blob: 2f6735dbf1a9ded47999ebc97590221b16eb6925 [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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090036#include <linux/slab.h>
Harvey Harrison29335c62008-07-23 21:30:06 -070037#include <asm/unaligned.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070038#include "ecryptfs_kernel.h"
39
Tyler Hicks00a69942013-04-05 23:26:22 -070040#define DECRYPT 0
41#define ENCRYPT 1
Michael Halcrow237fead2006-10-04 02:16:22 -070042
43/**
44 * ecryptfs_to_hex
45 * @dst: Buffer to take hex character representation of contents of
46 * src; must be at least of size (src_size * 2)
47 * @src: Buffer to be converted to a hex string respresentation
48 * @src_size: number of bytes to convert
49 */
50void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
51{
52 int x;
53
54 for (x = 0; x < src_size; x++)
55 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
56}
57
58/**
59 * ecryptfs_from_hex
60 * @dst: Buffer to take the bytes from src hex; must be at least of
61 * size (src_size / 2)
62 * @src: Buffer to be converted from a hex string respresentation to raw value
63 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
64 */
65void ecryptfs_from_hex(char *dst, char *src, int dst_size)
66{
67 int x;
68 char tmp[3] = { 0, };
69
70 for (x = 0; x < dst_size; x++) {
71 tmp[0] = src[x * 2];
72 tmp[1] = src[x * 2 + 1];
73 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
74 }
75}
76
77/**
78 * ecryptfs_calculate_md5 - calculates the md5 of @src
79 * @dst: Pointer to 16 bytes of allocated memory
80 * @crypt_stat: Pointer to crypt_stat struct for the current inode
81 * @src: Data to be md5'd
82 * @len: Length of @src
83 *
84 * Uses the allocated crypto context that crypt_stat references to
85 * generate the MD5 sum of the contents of src.
86 */
87static int ecryptfs_calculate_md5(char *dst,
88 struct ecryptfs_crypt_stat *crypt_stat,
89 char *src, int len)
90{
Michael Halcrow237fead2006-10-04 02:16:22 -070091 struct scatterlist sg;
Michael Halcrow565d97242006-10-30 22:07:17 -080092 struct hash_desc desc = {
93 .tfm = crypt_stat->hash_tfm,
94 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
95 };
96 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -070097
Michael Halcrow565d97242006-10-30 22:07:17 -080098 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -070099 sg_init_one(&sg, (u8 *)src, len);
Michael Halcrow565d97242006-10-30 22:07:17 -0800100 if (!desc.tfm) {
101 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
102 CRYPTO_ALG_ASYNC);
103 if (IS_ERR(desc.tfm)) {
104 rc = PTR_ERR(desc.tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700105 ecryptfs_printk(KERN_ERR, "Error attempting to "
Michael Halcrow565d97242006-10-30 22:07:17 -0800106 "allocate crypto context; rc = [%d]\n",
107 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700108 goto out;
109 }
Michael Halcrow565d97242006-10-30 22:07:17 -0800110 crypt_stat->hash_tfm = desc.tfm;
Michael Halcrow237fead2006-10-04 02:16:22 -0700111 }
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800112 rc = crypto_hash_init(&desc);
113 if (rc) {
114 printk(KERN_ERR
115 "%s: Error initializing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700116 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800117 goto out;
118 }
119 rc = crypto_hash_update(&desc, &sg, len);
120 if (rc) {
121 printk(KERN_ERR
122 "%s: Error updating crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700123 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800124 goto out;
125 }
126 rc = crypto_hash_final(&desc, dst);
127 if (rc) {
128 printk(KERN_ERR
129 "%s: Error finalizing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700130 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800131 goto out;
132 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700133out:
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800134 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700135 return rc;
136}
137
Michael Halcrowcd9d67d2007-10-16 01:28:04 -0700138static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
139 char *cipher_name,
140 char *chaining_modifier)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800141{
142 int cipher_name_len = strlen(cipher_name);
143 int chaining_modifier_len = strlen(chaining_modifier);
144 int algified_name_len;
145 int rc;
146
147 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
148 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
Michael Halcrow7bd473f2006-11-02 22:06:56 -0800149 if (!(*algified_name)) {
Michael Halcrow8bba0662006-10-30 22:07:18 -0800150 rc = -ENOMEM;
151 goto out;
152 }
153 snprintf((*algified_name), algified_name_len, "%s(%s)",
154 chaining_modifier, cipher_name);
155 rc = 0;
156out:
157 return rc;
158}
159
Michael Halcrow237fead2006-10-04 02:16:22 -0700160/**
161 * ecryptfs_derive_iv
162 * @iv: destination for the derived iv vale
163 * @crypt_stat: Pointer to crypt_stat struct for the current inode
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700164 * @offset: Offset of the extent whose IV we are to derive
Michael Halcrow237fead2006-10-04 02:16:22 -0700165 *
166 * Generate the initialization vector from the given root IV and page
167 * offset.
168 *
169 * Returns zero on success; non-zero on error.
170 */
Michael Halcrowa34f60f2009-01-06 14:41:58 -0800171int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
172 loff_t offset)
Michael Halcrow237fead2006-10-04 02:16:22 -0700173{
174 int rc = 0;
175 char dst[MD5_DIGEST_SIZE];
176 char src[ECRYPTFS_MAX_IV_BYTES + 16];
177
178 if (unlikely(ecryptfs_verbosity > 0)) {
179 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
180 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
181 }
182 /* TODO: It is probably secure to just cast the least
183 * significant bits of the root IV into an unsigned long and
184 * add the offset to that rather than go through all this
185 * hashing business. -Halcrow */
186 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
187 memset((src + crypt_stat->iv_bytes), 0, 16);
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700188 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700189 if (unlikely(ecryptfs_verbosity > 0)) {
190 ecryptfs_printk(KERN_DEBUG, "source:\n");
191 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
192 }
193 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
194 (crypt_stat->iv_bytes + 16));
195 if (rc) {
196 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
197 "MD5 while generating IV for a page\n");
198 goto out;
199 }
200 memcpy(iv, dst, crypt_stat->iv_bytes);
201 if (unlikely(ecryptfs_verbosity > 0)) {
202 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
203 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
204 }
205out:
206 return rc;
207}
208
209/**
210 * ecryptfs_init_crypt_stat
211 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
212 *
213 * Initialize the crypt_stat structure.
214 */
215void
216ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
217{
218 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
Michael Halcrowf4aad162007-10-16 01:27:53 -0700219 INIT_LIST_HEAD(&crypt_stat->keysig_list);
220 mutex_init(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700221 mutex_init(&crypt_stat->cs_mutex);
222 mutex_init(&crypt_stat->cs_tfm_mutex);
Michael Halcrow565d97242006-10-30 22:07:17 -0800223 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800224 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
Michael Halcrow237fead2006-10-04 02:16:22 -0700225}
226
227/**
Michael Halcrowfcd12832007-10-16 01:28:01 -0700228 * ecryptfs_destroy_crypt_stat
Michael Halcrow237fead2006-10-04 02:16:22 -0700229 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
230 *
231 * Releases all memory associated with a crypt_stat struct.
232 */
Michael Halcrowfcd12832007-10-16 01:28:01 -0700233void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -0700234{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700235 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
236
Michael Halcrow237fead2006-10-04 02:16:22 -0700237 if (crypt_stat->tfm)
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700238 crypto_free_ablkcipher(crypt_stat->tfm);
Michael Halcrow565d97242006-10-30 22:07:17 -0800239 if (crypt_stat->hash_tfm)
240 crypto_free_hash(crypt_stat->hash_tfm);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700241 list_for_each_entry_safe(key_sig, key_sig_tmp,
242 &crypt_stat->keysig_list, crypt_stat_list) {
243 list_del(&key_sig->crypt_stat_list);
244 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
245 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700246 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
247}
248
Michael Halcrowfcd12832007-10-16 01:28:01 -0700249void ecryptfs_destroy_mount_crypt_stat(
Michael Halcrow237fead2006-10-04 02:16:22 -0700250 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
251{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700252 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
253
254 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
255 return;
256 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
257 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
258 &mount_crypt_stat->global_auth_tok_list,
259 mount_crypt_stat_list) {
260 list_del(&auth_tok->mount_crypt_stat_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700261 if (auth_tok->global_auth_tok_key
262 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
263 key_put(auth_tok->global_auth_tok_key);
264 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
265 }
266 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700267 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
268}
269
270/**
271 * virt_to_scatterlist
272 * @addr: Virtual address
273 * @size: Size of data; should be an even multiple of the block size
274 * @sg: Pointer to scatterlist array; set to NULL to obtain only
275 * the number of scatterlist structs required in array
276 * @sg_size: Max array size
277 *
278 * Fills in a scatterlist array with page references for a passed
279 * virtual address.
