unsigned long and
172 * add the offset to that rather than go through all this
173 * hashing business. -Halcrow */
174 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
175 memset((src + crypt_stat->iv_bytes), 0, 16);
176 snprintf((src + crypt_stat->iv_bytes), 16, "%ld", offset);
177 if (unlikely(ecryptfs_verbosity > 0)) {
178 ecryptfs_printk(KERN_DEBUG, "source:\n");
179 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
180 }
181 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
182 (crypt_stat->iv_bytes + 16));
183 if (rc) {
184 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
185 "MD5 while generating IV for a page\n");
186 goto out;
187 }
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);
192 }
193out:
194 return rc;
195}
196
197/**
198 * ecryptfs_init_crypt_stat
199 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
200 *
201 * Initialize the crypt_stat structure.
202 */
203void
204ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
205{
206 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
Michael Halcrowf4aad162007-10-16 01:27:53 -0700207 INIT_LIST_HEAD(&crypt_stat->keysig_list);
208 mutex_init(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700209 mutex_init(&crypt_stat->cs_mutex);
210 mutex_init(&crypt_stat->cs_tfm_mutex);
Michael Halcrow565d9722006-10-30 22:07:17 -0800211 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800212 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
Michael Halcrow237fead2006-10-04 02:16:22 -0700213}
214
215/**
Michael Halcrowfcd12832007-10-16 01:28:01 -0700216 * ecryptfs_destroy_crypt_stat
Michael Halcrow237fead2006-10-04 02:16:22 -0700217 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
218 *
219 * Releases all memory associated with a crypt_stat struct.
220 */
Michael Halcrowfcd12832007-10-16 01:28:01 -0700221void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -0700222{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700223 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
224
Michael Halcrow237fead2006-10-04 02:16:22 -0700225 if (crypt_stat->tfm)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800226 crypto_free_blkcipher(crypt_stat->tfm);
Michael Halcrow565d9722006-10-30 22:07:17 -0800227 if (crypt_stat->hash_tfm)
228 crypto_free_hash(crypt_stat->hash_tfm);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700229 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);
234 }
235 mutex_unlock(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700236 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
237}
238
Michael Halcrowfcd12832007-10-16 01:28:01 -0700239void ecryptfs_destroy_mount_crypt_stat(
Michael Halcrow237fead2006-10-04 02:16:22 -0700240 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
241{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700242 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
243
244 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
245 return;
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);
256 }
257 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700258 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
259}
260
261/**
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
268 *
269 * Fills in a scatterlist array with page references for a passed
270 * virtual address.
271 *
272 * Returns the number of scatterlist structs in array used
273 */
274int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
275 int sg_size)
276{
277 int i = 0;
278 struct page *pg;
279 int offset;
280 int remainder_of_page;
281
282 while (size > 0 && i < sg_size) {
283 pg = virt_to_page(addr);
284 offset = offset_in_page(addr);
285 if (sg) {
286 sg[i].page = pg;
287 sg[i].offset = offset;
288 }
289 remainder_of_page = PAGE_CACHE_SIZE - offset;
290 if (size >= remainder_of_page) {
291 if (sg)
292 sg[i].length = remainder_of_page;
293 addr += remainder_of_page;
294 size -= remainder_of_page;
295 } else {
296 if (sg)
297 sg[i].length = size;
298 addr += size;
299 size = 0;
300 }
301 i++;
302 }
303 if (size > 0)
304 return -ENOMEM;
305 return i;
306}
307
308/**
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
315 *
316 * Returns the number of bytes encrypted; negative value on error
317 */
318static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
319 struct scatterlist *dest_sg,
320 struct scatterlist *src_sg, int size,
321 unsigned char *iv)
322{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800323 struct blkcipher_desc desc = {
324 .tfm = crypt_stat->tfm,
325 .info = iv,
326 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
327 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700328 int rc = 0;
329
330 BUG_ON(!crypt_stat || !crypt_stat->tfm
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800331 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
Michael Halcrow237fead2006-10-04 02:16:22 -0700332 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);
337 }
338 /* Consider doing this once, when the file is opened */
339 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800340 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
341 crypt_stat->key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700342 if (rc) {
343 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
344 rc);
345 mutex_unlock(&crypt_stat->cs_tfm_mutex);
346 rc = -EINVAL;
347 goto out;
348 }
349 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800350 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700351 mutex_unlock(&crypt_stat->cs_tfm_mutex);
352out:
353 return rc;
354}
355
356static void
357ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx,
358 int *byte_offset,
359 struct ecryptfs_crypt_stat *crypt_stat,
360 unsigned long extent_num)
361{
362 unsigned long lower_extent_num;
363 int extents_occupied_by_headers_at_front;
364 int bytes_occupied_by_headers_at_front;
365 int extent_offset;
366 int extents_per_page;
367
368 bytes_occupied_by_headers_at_front =
369 ( crypt_stat->header_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->header_extent_size = "
380 "[%d]\n", crypt_stat->header_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",
387 lower_extent_num);
388 ecryptfs_printk(KERN_DEBUG, " * extents_per_page = [%d]\n",
389 extents_per_page);
390 ecryptfs_printk(KERN_DEBUG, " * (*lower_page_idx) = [0x%.16x]\n",
391 (*lower_page_idx));
392 ecryptfs_printk(KERN_DEBUG, " * extent_offset = [%d]\n",
393 extent_offset);
394 ecryptfs_printk(KERN_DEBUG, " * (*byte_offset) = [%d]\n",
395 (*byte_offset));
396}
397
398static 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)
402{
403 int rc = 0;
404
405 if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) {
406 rc = ecryptfs_commit_lower_page(lower_page, lower_inode,
407 ctx->param.lower_file,
408 byte_offset_in_page,
409 bytes_to_write);
410 if (rc) {
411 ecryptfs_printk(KERN_ERR, "Error calling lower "
412 "commit; rc = [%d]\n", rc);
413 goto out;
414 }
415 } else {
416 rc = ecryptfs_writepage_and_release_lower_page(lower_page,
417 lower_inode,
418 ctx->param.wbc);
419 if (rc) {
420 ecryptfs_printk(KERN_ERR, "Error calling lower "
421 "writepage(); rc = [%d]\n", rc);
422 goto out;
423 }
424 }
425out:
426 return rc;
427}
428
429static 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)
434{
435 int rc = 0;
436
437 if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) {
438 /* TODO: Limit this to only the data extents that are
439 * needed */
440 rc = ecryptfs_get_lower_page(lower_page, lower_inode,
441 ctx->param.lower_file,
442 lower_page_idx,
443 byte_offset_in_page,
444 (PAGE_CACHE_SIZE
445 - byte_offset_in_page));
446 if (rc) {
447 ecryptfs_printk(
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);
451 goto out;
452 }
453 } else {
Michael Halcrow9d8b8ce2007-02-12 00:53:48 -0800454 *lower_page = grab_cache_page(lower_inode->i_mapping,
455 lower_page_idx);
456 if (!(*lower_page)) {
457 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -0700458 ecryptfs_printk(
459 KERN_ERR, "Error attempting to grab and map "
460 "lower page with index [0x%.16x]; rc = [%d]\n",
461 lower_page_idx, rc);
462 goto out;
463 }
464 }
465out:
466 return rc;
467}
468
469/**
470 * ecryptfs_encrypt_page
471 * @ctx: The context of the page
472 *
473 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
474 * that eCryptfs pages may straddle the lower pages -- for instance,
475 * if the file was created on a machine with an 8K page size
476 * (resulting in an 8K header), and then the file is copied onto a
477 * host with a 32K page size, then when reading page 0 of the eCryptfs
478 * file, 24K of page 0 of the lower file will be read and decrypted,
479 * and then 8K of page 1 of the lower file will be read and decrypted.
