blob: 80d6901493cf5e0867cd2572885cc16f66ff59c5 [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);
Markus Elfring0dad87f2015-06-26 18:18:54 +0200261 if (!(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
Michael Halcrowf4aad162007-10-16 01:27:53 -0700262 key_put(auth_tok->global_auth_tok_key);
263 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
264 }
265 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700266 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
267}
268
269/**
270 * virt_to_scatterlist
271 * @addr: Virtual address
272 * @size: Size of data; should be an even multiple of the block size
273 * @sg: Pointer to scatterlist array; set to NULL to obtain only
274 * the number of scatterlist structs required in array
275 * @sg_size: Max array size
276 *
277 * Fills in a scatterlist array with page references for a passed
278 * virtual address.
279 *
280 * Returns the number of scatterlist structs in array used
281 */
282int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
283 int sg_size)
284{
285 int i = 0;
286 struct page *pg;
287 int offset;
288 int remainder_of_page;
289
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700290 sg_init_table(sg, sg_size);
291
Michael Halcrow237fead2006-10-04 02:16:22 -0700292 while (size > 0 && i < sg_size) {
293 pg = virt_to_page(addr);
294 offset = offset_in_page(addr);
Dan Carpentera07c48a2013-01-26 10:48:42 +0300295 sg_set_page(&sg[i], pg, 0, offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700296 remainder_of_page = PAGE_CACHE_SIZE - offset;
297 if (size >= remainder_of_page) {
Dan Carpentera07c48a2013-01-26 10:48:42 +0300298 sg[i].length = remainder_of_page;
Michael Halcrow237fead2006-10-04 02:16:22 -0700299 addr += remainder_of_page;
300 size -= remainder_of_page;
301 } else {
Dan Carpentera07c48a2013-01-26 10:48:42 +0300302 sg[i].length = size;
Michael Halcrow237fead2006-10-04 02:16:22 -0700303 addr += size;
304 size = 0;
305 }
306 i++;
307 }
308 if (size > 0)
309 return -ENOMEM;
310 return i;
311}
312
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700313struct extent_crypt_result {
314 struct completion completion;
315 int rc;
316};
317
318static void extent_crypt_complete(struct crypto_async_request *req, int rc)
319{
320 struct extent_crypt_result *ecr = req->data;
321
322 if (rc == -EINPROGRESS)
323 return;
324
325 ecr->rc = rc;
326 complete(&ecr->completion);
327}
328
Michael Halcrow237fead2006-10-04 02:16:22 -0700329/**
Tyler Hicks00a69942013-04-05 23:26:22 -0700330 * crypt_scatterlist
Michael Halcrow237fead2006-10-04 02:16:22 -0700331 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700332 * @dst_sg: Destination of the data after performing the crypto operation
Tyler Hicks00a69942013-04-05 23:26:22 -0700333 * @src_sg: Data to be encrypted or decrypted
334 * @size: Length of data
335 * @iv: IV to use
336 * @op: ENCRYPT or DECRYPT to indicate the desired operation
Michael Halcrow237fead2006-10-04 02:16:22 -0700337 *
Tyler Hicks00a69942013-04-05 23:26:22 -0700338 * Returns the number of bytes encrypted or decrypted; negative value on error
Michael Halcrow237fead2006-10-04 02:16:22 -0700339 */
Tyler Hicks00a69942013-04-05 23:26:22 -0700340static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700341 struct scatterlist *dst_sg,
Tyler Hicks00a69942013-04-05 23:26:22 -0700342 struct scatterlist *src_sg, int size,
343 unsigned char *iv, int op)
Michael Halcrow237fead2006-10-04 02:16:22 -0700344{
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700345 struct ablkcipher_request *req = NULL;
346 struct extent_crypt_result ecr;
Michael Halcrow237fead2006-10-04 02:16:22 -0700347 int rc = 0;
348
349 BUG_ON(!crypt_stat || !crypt_stat->tfm
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800350 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
Michael Halcrow237fead2006-10-04 02:16:22 -0700351 if (unlikely(ecryptfs_verbosity > 0)) {
Tyler Hicksf24b3882010-11-15 17:36:38 -0600352 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700353 crypt_stat->key_size);
354 ecryptfs_dump_hex(crypt_stat->key,
355 crypt_stat->key_size);
356 }
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700357
358 init_completion(&ecr.completion);
359
Michael Halcrow237fead2006-10-04 02:16:22 -0700360 mutex_lock(&crypt_stat->cs_tfm_mutex);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700361 req = ablkcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
362 if (!req) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700363 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700364 rc = -ENOMEM;
Michael Halcrow237fead2006-10-04 02:16:22 -0700365 goto out;
366 }
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700367
368 ablkcipher_request_set_callback(req,
369 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
370 extent_crypt_complete, &ecr);
371 /* Consider doing this once, when the file is opened */
372 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
373 rc = crypto_ablkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
374 crypt_stat->key_size);
375 if (rc) {
376 ecryptfs_printk(KERN_ERR,
377 "Error setting key; rc = [%d]\n",
378 rc);
379 mutex_unlock(&crypt_stat->cs_tfm_mutex);
380 rc = -EINVAL;
381 goto out;
382 }
383 crypt_stat->flags |= ECRYPTFS_KEY_SET;
384 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700385 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700386 ablkcipher_request_set_crypt(req, src_sg, dst_sg, size, iv);
Tyler Hicks00a69942013-04-05 23:26:22 -0700387 rc = op == ENCRYPT ? crypto_ablkcipher_encrypt(req) :
388 crypto_ablkcipher_decrypt(req);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700389 if (rc == -EINPROGRESS || rc == -EBUSY) {
390 struct extent_crypt_result *ecr = req->base.data;
391
392 wait_for_completion(&ecr->completion);
393 rc = ecr->rc;
Wolfram Sang16735d02013-11-14 14:32:02 -0800394 reinit_completion(&ecr->completion);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700395 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700396out:
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700397 ablkcipher_request_free(req);
Michael Halcrow237fead2006-10-04 02:16:22 -0700398 return rc;
399}
400
Michael Halcrow237fead2006-10-04 02:16:22 -0700401/**
Tyler Hicks24d15262013-04-15 17:28:09 -0700402 * lower_offset_for_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700403 *
404 * Convert an eCryptfs page index into a lower byte offset
405 */
Tyler Hicks24d15262013-04-15 17:28:09 -0700406static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
407 struct page *page)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700408{
Tyler Hicks24d15262013-04-15 17:28:09 -0700409 return ecryptfs_lower_header_size(crypt_stat) +
Colin Ian King43b7c6c2013-10-24 14:08:07 +0000410 ((loff_t)page->index << PAGE_CACHE_SHIFT);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700411}
412
413/**
Tyler Hicksd78de612013-04-06 00:08:48 -0700414 * crypt_extent
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700415 * @crypt_stat: crypt_stat containing cryptographic context for the
416 * encryption operation
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700417 * @dst_page: The page to write the result into
Tyler Hicksd78de612013-04-06 00:08:48 -0700418 * @src_page: The page to read from
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700419 * @extent_offset: Page extent offset for use in generating IV
Tyler Hicksd78de612013-04-06 00:08:48 -0700420 * @op: ENCRYPT or DECRYPT to indicate the desired operation
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700421 *
Tyler Hicksd78de612013-04-06 00:08:48 -0700422 * Encrypts or decrypts one extent of data.