280 *
281 * Returns the number of scatterlist structs in array used
282 */
283int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
284 int sg_size)
285{
286 int i = 0;
287 struct page *pg;
288 int offset;
289 int remainder_of_page;
290
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700291 sg_init_table(sg, sg_size);
292
Michael Halcrow237fead2006-10-04 02:16:22 -0700293 while (size > 0 && i < sg_size) {
294 pg = virt_to_page(addr);
295 offset = offset_in_page(addr);
Dan Carpentera07c48a2013-01-26 10:48:42 +0300296 sg_set_page(&sg[i], pg, 0, offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700297 remainder_of_page = PAGE_CACHE_SIZE - offset;
298 if (size >= remainder_of_page) {
Dan Carpentera07c48a2013-01-26 10:48:42 +0300299 sg[i].length = remainder_of_page;
Michael Halcrow237fead2006-10-04 02:16:22 -0700300 addr += remainder_of_page;
301 size -= remainder_of_page;
302 } else {
Dan Carpentera07c48a2013-01-26 10:48:42 +0300303 sg[i].length = size;
Michael Halcrow237fead2006-10-04 02:16:22 -0700304 addr += size;
305 size = 0;
306 }
307 i++;
308 }
309 if (size > 0)
310 return -ENOMEM;
311 return i;
312}
313
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700314struct extent_crypt_result {
315 struct completion completion;
316 int rc;
317};
318
319static void extent_crypt_complete(struct crypto_async_request *req, int rc)
320{
321 struct extent_crypt_result *ecr = req->data;
322
323 if (rc == -EINPROGRESS)
324 return;
325
326 ecr->rc = rc;
327 complete(&ecr->completion);
328}
329
Michael Halcrow237fead2006-10-04 02:16:22 -0700330/**
Tyler Hicks00a69942013-04-05 23:26:22 -0700331 * crypt_scatterlist
Michael Halcrow237fead2006-10-04 02:16:22 -0700332 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700333 * @dst_sg: Destination of the data after performing the crypto operation
Tyler Hicks00a69942013-04-05 23:26:22 -0700334 * @src_sg: Data to be encrypted or decrypted
335 * @size: Length of data
336 * @iv: IV to use
337 * @op: ENCRYPT or DECRYPT to indicate the desired operation
Michael Halcrow237fead2006-10-04 02:16:22 -0700338 *
Tyler Hicks00a69942013-04-05 23:26:22 -0700339 * Returns the number of bytes encrypted or decrypted; negative value on error
Michael Halcrow237fead2006-10-04 02:16:22 -0700340 */
Tyler Hicks00a69942013-04-05 23:26:22 -0700341static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700342 struct scatterlist *dst_sg,
Tyler Hicks00a69942013-04-05 23:26:22 -0700343 struct scatterlist *src_sg, int size,
344 unsigned char *iv, int op)
Michael Halcrow237fead2006-10-04 02:16:22 -0700345{
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700346 struct ablkcipher_request *req = NULL;
347 struct extent_crypt_result ecr;
Michael Halcrow237fead2006-10-04 02:16:22 -0700348 int rc = 0;
349
350 BUG_ON(!crypt_stat || !crypt_stat->tfm
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800351 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
Michael Halcrow237fead2006-10-04 02:16:22 -0700352 if (unlikely(ecryptfs_verbosity > 0)) {
Tyler Hicksf24b3882010-11-15 17:36:38 -0600353 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700354 crypt_stat->key_size);
355 ecryptfs_dump_hex(crypt_stat->key,
356 crypt_stat->key_size);
357 }
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700358
359 init_completion(&ecr.completion);
360
Michael Halcrow237fead2006-10-04 02:16:22 -0700361 mutex_lock(&crypt_stat->cs_tfm_mutex);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700362 req = ablkcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
363 if (!req) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700364 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700365 rc = -ENOMEM;
Michael Halcrow237fead2006-10-04 02:16:22 -0700366 goto out;
367 }
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700368
369 ablkcipher_request_set_callback(req,
370 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
371 extent_crypt_complete, &ecr);
372 /* Consider doing this once, when the file is opened */
373 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
374 rc = crypto_ablkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
375 crypt_stat->key_size);
376 if (rc) {
377 ecryptfs_printk(KERN_ERR,
378 "Error setting key; rc = [%d]\n",
379 rc);
380 mutex_unlock(&crypt_stat->cs_tfm_mutex);
381 rc = -EINVAL;
382 goto out;
383 }
384 crypt_stat->flags |= ECRYPTFS_KEY_SET;
385 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700386 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700387 ablkcipher_request_set_crypt(req, src_sg, dst_sg, size, iv);
Tyler Hicks00a69942013-04-05 23:26:22 -0700388 rc = op == ENCRYPT ? crypto_ablkcipher_encrypt(req) :
389 crypto_ablkcipher_decrypt(req);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700390 if (rc == -EINPROGRESS || rc == -EBUSY) {
391 struct extent_crypt_result *ecr = req->base.data;
392
393 wait_for_completion(&ecr->completion);
394 rc = ecr->rc;
Wolfram Sang16735d02013-11-14 14:32:02 -0800395 reinit_completion(&ecr->completion);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700396 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700397out:
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700398 ablkcipher_request_free(req);
Michael Halcrow237fead2006-10-04 02:16:22 -0700399 return rc;
400}
401
Michael Halcrow237fead2006-10-04 02:16:22 -0700402/**
Tyler Hicks24d15262013-04-15 17:28:09 -0700403 * lower_offset_for_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700404 *
405 * Convert an eCryptfs page index into a lower byte offset
406 */
Tyler Hicks24d15262013-04-15 17:28:09 -0700407static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
408 struct page *page)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700409{
Tyler Hicks24d15262013-04-15 17:28:09 -0700410 return ecryptfs_lower_header_size(crypt_stat) +
Colin Ian King43b7c6c2013-10-24 14:08:07 +0000411 ((loff_t)page->index << PAGE_CACHE_SHIFT);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700412}
413
414/**
Tyler Hicksd78de612013-04-06 00:08:48 -0700415 * crypt_extent
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700416 * @crypt_stat: crypt_stat containing cryptographic context for the
417 * encryption operation
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700418 * @dst_page: The page to write the result into
Tyler Hicksd78de612013-04-06 00:08:48 -0700419 * @src_page: The page to read from
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700420 * @extent_offset: Page extent offset for use in generating IV
Tyler Hicksd78de612013-04-06 00:08:48 -0700421 * @op: ENCRYPT or DECRYPT to indicate the desired operation
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700422 *
Tyler Hicksd78de612013-04-06 00:08:48 -0700423 * Encrypts or decrypts one extent of data.
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700424 *
425 * Return zero on success; non-zero otherwise
426 */
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700427static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat,
428 struct page *dst_page,
Tyler Hicksd78de612013-04-06 00:08:48 -0700429 struct page *src_page,
430 unsigned long extent_offset, int op)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700431{
Tyler Hicksd78de612013-04-06 00:08:48 -0700432 pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index;
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700433 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700434 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
Tyler Hicks406c93d2013-04-15 17:49:31 -0700435 struct scatterlist src_sg, dst_sg;
436 size_t extent_size = crypt_stat->extent_size;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700437 int rc;
438
Tyler Hicks406c93d2013-04-15 17:49:31 -0700439 extent_base = (((loff_t)page_index) * (PAGE_CACHE_SIZE / extent_size));
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700440 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
441 (extent_base + extent_offset));
442 if (rc) {
Joe Perches888d57b2010-11-10 15:46:16 -0800443 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
444 "extent [0x%.16llx]; rc = [%d]\n",
445 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700446 goto out;
447 }
Tyler Hicks406c93d2013-04-15 17:49:31 -0700448
449 sg_init_table(&src_sg, 1);
450 sg_init_table(&dst_sg, 1);
451
452 sg_set_page(&src_sg, src_page, extent_size,
453 extent_offset * extent_size);
454 sg_set_page(&dst_sg, dst_page, extent_size,
455 extent_offset * extent_size);
456
457 rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size,
458 extent_iv, op);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700459 if (rc < 0) {
Tyler Hicksd78de612013-04-06 00:08:48 -0700460 printk(KERN_ERR "%s: Error attempting to crypt page with "
461 "page_index = [%ld], extent_offset = [%ld]; "
462 "rc = [%d]\n", __func__, page_index, extent_offset, rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700463 goto out;
464 }
465 rc = 0;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700466out:
467 return rc;
468}
469
470/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700471 * ecryptfs_encrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700472 * @page: Page mapped from the eCryptfs inode for the file; contains
473 * decrypted content that needs to be encrypted (to a temporary
474 * page; not in place) and written out to the lower file
Michael Halcrow237fead2006-10-04 02:16:22 -0700475 *
476 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
477 * that eCryptfs pages may straddle the lower pages -- for instance,
478 * if the file was created on a machine with an 8K page size
479 * (resulting in an 8K header), and then the file is copied onto a
480 * host with a 32K page size, then when reading page 0 of the eCryptfs
481 * file, 24K of page 0 of the lower file will be read and decrypted,
482 * and then 8K of page 1 of the lower file will be read and decrypted.