480 *
481 * The actual operations performed on each page depends on the
482 * contents of the ecryptfs_page_crypt_context struct.
483 *
484 * Returns zero on success; negative on error
485 */
486int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx)
487{
488 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
489 unsigned long base_extent;
490 unsigned long extent_offset = 0;
491 unsigned long lower_page_idx = 0;
492 unsigned long prior_lower_page_idx = 0;
493 struct page *lower_page;
494 struct inode *lower_inode;
495 struct ecryptfs_inode_info *inode_info;
496 struct ecryptfs_crypt_stat *crypt_stat;
497 int rc = 0;
498 int lower_byte_offset = 0;
499 int orig_byte_offset = 0;
500 int num_extents_per_page;
501#define ECRYPTFS_PAGE_STATE_UNREAD 0
502#define ECRYPTFS_PAGE_STATE_READ 1
503#define ECRYPTFS_PAGE_STATE_MODIFIED 2
504#define ECRYPTFS_PAGE_STATE_WRITTEN 3
505 int page_state;
506
507 lower_inode = ecryptfs_inode_to_lower(ctx->page->mapping->host);
508 inode_info = ecryptfs_inode_to_private(ctx->page->mapping->host);
509 crypt_stat = &inode_info->crypt_stat;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800510 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700511 rc = ecryptfs_copy_page_to_lower(ctx->page, lower_inode,
512 ctx->param.lower_file);
513 if (rc)
514 ecryptfs_printk(KERN_ERR, "Error attempting to copy "
515 "page at index [0x%.16x]\n",
516 ctx->page->index);
517 goto out;
518 }
519 num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size;
520 base_extent = (ctx->page->index * num_extents_per_page);
521 page_state = ECRYPTFS_PAGE_STATE_UNREAD;
522 while (extent_offset < num_extents_per_page) {
523 ecryptfs_extent_to_lwr_pg_idx_and_offset(
524 &lower_page_idx, &lower_byte_offset, crypt_stat,
525 (base_extent + extent_offset));
526 if (prior_lower_page_idx != lower_page_idx
527 && page_state == ECRYPTFS_PAGE_STATE_MODIFIED) {
528 rc = ecryptfs_write_out_page(ctx, lower_page,
529 lower_inode,
530 orig_byte_offset,
531 (PAGE_CACHE_SIZE
532 - orig_byte_offset));
533 if (rc) {
534 ecryptfs_printk(KERN_ERR, "Error attempting "
535 "to write out page; rc = [%d]"
536 "\n", rc);
537 goto out;
538 }
539 page_state = ECRYPTFS_PAGE_STATE_WRITTEN;
540 }
541 if (page_state == ECRYPTFS_PAGE_STATE_UNREAD
542 || page_state == ECRYPTFS_PAGE_STATE_WRITTEN) {
543 rc = ecryptfs_read_in_page(ctx, &lower_page,
544 lower_inode, lower_page_idx,
545 lower_byte_offset);
546 if (rc) {
547 ecryptfs_printk(KERN_ERR, "Error attempting "
548 "to read in lower page with "
549 "index [0x%.16x]; rc = [%d]\n",
550 lower_page_idx, rc);
551 goto out;
552 }
553 orig_byte_offset = lower_byte_offset;
554 prior_lower_page_idx = lower_page_idx;
555 page_state = ECRYPTFS_PAGE_STATE_READ;
556 }
557 BUG_ON(!(page_state == ECRYPTFS_PAGE_STATE_MODIFIED
558 || page_state == ECRYPTFS_PAGE_STATE_READ));
559 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
560 (base_extent + extent_offset));
561 if (rc) {
562 ecryptfs_printk(KERN_ERR, "Error attempting to "
563 "derive IV for extent [0x%.16x]; "
564 "rc = [%d]\n",
565 (base_extent + extent_offset), rc);
566 goto out;
567 }
568 if (unlikely(ecryptfs_verbosity > 0)) {
569 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
570 "with iv:\n");
571 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
572 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
573 "encryption:\n");
574 ecryptfs_dump_hex((char *)
575 (page_address(ctx->page)
576 + (extent_offset
577 * crypt_stat->extent_size)), 8);
578 }
579 rc = ecryptfs_encrypt_page_offset(
580 crypt_stat, lower_page, lower_byte_offset, ctx->page,
581 (extent_offset * crypt_stat->extent_size),
582 crypt_stat->extent_size, extent_iv);
583 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
584 "rc = [%d]\n",
585 (base_extent + extent_offset), rc);
586 if (unlikely(ecryptfs_verbosity > 0)) {
587 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
588 "encryption:\n");
589 ecryptfs_dump_hex((char *)(page_address(lower_page)
590 + lower_byte_offset), 8);
591 }
592 page_state = ECRYPTFS_PAGE_STATE_MODIFIED;
593 extent_offset++;
594 }
595 BUG_ON(orig_byte_offset != 0);
596 rc = ecryptfs_write_out_page(ctx, lower_page, lower_inode, 0,
597 (lower_byte_offset
598 + crypt_stat->extent_size));
599 if (rc) {
600 ecryptfs_printk(KERN_ERR, "Error attempting to write out "
601 "page; rc = [%d]\n", rc);
602 goto out;
603 }
604out:
605 return rc;
606}
607
608/**
609 * ecryptfs_decrypt_page
610 * @file: The ecryptfs file
611 * @page: The page in ecryptfs to decrypt
612 *
613 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
614 * that eCryptfs pages may straddle the lower pages -- for instance,
615 * if the file was created on a machine with an 8K page size
616 * (resulting in an 8K header), and then the file is copied onto a
617 * host with a 32K page size, then when reading page 0 of the eCryptfs
618 * file, 24K of page 0 of the lower file will be read and decrypted,
619 * and then 8K of page 1 of the lower file will be read and decrypted.