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700423 *
424 * Return zero on success; non-zero otherwise
425 */
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700426static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat,
427 struct page *dst_page,
Tyler Hicksd78de612013-04-06 00:08:48 -0700428 struct page *src_page,
429 unsigned long extent_offset, int op)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700430{
Tyler Hicksd78de612013-04-06 00:08:48 -0700431 pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index;
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700432 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700433 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
Tyler Hicks406c93d2013-04-15 17:49:31 -0700434 struct scatterlist src_sg, dst_sg;
435 size_t extent_size = crypt_stat->extent_size;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700436 int rc;
437
Tyler Hicks406c93d2013-04-15 17:49:31 -0700438 extent_base = (((loff_t)page_index) * (PAGE_CACHE_SIZE / extent_size));
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700439 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
440 (extent_base + extent_offset));
441 if (rc) {
Joe Perches888d57b2010-11-10 15:46:16 -0800442 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
443 "extent [0x%.16llx]; rc = [%d]\n",
444 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700445 goto out;
446 }
Tyler Hicks406c93d2013-04-15 17:49:31 -0700447
448 sg_init_table(&src_sg, 1);
449 sg_init_table(&dst_sg, 1);
450
451 sg_set_page(&src_sg, src_page, extent_size,
452 extent_offset * extent_size);
453 sg_set_page(&dst_sg, dst_page, extent_size,
454 extent_offset * extent_size);
455
456 rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size,
457 extent_iv, op);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700458 if (rc < 0) {
Tyler Hicksd78de612013-04-06 00:08:48 -0700459 printk(KERN_ERR "%s: Error attempting to crypt page with "
460 "page_index = [%ld], extent_offset = [%ld]; "
461 "rc = [%d]\n", __func__, page_index, extent_offset, rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700462 goto out;
463 }
464 rc = 0;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700465out:
466 return rc;
467}
468
469/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700470 * ecryptfs_encrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700471 * @page: Page mapped from the eCryptfs inode for the file; contains
472 * decrypted content that needs to be encrypted (to a temporary
473 * page; not in place) and written out to the lower file
Michael Halcrow237fead2006-10-04 02:16:22 -0700474 *
475 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
476 * that eCryptfs pages may straddle the lower pages -- for instance,
477 * if the file was created on a machine with an 8K page size
478 * (resulting in an 8K header), and then the file is copied onto a
479 * host with a 32K page size, then when reading page 0 of the eCryptfs
480 * file, 24K of page 0 of the lower file will be read and decrypted,
481 * and then 8K of page 1 of the lower file will be read and decrypted.
482 *
Michael Halcrow237fead2006-10-04 02:16:22 -0700483 * Returns zero on success; negative on error
484 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700485int ecryptfs_encrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700486{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700487 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700488 struct ecryptfs_crypt_stat *crypt_stat;
Eric Sandeen7fcba052008-07-28 15:46:39 -0700489 char *enc_extent_virt;
490 struct page *enc_extent_page = NULL;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700491 loff_t extent_offset;
Tyler Hicks0f896172013-04-15 16:16:24 -0700492 loff_t lower_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700493 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700494
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700495 ecryptfs_inode = page->mapping->host;
496 crypt_stat =
497 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500498 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Eric Sandeen7fcba052008-07-28 15:46:39 -0700499 enc_extent_page = alloc_page(GFP_USER);
500 if (!enc_extent_page) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700501 rc = -ENOMEM;
502 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
503 "encrypted extent\n");
504 goto out;
505 }
Tyler Hicks0f896172013-04-15 16:16:24 -0700506
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700507 for (extent_offset = 0;
508 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
509 extent_offset++) {
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700510 rc = crypt_extent(crypt_stat, enc_extent_page, page,
Tyler Hicksd78de612013-04-06 00:08:48 -0700511 extent_offset, ENCRYPT);
Michael Halcrow237fead2006-10-04 02:16:22 -0700512 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700513 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700514 "rc = [%d]\n", __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700515 goto out;
516 }
Tyler Hicks0f896172013-04-15 16:16:24 -0700517 }
518
Tyler Hicks24d15262013-04-15 17:28:09 -0700519 lower_offset = lower_offset_for_page(crypt_stat, page);
Tyler Hicks0f896172013-04-15 16:16:24 -0700520 enc_extent_virt = kmap(enc_extent_page);
521 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
522 PAGE_CACHE_SIZE);
523 kunmap(enc_extent_page);
524 if (rc < 0) {
525 ecryptfs_printk(KERN_ERR,
526 "Error attempting to write lower page; rc = [%d]\n",
527 rc);
528 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700529 }
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500530 rc = 0;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700531out:
Eric Sandeen7fcba052008-07-28 15:46:39 -0700532 if (enc_extent_page) {
Eric Sandeen7fcba052008-07-28 15:46:39 -0700533 __free_page(enc_extent_page);
534 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700535 return rc;
536}
537
Michael Halcrow237fead2006-10-04 02:16:22 -0700538/**
539 * ecryptfs_decrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700540 * @page: Page mapped from the eCryptfs inode for the file; data read
541 * and decrypted from the lower file will be written into this
542 * page
Michael Halcrow237fead2006-10-04 02:16:22 -0700543 *
544 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
545 * that eCryptfs pages may straddle the lower pages -- for instance,
546 * if the file was created on a machine with an 8K page size
547 * (resulting in an 8K header), and then the file is copied onto a
548 * host with a 32K page size, then when reading page 0 of the eCryptfs
549 * file, 24K of page 0 of the lower file will be read and decrypted,
550 * and then 8K of page 1 of the lower file will be read and decrypted.
551 *
552 * Returns zero on success; negative on error
553 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700554int ecryptfs_decrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700555{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700556 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700557 struct ecryptfs_crypt_stat *crypt_stat;
Tyler Hicks9c6043f2013-04-06 00:41:48 -0700558 char *page_virt;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700559 unsigned long extent_offset;
Tyler Hicks0f896172013-04-15 16:16:24 -0700560 loff_t lower_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700561 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700562
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700563 ecryptfs_inode = page->mapping->host;
564 crypt_stat =
565 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500566 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Tyler Hicks0f896172013-04-15 16:16:24 -0700567
Tyler Hicks24d15262013-04-15 17:28:09 -0700568 lower_offset = lower_offset_for_page(crypt_stat, page);
Tyler Hicks9c6043f2013-04-06 00:41:48 -0700569 page_virt = kmap(page);
570 rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_CACHE_SIZE,
Tyler Hicks0f896172013-04-15 16:16:24 -0700571 ecryptfs_inode);
Tyler Hicks9c6043f2013-04-06 00:41:48 -0700572 kunmap(page);
Tyler Hicks0f896172013-04-15 16:16:24 -0700573 if (rc < 0) {
574 ecryptfs_printk(KERN_ERR,
575 "Error attempting to read lower page; rc = [%d]\n",
576 rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700577 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700578 }
Tyler Hicks0f896172013-04-15 16:16:24 -0700579
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700580 for (extent_offset = 0;
581 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
582 extent_offset++) {
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700583 rc = crypt_extent(crypt_stat, page, page,
Tyler Hicksd78de612013-04-06 00:08:48 -0700584 extent_offset, DECRYPT);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700585 if (rc) {
586 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700587 "rc = [%d]\n", __func__, rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700588 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700589 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700590 }
591out:
Michael Halcrow237fead2006-10-04 02:16:22 -0700592 return rc;
593}
594
Michael Halcrow237fead2006-10-04 02:16:22 -0700595#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
596
597/**
598 * ecryptfs_init_crypt_ctx
Uwe Kleine-König421f91d2010-06-11 12:17:00 +0200599 * @crypt_stat: Uninitialized crypt stats structure
Michael Halcrow237fead2006-10-04 02:16:22 -0700600 *
601 * Initialize the crypto context.