483 *
Michael Halcrow237fead2006-10-04 02:16:22 -0700484 * Returns zero on success; negative on error
485 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700486int ecryptfs_encrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700487{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700488 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700489 struct ecryptfs_crypt_stat *crypt_stat;
Eric Sandeen7fcba052008-07-28 15:46:39 -0700490 char *enc_extent_virt;
491 struct page *enc_extent_page = NULL;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700492 loff_t extent_offset;
Tyler Hicks0f896172013-04-15 16:16:24 -0700493 loff_t lower_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700494 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700495
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700496 ecryptfs_inode = page->mapping->host;
497 crypt_stat =
498 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500499 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Eric Sandeen7fcba052008-07-28 15:46:39 -0700500 enc_extent_page = alloc_page(GFP_USER);
501 if (!enc_extent_page) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700502 rc = -ENOMEM;
503 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
504 "encrypted extent\n");
505 goto out;
506 }
Tyler Hicks0f896172013-04-15 16:16:24 -0700507
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700508 for (extent_offset = 0;
509 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
510 extent_offset++) {
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700511 rc = crypt_extent(crypt_stat, enc_extent_page, page,
Tyler Hicksd78de612013-04-06 00:08:48 -0700512 extent_offset, ENCRYPT);
Michael Halcrow237fead2006-10-04 02:16:22 -0700513 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700514 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700515 "rc = [%d]\n", __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700516 goto out;
517 }
Tyler Hicks0f896172013-04-15 16:16:24 -0700518 }
519
Tyler Hicks24d15262013-04-15 17:28:09 -0700520 lower_offset = lower_offset_for_page(crypt_stat, page);
Tyler Hicks0f896172013-04-15 16:16:24 -0700521 enc_extent_virt = kmap(enc_extent_page);
522 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
523 PAGE_CACHE_SIZE);
524 kunmap(enc_extent_page);
525 if (rc < 0) {
526 ecryptfs_printk(KERN_ERR,
527 "Error attempting to write lower page; rc = [%d]\n",
528 rc);
529 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700530 }
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500531 rc = 0;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700532out:
Eric Sandeen7fcba052008-07-28 15:46:39 -0700533 if (enc_extent_page) {
Eric Sandeen7fcba052008-07-28 15:46:39 -0700534 __free_page(enc_extent_page);
535 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700536 return rc;
537}
538
Michael Halcrow237fead2006-10-04 02:16:22 -0700539/**
540 * ecryptfs_decrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700541 * @page: Page mapped from the eCryptfs inode for the file; data read
542 * and decrypted from the lower file will be written into this
543 * page
Michael Halcrow237fead2006-10-04 02:16:22 -0700544 *
545 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
546 * that eCryptfs pages may straddle the lower pages -- for instance,
547 * if the file was created on a machine with an 8K page size
548 * (resulting in an 8K header), and then the file is copied onto a
549 * host with a 32K page size, then when reading page 0 of the eCryptfs
550 * file, 24K of page 0 of the lower file will be read and decrypted,
551 * and then 8K of page 1 of the lower file will be read and decrypted.
552 *
553 * Returns zero on success; negative on error
554 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700555int ecryptfs_decrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700556{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700557 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700558 struct ecryptfs_crypt_stat *crypt_stat;
Tyler Hicks9c6043f2013-04-06 00:41:48 -0700559 char *page_virt;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700560 unsigned long extent_offset;
Tyler Hicks0f896172013-04-15 16:16:24 -0700561 loff_t lower_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700562 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700563
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700564 ecryptfs_inode = page->mapping->host;
565 crypt_stat =
566 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500567 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Tyler Hicks0f896172013-04-15 16:16:24 -0700568
Tyler Hicks24d15262013-04-15 17:28:09 -0700569 lower_offset = lower_offset_for_page(crypt_stat, page);
Tyler Hicks9c6043f2013-04-06 00:41:48 -0700570 page_virt = kmap(page);
571 rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_CACHE_SIZE,
Tyler Hicks0f896172013-04-15 16:16:24 -0700572 ecryptfs_inode);
Tyler Hicks9c6043f2013-04-06 00:41:48 -0700573 kunmap(page);
Tyler Hicks0f896172013-04-15 16:16:24 -0700574 if (rc < 0) {
575 ecryptfs_printk(KERN_ERR,
576 "Error attempting to read lower page; rc = [%d]\n",
577 rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700578 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700579 }
Tyler Hicks0f896172013-04-15 16:16:24 -0700580
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700581 for (extent_offset = 0;
582 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
583 extent_offset++) {
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700584 rc = crypt_extent(crypt_stat, page, page,
Tyler Hicksd78de612013-04-06 00:08:48 -0700585 extent_offset, DECRYPT);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700586 if (rc) {
587 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700588 "rc = [%d]\n", __func__, rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700589 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700590 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700591 }
592out:
Michael Halcrow237fead2006-10-04 02:16:22 -0700593 return rc;
594}
595
Michael Halcrow237fead2006-10-04 02:16:22 -0700596#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
597
598/**
599 * ecryptfs_init_crypt_ctx
Uwe Kleine-König421f91d2010-06-11 12:17:00 +0200600 * @crypt_stat: Uninitialized crypt stats structure
Michael Halcrow237fead2006-10-04 02:16:22 -0700601 *
602 * Initialize the crypto context.
603 *
604 * TODO: Performance: Keep a cache of initialized cipher contexts;
605 * only init if needed
606 */
607int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
608{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800609 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700610 int rc = -EINVAL;
611
Michael Halcrow237fead2006-10-04 02:16:22 -0700612 ecryptfs_printk(KERN_DEBUG,
613 "Initializing cipher [%s]; strlen = [%d]; "
Tyler Hicksf24b3882010-11-15 17:36:38 -0600614 "key_size_bits = [%zd]\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700615 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
616 crypt_stat->key_size << 3);
Kees Cookcb69f362013-08-13 15:02:27 -0700617 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700618 if (crypt_stat->tfm) {
619 rc = 0;
Kees Cookcb69f362013-08-13 15:02:27 -0700620 goto out_unlock;
Michael Halcrow237fead2006-10-04 02:16:22 -0700621 }
Michael Halcrow8bba0662006-10-30 22:07:18 -0800622 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
623 crypt_stat->cipher, "cbc");
624 if (rc)
Eric Sandeenc8161f62007-12-22 14:03:26 -0800625 goto out_unlock;
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700626 crypt_stat->tfm = crypto_alloc_ablkcipher(full_alg_name, 0, 0);
Akinobu Mitade887772006-11-28 12:29:49 -0800627 if (IS_ERR(crypt_stat->tfm)) {
628 rc = PTR_ERR(crypt_stat->tfm);
Tyler Hicksb0105ea2009-08-11 00:36:32 -0500629 crypt_stat->tfm = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -0700630 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
631 "Error initializing cipher [%s]\n",
Kees Cookcb69f362013-08-13 15:02:27 -0700632 full_alg_name);
633 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -0700634 }
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700635 crypto_ablkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow237fead2006-10-04 02:16:22 -0700636 rc = 0;
Kees Cookcb69f362013-08-13 15:02:27 -0700637out_free:
638 kfree(full_alg_name);
Eric Sandeenc8161f62007-12-22 14:03:26 -0800639out_unlock:
640 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700641 return rc;
642}
643
644static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
645{
646 int extent_size_tmp;
647
648 crypt_stat->extent_mask = 0xFFFFFFFF;
649 crypt_stat->extent_shift = 0;
650 if (crypt_stat->extent_size == 0)
651 return;
652 extent_size_tmp = crypt_stat->extent_size;
653 while ((extent_size_tmp & 0x01) == 0) {
654 extent_size_tmp >>= 1;
655 crypt_stat->extent_mask <<= 1;
656 crypt_stat->extent_shift++;
657 }
658}
659
660void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
661{
662 /* Default values; may be overwritten as we are parsing the
663 * packets. */
664 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
665 set_extent_mask_and_shift(crypt_stat);
666 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800667 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600668 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700669 else {
670 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600671 crypt_stat->metadata_size =
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800672 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700673 else
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600674 crypt_stat->metadata_size = PAGE_CACHE_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700675 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700676}
677
678/**
679 * ecryptfs_compute_root_iv
680 * @crypt_stats
681 *
682 * On error, sets the root IV to all 0's.
683 */
684int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
685{
686 int rc = 0;
687 char dst[MD5_DIGEST_SIZE];
688
689 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
690 BUG_ON(crypt_stat->iv_bytes <= 0);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800691 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700692 rc = -EINVAL;
693 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
694 "cannot generate root IV\n");
695 goto out;
696 }
697 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
698 crypt_stat->key_size);
699 if (rc) {
700 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
701 "MD5 while generating root IV\n");
702 goto out;
703 }
704 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
705out:
706 if (rc) {
707 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800708 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
Michael Halcrow237fead2006-10-04 02:16:22 -0700709 }
710 return rc;
711}
712
713static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
714{
715 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800716 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
Michael Halcrow237fead2006-10-04 02:16:22 -0700717 ecryptfs_compute_root_iv(crypt_stat);
718 if (unlikely(ecryptfs_verbosity > 0)) {
719 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
720 ecryptfs_dump_hex(crypt_stat->key,
721 crypt_stat->key_size);
722 }
723}
724
725/**
Michael Halcrow17398952007-02-12 00:53:45 -0800726 * ecryptfs_copy_mount_wide_flags_to_inode_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700727 * @crypt_stat: The inode's cryptographic context
728 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow17398952007-02-12 00:53:45 -0800729 *
730 * This function propagates the mount-wide flags to individual inode
731 * flags.