620 *
621 * Returns zero on success; negative on error
622 */
623int ecryptfs_decrypt_page(struct file *file, struct page *page)
624{
625 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
626 unsigned long base_extent;
627 unsigned long extent_offset = 0;
628 unsigned long lower_page_idx = 0;
629 unsigned long prior_lower_page_idx = 0;
630 struct page *lower_page;
631 char *lower_page_virt = NULL;
632 struct inode *lower_inode;
633 struct ecryptfs_crypt_stat *crypt_stat;
634 int rc = 0;
635 int byte_offset;
636 int num_extents_per_page;
637 int page_state;
638
639 crypt_stat = &(ecryptfs_inode_to_private(
640 page->mapping->host)->crypt_stat);
641 lower_inode = ecryptfs_inode_to_lower(page->mapping->host);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800642 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700643 rc = ecryptfs_do_readpage(file, page, page->index);
644 if (rc)
645 ecryptfs_printk(KERN_ERR, "Error attempting to copy "
646 "page at index [0x%.16x]\n",
647 page->index);
648 goto out;
649 }
650 num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size;
651 base_extent = (page->index * num_extents_per_page);
652 lower_page_virt = kmem_cache_alloc(ecryptfs_lower_page_cache,
Christoph Lametere94b1762006-12-06 20:33:17 -0800653 GFP_KERNEL);
Michael Halcrow237fead2006-10-04 02:16:22 -0700654 if (!lower_page_virt) {
655 rc = -ENOMEM;
656 ecryptfs_printk(KERN_ERR, "Error getting page for encrypted "
657 "lower page(s)\n");
658 goto out;
659 }
660 lower_page = virt_to_page(lower_page_virt);
661 page_state = ECRYPTFS_PAGE_STATE_UNREAD;
662 while (extent_offset < num_extents_per_page) {
663 ecryptfs_extent_to_lwr_pg_idx_and_offset(
664 &lower_page_idx, &byte_offset, crypt_stat,
665 (base_extent + extent_offset));
666 if (prior_lower_page_idx != lower_page_idx
667 || page_state == ECRYPTFS_PAGE_STATE_UNREAD) {
668 rc = ecryptfs_do_readpage(file, lower_page,
669 lower_page_idx);
670 if (rc) {
671 ecryptfs_printk(KERN_ERR, "Error reading "
672 "lower encrypted page; rc = "
673 "[%d]\n", rc);
674 goto out;
675 }
676 prior_lower_page_idx = lower_page_idx;
677 page_state = ECRYPTFS_PAGE_STATE_READ;
678 }
679 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
680 (base_extent + extent_offset));
681 if (rc) {
682 ecryptfs_printk(KERN_ERR, "Error attempting to "
683 "derive IV for extent [0x%.16x]; rc = "
684 "[%d]\n",
685 (base_extent + extent_offset), rc);
686 goto out;
687 }
688 if (unlikely(ecryptfs_verbosity > 0)) {
689 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
690 "with iv:\n");
691 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
692 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
693 "decryption:\n");
694 ecryptfs_dump_hex((lower_page_virt + byte_offset), 8);
695 }
696 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
697 (extent_offset
698 * crypt_stat->extent_size),
699 lower_page, byte_offset,
700 crypt_stat->extent_size,
701 extent_iv);
702 if (rc != crypt_stat->extent_size) {
703 ecryptfs_printk(KERN_ERR, "Error attempting to "
704 "decrypt extent [0x%.16x]\n",
705 (base_extent + extent_offset));
706 goto out;
707 }
708 rc = 0;
709 if (unlikely(ecryptfs_verbosity > 0)) {
710 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
711 "decryption:\n");
712 ecryptfs_dump_hex((char *)(page_address(page)
713 + byte_offset), 8);
714 }
715 extent_offset++;
716 }
717out:
718 if (lower_page_virt)
719 kmem_cache_free(ecryptfs_lower_page_cache, lower_page_virt);
720 return rc;
721}
722
723/**
724 * decrypt_scatterlist
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700725 * @crypt_stat: Cryptographic context
726 * @dest_sg: The destination scatterlist to decrypt into
727 * @src_sg: The source scatterlist to decrypt from
728 * @size: The number of bytes to decrypt
729 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700730 *
731 * Returns the number of bytes decrypted; negative value on error
732 */
733static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
734 struct scatterlist *dest_sg,
735 struct scatterlist *src_sg, int size,
736 unsigned char *iv)
737{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800738 struct blkcipher_desc desc = {
739 .tfm = crypt_stat->tfm,
740 .info = iv,
741 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
742 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700743 int rc = 0;
744
745 /* Consider doing this once, when the file is opened */
746 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800747 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
748 crypt_stat->key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700749 if (rc) {
750 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
751 rc);
752 mutex_unlock(&crypt_stat->cs_tfm_mutex);
753 rc = -EINVAL;
754 goto out;
755 }
756 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800757 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700758 mutex_unlock(&crypt_stat->cs_tfm_mutex);
759 if (rc) {
760 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
761 rc);
762 goto out;
763 }
764 rc = size;
765out:
766 return rc;
767}
768
769/**
770 * ecryptfs_encrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700771 * @crypt_stat: The cryptographic context
772 * @dst_page: The page to encrypt into
773 * @dst_offset: The offset in the page to encrypt into
774 * @src_page: The page to encrypt from
775 * @src_offset: The offset in the page to encrypt from
776 * @size: The number of bytes to encrypt
777 * @iv: The initialization vector to use for the encryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700778 *
779 * Returns the number of bytes encrypted
780 */
781static int
782ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
783 struct page *dst_page, int dst_offset,
784 struct page *src_page, int src_offset, int size,
785 unsigned char *iv)
786{
787 struct scatterlist src_sg, dst_sg;
788
789 src_sg.page = src_page;
790 src_sg.offset = src_offset;
791 src_sg.length = size;
792 dst_sg.page = dst_page;
793 dst_sg.offset = dst_offset;
794 dst_sg.length = size;
795 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
796}
797
798/**
799 * ecryptfs_decrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700800 * @crypt_stat: The cryptographic context
801 * @dst_page: The page to decrypt into
802 * @dst_offset: The offset in the page to decrypt into
803 * @src_page: The page to decrypt from
804 * @src_offset: The offset in the page to decrypt from
805 * @size: The number of bytes to decrypt
806 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700807 *
808 * Returns the number of bytes decrypted
809 */
810static int
811ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
812 struct page *dst_page, int dst_offset,
813 struct page *src_page, int src_offset, int size,
814 unsigned char *iv)
815{
816 struct scatterlist src_sg, dst_sg;
817
818 src_sg.page = src_page;
819 src_sg.offset = src_offset;
820 src_sg.length = size;
821 dst_sg.page = dst_page;
822 dst_sg.offset = dst_offset;
823 dst_sg.length = size;
824 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
825}
826
827#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
828
829/**
830 * ecryptfs_init_crypt_ctx
831 * @crypt_stat: Uninitilized crypt stats structure
832 *
833 * Initialize the crypto context.