602 *
603 * TODO: Performance: Keep a cache of initialized cipher contexts;
604 * only init if needed
605 */
606int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
607{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800608 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700609 int rc = -EINVAL;
610
Michael Halcrow237fead2006-10-04 02:16:22 -0700611 ecryptfs_printk(KERN_DEBUG,
612 "Initializing cipher [%s]; strlen = [%d]; "
Tyler Hicksf24b3882010-11-15 17:36:38 -0600613 "key_size_bits = [%zd]\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700614 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
615 crypt_stat->key_size << 3);
Kees Cookcb69f362013-08-13 15:02:27 -0700616 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700617 if (crypt_stat->tfm) {
618 rc = 0;
Kees Cookcb69f362013-08-13 15:02:27 -0700619 goto out_unlock;
Michael Halcrow237fead2006-10-04 02:16:22 -0700620 }
Michael Halcrow8bba0662006-10-30 22:07:18 -0800621 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
622 crypt_stat->cipher, "cbc");
623 if (rc)
Eric Sandeenc8161f62007-12-22 14:03:26 -0800624 goto out_unlock;
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700625 crypt_stat->tfm = crypto_alloc_ablkcipher(full_alg_name, 0, 0);
Akinobu Mitade887772006-11-28 12:29:49 -0800626 if (IS_ERR(crypt_stat->tfm)) {
627 rc = PTR_ERR(crypt_stat->tfm);
Tyler Hicksb0105ea2009-08-11 00:36:32 -0500628 crypt_stat->tfm = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -0700629 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
630 "Error initializing cipher [%s]\n",
Kees Cookcb69f362013-08-13 15:02:27 -0700631 full_alg_name);
632 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -0700633 }
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700634 crypto_ablkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow237fead2006-10-04 02:16:22 -0700635 rc = 0;
Kees Cookcb69f362013-08-13 15:02:27 -0700636out_free:
637 kfree(full_alg_name);
Eric Sandeenc8161f62007-12-22 14:03:26 -0800638out_unlock:
639 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700640 return rc;
641}
642
643static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
644{
645 int extent_size_tmp;
646
647 crypt_stat->extent_mask = 0xFFFFFFFF;
648 crypt_stat->extent_shift = 0;
649 if (crypt_stat->extent_size == 0)
650 return;
651 extent_size_tmp = crypt_stat->extent_size;
652 while ((extent_size_tmp & 0x01) == 0) {
653 extent_size_tmp >>= 1;
654 crypt_stat->extent_mask <<= 1;
655 crypt_stat->extent_shift++;
656 }
657}
658
659void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
660{
661 /* Default values; may be overwritten as we are parsing the
662 * packets. */
663 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
664 set_extent_mask_and_shift(crypt_stat);
665 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800666 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600667 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700668 else {
669 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600670 crypt_stat->metadata_size =
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800671 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700672 else
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600673 crypt_stat->metadata_size = PAGE_CACHE_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700674 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700675}
676
677/**
678 * ecryptfs_compute_root_iv
679 * @crypt_stats
680 *
681 * On error, sets the root IV to all 0's.
682 */
683int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
684{
685 int rc = 0;
686 char dst[MD5_DIGEST_SIZE];
687
688 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
689 BUG_ON(crypt_stat->iv_bytes <= 0);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800690 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700691 rc = -EINVAL;
692 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
693 "cannot generate root IV\n");
694 goto out;
695 }
696 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
697 crypt_stat->key_size);
698 if (rc) {
699 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
700 "MD5 while generating root IV\n");
701 goto out;
702 }
703 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
704out:
705 if (rc) {
706 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800707 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
Michael Halcrow237fead2006-10-04 02:16:22 -0700708 }
709 return rc;
710}
711
712static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
713{
714 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800715 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
Michael Halcrow237fead2006-10-04 02:16:22 -0700716 ecryptfs_compute_root_iv(crypt_stat);
717 if (unlikely(ecryptfs_verbosity > 0)) {
718 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
719 ecryptfs_dump_hex(crypt_stat->key,
720 crypt_stat->key_size);
721 }
722}
723
724/**
Michael Halcrow17398952007-02-12 00:53:45 -0800725 * ecryptfs_copy_mount_wide_flags_to_inode_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700726 * @crypt_stat: The inode's cryptographic context
727 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow17398952007-02-12 00:53:45 -0800728 *
729 * This function propagates the mount-wide flags to individual inode
730 * flags.
731 */
732static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
733 struct ecryptfs_crypt_stat *crypt_stat,
734 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
735{
736 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
737 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
738 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
739 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800740 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
741 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
742 if (mount_crypt_stat->flags
743 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
744 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
745 else if (mount_crypt_stat->flags
746 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
747 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
748 }
Michael Halcrow17398952007-02-12 00:53:45 -0800749}
750
Michael Halcrowf4aad162007-10-16 01:27:53 -0700751static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
752 struct ecryptfs_crypt_stat *crypt_stat,
753 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
754{
755 struct ecryptfs_global_auth_tok *global_auth_tok;
756 int rc = 0;
757
Roland Dreieraa061172009-07-01 15:48:18 -0700758 mutex_lock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700759 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
Roland Dreieraa061172009-07-01 15:48:18 -0700760
Michael Halcrowf4aad162007-10-16 01:27:53 -0700761 list_for_each_entry(global_auth_tok,
762 &mount_crypt_stat->global_auth_tok_list,
763 mount_crypt_stat_list) {
Tyler Hicks84814d62009-03-13 13:51:59 -0700764 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
765 continue;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700766 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
767 if (rc) {
768 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700769 goto out;
770 }
771 }
Roland Dreieraa061172009-07-01 15:48:18 -0700772
Michael Halcrowf4aad162007-10-16 01:27:53 -0700773out:
Roland Dreieraa061172009-07-01 15:48:18 -0700774 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
775 mutex_unlock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700776 return rc;
777}
778
Michael Halcrow17398952007-02-12 00:53:45 -0800779/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700780 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700781 * @crypt_stat: The inode's cryptographic context
782 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700783 *
784 * Default values in the event that policy does not override them.