732 */
733static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
734 struct ecryptfs_crypt_stat *crypt_stat,
735 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
736{
737 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
738 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
739 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
740 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800741 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
742 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
743 if (mount_crypt_stat->flags
744 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
745 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
746 else if (mount_crypt_stat->flags
747 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
748 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
749 }
Michael Halcrow17398952007-02-12 00:53:45 -0800750}
751
Michael Halcrowf4aad162007-10-16 01:27:53 -0700752static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
753 struct ecryptfs_crypt_stat *crypt_stat,
754 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
755{
756 struct ecryptfs_global_auth_tok *global_auth_tok;
757 int rc = 0;
758
Roland Dreieraa061172009-07-01 15:48:18 -0700759 mutex_lock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700760 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
Roland Dreieraa061172009-07-01 15:48:18 -0700761
Michael Halcrowf4aad162007-10-16 01:27:53 -0700762 list_for_each_entry(global_auth_tok,
763 &mount_crypt_stat->global_auth_tok_list,
764 mount_crypt_stat_list) {
Tyler Hicks84814d62009-03-13 13:51:59 -0700765 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
766 continue;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700767 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
768 if (rc) {
769 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700770 goto out;
771 }
772 }
Roland Dreieraa061172009-07-01 15:48:18 -0700773
Michael Halcrowf4aad162007-10-16 01:27:53 -0700774out:
Roland Dreieraa061172009-07-01 15:48:18 -0700775 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
776 mutex_unlock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700777 return rc;
778}
779
Michael Halcrow17398952007-02-12 00:53:45 -0800780/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700781 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700782 * @crypt_stat: The inode's cryptographic context
783 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700784 *
785 * Default values in the event that policy does not override them.
786 */
787static void ecryptfs_set_default_crypt_stat_vals(
788 struct ecryptfs_crypt_stat *crypt_stat,
789 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
790{
Michael Halcrow17398952007-02-12 00:53:45 -0800791 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
792 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700793 ecryptfs_set_default_sizes(crypt_stat);
794 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
795 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800796 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -0700797 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
798 crypt_stat->mount_crypt_stat = mount_crypt_stat;
799}
800
801/**
802 * ecryptfs_new_file_context
Tyler Hicksb59db432011-11-21 17:31:02 -0600803 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrow237fead2006-10-04 02:16:22 -0700804 *
805 * If the crypto context for the file has not yet been established,
806 * this is where we do that. Establishing a new crypto context
807 * involves the following decisions:
808 * - What cipher to use?
809 * - What set of authentication tokens to use?
810 * Here we just worry about getting enough information into the
811 * authentication tokens so that we know that they are available.
812 * We associate the available authentication tokens with the new file
813 * via the set of signatures in the crypt_stat struct. Later, when
814 * the headers are actually written out, we may again defer to
815 * userspace to perform the encryption of the session key; for the
816 * foreseeable future, this will be the case with public key packets.
817 *
818 * Returns zero on success; non-zero otherwise
819 */
Tyler Hicksb59db432011-11-21 17:31:02 -0600820int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
Michael Halcrow237fead2006-10-04 02:16:22 -0700821{
Michael Halcrow237fead2006-10-04 02:16:22 -0700822 struct ecryptfs_crypt_stat *crypt_stat =
Tyler Hicksb59db432011-11-21 17:31:02 -0600823 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700824 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
825 &ecryptfs_superblock_to_private(
Tyler Hicksb59db432011-11-21 17:31:02 -0600826 ecryptfs_inode->i_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700827 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700828 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700829
830 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -0700831 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700832 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
833 mount_crypt_stat);
834 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
835 mount_crypt_stat);
836 if (rc) {
837 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
838 "to the inode key sigs; rc = [%d]\n", rc);
839 goto out;
840 }
841 cipher_name_len =
842 strlen(mount_crypt_stat->global_default_cipher_name);
843 memcpy(crypt_stat->cipher,
844 mount_crypt_stat->global_default_cipher_name,
845 cipher_name_len);
846 crypt_stat->cipher[cipher_name_len] = '\0';
847 crypt_stat->key_size =
848 mount_crypt_stat->global_default_cipher_key_size;
849 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700850 rc = ecryptfs_init_crypt_ctx(crypt_stat);
851 if (rc)
852 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
853 "context for cipher [%s]: rc = [%d]\n",
854 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700855out:
Michael Halcrow237fead2006-10-04 02:16:22 -0700856 return rc;
857}
858
859/**
Tyler Hicks7a866172011-05-02 00:39:54 -0500860 * ecryptfs_validate_marker - check for the ecryptfs marker
Michael Halcrow237fead2006-10-04 02:16:22 -0700861 * @data: The data block in which to check
862 *
Tyler Hicks7a866172011-05-02 00:39:54 -0500863 * Returns zero if marker found; -EINVAL if not found
Michael Halcrow237fead2006-10-04 02:16:22 -0700864 */
Tyler Hicks7a866172011-05-02 00:39:54 -0500865static int ecryptfs_validate_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -0700866{
867 u32 m_1, m_2;
868
Harvey Harrison29335c62008-07-23 21:30:06 -0700869 m_1 = get_unaligned_be32(data);
870 m_2 = get_unaligned_be32(data + 4);
Michael Halcrow237fead2006-10-04 02:16:22 -0700871 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
Tyler Hicks7a866172011-05-02 00:39:54 -0500872 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700873 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
874 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
875 MAGIC_ECRYPTFS_MARKER);
876 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
877 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
Tyler Hicks7a866172011-05-02 00:39:54 -0500878 return -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -0700879}
880
881struct ecryptfs_flag_map_elem {
882 u32 file_flag;
883 u32 local_flag;
884};
885
886/* Add support for additional flags by adding elements here. */
887static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
888 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800889 {0x00000002, ECRYPTFS_ENCRYPTED},
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800890 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
891 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
Michael Halcrow237fead2006-10-04 02:16:22 -0700892};
893
894/**
895 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700896 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700897 * @page_virt: Source data to be parsed
898 * @bytes_read: Updated with the number of bytes read
899 *
900 * Returns zero on success; non-zero if the flag set is invalid
901 */
902static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
903 char *page_virt, int *bytes_read)
904{
905 int rc = 0;
906 int i;
907 u32 flags;
908
Harvey Harrison29335c62008-07-23 21:30:06 -0700909 flags = get_unaligned_be32(page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700910 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
911 / sizeof(struct ecryptfs_flag_map_elem))); i++)
912 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800913 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -0700914 } else
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800915 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
Michael Halcrow237fead2006-10-04 02:16:22 -0700916 /* Version is in top 8 bits of the 32-bit flag vector */
917 crypt_stat->file_version = ((flags >> 24) & 0xFF);
918 (*bytes_read) = 4;
919 return rc;
920}
921
922/**
923 * write_ecryptfs_marker
924 * @page_virt: The pointer to in a page to begin writing the marker
925 * @written: Number of bytes written
926 *
927 * Marker = 0x3c81b7f5
928 */
929static void write_ecryptfs_marker(char *page_virt, size_t *written)
930{
931 u32 m_1, m_2;
932
933 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
934 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
Harvey Harrison29335c62008-07-23 21:30:06 -0700935 put_unaligned_be32(m_1, page_virt);
936 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
937 put_unaligned_be32(m_2, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700938 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
939}
940
Tyler Hicksf4e60e62010-02-11 00:02:32 -0600941void ecryptfs_write_crypt_stat_flags(char *page_virt,
942 struct ecryptfs_crypt_stat *crypt_stat,
943 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -0700944{
945 u32 flags = 0;
946 int i;
947
948 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
949 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800950 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -0700951 flags |= ecryptfs_flag_map[i].file_flag;
952 /* Version is in top 8 bits of the 32-bit flag vector */
953 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
Harvey Harrison29335c62008-07-23 21:30:06 -0700954 put_unaligned_be32(flags, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700955 (*written) = 4;
956}
957
958struct ecryptfs_cipher_code_str_map_elem {
959 char cipher_str[16];
Trevor Highland19e66a62008-02-06 01:38:36 -0800960 u8 cipher_code;
Michael Halcrow237fead2006-10-04 02:16:22 -0700961};
962
963/* Add support for additional ciphers by adding elements here. The
964 * cipher_code is whatever OpenPGP applicatoins use to identify the
965 * ciphers. List in order of probability. */
966static struct ecryptfs_cipher_code_str_map_elem
967ecryptfs_cipher_code_str_map[] = {
968 {"aes",RFC2440_CIPHER_AES_128 },
969 {"blowfish", RFC2440_CIPHER_BLOWFISH},
970 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
971 {"cast5", RFC2440_CIPHER_CAST_5},
972 {"twofish", RFC2440_CIPHER_TWOFISH},
973 {"cast6", RFC2440_CIPHER_CAST_6},
974 {"aes", RFC2440_CIPHER_AES_192},
975 {"aes", RFC2440_CIPHER_AES_256}
976};
977
978/**
979 * ecryptfs_code_for_cipher_string
Michael Halcrow9c79f342009-01-06 14:41:57 -0800980 * @cipher_name: The string alias for the cipher
981 * @key_bytes: Length of key in bytes; used for AES code selection
Michael Halcrow237fead2006-10-04 02:16:22 -0700982 *
983 * Returns zero on no match, or the cipher code on match
984 */
Michael Halcrow9c79f342009-01-06 14:41:57 -0800985u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
Michael Halcrow237fead2006-10-04 02:16:22 -0700986{
987 int i;
Trevor Highland19e66a62008-02-06 01:38:36 -0800988 u8 code = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700989 struct ecryptfs_cipher_code_str_map_elem *map =
990 ecryptfs_cipher_code_str_map;
991
Michael Halcrow9c79f342009-01-06 14:41:57 -0800992 if (strcmp(cipher_name, "aes") == 0) {
993 switch (key_bytes) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700994 case 16:
995 code = RFC2440_CIPHER_AES_128;
996 break;
997 case 24:
998 code = RFC2440_CIPHER_AES_192;
999 break;
1000 case 32:
1001 code = RFC2440_CIPHER_AES_256;
1002 }
1003 } else {
1004 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
Michael Halcrow9c79f342009-01-06 14:41:57 -08001005 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001006 code = map[i].cipher_code;