834 *
835 * TODO: Performance: Keep a cache of initialized cipher contexts;
836 * only init if needed
837 */
838int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
839{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800840 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700841 int rc = -EINVAL;
842
843 if (!crypt_stat->cipher) {
844 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
845 goto out;
846 }
847 ecryptfs_printk(KERN_DEBUG,
848 "Initializing cipher [%s]; strlen = [%d]; "
849 "key_size_bits = [%d]\n",
850 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
851 crypt_stat->key_size << 3);
852 if (crypt_stat->tfm) {
853 rc = 0;
854 goto out;
855 }
856 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800857 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
858 crypt_stat->cipher, "cbc");
859 if (rc)
860 goto out;
861 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
862 CRYPTO_ALG_ASYNC);
863 kfree(full_alg_name);
Akinobu Mitade887772006-11-28 12:29:49 -0800864 if (IS_ERR(crypt_stat->tfm)) {
865 rc = PTR_ERR(crypt_stat->tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700866 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
867 "Error initializing cipher [%s]\n",
868 crypt_stat->cipher);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800869 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700870 goto out;
871 }
Herbert Xuf1ddcaf2007-01-27 10:05:15 +1100872 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800873 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700874 rc = 0;
875out:
876 return rc;
877}
878
879static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
880{
881 int extent_size_tmp;
882
883 crypt_stat->extent_mask = 0xFFFFFFFF;
884 crypt_stat->extent_shift = 0;
885 if (crypt_stat->extent_size == 0)
886 return;
887 extent_size_tmp = crypt_stat->extent_size;
888 while ((extent_size_tmp & 0x01) == 0) {
889 extent_size_tmp >>= 1;
890 crypt_stat->extent_mask <<= 1;
891 crypt_stat->extent_shift++;
892 }
893}
894
895void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
896{
897 /* Default values; may be overwritten as we are parsing the
898 * packets. */
899 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
900 set_extent_mask_and_shift(crypt_stat);
901 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
902 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
903 crypt_stat->header_extent_size =
904 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
905 } else
906 crypt_stat->header_extent_size = PAGE_CACHE_SIZE;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800907 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
908 crypt_stat->num_header_extents_at_front = 0;
909 else
910 crypt_stat->num_header_extents_at_front = 1;
Michael Halcrow237fead2006-10-04 02:16:22 -0700911}
912
913/**
914 * ecryptfs_compute_root_iv
915 * @crypt_stats
916 *
917 * On error, sets the root IV to all 0's.
918 */
919int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
920{
921 int rc = 0;
922 char dst[MD5_DIGEST_SIZE];
923
924 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
925 BUG_ON(crypt_stat->iv_bytes <= 0);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800926 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700927 rc = -EINVAL;
928 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
929 "cannot generate root IV\n");
930 goto out;
931 }
932 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
933 crypt_stat->key_size);
934 if (rc) {
935 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
936 "MD5 while generating root IV\n");
937 goto out;
938 }
939 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
940out:
941 if (rc) {
942 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800943 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
Michael Halcrow237fead2006-10-04 02:16:22 -0700944 }
945 return rc;
946}
947
948static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
949{
950 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800951 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
Michael Halcrow237fead2006-10-04 02:16:22 -0700952 ecryptfs_compute_root_iv(crypt_stat);
953 if (unlikely(ecryptfs_verbosity > 0)) {
954 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
955 ecryptfs_dump_hex(crypt_stat->key,
956 crypt_stat->key_size);
957 }
958}
959
960/**
Michael Halcrow17398952007-02-12 00:53:45 -0800961 * ecryptfs_copy_mount_wide_flags_to_inode_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700962 * @crypt_stat: The inode's cryptographic context
963 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow17398952007-02-12 00:53:45 -0800964 *
965 * This function propagates the mount-wide flags to individual inode
966 * flags.
967 */
968static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
969 struct ecryptfs_crypt_stat *crypt_stat,
970 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
971{
972 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
973 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
974 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
975 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
976}
977
Michael Halcrowf4aad162007-10-16 01:27:53 -0700978static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
979 struct ecryptfs_crypt_stat *crypt_stat,
980 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
981{
982 struct ecryptfs_global_auth_tok *global_auth_tok;
983 int rc = 0;
984
985 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
986 list_for_each_entry(global_auth_tok,
987 &mount_crypt_stat->global_auth_tok_list,
988 mount_crypt_stat_list) {
989 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
990 if (rc) {
991 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
992 mutex_unlock(
993 &mount_crypt_stat->global_auth_tok_list_mutex);
994 goto out;
995 }
996 }
997 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
998out:
999 return rc;
1000}
1001
Michael Halcrow17398952007-02-12 00:53:45 -08001002/**
Michael Halcrow237fead2006-10-04 02:16:22 -07001003 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001004 * @crypt_stat: The inode's cryptographic context
1005 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001006 *
1007 * Default values in the event that policy does not override them.
1008 */
1009static void ecryptfs_set_default_crypt_stat_vals(
1010 struct ecryptfs_crypt_stat *crypt_stat,
1011 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1012{
Michael Halcrow17398952007-02-12 00:53:45 -08001013 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1014 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001015 ecryptfs_set_default_sizes(crypt_stat);
1016 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
1017 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001018 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -07001019 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
1020 crypt_stat->mount_crypt_stat = mount_crypt_stat;
1021}
1022
1023/**
1024 * ecryptfs_new_file_context
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001025 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001026 *
1027 * If the crypto context for the file has not yet been established,
1028 * this is where we do that. Establishing a new crypto context
1029 * involves the following decisions:
1030 * - What cipher to use?
1031 * - What set of authentication tokens to use?
1032 * Here we just worry about getting enough information into the
1033 * authentication tokens so that we know that they are available.
1034 * We associate the available authentication tokens with the new file
1035 * via the set of signatures in the crypt_stat struct. Later, when
1036 * the headers are actually written out, we may again defer to
1037 * userspace to perform the encryption of the session key; for the
1038 * foreseeable future, this will be the case with public key packets.