785 */
786static void ecryptfs_set_default_crypt_stat_vals(
787 struct ecryptfs_crypt_stat *crypt_stat,
788 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
789{
Michael Halcrow17398952007-02-12 00:53:45 -0800790 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
791 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700792 ecryptfs_set_default_sizes(crypt_stat);
793 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
794 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800795 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -0700796 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
797 crypt_stat->mount_crypt_stat = mount_crypt_stat;
798}
799
800/**
801 * ecryptfs_new_file_context
Tyler Hicksb59db432011-11-21 17:31:02 -0600802 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrow237fead2006-10-04 02:16:22 -0700803 *
804 * If the crypto context for the file has not yet been established,
805 * this is where we do that. Establishing a new crypto context
806 * involves the following decisions:
807 * - What cipher to use?
808 * - What set of authentication tokens to use?
809 * Here we just worry about getting enough information into the
810 * authentication tokens so that we know that they are available.
811 * We associate the available authentication tokens with the new file
812 * via the set of signatures in the crypt_stat struct. Later, when
813 * the headers are actually written out, we may again defer to
814 * userspace to perform the encryption of the session key; for the
815 * foreseeable future, this will be the case with public key packets.
816 *
817 * Returns zero on success; non-zero otherwise
818 */
Tyler Hicksb59db432011-11-21 17:31:02 -0600819int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
Michael Halcrow237fead2006-10-04 02:16:22 -0700820{
Michael Halcrow237fead2006-10-04 02:16:22 -0700821 struct ecryptfs_crypt_stat *crypt_stat =
Tyler Hicksb59db432011-11-21 17:31:02 -0600822 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700823 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
824 &ecryptfs_superblock_to_private(
Tyler Hicksb59db432011-11-21 17:31:02 -0600825 ecryptfs_inode->i_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700826 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700827 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700828
829 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -0700830 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700831 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
832 mount_crypt_stat);
833 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
834 mount_crypt_stat);
835 if (rc) {
836 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
837 "to the inode key sigs; rc = [%d]\n", rc);
838 goto out;
839 }
840 cipher_name_len =
841 strlen(mount_crypt_stat->global_default_cipher_name);
842 memcpy(crypt_stat->cipher,
843 mount_crypt_stat->global_default_cipher_name,
844 cipher_name_len);
845 crypt_stat->cipher[cipher_name_len] = '\0';
846 crypt_stat->key_size =
847 mount_crypt_stat->global_default_cipher_key_size;
848 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700849 rc = ecryptfs_init_crypt_ctx(crypt_stat);
850 if (rc)
851 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
852 "context for cipher [%s]: rc = [%d]\n",
853 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700854out:
Michael Halcrow237fead2006-10-04 02:16:22 -0700855 return rc;
856}
857
858/**
Tyler Hicks7a866172011-05-02 00:39:54 -0500859 * ecryptfs_validate_marker - check for the ecryptfs marker
Michael Halcrow237fead2006-10-04 02:16:22 -0700860 * @data: The data block in which to check
861 *
Tyler Hicks7a866172011-05-02 00:39:54 -0500862 * Returns zero if marker found; -EINVAL if not found
Michael Halcrow237fead2006-10-04 02:16:22 -0700863 */
Tyler Hicks7a866172011-05-02 00:39:54 -0500864static int ecryptfs_validate_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -0700865{
866 u32 m_1, m_2;
867
Harvey Harrison29335c62008-07-23 21:30:06 -0700868 m_1 = get_unaligned_be32(data);
869 m_2 = get_unaligned_be32(data + 4);
Michael Halcrow237fead2006-10-04 02:16:22 -0700870 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
Tyler Hicks7a866172011-05-02 00:39:54 -0500871 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700872 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
873 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
874 MAGIC_ECRYPTFS_MARKER);
875 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
876 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
Tyler Hicks7a866172011-05-02 00:39:54 -0500877 return -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -0700878}
879
880struct ecryptfs_flag_map_elem {
881 u32 file_flag;
882 u32 local_flag;
883};
884
885/* Add support for additional flags by adding elements here. */
886static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
887 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800888 {0x00000002, ECRYPTFS_ENCRYPTED},
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800889 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
890 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
Michael Halcrow237fead2006-10-04 02:16:22 -0700891};
892
893/**
894 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700895 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700896 * @page_virt: Source data to be parsed
897 * @bytes_read: Updated with the number of bytes read
898 *
899 * Returns zero on success; non-zero if the flag set is invalid
900 */
901static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
902 char *page_virt, int *bytes_read)
903{
904 int rc = 0;
905 int i;
906 u32 flags;
907
Harvey Harrison29335c62008-07-23 21:30:06 -0700908 flags = get_unaligned_be32(page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700909 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
910 / sizeof(struct ecryptfs_flag_map_elem))); i++)
911 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800912 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -0700913 } else
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800914 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
Michael Halcrow237fead2006-10-04 02:16:22 -0700915 /* Version is in top 8 bits of the 32-bit flag vector */
916 crypt_stat->file_version = ((flags >> 24) & 0xFF);
917 (*bytes_read) = 4;
918 return rc;
919}
920
921/**
922 * write_ecryptfs_marker
923 * @page_virt: The pointer to in a page to begin writing the marker
924 * @written: Number of bytes written
925 *
926 * Marker = 0x3c81b7f5
927 */
928static void write_ecryptfs_marker(char *page_virt, size_t *written)
929{
930 u32 m_1, m_2;
931
932 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
933 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
Harvey Harrison29335c62008-07-23 21:30:06 -0700934 put_unaligned_be32(m_1, page_virt);
935 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
936 put_unaligned_be32(m_2, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700937 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
938}
939
Tyler Hicksf4e60e62010-02-11 00:02:32 -0600940void ecryptfs_write_crypt_stat_flags(char *page_virt,
941 struct ecryptfs_crypt_stat *crypt_stat,
942 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -0700943{
944 u32 flags = 0;
945 int i;
946
947 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
948 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800949 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -0700950 flags |= ecryptfs_flag_map[i].file_flag;
951 /* Version is in top 8 bits of the 32-bit flag vector */
952 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
Harvey Harrison29335c62008-07-23 21:30:06 -0700953 put_unaligned_be32(flags, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700954 (*written) = 4;
955}
956
957struct ecryptfs_cipher_code_str_map_elem {
958 char cipher_str[16];
Trevor Highland19e66a62008-02-06 01:38:36 -0800959 u8 cipher_code;
Michael Halcrow237fead2006-10-04 02:16:22 -0700960};
961
962/* Add support for additional ciphers by adding elements here. The
963 * cipher_code is whatever OpenPGP applicatoins use to identify the
964 * ciphers. List in order of probability. */
965static struct ecryptfs_cipher_code_str_map_elem
966ecryptfs_cipher_code_str_map[] = {
967 {"aes",RFC2440_CIPHER_AES_128 },
968 {"blowfish", RFC2440_CIPHER_BLOWFISH},
969 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
970 {"cast5", RFC2440_CIPHER_CAST_5},
971 {"twofish", RFC2440_CIPHER_TWOFISH},
972 {"cast6", RFC2440_CIPHER_CAST_6},
973 {"aes", RFC2440_CIPHER_AES_192},
974 {"aes", RFC2440_CIPHER_AES_256}
975};
976
977/**