1007 break;
1008 }
1009 }
1010 return code;
1011}
1012
1013/**
1014 * ecryptfs_cipher_code_to_string
1015 * @str: Destination to write out the cipher name
1016 * @cipher_code: The code to convert to cipher name string
1017 *
1018 * Returns zero on success
1019 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001020int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
Michael Halcrow237fead2006-10-04 02:16:22 -07001021{
1022 int rc = 0;
1023 int i;
1024
1025 str[0] = '\0';
1026 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1027 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1028 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1029 if (str[0] == '\0') {
1030 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1031 "[%d]\n", cipher_code);
1032 rc = -EINVAL;
1033 }
1034 return rc;
1035}
1036
Tyler Hicks778aeb42011-05-24 04:56:23 -05001037int ecryptfs_read_and_validate_header_region(struct inode *inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001038{
Tyler Hicks778aeb42011-05-24 04:56:23 -05001039 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1040 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001041 int rc;
1042
Tyler Hicks778aeb42011-05-24 04:56:23 -05001043 rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
1044 inode);
1045 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1046 return rc >= 0 ? -EINVAL : rc;
1047 rc = ecryptfs_validate_marker(marker);
1048 if (!rc)
1049 ecryptfs_i_size_init(file_size, inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001050 return rc;
1051}
1052
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001053void
1054ecryptfs_write_header_metadata(char *virt,
1055 struct ecryptfs_crypt_stat *crypt_stat,
1056 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001057{
1058 u32 header_extent_size;
1059 u16 num_header_extents_at_front;
1060
Michael Halcrow45eaab72007-10-16 01:28:05 -07001061 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001062 num_header_extents_at_front =
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001063 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
Harvey Harrison29335c62008-07-23 21:30:06 -07001064 put_unaligned_be32(header_extent_size, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001065 virt += 4;
Harvey Harrison29335c62008-07-23 21:30:06 -07001066 put_unaligned_be16(num_header_extents_at_front, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001067 (*written) = 6;
1068}
1069
Tyler Hicks30632872011-05-24 05:11:12 -05001070struct kmem_cache *ecryptfs_header_cache;
Michael Halcrow237fead2006-10-04 02:16:22 -07001071
1072/**
1073 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001074 * @page_virt: The virtual address to write the headers to
Eric Sandeen87b811c2008-10-29 14:01:08 -07001075 * @max: The size of memory allocated at page_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001076 * @size: Set to the number of bytes written by this function
1077 * @crypt_stat: The cryptographic context
1078 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001079 *
1080 * Format version: 1
1081 *
1082 * Header Extent:
1083 * Octets 0-7: Unencrypted file size (big-endian)
1084 * Octets 8-15: eCryptfs special marker
1085 * Octets 16-19: Flags
1086 * Octet 16: File format version number (between 0 and 255)
1087 * Octets 17-18: Reserved
1088 * Octet 19: Bit 1 (lsb): Reserved
1089 * Bit 2: Encrypted?
1090 * Bits 3-8: Reserved
1091 * Octets 20-23: Header extent size (big-endian)
1092 * Octets 24-25: Number of header extents at front of file
1093 * (big-endian)
1094 * Octet 26: Begin RFC 2440 authentication token packet set
1095 * Data Extent 0:
1096 * Lower data (CBC encrypted)
1097 * Data Extent 1:
1098 * Lower data (CBC encrypted)
1099 * ...
1100 *
1101 * Returns zero on success
1102 */
Eric Sandeen87b811c2008-10-29 14:01:08 -07001103static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1104 size_t *size,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001105 struct ecryptfs_crypt_stat *crypt_stat,
1106 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001107{
1108 int rc;
1109 size_t written;
1110 size_t offset;
1111
1112 offset = ECRYPTFS_FILE_SIZE_BYTES;
1113 write_ecryptfs_marker((page_virt + offset), &written);
1114 offset += written;
Tyler Hicksf4e60e62010-02-11 00:02:32 -06001115 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1116 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001117 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001118 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1119 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001120 offset += written;
1121 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1122 ecryptfs_dentry, &written,
Eric Sandeen87b811c2008-10-29 14:01:08 -07001123 max - offset);
Michael Halcrow237fead2006-10-04 02:16:22 -07001124 if (rc)
1125 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1126 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001127 if (size) {
1128 offset += written;
1129 *size = offset;
1130 }
1131 return rc;
1132}
1133
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001134static int
Tyler Hicksb59db432011-11-21 17:31:02 -06001135ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
Tyler Hicks8faece52009-03-20 01:25:09 -05001136 char *virt, size_t virt_len)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001137{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001138 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001139
Tyler Hicksb59db432011-11-21 17:31:02 -06001140 rc = ecryptfs_write_lower(ecryptfs_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001141 0, virt_len);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001142 if (rc < 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001143 printk(KERN_ERR "%s: Error attempting to write header "
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001144 "information to lower file; rc = [%d]\n", __func__, rc);
1145 else
1146 rc = 0;
Michael Halcrow70456602007-02-12 00:53:48 -08001147 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001148}
1149
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001150static int
1151ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001152 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001153{
1154 int rc;
1155
1156 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1157 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001158 return rc;
1159}
1160
Tyler Hicks8faece52009-03-20 01:25:09 -05001161static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1162 unsigned int order)
1163{
1164 struct page *page;
1165
1166 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1167 if (page)
1168 return (unsigned long) page_address(page);
1169 return 0;
1170}
1171
Michael Halcrow237fead2006-10-04 02:16:22 -07001172/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001173 * ecryptfs_write_metadata
Tyler Hicksb59db432011-11-21 17:31:02 -06001174 * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1175 * @ecryptfs_inode: The newly created eCryptfs inode
Michael Halcrow237fead2006-10-04 02:16:22 -07001176 *
1177 * Write the file headers out. This will likely involve a userspace
1178 * callout, in which the session key is encrypted with one or more
1179 * public keys and/or the passphrase necessary to do the encryption is
1180 * retrieved via a prompt. Exactly what happens at this point should
1181 * be policy-dependent.
1182 *
1183 * Returns zero on success; non-zero on error
1184 */
Tyler Hicksb59db432011-11-21 17:31:02 -06001185int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1186 struct inode *ecryptfs_inode)
Michael Halcrow237fead2006-10-04 02:16:22 -07001187{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001188 struct ecryptfs_crypt_stat *crypt_stat =
Tyler Hicksb59db432011-11-21 17:31:02 -06001189 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Tyler Hicks8faece52009-03-20 01:25:09 -05001190 unsigned int order;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001191 char *virt;
Tyler Hicks8faece52009-03-20 01:25:09 -05001192 size_t virt_len;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001193 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001194 int rc = 0;
1195
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001196 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1197 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001198 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001199 rc = -EINVAL;
1200 goto out;
1201 }
1202 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001203 printk(KERN_WARNING "%s: Encrypted flag not set\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001204 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001205 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001206 goto out;
1207 }
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001208 virt_len = crypt_stat->metadata_size;
Tyler Hicks8faece52009-03-20 01:25:09 -05001209 order = get_order(virt_len);
Michael Halcrow237fead2006-10-04 02:16:22 -07001210 /* Released in this function */
Tyler Hicks8faece52009-03-20 01:25:09 -05001211 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001212 if (!virt) {
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001213 printk(KERN_ERR "%s: Out of memory\n", __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001214 rc = -ENOMEM;
1215 goto out;
1216 }
Tyler Hicksbd4f0fe2011-02-23 00:14:19 -06001217 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
Tyler Hicks8faece52009-03-20 01:25:09 -05001218 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1219 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001220 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001221 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001222 __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001223 goto out_free;
1224 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001225 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicks8faece52009-03-20 01:25:09 -05001226 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1227 size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001228 else
Tyler Hicksb59db432011-11-21 17:31:02 -06001229 rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001230 virt_len);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001231 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001232 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001233 "rc = [%d]\n", __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001234 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001235 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001236out_free:
Tyler Hicks8faece52009-03-20 01:25:09 -05001237 free_pages((unsigned long)virt, order);
Michael Halcrow237fead2006-10-04 02:16:22 -07001238out:
1239 return rc;
1240}
1241
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001242#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1243#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001244static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001245 char *virt, int *bytes_read,
1246 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001247{
1248 int rc = 0;
1249 u32 header_extent_size;
1250 u16 num_header_extents_at_front;
1251
Harvey Harrison29335c62008-07-23 21:30:06 -07001252 header_extent_size = get_unaligned_be32(virt);
1253 virt += sizeof(__be32);
1254 num_header_extents_at_front = get_unaligned_be16(virt);
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001255 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1256 * (size_t)header_extent_size));
Harvey Harrison29335c62008-07-23 21:30:06 -07001257 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001258 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001259 && (crypt_stat->metadata_size
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001260 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001261 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001262 printk(KERN_WARNING "Invalid header size: [%zd]\n",
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001263 crypt_stat->metadata_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001264 }
1265 return rc;
1266}
1267
1268/**
1269 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001270 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001271 *
1272 * For version 0 file format; this function is only for backwards
1273 * compatibility for files created with the prior versions of
1274 * eCryptfs.