1039 *
1040 * Returns zero on success; non-zero otherwise
1041 */
Michael Halcrow237fead2006-10-04 02:16:22 -07001042int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
1043{
Michael Halcrow237fead2006-10-04 02:16:22 -07001044 struct ecryptfs_crypt_stat *crypt_stat =
1045 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1046 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1047 &ecryptfs_superblock_to_private(
1048 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1049 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001050 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001051
1052 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -07001053 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001054 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1055 mount_crypt_stat);
1056 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1057 mount_crypt_stat);
1058 if (rc) {
1059 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1060 "to the inode key sigs; rc = [%d]\n", rc);
1061 goto out;
1062 }
1063 cipher_name_len =
1064 strlen(mount_crypt_stat->global_default_cipher_name);
1065 memcpy(crypt_stat->cipher,
1066 mount_crypt_stat->global_default_cipher_name,
1067 cipher_name_len);
1068 crypt_stat->cipher[cipher_name_len] = '\0';
1069 crypt_stat->key_size =
1070 mount_crypt_stat->global_default_cipher_key_size;
1071 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001072 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1073 if (rc)
1074 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1075 "context for cipher [%s]: rc = [%d]\n",
1076 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001077out:
Michael Halcrow237fead2006-10-04 02:16:22 -07001078 return rc;
1079}
1080
1081/**
1082 * contains_ecryptfs_marker - check for the ecryptfs marker
1083 * @data: The data block in which to check
1084 *
1085 * Returns one if marker found; zero if not found
1086 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001087static int contains_ecryptfs_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -07001088{
1089 u32 m_1, m_2;
1090
1091 memcpy(&m_1, data, 4);
1092 m_1 = be32_to_cpu(m_1);
1093 memcpy(&m_2, (data + 4), 4);
1094 m_2 = be32_to_cpu(m_2);
1095 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1096 return 1;
1097 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1098 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1099 MAGIC_ECRYPTFS_MARKER);
1100 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1101 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1102 return 0;
1103}
1104
1105struct ecryptfs_flag_map_elem {
1106 u32 file_flag;
1107 u32 local_flag;
1108};
1109
1110/* Add support for additional flags by adding elements here. */
1111static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1112 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001113 {0x00000002, ECRYPTFS_ENCRYPTED},
1114 {0x00000004, ECRYPTFS_METADATA_IN_XATTR}
Michael Halcrow237fead2006-10-04 02:16:22 -07001115};
1116
1117/**
1118 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001119 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001120 * @page_virt: Source data to be parsed
1121 * @bytes_read: Updated with the number of bytes read
1122 *
1123 * Returns zero on success; non-zero if the flag set is invalid
1124 */
1125static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1126 char *page_virt, int *bytes_read)
1127{
1128 int rc = 0;
1129 int i;
1130 u32 flags;
1131
1132 memcpy(&flags, page_virt, 4);
1133 flags = be32_to_cpu(flags);
1134 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1135 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1136 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001137 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -07001138 } else
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001139 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
Michael Halcrow237fead2006-10-04 02:16:22 -07001140 /* Version is in top 8 bits of the 32-bit flag vector */
1141 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1142 (*bytes_read) = 4;
1143 return rc;
1144}
1145
1146/**
1147 * write_ecryptfs_marker
1148 * @page_virt: The pointer to in a page to begin writing the marker
1149 * @written: Number of bytes written
1150 *
1151 * Marker = 0x3c81b7f5
1152 */
1153static void write_ecryptfs_marker(char *page_virt, size_t *written)
1154{
1155 u32 m_1, m_2;
1156
1157 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1158 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1159 m_1 = cpu_to_be32(m_1);
1160 memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1161 m_2 = cpu_to_be32(m_2);
1162 memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2,
1163 (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1164 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1165}
1166
1167static void
1168write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1169 size_t *written)
1170{
1171 u32 flags = 0;
1172 int i;
1173
1174 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1175 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001176 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -07001177 flags |= ecryptfs_flag_map[i].file_flag;
1178 /* Version is in top 8 bits of the 32-bit flag vector */
1179 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1180 flags = cpu_to_be32(flags);
1181 memcpy(page_virt, &flags, 4);
1182 (*written) = 4;
1183}
1184
1185struct ecryptfs_cipher_code_str_map_elem {
1186 char cipher_str[16];
1187 u16 cipher_code;
1188};
1189
1190/* Add support for additional ciphers by adding elements here. The
1191 * cipher_code is whatever OpenPGP applicatoins use to identify the
1192 * ciphers. List in order of probability. */
1193static struct ecryptfs_cipher_code_str_map_elem
1194ecryptfs_cipher_code_str_map[] = {
1195 {"aes",RFC2440_CIPHER_AES_128 },
1196 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1197 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1198 {"cast5", RFC2440_CIPHER_CAST_5},
1199 {"twofish", RFC2440_CIPHER_TWOFISH},
1200 {"cast6", RFC2440_CIPHER_CAST_6},
1201 {"aes", RFC2440_CIPHER_AES_192},
1202 {"aes", RFC2440_CIPHER_AES_256}
1203};
1204
1205/**
1206 * ecryptfs_code_for_cipher_string
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001207 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001208 *
1209 * Returns zero on no match, or the cipher code on match
1210 */
1211u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat)
1212{
1213 int i;
1214 u16 code = 0;
1215 struct ecryptfs_cipher_code_str_map_elem *map =
1216 ecryptfs_cipher_code_str_map;
1217
1218 if (strcmp(crypt_stat->cipher, "aes") == 0) {
1219 switch (crypt_stat->key_size) {
1220 case 16:
1221 code = RFC2440_CIPHER_AES_128;
1222 break;
1223 case 24:
1224 code = RFC2440_CIPHER_AES_192;
1225 break;
1226 case 32:
1227 code = RFC2440_CIPHER_AES_256;
1228 }
1229 } else {
1230 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1231 if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){
1232 code = map[i].cipher_code;
1233 break;
1234 }
1235 }
1236 return code;
1237}
1238
1239/**
1240 * ecryptfs_cipher_code_to_string
1241 * @str: Destination to write out the cipher name
1242 * @cipher_code: The code to convert to cipher name string
1243 *
1244 * Returns zero on success
1245 */
1246int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
1247{
1248 int rc = 0;
1249 int i;
1250
1251 str[0] = '\0';
1252 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1253 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1254 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1255 if (str[0] == '\0') {
1256 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1257 "[%d]\n", cipher_code);
1258 rc = -EINVAL;
1259 }
1260 return rc;
1261}
1262
1263/**
1264 * ecryptfs_read_header_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001265 * @data: The virtual address to write header region data into
1266 * @dentry: The lower dentry
1267 * @mnt: The lower VFS mount
Michael Halcrow237fead2006-10-04 02:16:22 -07001268 *
1269 * Returns zero on success; non-zero otherwise
1270 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001271static int ecryptfs_read_header_region(char *data, struct dentry *dentry,
1272 struct vfsmount *mnt)
Michael Halcrow237fead2006-10-04 02:16:22 -07001273{
Michael Halcrow7ff1d742006-10-30 22:07:19 -08001274 struct file *lower_file;
Michael Halcrow237fead2006-10-04 02:16:22 -07001275 mm_segment_t oldfs;
1276 int rc;
1277
Michael Halcrow7ff1d742006-10-30 22:07:19 -08001278 if ((rc = ecryptfs_open_lower_file(&lower_file, dentry, mnt,
1279 O_RDONLY))) {
1280 printk(KERN_ERR
1281 "Error opening lower_file to read header region\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001282 goto out;
1283 }
Michael Halcrow7ff1d742006-10-30 22:07:19 -08001284 lower_file->f_pos = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001285 oldfs = get_fs();
1286 set_fs(get_ds());
Michael Halcrow7ff1d742006-10-30 22:07:19 -08001287 rc = lower_file->f_op->read(lower_file, (char __user *)data,
1288 ECRYPTFS_DEFAULT_EXTENT_SIZE, &lower_file->f_pos);
Michael Halcrow237fead2006-10-04 02:16:22 -07001289 set_fs(oldfs);
Michael Halcrow7ff1d742006-10-30 22:07:19 -08001290 if ((rc = ecryptfs_close_lower_file(lower_file))) {
1291 printk(KERN_ERR "Error closing lower_file\n");
1292 goto out;
1293 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001294 rc = 0;
1295out:
1296 return rc;
1297}
1298
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001299int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry,
1300 struct vfsmount *mnt)
1301{
1302 int rc;
1303
1304 rc = ecryptfs_read_header_region(data, dentry, mnt);
1305 if (rc)
1306 goto out;
1307 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES))
1308 rc = -EINVAL;
1309out:
1310 return rc;
1311}
1312
1313
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001314void
1315ecryptfs_write_header_metadata(char *virt,
1316 struct ecryptfs_crypt_stat *crypt_stat,
1317 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001318{
1319 u32 header_extent_size;
1320 u16 num_header_extents_at_front;
1321
1322 header_extent_size = (u32)crypt_stat->header_extent_size;
1323 num_header_extents_at_front =
1324 (u16)crypt_stat->num_header_extents_at_front;
1325 header_extent_size = cpu_to_be32(header_extent_size);
1326 memcpy(virt, &header_extent_size, 4);
1327 virt += 4;
1328 num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front);
1329 memcpy(virt, &num_header_extents_at_front, 2);
1330 (*written) = 6;
1331}
1332
1333struct kmem_cache *ecryptfs_header_cache_0;
1334struct kmem_cache *ecryptfs_header_cache_1;
1335struct kmem_cache *ecryptfs_header_cache_2;
1336
1337/**
1338 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001339 * @page_virt: The virtual address to write the headers to
1340 * @size: Set to the number of bytes written by this function
1341 * @crypt_stat: The cryptographic context
1342 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001343 *
1344 * Format version: 1
1345 *
1346 * Header Extent:
1347 * Octets 0-7: Unencrypted file size (big-endian)
1348 * Octets 8-15: eCryptfs special marker
1349 * Octets 16-19: Flags
1350 * Octet 16: File format version number (between 0 and 255)
1351 * Octets 17-18: Reserved
1352 * Octet 19: Bit 1 (lsb): Reserved
1353 * Bit 2: Encrypted?