978 * ecryptfs_code_for_cipher_string
Michael Halcrow9c79f342009-01-06 14:41:57 -0800979 * @cipher_name: The string alias for the cipher
980 * @key_bytes: Length of key in bytes; used for AES code selection
Michael Halcrow237fead2006-10-04 02:16:22 -0700981 *
982 * Returns zero on no match, or the cipher code on match
983 */
Michael Halcrow9c79f342009-01-06 14:41:57 -0800984u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
Michael Halcrow237fead2006-10-04 02:16:22 -0700985{
986 int i;
Trevor Highland19e66a62008-02-06 01:38:36 -0800987 u8 code = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700988 struct ecryptfs_cipher_code_str_map_elem *map =
989 ecryptfs_cipher_code_str_map;
990
Michael Halcrow9c79f342009-01-06 14:41:57 -0800991 if (strcmp(cipher_name, "aes") == 0) {
992 switch (key_bytes) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700993 case 16:
994 code = RFC2440_CIPHER_AES_128;
995 break;
996 case 24:
997 code = RFC2440_CIPHER_AES_192;
998 break;
999 case 32:
1000 code = RFC2440_CIPHER_AES_256;
1001 }
1002 } else {
1003 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
Michael Halcrow9c79f342009-01-06 14:41:57 -08001004 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001005 code = map[i].cipher_code;
1006 break;
1007 }
1008 }
1009 return code;
1010}
1011
1012/**
1013 * ecryptfs_cipher_code_to_string
1014 * @str: Destination to write out the cipher name
1015 * @cipher_code: The code to convert to cipher name string
1016 *
1017 * Returns zero on success
1018 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001019int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
Michael Halcrow237fead2006-10-04 02:16:22 -07001020{
1021 int rc = 0;
1022 int i;
1023
1024 str[0] = '\0';
1025 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1026 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1027 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1028 if (str[0] == '\0') {
1029 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1030 "[%d]\n", cipher_code);
1031 rc = -EINVAL;
1032 }
1033 return rc;
1034}
1035
Tyler Hicks778aeb42011-05-24 04:56:23 -05001036int ecryptfs_read_and_validate_header_region(struct inode *inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001037{
Tyler Hicks778aeb42011-05-24 04:56:23 -05001038 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1039 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001040 int rc;
1041
Tyler Hicks778aeb42011-05-24 04:56:23 -05001042 rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
1043 inode);
1044 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1045 return rc >= 0 ? -EINVAL : rc;
1046 rc = ecryptfs_validate_marker(marker);
1047 if (!rc)
1048 ecryptfs_i_size_init(file_size, inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001049 return rc;
1050}
1051
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001052void
1053ecryptfs_write_header_metadata(char *virt,
1054 struct ecryptfs_crypt_stat *crypt_stat,
1055 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001056{
1057 u32 header_extent_size;
1058 u16 num_header_extents_at_front;
1059
Michael Halcrow45eaab72007-10-16 01:28:05 -07001060 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001061 num_header_extents_at_front =
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001062 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
Harvey Harrison29335c62008-07-23 21:30:06 -07001063 put_unaligned_be32(header_extent_size, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001064 virt += 4;
Harvey Harrison29335c62008-07-23 21:30:06 -07001065 put_unaligned_be16(num_header_extents_at_front, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001066 (*written) = 6;
1067}
1068
Tyler Hicks30632872011-05-24 05:11:12 -05001069struct kmem_cache *ecryptfs_header_cache;
Michael Halcrow237fead2006-10-04 02:16:22 -07001070
1071/**
1072 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001073 * @page_virt: The virtual address to write the headers to
Eric Sandeen87b811c2008-10-29 14:01:08 -07001074 * @max: The size of memory allocated at page_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001075 * @size: Set to the number of bytes written by this function
1076 * @crypt_stat: The cryptographic context
1077 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001078 *
1079 * Format version: 1
1080 *
1081 * Header Extent:
1082 * Octets 0-7: Unencrypted file size (big-endian)
1083 * Octets 8-15: eCryptfs special marker
1084 * Octets 16-19: Flags
1085 * Octet 16: File format version number (between 0 and 255)
1086 * Octets 17-18: Reserved
1087 * Octet 19: Bit 1 (lsb): Reserved
1088 * Bit 2: Encrypted?
1089 * Bits 3-8: Reserved
1090 * Octets 20-23: Header extent size (big-endian)
1091 * Octets 24-25: Number of header extents at front of file
1092 * (big-endian)
1093 * Octet 26: Begin RFC 2440 authentication token packet set
1094 * Data Extent 0:
1095 * Lower data (CBC encrypted)
1096 * Data Extent 1:
1097 * Lower data (CBC encrypted)
1098 * ...
1099 *
1100 * Returns zero on success
1101 */
Eric Sandeen87b811c2008-10-29 14:01:08 -07001102static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1103 size_t *size,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001104 struct ecryptfs_crypt_stat *crypt_stat,
1105 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001106{
1107 int rc;
1108 size_t written;
1109 size_t offset;
1110
1111 offset = ECRYPTFS_FILE_SIZE_BYTES;
1112 write_ecryptfs_marker((page_virt + offset), &written);
1113 offset += written;
Tyler Hicksf4e60e62010-02-11 00:02:32 -06001114 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1115 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001116 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001117 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1118 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001119 offset += written;
1120 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1121 ecryptfs_dentry, &written,
Eric Sandeen87b811c2008-10-29 14:01:08 -07001122 max - offset);
Michael Halcrow237fead2006-10-04 02:16:22 -07001123 if (rc)
1124 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1125 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001126 if (size) {
1127 offset += written;
1128 *size = offset;
1129 }
1130 return rc;
1131}
1132
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001133static int
Tyler Hicksb59db432011-11-21 17:31:02 -06001134ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
Tyler Hicks8faece52009-03-20 01:25:09 -05001135 char *virt, size_t virt_len)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001136{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001137 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001138
Tyler Hicksb59db432011-11-21 17:31:02 -06001139 rc = ecryptfs_write_lower(ecryptfs_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001140 0, virt_len);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001141 if (rc < 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001142 printk(KERN_ERR "%s: Error attempting to write header "
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001143 "information to lower file; rc = [%d]\n", __func__, rc);
1144 else
1145 rc = 0;
Michael Halcrow70456602007-02-12 00:53:48 -08001146 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001147}
1148
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001149static int
1150ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001151 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001152{
1153 int rc;
1154
1155 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1156 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001157 return rc;
1158}
1159
Tyler Hicks8faece52009-03-20 01:25:09 -05001160static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1161 unsigned int order)
1162{
1163 struct page *page;
1164
1165 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1166 if (page)
1167 return (unsigned long) page_address(page);
1168 return 0;
1169}
1170
Michael Halcrow237fead2006-10-04 02:16:22 -07001171/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001172 * ecryptfs_write_metadata
Tyler Hicksb59db432011-11-21 17:31:02 -06001173 * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1174 * @ecryptfs_inode: The newly created eCryptfs inode
Michael Halcrow237fead2006-10-04 02:16:22 -07001175 *
1176 * Write the file headers out. This will likely involve a userspace
1177 * callout, in which the session key is encrypted with one or more
1178 * public keys and/or the passphrase necessary to do the encryption is
1179 * retrieved via a prompt. Exactly what happens at this point should
1180 * be policy-dependent.