1275 */
1276static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1277{
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001278 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001279}
1280
Tyler Hicks3aeb86e2011-03-15 14:54:00 -05001281void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1282{
1283 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1284 struct ecryptfs_crypt_stat *crypt_stat;
1285 u64 file_size;
1286
1287 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1288 mount_crypt_stat =
1289 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1290 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1291 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1292 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1293 file_size += crypt_stat->metadata_size;
1294 } else
1295 file_size = get_unaligned_be64(page_virt);
1296 i_size_write(inode, (loff_t)file_size);
1297 crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1298}
1299
Michael Halcrow237fead2006-10-04 02:16:22 -07001300/**
1301 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001302 * @page_virt: The virtual address into which to read the headers
1303 * @crypt_stat: The cryptographic context
1304 * @ecryptfs_dentry: The eCryptfs dentry
1305 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001306 *
1307 * Read/parse the header data. The header format is detailed in the
1308 * comment block for the ecryptfs_write_headers_virt() function.
1309 *
1310 * Returns zero on success
1311 */
1312static int ecryptfs_read_headers_virt(char *page_virt,
1313 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001314 struct dentry *ecryptfs_dentry,
1315 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001316{
1317 int rc = 0;
1318 int offset;
1319 int bytes_read;
1320
1321 ecryptfs_set_default_sizes(crypt_stat);
1322 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1323 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1324 offset = ECRYPTFS_FILE_SIZE_BYTES;
Tyler Hicks7a866172011-05-02 00:39:54 -05001325 rc = ecryptfs_validate_marker(page_virt + offset);
1326 if (rc)
Michael Halcrow237fead2006-10-04 02:16:22 -07001327 goto out;
Tyler Hicks3aeb86e2011-03-15 14:54:00 -05001328 if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1329 ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -07001330 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1331 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1332 &bytes_read);
1333 if (rc) {
1334 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1335 goto out;
1336 }
1337 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1338 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1339 "file version [%d] is supported by this "
1340 "version of eCryptfs\n",
1341 crypt_stat->file_version,
1342 ECRYPTFS_SUPPORTED_FILE_VERSION);
1343 rc = -EINVAL;
1344 goto out;
1345 }
1346 offset += bytes_read;
1347 if (crypt_stat->file_version >= 1) {
1348 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001349 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001350 if (rc) {
1351 ecryptfs_printk(KERN_WARNING, "Error reading header "
1352 "metadata; rc = [%d]\n", rc);
1353 }
1354 offset += bytes_read;
1355 } else
1356 set_default_header_data(crypt_stat);
1357 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1358 ecryptfs_dentry);
1359out:
1360 return rc;
1361}
1362
1363/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001364 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001365 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001366 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001367 *
1368 * Attempts to read the crypto metadata from the extended attribute
1369 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001370 *
1371 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001372 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001373int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001374{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001375 struct dentry *lower_dentry =
1376 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001377 ssize_t size;
1378 int rc = 0;
1379
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001380 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1381 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001382 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001383 if (unlikely(ecryptfs_verbosity > 0))
1384 printk(KERN_INFO "Error attempting to read the [%s] "
1385 "xattr from the lower file; return value = "
1386 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001387 rc = -EINVAL;
1388 goto out;
1389 }
1390out:
1391 return rc;
1392}
1393
Tyler Hicks778aeb42011-05-24 04:56:23 -05001394int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
Tyler Hicks3b06b3e2011-05-24 03:49:02 -05001395 struct inode *inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001396{
Tyler Hicks778aeb42011-05-24 04:56:23 -05001397 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1398 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001399 int rc;
1400
Tyler Hicks778aeb42011-05-24 04:56:23 -05001401 rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1402 ECRYPTFS_XATTR_NAME, file_size,
1403 ECRYPTFS_SIZE_AND_MARKER_BYTES);
1404 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1405 return rc >= 0 ? -EINVAL : rc;
1406 rc = ecryptfs_validate_marker(marker);
1407 if (!rc)
1408 ecryptfs_i_size_init(file_size, inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001409 return rc;
1410}
1411
1412/**
1413 * ecryptfs_read_metadata
1414 *
1415 * Common entry point for reading file metadata. From here, we could
1416 * retrieve the header information from the header region of the file,
1417 * the xattr region of the file, or some other repostory that is
1418 * stored separately from the file itself. The current implementation
1419 * supports retrieving the metadata information from the file contents
1420 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001421 *
1422 * Returns zero if valid headers found and parsed; non-zero otherwise
1423 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001424int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001425{
Tim Gardnerbb450362012-01-12 16:31:55 +01001426 int rc;
1427 char *page_virt;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001428 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -07001429 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001430 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001431 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1432 &ecryptfs_superblock_to_private(
1433 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001434
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001435 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1436 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001437 /* Read the first page from the underlying file */
Tyler Hicks30632872011-05-24 05:11:12 -05001438 page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001439 if (!page_virt) {
1440 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001441 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001442 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001443 goto out;
1444 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001445 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1446 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001447 if (rc >= 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001448 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1449 ecryptfs_dentry,
1450 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001451 if (rc) {
Tim Gardnerbb450362012-01-12 16:31:55 +01001452 /* metadata is not in the file header, so try xattrs */
Tyler Hicks1984c232010-02-10 23:17:44 -06001453 memset(page_virt, 0, PAGE_CACHE_SIZE);
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001454 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001455 if (rc) {
1456 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
Tim Gardner30373dc2012-01-12 16:31:55 +01001457 "file header region or xattr region, inode %lu\n",
1458 ecryptfs_inode->i_ino);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001459 rc = -EINVAL;
1460 goto out;
1461 }
1462 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1463 ecryptfs_dentry,
1464 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1465 if (rc) {
1466 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
Tim Gardner30373dc2012-01-12 16:31:55 +01001467 "file xattr region either, inode %lu\n",
1468 ecryptfs_inode->i_ino);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001469 rc = -EINVAL;
1470 }
1471 if (crypt_stat->mount_crypt_stat->flags
1472 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1473 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1474 } else {
1475 printk(KERN_WARNING "Attempt to access file with "
1476 "crypto metadata only in the extended attribute "
1477 "region, but eCryptfs was mounted without "
1478 "xattr support enabled. eCryptfs will not treat "
Tim Gardner30373dc2012-01-12 16:31:55 +01001479 "this like an encrypted file, inode %lu\n",
1480 ecryptfs_inode->i_ino);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001481 rc = -EINVAL;
1482 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001483 }
1484out:
1485 if (page_virt) {
1486 memset(page_virt, 0, PAGE_CACHE_SIZE);
Tyler Hicks30632872011-05-24 05:11:12 -05001487 kmem_cache_free(ecryptfs_header_cache, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001488 }
1489 return rc;
1490}
1491
1492/**
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001493 * ecryptfs_encrypt_filename - encrypt filename
1494 *
1495 * CBC-encrypts the filename. We do not want to encrypt the same
1496 * filename with the same key and IV, which may happen with hard
1497 * links, so we prepend random bits to each filename.
1498 *
1499 * Returns zero on success; non-zero otherwise
1500 */
1501static int
1502ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1503 struct ecryptfs_crypt_stat *crypt_stat,
1504 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1505{
1506 int rc = 0;
1507
1508 filename->encrypted_filename = NULL;
1509 filename->encrypted_filename_size = 0;
1510 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1511 || (mount_crypt_stat && (mount_crypt_stat->flags
1512 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1513 size_t packet_size;
1514 size_t remaining_bytes;
1515
1516 rc = ecryptfs_write_tag_70_packet(
1517 NULL, NULL,
1518 &filename->encrypted_filename_size,
1519 mount_crypt_stat, NULL,
1520 filename->filename_size);
1521 if (rc) {
1522 printk(KERN_ERR "%s: Error attempting to get packet "
1523 "size for tag 72; rc = [%d]\n", __func__,
1524 rc);
1525 filename->encrypted_filename_size = 0;
1526 goto out;
1527 }
1528 filename->encrypted_filename =
1529 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1530 if (!filename->encrypted_filename) {
1531 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08001532 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001533 filename->encrypted_filename_size);
1534 rc = -ENOMEM;
1535 goto out;
1536 }
1537 remaining_bytes = filename->encrypted_filename_size;
1538 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1539 &remaining_bytes,
1540 &packet_size,
1541 mount_crypt_stat,
1542 filename->filename,
1543 filename->filename_size);
1544 if (rc) {
1545 printk(KERN_ERR "%s: Error attempting to generate "
1546 "tag 70 packet; rc = [%d]\n", __func__,
1547 rc);
1548 kfree(filename->encrypted_filename);
1549 filename->encrypted_filename = NULL;
1550 filename->encrypted_filename_size = 0;
1551 goto out;
1552 }
1553 filename->encrypted_filename_size = packet_size;
1554 } else {
1555 printk(KERN_ERR "%s: No support for requested filename "
1556 "encryption method in this release\n", __func__);
Tyler Hicksdf6ad332009-08-21 04:27:46 -05001557 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001558 goto out;
1559 }
1560out:
1561 return rc;
1562}
1563
1564static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1565 const char *name, size_t name_size)
1566{
1567 int rc = 0;
1568
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001569 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001570 if (!(*copied_name)) {
1571 rc = -ENOMEM;
1572 goto out;
1573 }
1574 memcpy((void *)(*copied_name), (void *)name, name_size);
1575 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1576 * in printing out the
1577 * string in debug
1578 * messages */
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001579 (*copied_name_size) = name_size;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001580out:
1581 return rc;
1582}
1583
1584/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001585 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001586 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001587 * @cipher_name: Name of the cipher
1588 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001589 *
1590 * Returns zero on success. Any crypto_tfm structs allocated here
1591 * should be released by other functions, such as on a superblock put
1592 * event, regardless of whether this function succeeds for fails.