1354 * Bits 3-8: Reserved
1355 * Octets 20-23: Header extent size (big-endian)
1356 * Octets 24-25: Number of header extents at front of file
1357 * (big-endian)
1358 * Octet 26: Begin RFC 2440 authentication token packet set
1359 * Data Extent 0:
1360 * Lower data (CBC encrypted)
1361 * Data Extent 1:
1362 * Lower data (CBC encrypted)
1363 * ...
1364 *
1365 * Returns zero on success
1366 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001367static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
1368 struct ecryptfs_crypt_stat *crypt_stat,
1369 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001370{
1371 int rc;
1372 size_t written;
1373 size_t offset;
1374
1375 offset = ECRYPTFS_FILE_SIZE_BYTES;
1376 write_ecryptfs_marker((page_virt + offset), &written);
1377 offset += written;
1378 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1379 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001380 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1381 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001382 offset += written;
1383 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1384 ecryptfs_dentry, &written,
1385 PAGE_CACHE_SIZE - offset);
1386 if (rc)
1387 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1388 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001389 if (size) {
1390 offset += written;
1391 *size = offset;
1392 }
1393 return rc;
1394}
1395
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001396static int
1397ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
1398 struct file *lower_file, char *page_virt)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001399{
1400 mm_segment_t oldfs;
1401 int current_header_page;
1402 int header_pages;
Michael Halcrow70456602007-02-12 00:53:48 -08001403 ssize_t size;
1404 int rc = 0;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001405
1406 lower_file->f_pos = 0;
1407 oldfs = get_fs();
1408 set_fs(get_ds());
Michael Halcrow70456602007-02-12 00:53:48 -08001409 size = vfs_write(lower_file, (char __user *)page_virt, PAGE_CACHE_SIZE,
1410 &lower_file->f_pos);
1411 if (size < 0) {
1412 rc = (int)size;
1413 printk(KERN_ERR "Error attempting to write lower page; "
1414 "rc = [%d]\n", rc);
1415 set_fs(oldfs);
1416 goto out;
1417 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001418 header_pages = ((crypt_stat->header_extent_size
1419 * crypt_stat->num_header_extents_at_front)
1420 / PAGE_CACHE_SIZE);
1421 memset(page_virt, 0, PAGE_CACHE_SIZE);
1422 current_header_page = 1;
1423 while (current_header_page < header_pages) {
Michael Halcrow70456602007-02-12 00:53:48 -08001424 size = vfs_write(lower_file, (char __user *)page_virt,
1425 PAGE_CACHE_SIZE, &lower_file->f_pos);
1426 if (size < 0) {
1427 rc = (int)size;
1428 printk(KERN_ERR "Error attempting to write lower page; "
1429 "rc = [%d]\n", rc);
1430 set_fs(oldfs);
1431 goto out;
1432 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001433 current_header_page++;
1434 }
1435 set_fs(oldfs);
Michael Halcrow70456602007-02-12 00:53:48 -08001436out:
1437 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001438}
1439
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001440static int
1441ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1442 struct ecryptfs_crypt_stat *crypt_stat,
1443 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001444{
1445 int rc;
1446
1447 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1448 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001449 return rc;
1450}
1451
1452/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001453 * ecryptfs_write_metadata
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001454 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001455 * @lower_file: The lower file struct, which was returned from dentry_open
1456 *
1457 * Write the file headers out. This will likely involve a userspace
1458 * callout, in which the session key is encrypted with one or more
1459 * public keys and/or the passphrase necessary to do the encryption is
1460 * retrieved via a prompt. Exactly what happens at this point should
1461 * be policy-dependent.
1462 *
1463 * Returns zero on success; non-zero on error
1464 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001465int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1466 struct file *lower_file)
Michael Halcrow237fead2006-10-04 02:16:22 -07001467{
Michael Halcrow237fead2006-10-04 02:16:22 -07001468 struct ecryptfs_crypt_stat *crypt_stat;
1469 char *page_virt;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001470 size_t size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001471 int rc = 0;
1472
1473 crypt_stat = &ecryptfs_inode_to_private(
1474 ecryptfs_dentry->d_inode)->crypt_stat;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001475 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1476 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001477 ecryptfs_printk(KERN_DEBUG, "Key is "
1478 "invalid; bailing out\n");
1479 rc = -EINVAL;
1480 goto out;
1481 }
1482 } else {
1483 rc = -EINVAL;
1484 ecryptfs_printk(KERN_WARNING,
1485 "Called with crypt_stat->encrypted == 0\n");
1486 goto out;
1487 }
1488 /* Released in this function */
Robert P. J. Dayc3762222007-02-10 01:45:03 -08001489 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001490 if (!page_virt) {
1491 ecryptfs_printk(KERN_ERR, "Out of memory\n");
1492 rc = -ENOMEM;
1493 goto out;
1494 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001495 rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat,
1496 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001497 if (unlikely(rc)) {
1498 ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n");
1499 memset(page_virt, 0, PAGE_CACHE_SIZE);
1500 goto out_free;
1501 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001502 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1503 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
1504 crypt_stat, page_virt,
1505 size);
1506 else
1507 rc = ecryptfs_write_metadata_to_contents(crypt_stat, lower_file,
1508 page_virt);
1509 if (rc) {
1510 printk(KERN_ERR "Error writing metadata out to lower file; "
1511 "rc = [%d]\n", rc);
1512 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001513 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001514out_free:
1515 kmem_cache_free(ecryptfs_header_cache_0, page_virt);
1516out:
1517 return rc;
1518}
1519
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001520#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1521#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001522static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001523 char *virt, int *bytes_read,
1524 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001525{
1526 int rc = 0;
1527 u32 header_extent_size;
1528 u16 num_header_extents_at_front;
1529
1530 memcpy(&header_extent_size, virt, 4);
1531 header_extent_size = be32_to_cpu(header_extent_size);
1532 virt += 4;
1533 memcpy(&num_header_extents_at_front, virt, 2);
1534 num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
1535 crypt_stat->header_extent_size = (int)header_extent_size;
1536 crypt_stat->num_header_extents_at_front =
1537 (int)num_header_extents_at_front;
1538 (*bytes_read) = 6;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001539 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1540 && ((crypt_stat->header_extent_size
1541 * crypt_stat->num_header_extents_at_front)
1542 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001543 rc = -EINVAL;
1544 ecryptfs_printk(KERN_WARNING, "Invalid header extent size: "
1545 "[%d]\n", crypt_stat->header_extent_size);
1546 }
1547 return rc;
1548}
1549
1550/**
1551 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001552 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001553 *
1554 * For version 0 file format; this function is only for backwards
1555 * compatibility for files created with the prior versions of
1556 * eCryptfs.