1181 *
1182 * Returns zero on success; non-zero on error
1183 */
Tyler Hicksb59db432011-11-21 17:31:02 -06001184int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1185 struct inode *ecryptfs_inode)
Michael Halcrow237fead2006-10-04 02:16:22 -07001186{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001187 struct ecryptfs_crypt_stat *crypt_stat =
Tyler Hicksb59db432011-11-21 17:31:02 -06001188 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Tyler Hicks8faece52009-03-20 01:25:09 -05001189 unsigned int order;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001190 char *virt;
Tyler Hicks8faece52009-03-20 01:25:09 -05001191 size_t virt_len;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001192 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001193 int rc = 0;
1194
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001195 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1196 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001197 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001198 rc = -EINVAL;
1199 goto out;
1200 }
1201 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001202 printk(KERN_WARNING "%s: Encrypted flag not set\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001203 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001204 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001205 goto out;
1206 }
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001207 virt_len = crypt_stat->metadata_size;
Tyler Hicks8faece52009-03-20 01:25:09 -05001208 order = get_order(virt_len);
Michael Halcrow237fead2006-10-04 02:16:22 -07001209 /* Released in this function */
Tyler Hicks8faece52009-03-20 01:25:09 -05001210 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001211 if (!virt) {
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001212 printk(KERN_ERR "%s: Out of memory\n", __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001213 rc = -ENOMEM;
1214 goto out;
1215 }
Tyler Hicksbd4f0fe2011-02-23 00:14:19 -06001216 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
Tyler Hicks8faece52009-03-20 01:25:09 -05001217 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1218 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001219 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001220 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001221 __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001222 goto out_free;
1223 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001224 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicks8faece52009-03-20 01:25:09 -05001225 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1226 size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001227 else
Tyler Hicksb59db432011-11-21 17:31:02 -06001228 rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001229 virt_len);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001230 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001231 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001232 "rc = [%d]\n", __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001233 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001234 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001235out_free:
Tyler Hicks8faece52009-03-20 01:25:09 -05001236 free_pages((unsigned long)virt, order);
Michael Halcrow237fead2006-10-04 02:16:22 -07001237out:
1238 return rc;
1239}
1240
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001241#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1242#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001243static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001244 char *virt, int *bytes_read,
1245 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001246{
1247 int rc = 0;
1248 u32 header_extent_size;
1249 u16 num_header_extents_at_front;
1250
Harvey Harrison29335c62008-07-23 21:30:06 -07001251 header_extent_size = get_unaligned_be32(virt);
1252 virt += sizeof(__be32);
1253 num_header_extents_at_front = get_unaligned_be16(virt);
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001254 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1255 * (size_t)header_extent_size));
Harvey Harrison29335c62008-07-23 21:30:06 -07001256 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001257 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001258 && (crypt_stat->metadata_size
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001259 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001260 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001261 printk(KERN_WARNING "Invalid header size: [%zd]\n",
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001262 crypt_stat->metadata_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001263 }
1264 return rc;
1265}
1266
1267/**
1268 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001269 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001270 *
1271 * For version 0 file format; this function is only for backwards
1272 * compatibility for files created with the prior versions of
1273 * eCryptfs.
1274 */
1275static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1276{
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001277 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001278}
1279
Tyler Hicks3aeb86e2011-03-15 14:54:00 -05001280void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1281{
1282 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1283 struct ecryptfs_crypt_stat *crypt_stat;
1284 u64 file_size;
1285
1286 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1287 mount_crypt_stat =
1288 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1289 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1290 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1291 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1292 file_size += crypt_stat->metadata_size;
1293 } else
1294 file_size = get_unaligned_be64(page_virt);
1295 i_size_write(inode, (loff_t)file_size);
1296 crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1297}
1298
Michael Halcrow237fead2006-10-04 02:16:22 -07001299/**
1300 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001301 * @page_virt: The virtual address into which to read the headers
1302 * @crypt_stat: The cryptographic context
1303 * @ecryptfs_dentry: The eCryptfs dentry
1304 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001305 *
1306 * Read/parse the header data. The header format is detailed in the
1307 * comment block for the ecryptfs_write_headers_virt() function.
1308 *
1309 * Returns zero on success
1310 */
1311static int ecryptfs_read_headers_virt(char *page_virt,
1312 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001313 struct dentry *ecryptfs_dentry,
1314 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001315{
1316 int rc = 0;
1317 int offset;
1318 int bytes_read;
1319
1320 ecryptfs_set_default_sizes(crypt_stat);
1321 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1322 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1323 offset = ECRYPTFS_FILE_SIZE_BYTES;
Tyler Hicks7a866172011-05-02 00:39:54 -05001324 rc = ecryptfs_validate_marker(page_virt + offset);
1325 if (rc)
Michael Halcrow237fead2006-10-04 02:16:22 -07001326 goto out;
Tyler Hicks3aeb86e2011-03-15 14:54:00 -05001327 if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
David Howells2b0143b2015-03-17 22:25:59 +00001328 ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry));
Michael Halcrow237fead2006-10-04 02:16:22 -07001329 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1330 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1331 &bytes_read);
1332 if (rc) {
1333 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1334 goto out;
1335 }
1336 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1337 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1338 "file version [%d] is supported by this "
1339 "version of eCryptfs\n",
1340 crypt_stat->file_version,
1341 ECRYPTFS_SUPPORTED_FILE_VERSION);
1342 rc = -EINVAL;
1343 goto out;
1344 }
1345 offset += bytes_read;
1346 if (crypt_stat->file_version >= 1) {
1347 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001348 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001349 if (rc) {
1350 ecryptfs_printk(KERN_WARNING, "Error reading header "
1351 "metadata; rc = [%d]\n", rc);
1352 }
1353 offset += bytes_read;
1354 } else
1355 set_default_header_data(crypt_stat);
1356 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1357 ecryptfs_dentry);
1358out:
1359 return rc;
1360}
1361
1362/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001363 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001364 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001365 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001366 *
1367 * Attempts to read the crypto metadata from the extended attribute
1368 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001369 *
1370 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001371 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001372int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001373{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001374 struct dentry *lower_dentry =