1593 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001594static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001595ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1596 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001597{
1598 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Dan Carpenterece550f2010-01-19 12:34:32 +03001599 char *full_alg_name = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001600 int rc;
1601
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001602 *key_tfm = NULL;
1603 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001604 rc = -EINVAL;
Michael Halcrowdf261c52009-01-06 14:42:02 -08001605 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001606 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001607 goto out;
1608 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001609 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1610 "ecb");
1611 if (rc)
1612 goto out;
1613 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001614 if (IS_ERR(*key_tfm)) {
1615 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001616 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Dave Hansen38268492009-08-27 09:47:07 -07001617 "[%s]; rc = [%d]\n", full_alg_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001618 goto out;
1619 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001620 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1621 if (*key_size == 0) {
1622 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1623
1624 *key_size = alg->max_keysize;
1625 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001626 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001627 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001628 if (rc) {
Michael Halcrowdf261c52009-01-06 14:42:02 -08001629 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
Dave Hansen38268492009-08-27 09:47:07 -07001630 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1631 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001632 rc = -EINVAL;
1633 goto out;
1634 }
1635out:
Dan Carpenterece550f2010-01-19 12:34:32 +03001636 kfree(full_alg_name);
Michael Halcrow237fead2006-10-04 02:16:22 -07001637 return rc;
1638}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001639
1640struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001641static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001642struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001643
Jerome Marchand7371a382010-08-17 17:24:05 +02001644int __init ecryptfs_init_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001645{
1646 mutex_init(&key_tfm_list_mutex);
1647 INIT_LIST_HEAD(&key_tfm_list);
1648 return 0;
1649}
1650
Eric Sandeenaf440f52008-02-06 01:38:37 -08001651/**
1652 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1653 *
1654 * Called only at module unload time
1655 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001656int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001657{
1658 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1659
1660 mutex_lock(&key_tfm_list_mutex);
1661 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1662 key_tfm_list) {
1663 list_del(&key_tfm->key_tfm_list);
1664 if (key_tfm->key_tfm)
1665 crypto_free_blkcipher(key_tfm->key_tfm);
1666 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1667 }
1668 mutex_unlock(&key_tfm_list_mutex);
1669 return 0;
1670}
1671
1672int
1673ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1674 size_t key_size)
1675{
1676 struct ecryptfs_key_tfm *tmp_tfm;
1677 int rc = 0;
1678
Eric Sandeenaf440f52008-02-06 01:38:37 -08001679 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1680
Michael Halcrowf4aad162007-10-16 01:27:53 -07001681 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1682 if (key_tfm != NULL)
1683 (*key_tfm) = tmp_tfm;
1684 if (!tmp_tfm) {
1685 rc = -ENOMEM;
1686 printk(KERN_ERR "Error attempting to allocate from "
1687 "ecryptfs_key_tfm_cache\n");
1688 goto out;
1689 }
1690 mutex_init(&tmp_tfm->key_tfm_mutex);
1691 strncpy(tmp_tfm->cipher_name, cipher_name,
1692 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001693 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001694 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001695 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1696 tmp_tfm->cipher_name,
1697 &tmp_tfm->key_size);
1698 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001699 printk(KERN_ERR "Error attempting to initialize key TFM "
1700 "cipher with name = [%s]; rc = [%d]\n",
1701 tmp_tfm->cipher_name, rc);
1702 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1703 if (key_tfm != NULL)
1704 (*key_tfm) = NULL;
1705 goto out;
1706 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001707 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001708out:
1709 return rc;
1710}
1711
Eric Sandeenaf440f52008-02-06 01:38:37 -08001712/**
1713 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1714 * @cipher_name: the name of the cipher to search for
1715 * @key_tfm: set to corresponding tfm if found
1716 *
1717 * Searches for cached key_tfm matching @cipher_name
1718 * Must be called with &key_tfm_list_mutex held
1719 * Returns 1 if found, with @key_tfm set
1720 * Returns 0 if not found, with @key_tfm set to NULL
1721 */
1722int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1723{
1724 struct ecryptfs_key_tfm *tmp_key_tfm;
1725
1726 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1727
1728 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1729 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1730 if (key_tfm)
1731 (*key_tfm) = tmp_key_tfm;
1732 return 1;
1733 }
1734 }
1735 if (key_tfm)
1736 (*key_tfm) = NULL;
1737 return 0;
1738}
1739
1740/**
1741 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1742 *
1743 * @tfm: set to cached tfm found, or new tfm created
1744 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1745 * @cipher_name: the name of the cipher to search for and/or add
1746 *
1747 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1748 * Searches for cached item first, and creates new if not found.
1749 * Returns 0 on success, non-zero if adding new cipher failed
1750 */
Michael Halcrowf4aad162007-10-16 01:27:53 -07001751int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1752 struct mutex **tfm_mutex,
1753 char *cipher_name)
1754{
1755 struct ecryptfs_key_tfm *key_tfm;
1756 int rc = 0;
1757
1758 (*tfm) = NULL;
1759 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001760
Michael Halcrowf4aad162007-10-16 01:27:53 -07001761 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001762 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1763 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1764 if (rc) {
1765 printk(KERN_ERR "Error adding new key_tfm to list; "
1766 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001767 goto out;
1768 }
1769 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001770 (*tfm) = key_tfm->key_tfm;
1771 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1772out:
Cyrill Gorcunov71fd5172008-05-23 13:04:20 -07001773 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001774 return rc;
1775}
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001776
1777/* 64 characters forming a 6-bit target field */
1778static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1779 "EFGHIJKLMNOPQRST"
1780 "UVWXYZabcdefghij"
1781 "klmnopqrstuvwxyz");
1782
1783/* We could either offset on every reverse map or just pad some 0x00's
1784 * at the front here */
Tyler Hicks0f751e62011-11-23 11:31:24 -06001785static const unsigned char filename_rev_map[256] = {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001786 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1787 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1788 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1789 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1790 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1791 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1792 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1793 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1794 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1795 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1796 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1797 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1798 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1799 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1800 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
Tyler Hicks0f751e62011-11-23 11:31:24 -06001801 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001802};
1803
1804/**
1805 * ecryptfs_encode_for_filename
1806 * @dst: Destination location for encoded filename
1807 * @dst_size: Size of the encoded filename in bytes
1808 * @src: Source location for the filename to encode
1809 * @src_size: Size of the source in bytes
1810 */
Cong Ding37028752012-12-07 22:21:56 +00001811static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001812 unsigned char *src, size_t src_size)
1813{
1814 size_t num_blocks;
1815 size_t block_num = 0;
1816 size_t dst_offset = 0;
1817 unsigned char last_block[3];
1818
1819 if (src_size == 0) {
1820 (*dst_size) = 0;
1821 goto out;
1822 }
1823 num_blocks = (src_size / 3);
1824 if ((src_size % 3) == 0) {
1825 memcpy(last_block, (&src[src_size - 3]), 3);
1826 } else {
1827 num_blocks++;
1828 last_block[2] = 0x00;
1829 switch (src_size % 3) {
1830 case 1:
1831 last_block[0] = src[src_size - 1];
1832 last_block[1] = 0x00;
1833 break;
1834 case 2:
1835 last_block[0] = src[src_size - 2];
1836 last_block[1] = src[src_size - 1];
1837 }
1838 }
1839 (*dst_size) = (num_blocks * 4);
1840 if (!dst)
1841 goto out;
1842 while (block_num < num_blocks) {
1843 unsigned char *src_block;
1844 unsigned char dst_block[4];
1845
1846 if (block_num == (num_blocks - 1))
1847 src_block = last_block;
1848 else
1849 src_block = &src[block_num * 3];
1850 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
1851 dst_block[1] = (((src_block[0] << 4) & 0x30)
1852 | ((src_block[1] >> 4) & 0x0F));
1853 dst_block[2] = (((src_block[1] << 2) & 0x3C)
1854 | ((src_block[2] >> 6) & 0x03));
1855 dst_block[3] = (src_block[2] & 0x3F);
1856 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
1857 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
1858 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
1859 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
1860 block_num++;
1861 }
1862out:
1863 return;
1864}
1865
Tyler Hicks4a266202011-11-05 13:45:08 -04001866static size_t ecryptfs_max_decoded_size(size_t encoded_size)
1867{
1868 /* Not exact; conservatively long. Every block of 4
1869 * encoded characters decodes into a block of 3
1870 * decoded characters. This segment of code provides
1871 * the caller with the maximum amount of allocated
1872 * space that @dst will need to point to in a
1873 * subsequent call. */
1874 return ((encoded_size + 1) * 3) / 4;
1875}
1876
Michael Halcrow71c11c32009-01-06 14:42:05 -08001877/**
1878 * ecryptfs_decode_from_filename
1879 * @dst: If NULL, this function only sets @dst_size and returns. If
1880 * non-NULL, this function decodes the encoded octets in @src
1881 * into the memory that @dst points to.