1557 */
1558static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1559{
1560 crypt_stat->header_extent_size = 4096;
1561 crypt_stat->num_header_extents_at_front = 1;
1562}
1563
1564/**
1565 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001566 * @page_virt: The virtual address into which to read the headers
1567 * @crypt_stat: The cryptographic context
1568 * @ecryptfs_dentry: The eCryptfs dentry
1569 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001570 *
1571 * Read/parse the header data. The header format is detailed in the
1572 * comment block for the ecryptfs_write_headers_virt() function.
1573 *
1574 * Returns zero on success
1575 */
1576static int ecryptfs_read_headers_virt(char *page_virt,
1577 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001578 struct dentry *ecryptfs_dentry,
1579 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001580{
1581 int rc = 0;
1582 int offset;
1583 int bytes_read;
1584
1585 ecryptfs_set_default_sizes(crypt_stat);
1586 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1587 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1588 offset = ECRYPTFS_FILE_SIZE_BYTES;
1589 rc = contains_ecryptfs_marker(page_virt + offset);
1590 if (rc == 0) {
1591 rc = -EINVAL;
1592 goto out;
1593 }
1594 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1595 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1596 &bytes_read);
1597 if (rc) {
1598 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1599 goto out;
1600 }
1601 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1602 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1603 "file version [%d] is supported by this "
1604 "version of eCryptfs\n",
1605 crypt_stat->file_version,
1606 ECRYPTFS_SUPPORTED_FILE_VERSION);
1607 rc = -EINVAL;
1608 goto out;
1609 }
1610 offset += bytes_read;
1611 if (crypt_stat->file_version >= 1) {
1612 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001613 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001614 if (rc) {
1615 ecryptfs_printk(KERN_WARNING, "Error reading header "
1616 "metadata; rc = [%d]\n", rc);
1617 }
1618 offset += bytes_read;
1619 } else
1620 set_default_header_data(crypt_stat);
1621 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1622 ecryptfs_dentry);
1623out:
1624 return rc;
1625}
1626
1627/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001628 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001629 * @page_virt: The vitual address into which to read the xattr data
1630 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001631 *
1632 * Attempts to read the crypto metadata from the extended attribute
1633 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001634 *
1635 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001636 */
1637int ecryptfs_read_xattr_region(char *page_virt, struct dentry *ecryptfs_dentry)
1638{
1639 ssize_t size;
1640 int rc = 0;
1641
1642 size = ecryptfs_getxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME,
1643 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1644 if (size < 0) {
1645 printk(KERN_DEBUG "Error attempting to read the [%s] "
1646 "xattr from the lower file; return value = [%zd]\n",
1647 ECRYPTFS_XATTR_NAME, size);
1648 rc = -EINVAL;
1649 goto out;
1650 }
1651out:
1652 return rc;
1653}
1654
1655int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1656 struct dentry *ecryptfs_dentry)
1657{
1658 int rc;
1659
1660 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry);
1661 if (rc)
1662 goto out;
1663 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1664 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1665 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1666 rc = -EINVAL;
1667 }
1668out:
1669 return rc;
1670}
1671
1672/**
1673 * ecryptfs_read_metadata
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001674 * @ecryptfs_dentry: The eCryptfs dentry
1675 * @lower_file: The lower file from which to read the metadata
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001676 *
1677 * Common entry point for reading file metadata. From here, we could
1678 * retrieve the header information from the header region of the file,
1679 * the xattr region of the file, or some other repostory that is
1680 * stored separately from the file itself. The current implementation
1681 * supports retrieving the metadata information from the file contents
1682 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001683 *
1684 * Returns zero if valid headers found and parsed; non-zero otherwise
1685 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001686int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
1687 struct file *lower_file)
Michael Halcrow237fead2006-10-04 02:16:22 -07001688{
1689 int rc = 0;
1690 char *page_virt = NULL;
1691 mm_segment_t oldfs;
1692 ssize_t bytes_read;
1693 struct ecryptfs_crypt_stat *crypt_stat =
1694 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001695 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1696 &ecryptfs_superblock_to_private(
1697 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001698
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001699 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1700 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001701 /* Read the first page from the underlying file */
Christoph Lameterf7267c02006-12-06 20:33:15 -08001702 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001703 if (!page_virt) {
1704 rc = -ENOMEM;
1705 ecryptfs_printk(KERN_ERR, "Unable to allocate page_virt\n");
1706 goto out;
1707 }
1708 lower_file->f_pos = 0;
1709 oldfs = get_fs();
1710 set_fs(get_ds());
1711 bytes_read = lower_file->f_op->read(lower_file,
1712 (char __user *)page_virt,
1713 ECRYPTFS_DEFAULT_EXTENT_SIZE,
1714 &lower_file->f_pos);
1715 set_fs(oldfs);
1716 if (bytes_read != ECRYPTFS_DEFAULT_EXTENT_SIZE) {
1717 rc = -EINVAL;
1718 goto out;
1719 }
1720 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001721 ecryptfs_dentry,
1722 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001723 if (rc) {
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001724 rc = ecryptfs_read_xattr_region(page_virt,
1725 ecryptfs_dentry);
1726 if (rc) {
1727 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1728 "file header region or xattr region\n");
1729 rc = -EINVAL;
1730 goto out;
1731 }
1732 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1733 ecryptfs_dentry,
1734 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1735 if (rc) {
1736 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1737 "file xattr region either\n");
1738 rc = -EINVAL;
1739 }
1740 if (crypt_stat->mount_crypt_stat->flags
1741 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1742 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1743 } else {
1744 printk(KERN_WARNING "Attempt to access file with "
1745 "crypto metadata only in the extended attribute "
1746 "region, but eCryptfs was mounted without "
1747 "xattr support enabled. eCryptfs will not treat "
1748 "this like an encrypted file.\n");
1749 rc = -EINVAL;
1750 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001751 }
1752out:
1753 if (page_virt) {
1754 memset(page_virt, 0, PAGE_CACHE_SIZE);
1755 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1756 }
1757 return rc;
1758}
1759
1760/**
1761 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1762 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1763 * @name: The plaintext name
1764 * @length: The length of the plaintext
1765 * @encoded_name: The encypted name
1766 *
1767 * Encrypts and encodes a filename into something that constitutes a
1768 * valid filename for a filesystem, with printable characters.