Al Virob5830432014-10-31 01:22:04 -04001375 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001376 ssize_t size;
1377 int rc = 0;
1378
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001379 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1380 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001381 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001382 if (unlikely(ecryptfs_verbosity > 0))
1383 printk(KERN_INFO "Error attempting to read the [%s] "
1384 "xattr from the lower file; return value = "
1385 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001386 rc = -EINVAL;
1387 goto out;
1388 }
1389out:
1390 return rc;
1391}
1392
Tyler Hicks778aeb42011-05-24 04:56:23 -05001393int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
Tyler Hicks3b06b3e2011-05-24 03:49:02 -05001394 struct inode *inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001395{
Tyler Hicks778aeb42011-05-24 04:56:23 -05001396 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1397 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001398 int rc;
1399
Tyler Hicks778aeb42011-05-24 04:56:23 -05001400 rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1401 ECRYPTFS_XATTR_NAME, file_size,
1402 ECRYPTFS_SIZE_AND_MARKER_BYTES);
1403 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1404 return rc >= 0 ? -EINVAL : rc;
1405 rc = ecryptfs_validate_marker(marker);
1406 if (!rc)
1407 ecryptfs_i_size_init(file_size, inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001408 return rc;
1409}
1410
1411/**
1412 * ecryptfs_read_metadata
1413 *
1414 * Common entry point for reading file metadata. From here, we could
1415 * retrieve the header information from the header region of the file,
1416 * the xattr region of the file, or some other repostory that is
1417 * stored separately from the file itself. The current implementation
1418 * supports retrieving the metadata information from the file contents
1419 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001420 *
1421 * Returns zero if valid headers found and parsed; non-zero otherwise
1422 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001423int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001424{
Tim Gardnerbb450362012-01-12 16:31:55 +01001425 int rc;
1426 char *page_virt;
David Howells2b0143b2015-03-17 22:25:59 +00001427 struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001428 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001429 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001430 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1431 &ecryptfs_superblock_to_private(
1432 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001433
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001434 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1435 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001436 /* Read the first page from the underlying file */
Tyler Hicks30632872011-05-24 05:11:12 -05001437 page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001438 if (!page_virt) {
1439 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001440 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001441 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001442 goto out;
1443 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001444 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1445 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001446 if (rc >= 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001447 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1448 ecryptfs_dentry,
1449 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001450 if (rc) {
Tim Gardnerbb450362012-01-12 16:31:55 +01001451 /* metadata is not in the file header, so try xattrs */
Tyler Hicks1984c232010-02-10 23:17:44 -06001452 memset(page_virt, 0, PAGE_CACHE_SIZE);
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001453 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001454 if (rc) {
1455 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
Tim Gardner30373dc2012-01-12 16:31:55 +01001456 "file header region or xattr region, inode %lu\n",
1457 ecryptfs_inode->i_ino);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001458 rc = -EINVAL;
1459 goto out;
1460 }
1461 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1462 ecryptfs_dentry,
1463 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1464 if (rc) {
1465 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
Tim Gardner30373dc2012-01-12 16:31:55 +01001466 "file xattr region either, inode %lu\n",
1467 ecryptfs_inode->i_ino);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001468 rc = -EINVAL;
1469 }
1470 if (crypt_stat->mount_crypt_stat->flags
1471 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1472 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1473 } else {
1474 printk(KERN_WARNING "Attempt to access file with "
1475 "crypto metadata only in the extended attribute "
1476 "region, but eCryptfs was mounted without "
1477 "xattr support enabled. eCryptfs will not treat "
Tim Gardner30373dc2012-01-12 16:31:55 +01001478 "this like an encrypted file, inode %lu\n",
1479 ecryptfs_inode->i_ino);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001480 rc = -EINVAL;
1481 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001482 }
1483out:
1484 if (page_virt) {
1485 memset(page_virt, 0, PAGE_CACHE_SIZE);
Tyler Hicks30632872011-05-24 05:11:12 -05001486 kmem_cache_free(ecryptfs_header_cache, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001487 }
1488 return rc;
1489}
1490
1491/**
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001492 * ecryptfs_encrypt_filename - encrypt filename
1493 *
1494 * CBC-encrypts the filename. We do not want to encrypt the same
1495 * filename with the same key and IV, which may happen with hard
1496 * links, so we prepend random bits to each filename.
1497 *
1498 * Returns zero on success; non-zero otherwise
1499 */
1500static int
1501ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1502 struct ecryptfs_crypt_stat *crypt_stat,
1503 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1504{
1505 int rc = 0;
1506
1507 filename->encrypted_filename = NULL;
1508 filename->encrypted_filename_size = 0;
1509 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1510 || (mount_crypt_stat && (mount_crypt_stat->flags
1511 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1512 size_t packet_size;
1513 size_t remaining_bytes;
1514
1515 rc = ecryptfs_write_tag_70_packet(
1516 NULL, NULL,
1517 &filename->encrypted_filename_size,
1518 mount_crypt_stat, NULL,
1519 filename->filename_size);
1520 if (rc) {
1521 printk(KERN_ERR "%s: Error attempting to get packet "
1522 "size for tag 72; rc = [%d]\n", __func__,
1523 rc);
1524 filename->encrypted_filename_size = 0;
1525 goto out;
1526 }
1527 filename->encrypted_filename =
1528 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1529 if (!filename->encrypted_filename) {
1530 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08001531 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001532 filename->encrypted_filename_size);
1533 rc = -ENOMEM;
1534 goto out;
1535 }
1536 remaining_bytes = filename->encrypted_filename_size;
1537 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1538 &remaining_bytes,
1539 &packet_size,
1540 mount_crypt_stat,
1541 filename->filename,
1542 filename->filename_size);
1543 if (rc) {
1544 printk(KERN_ERR "%s: Error attempting to generate "
1545 "tag 70 packet; rc = [%d]\n", __func__,
1546 rc);
1547 kfree(filename->encrypted_filename);
1548 filename->encrypted_filename = NULL;
1549 filename->encrypted_filename_size = 0;
1550 goto out;
1551 }
1552 filename->encrypted_filename_size = packet_size;
1553 } else {
1554 printk(KERN_ERR "%s: No support for requested filename "
1555 "encryption method in this release\n", __func__);
Tyler Hicksdf6ad332009-08-21 04:27:46 -05001556 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001557 goto out;
1558 }
1559out:
1560 return rc;
1561}
1562
1563static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1564 const char *name, size_t name_size)
1565{
1566 int rc = 0;
1567
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001568 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001569 if (!(*copied_name)) {
1570 rc = -ENOMEM;
1571 goto out;
1572 }
1573 memcpy((void *)(*copied_name), (void *)name, name_size);
1574 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1575 * in printing out the
1576 * string in debug
1577 * messages */
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001578 (*copied_name_size) = name_size;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001579out:
1580 return rc;
1581}
1582
1583/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001584 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001585 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001586 * @cipher_name: Name of the cipher
1587 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001588 *
1589 * Returns zero on success. Any crypto_tfm structs allocated here
1590 * should be released by other functions, such as on a superblock put
1591 * event, regardless of whether this function succeeds for fails.