1882 * @dst_size: Set to the size of the decoded string.
1883 * @src: The encoded set of octets to decode.
1884 * @src_size: The size of the encoded set of octets to decode.
1885 */
1886static void
1887ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
1888 const unsigned char *src, size_t src_size)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001889{
1890 u8 current_bit_offset = 0;
1891 size_t src_byte_offset = 0;
1892 size_t dst_byte_offset = 0;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001893
1894 if (dst == NULL) {
Tyler Hicks4a266202011-11-05 13:45:08 -04001895 (*dst_size) = ecryptfs_max_decoded_size(src_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001896 goto out;
1897 }
1898 while (src_byte_offset < src_size) {
1899 unsigned char src_byte =
1900 filename_rev_map[(int)src[src_byte_offset]];
1901
1902 switch (current_bit_offset) {
1903 case 0:
1904 dst[dst_byte_offset] = (src_byte << 2);
1905 current_bit_offset = 6;
1906 break;
1907 case 6:
1908 dst[dst_byte_offset++] |= (src_byte >> 4);
1909 dst[dst_byte_offset] = ((src_byte & 0xF)
1910 << 4);
1911 current_bit_offset = 4;
1912 break;
1913 case 4:
1914 dst[dst_byte_offset++] |= (src_byte >> 2);
1915 dst[dst_byte_offset] = (src_byte << 6);
1916 current_bit_offset = 2;
1917 break;
1918 case 2:
1919 dst[dst_byte_offset++] |= (src_byte);
1920 dst[dst_byte_offset] = 0;
1921 current_bit_offset = 0;
1922 break;
1923 }
1924 src_byte_offset++;
1925 }
1926 (*dst_size) = dst_byte_offset;
1927out:
Michael Halcrow71c11c32009-01-06 14:42:05 -08001928 return;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001929}
1930
1931/**
1932 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
1933 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1934 * @name: The plaintext name
1935 * @length: The length of the plaintext
1936 * @encoded_name: The encypted name
1937 *
1938 * Encrypts and encodes a filename into something that constitutes a
1939 * valid filename for a filesystem, with printable characters.
1940 *
1941 * We assume that we have a properly initialized crypto context,
1942 * pointed to by crypt_stat->tfm.
1943 *
1944 * Returns zero on success; non-zero on otherwise
1945 */
1946int ecryptfs_encrypt_and_encode_filename(
1947 char **encoded_name,
1948 size_t *encoded_name_size,
1949 struct ecryptfs_crypt_stat *crypt_stat,
1950 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1951 const char *name, size_t name_size)
1952{
1953 size_t encoded_name_no_prefix_size;
1954 int rc = 0;
1955
1956 (*encoded_name) = NULL;
1957 (*encoded_name_size) = 0;
1958 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
1959 || (mount_crypt_stat && (mount_crypt_stat->flags
1960 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
1961 struct ecryptfs_filename *filename;
1962
1963 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
1964 if (!filename) {
1965 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08001966 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001967 sizeof(*filename));
1968 rc = -ENOMEM;
1969 goto out;
1970 }
1971 filename->filename = (char *)name;
1972 filename->filename_size = name_size;
1973 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
1974 mount_crypt_stat);
1975 if (rc) {
1976 printk(KERN_ERR "%s: Error attempting to encrypt "
1977 "filename; rc = [%d]\n", __func__, rc);
1978 kfree(filename);
1979 goto out;
1980 }
1981 ecryptfs_encode_for_filename(
1982 NULL, &encoded_name_no_prefix_size,
1983 filename->encrypted_filename,
1984 filename->encrypted_filename_size);
1985 if ((crypt_stat && (crypt_stat->flags
1986 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1987 || (mount_crypt_stat
1988 && (mount_crypt_stat->flags
1989 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
1990 (*encoded_name_size) =
1991 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1992 + encoded_name_no_prefix_size);
1993 else
1994 (*encoded_name_size) =
1995 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1996 + encoded_name_no_prefix_size);
1997 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
1998 if (!(*encoded_name)) {
1999 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002000 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002001 (*encoded_name_size));
2002 rc = -ENOMEM;
2003 kfree(filename->encrypted_filename);
2004 kfree(filename);
2005 goto out;
2006 }
2007 if ((crypt_stat && (crypt_stat->flags
2008 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2009 || (mount_crypt_stat
2010 && (mount_crypt_stat->flags
2011 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2012 memcpy((*encoded_name),
2013 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2014 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2015 ecryptfs_encode_for_filename(
2016 ((*encoded_name)
2017 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2018 &encoded_name_no_prefix_size,
2019 filename->encrypted_filename,
2020 filename->encrypted_filename_size);
2021 (*encoded_name_size) =
2022 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2023 + encoded_name_no_prefix_size);
2024 (*encoded_name)[(*encoded_name_size)] = '\0';
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002025 } else {
Tyler Hicksdf6ad332009-08-21 04:27:46 -05002026 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002027 }
2028 if (rc) {
2029 printk(KERN_ERR "%s: Error attempting to encode "
2030 "encrypted filename; rc = [%d]\n", __func__,
2031 rc);
2032 kfree((*encoded_name));
2033 (*encoded_name) = NULL;
2034 (*encoded_name_size) = 0;
2035 }
2036 kfree(filename->encrypted_filename);
2037 kfree(filename);
2038 } else {
2039 rc = ecryptfs_copy_filename(encoded_name,
2040 encoded_name_size,
2041 name, name_size);
2042 }
2043out:
2044 return rc;
2045}
2046
2047/**
2048 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2049 * @plaintext_name: The plaintext name
2050 * @plaintext_name_size: The plaintext name size
2051 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2052 * @name: The filename in cipher text
2053 * @name_size: The cipher text name size
2054 *
2055 * Decrypts and decodes the filename.
2056 *
2057 * Returns zero on error; non-zero otherwise
2058 */
2059int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2060 size_t *plaintext_name_size,
Al Viro0747fdb2013-06-16 20:05:38 +04002061 struct super_block *sb,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002062 const char *name, size_t name_size)
2063{
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002064 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
Al Viro0747fdb2013-06-16 20:05:38 +04002065 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002066 char *decoded_name;
2067 size_t decoded_name_size;
2068 size_t packet_size;
2069 int rc = 0;
2070
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002071 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2072 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2073 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002074 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2075 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002076 const char *orig_name = name;
2077 size_t orig_name_size = name_size;
2078
2079 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2080 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
Michael Halcrow71c11c32009-01-06 14:42:05 -08002081 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2082 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002083 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2084 if (!decoded_name) {
2085 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08002086 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002087 decoded_name_size);
2088 rc = -ENOMEM;
2089 goto out;
2090 }
Michael Halcrow71c11c32009-01-06 14:42:05 -08002091 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2092 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002093 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2094 plaintext_name_size,
2095 &packet_size,
2096 mount_crypt_stat,
2097 decoded_name,
2098 decoded_name_size);
2099 if (rc) {
2100 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2101 "from filename; copying through filename "
2102 "as-is\n", __func__);
2103 rc = ecryptfs_copy_filename(plaintext_name,
2104 plaintext_name_size,
2105 orig_name, orig_name_size);
2106 goto out_free;
2107 }
2108 } else {
2109 rc = ecryptfs_copy_filename(plaintext_name,
2110 plaintext_name_size,
2111 name, name_size);
2112 goto out;
2113 }
2114out_free:
2115 kfree(decoded_name);
2116out:
2117 return rc;
2118}
Tyler Hicks4a266202011-11-05 13:45:08 -04002119
2120#define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
2121
2122int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
2123 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
2124{
2125 struct blkcipher_desc desc;
2126 struct mutex *tfm_mutex;
2127 size_t cipher_blocksize;
2128 int rc;
2129
2130 if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
2131 (*namelen) = lower_namelen;
2132 return 0;
2133 }
2134
2135 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2136 mount_crypt_stat->global_default_fn_cipher_name);
2137 if (unlikely(rc)) {
2138 (*namelen) = 0;
2139 return rc;
2140 }
2141
2142 mutex_lock(tfm_mutex);
2143 cipher_blocksize = crypto_blkcipher_blocksize(desc.tfm);
2144 mutex_unlock(tfm_mutex);
2145
2146 /* Return an exact amount for the common cases */
2147 if (lower_namelen == NAME_MAX
2148 && (cipher_blocksize == 8 || cipher_blocksize == 16)) {
2149 (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
2150 return 0;
2151 }
2152
2153 /* Return a safe estimate for the uncommon cases */
2154 (*namelen) = lower_namelen;
2155 (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2156 /* Since this is the max decoded size, subtract 1 "decoded block" len */
2157 (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3;
2158 (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
2159 (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
2160 /* Worst case is that the filename is padded nearly a full block size */
2161 (*namelen) -= cipher_blocksize - 1;
2162
2163 if ((*namelen) < 0)
2164 (*namelen) = 0;
2165
2166 return 0;
2167}