1769 *
1770 * We assume that we have a properly initialized crypto context,
1771 * pointed to by crypt_stat->tfm.
1772 *
1773 * TODO: Implement filename decoding and decryption here, in place of
1774 * memcpy. We are keeping the framework around for now to (1)
1775 * facilitate testing of the components needed to implement filename
1776 * encryption and (2) to provide a code base from which other
1777 * developers in the community can easily implement this feature.
1778 *
1779 * Returns the length of encoded filename; negative if error
1780 */
1781int
1782ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1783 const char *name, int length, char **encoded_name)
1784{
1785 int error = 0;
1786
1787 (*encoded_name) = kmalloc(length + 2, GFP_KERNEL);
1788 if (!(*encoded_name)) {
1789 error = -ENOMEM;
1790 goto out;
1791 }
1792 /* TODO: Filename encryption is a scheduled feature for a
1793 * future version of eCryptfs. This function is here only for
1794 * the purpose of providing a framework for other developers
1795 * to easily implement filename encryption. Hint: Replace this
1796 * memcpy() with a call to encrypt and encode the
1797 * filename, the set the length accordingly. */
1798 memcpy((void *)(*encoded_name), (void *)name, length);
1799 (*encoded_name)[length] = '\0';
1800 error = length + 1;
1801out:
1802 return error;
1803}
1804
1805/**
1806 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1807 * @crypt_stat: The crypt_stat struct associated with the file
1808 * @name: The filename in cipher text
1809 * @length: The length of the cipher text name
1810 * @decrypted_name: The plaintext name
1811 *
1812 * Decodes and decrypts the filename.
1813 *
1814 * We assume that we have a properly initialized crypto context,
1815 * pointed to by crypt_stat->tfm.
1816 *
1817 * TODO: Implement filename decoding and decryption here, in place of
1818 * memcpy. We are keeping the framework around for now to (1)
1819 * facilitate testing of the components needed to implement filename
1820 * encryption and (2) to provide a code base from which other
1821 * developers in the community can easily implement this feature.
1822 *
1823 * Returns the length of decoded filename; negative if error
1824 */
1825int
1826ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1827 const char *name, int length, char **decrypted_name)
1828{
1829 int error = 0;
1830
1831 (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL);
1832 if (!(*decrypted_name)) {
1833 error = -ENOMEM;
1834 goto out;
1835 }
1836 /* TODO: Filename encryption is a scheduled feature for a
1837 * future version of eCryptfs. This function is here only for
1838 * the purpose of providing a framework for other developers
1839 * to easily implement filename encryption. Hint: Replace this
1840 * memcpy() with a call to decode and decrypt the
1841 * filename, the set the length accordingly. */
1842 memcpy((void *)(*decrypted_name), (void *)name, length);
1843 (*decrypted_name)[length + 1] = '\0'; /* Only for convenience
1844 * in printing out the
1845 * string in debug
1846 * messages */
1847 error = length;
1848out:
1849 return error;
1850}
1851
1852/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001853 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001854 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001855 * @cipher_name: Name of the cipher
1856 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001857 *
1858 * Returns zero on success. Any crypto_tfm structs allocated here
1859 * should be released by other functions, such as on a superblock put
1860 * event, regardless of whether this function succeeds for fails.
1861 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001862static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001863ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1864 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001865{
1866 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Michael Halcrow8bba0662006-10-30 22:07:18 -08001867 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -07001868 int rc;
1869
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001870 *key_tfm = NULL;
1871 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001872 rc = -EINVAL;
1873 printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001874 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001875 goto out;
1876 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001877 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1878 "ecb");
1879 if (rc)
1880 goto out;
1881 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1882 kfree(full_alg_name);
1883 if (IS_ERR(*key_tfm)) {
1884 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001885 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Michael Halcrow8bba0662006-10-30 22:07:18 -08001886 "[%s]; rc = [%d]\n", cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001887 goto out;
1888 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001889 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1890 if (*key_size == 0) {
1891 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1892
1893 *key_size = alg->max_keysize;
1894 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001895 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001896 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001897 if (rc) {
1898 printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001899 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001900 rc = -EINVAL;
1901 goto out;
1902 }
1903out:
1904 return rc;
1905}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001906
1907struct kmem_cache *ecryptfs_key_tfm_cache;
1908struct list_head key_tfm_list;
1909struct mutex key_tfm_list_mutex;
1910
1911int ecryptfs_init_crypto(void)
1912{
1913 mutex_init(&key_tfm_list_mutex);
1914 INIT_LIST_HEAD(&key_tfm_list);
1915 return 0;
1916}
1917
Michael Halcrowfcd12832007-10-16 01:28:01 -07001918int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001919{
1920 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1921
1922 mutex_lock(&key_tfm_list_mutex);
1923 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1924 key_tfm_list) {
1925 list_del(&key_tfm->key_tfm_list);
1926 if (key_tfm->key_tfm)
1927 crypto_free_blkcipher(key_tfm->key_tfm);
1928 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1929 }
1930 mutex_unlock(&key_tfm_list_mutex);
1931 return 0;
1932}
1933
1934int
1935ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1936 size_t key_size)
1937{
1938 struct ecryptfs_key_tfm *tmp_tfm;
1939 int rc = 0;
1940
1941 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1942 if (key_tfm != NULL)
1943 (*key_tfm) = tmp_tfm;
1944 if (!tmp_tfm) {
1945 rc = -ENOMEM;
1946 printk(KERN_ERR "Error attempting to allocate from "
1947 "ecryptfs_key_tfm_cache\n");
1948 goto out;
1949 }
1950 mutex_init(&tmp_tfm->key_tfm_mutex);
1951 strncpy(tmp_tfm->cipher_name, cipher_name,
1952 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1953 tmp_tfm->key_size = key_size;
1954 if ((rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1955 tmp_tfm->cipher_name,
1956 &tmp_tfm->key_size))) {
1957 printk(KERN_ERR "Error attempting to initialize key TFM "
1958 "cipher with name = [%s]; rc = [%d]\n",
1959 tmp_tfm->cipher_name, rc);
1960 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1961 if (key_tfm != NULL)
1962 (*key_tfm) = NULL;
1963 goto out;
1964 }
1965 mutex_lock(&key_tfm_list_mutex);
1966 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1967 mutex_unlock(&key_tfm_list_mutex);
1968out:
1969 return rc;
1970}
1971
1972int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1973 struct mutex **tfm_mutex,
1974 char *cipher_name)
1975{
1976 struct ecryptfs_key_tfm *key_tfm;
1977 int rc = 0;
1978
1979 (*tfm) = NULL;
1980 (*tfm_mutex) = NULL;
1981 mutex_lock(&key_tfm_list_mutex);
1982 list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) {
1983 if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
1984 (*tfm) = key_tfm->key_tfm;
1985 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1986 mutex_unlock(&key_tfm_list_mutex);
1987 goto out;
1988 }
1989 }
1990 mutex_unlock(&key_tfm_list_mutex);
1991 if ((rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0))) {
1992 printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
1993 rc);
1994 goto out;
1995 }
1996 (*tfm) = key_tfm->key_tfm;
1997 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1998out:
1999 return rc;
2000}