1592 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001593static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001594ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1595 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001596{
1597 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Dan Carpenterece550f2010-01-19 12:34:32 +03001598 char *full_alg_name = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001599 int rc;
1600
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001601 *key_tfm = NULL;
1602 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001603 rc = -EINVAL;
Michael Halcrowdf261c52009-01-06 14:42:02 -08001604 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001605 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001606 goto out;
1607 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001608 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1609 "ecb");
1610 if (rc)
1611 goto out;
1612 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001613 if (IS_ERR(*key_tfm)) {
1614 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001615 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Dave Hansen38268492009-08-27 09:47:07 -07001616 "[%s]; rc = [%d]\n", full_alg_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001617 goto out;
1618 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001619 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1620 if (*key_size == 0) {
1621 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1622
1623 *key_size = alg->max_keysize;
1624 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001625 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001626 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001627 if (rc) {
Michael Halcrowdf261c52009-01-06 14:42:02 -08001628 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
Dave Hansen38268492009-08-27 09:47:07 -07001629 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1630 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001631 rc = -EINVAL;
1632 goto out;
1633 }
1634out:
Dan Carpenterece550f2010-01-19 12:34:32 +03001635 kfree(full_alg_name);
Michael Halcrow237fead2006-10-04 02:16:22 -07001636 return rc;
1637}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001638
1639struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001640static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001641struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001642
Jerome Marchand7371a382010-08-17 17:24:05 +02001643int __init ecryptfs_init_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001644{
1645 mutex_init(&key_tfm_list_mutex);
1646 INIT_LIST_HEAD(&key_tfm_list);
1647 return 0;
1648}
1649
Eric Sandeenaf440f52008-02-06 01:38:37 -08001650/**
1651 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1652 *
1653 * Called only at module unload time
1654 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001655int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001656{
1657 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1658
1659 mutex_lock(&key_tfm_list_mutex);
1660 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1661 key_tfm_list) {
1662 list_del(&key_tfm->key_tfm_list);
1663 if (key_tfm->key_tfm)
1664 crypto_free_blkcipher(key_tfm->key_tfm);
1665 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1666 }
1667 mutex_unlock(&key_tfm_list_mutex);
1668 return 0;
1669}
1670
1671int
1672ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1673 size_t key_size)
1674{
1675 struct ecryptfs_key_tfm *tmp_tfm;
1676 int rc = 0;
1677
Eric Sandeenaf440f52008-02-06 01:38:37 -08001678 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1679
Michael Halcrowf4aad162007-10-16 01:27:53 -07001680 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1681 if (key_tfm != NULL)
1682 (*key_tfm) = tmp_tfm;
1683 if (!tmp_tfm) {
1684 rc = -ENOMEM;
1685 printk(KERN_ERR "Error attempting to allocate from "
1686 "ecryptfs_key_tfm_cache\n");
1687 goto out;
1688 }
1689 mutex_init(&tmp_tfm->key_tfm_mutex);
1690 strncpy(tmp_tfm->cipher_name, cipher_name,
1691 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001692 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001693 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001694 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1695 tmp_tfm->cipher_name,
1696 &tmp_tfm->key_size);
1697 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001698 printk(KERN_ERR "Error attempting to initialize key TFM "
1699 "cipher with name = [%s]; rc = [%d]\n",
1700 tmp_tfm->cipher_name, rc);
1701 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1702 if (key_tfm != NULL)
1703 (*key_tfm) = NULL;
1704 goto out;
1705 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001706 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001707out:
1708 return rc;
1709}
1710
Eric Sandeenaf440f52008-02-06 01:38:37 -08001711/**
1712 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1713 * @cipher_name: the name of the cipher to search for
1714 * @key_tfm: set to corresponding tfm if found
1715 *
1716 * Searches for cached key_tfm matching @cipher_name
1717 * Must be called with &key_tfm_list_mutex held
1718 * Returns 1 if found, with @key_tfm set
1719 * Returns 0 if not found, with @key_tfm set to NULL
1720 */
1721int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1722{
1723 struct ecryptfs_key_tfm *tmp_key_tfm;
1724
1725 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1726
1727 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1728 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1729 if (key_tfm)
1730 (*key_tfm) = tmp_key_tfm;
1731 return 1;
1732 }
1733 }
1734 if (key_tfm)
1735 (*key_tfm) = NULL;
1736 return 0;
1737}
1738
1739/**
1740 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1741 *
1742 * @tfm: set to cached tfm found, or new tfm created
1743 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1744 * @cipher_name: the name of the cipher to search for and/or add
1745 *
1746 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1747 * Searches for cached item first, and creates new if not found.
1748 * Returns 0 on success, non-zero if adding new cipher failed
1749 */
Michael Halcrowf4aad162007-10-16 01:27:53 -07001750int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1751 struct mutex **tfm_mutex,
1752 char *cipher_name)
1753{
1754 struct ecryptfs_key_tfm *key_tfm;
1755 int rc = 0;
1756
1757 (*tfm) = NULL;
1758 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001759
Michael Halcrowf4aad162007-10-16 01:27:53 -07001760 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001761 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1762 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1763 if (rc) {
1764 printk(KERN_ERR "Error adding new key_tfm to list; "
1765 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001766 goto out;
1767 }
1768 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001769 (*tfm) = key_tfm->key_tfm;
1770 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1771out:
Cyrill Gorcunov71fd5172008-05-23 13:04:20 -07001772 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001773 return rc;
1774}
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001775
1776/* 64 characters forming a 6-bit target field */
1777static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1778 "EFGHIJKLMNOPQRST"
1779 "UVWXYZabcdefghij"
1780 "klmnopqrstuvwxyz");
1781
1782/* We could either offset on every reverse map or just pad some 0x00's
1783 * at the front here */
Tyler Hicks0f751e62011-11-23 11:31:24 -06001784static const unsigned char filename_rev_map[256] = {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001785 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1786 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1787 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1788 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1789 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1790 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1791 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1792 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1793 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1794 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1795 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1796 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1797 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1798 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1799 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
Tyler Hicks0f751e62011-11-23 11:31:24 -06001800 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001801};
1802
1803/**
1804 * ecryptfs_encode_for_filename
1805 * @dst: Destination location for encoded filename
1806 * @dst_size: Size of the encoded filename in bytes
1807 * @src: Source location for the filename to encode
1808 * @src_size: Size of the source in bytes
1809 */
Cong Ding37028752012-12-07 22:21:56 +00001810static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001811 unsigned char *src, size_t src_size)
1812{
1813 size_t num_blocks;
1814 size_t block_num = 0;
1815 size_t dst_offset = 0;
1816 unsigned char last_block[3];
1817
1818 if (src_size == 0) {
1819 (*dst_size) = 0;
1820 goto out;
1821 }
1822 num_blocks = (src_size / 3);
1823 if ((src_size % 3) == 0) {
1824 memcpy(last_block, (&src[src_size - 3]), 3);
1825 } else {
1826 num_blocks++;
1827 last_block[2] = 0x00;
1828 switch (src_size % 3) {
1829 case 1:
1830 last_block[0] = src[src_size - 1];
1831 last_block[1] = 0x00;
1832 break;
1833 case 2:
1834 last_block[0] = src[src_size - 2];
1835 last_block[1] = src[src_size - 1];
1836 }
1837 }
1838 (*dst_size) = (num_blocks * 4);
1839 if (!dst)
1840 goto out;
1841 while (block_num < num_blocks) {
1842 unsigned char *src_block;
1843 unsigned char dst_block[4];
1844
1845 if (block_num == (num_blocks - 1))
1846 src_block = last_block;
1847 else
1848 src_block = &src[block_num * 3];
1849 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
1850 dst_block[1] = (((src_block[0] << 4) & 0x30)
1851 | ((src_block[1] >> 4) & 0x0F));
1852 dst_block[2] = (((src_block[1] << 2) & 0x3C)
1853 | ((src_block[2] >> 6) & 0x03));
1854 dst_block[3] = (src_block[2] & 0x3F);
1855 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
1856 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
1857 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
1858 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
1859 block_num++;
1860 }
1861out:
1862 return;
1863}
1864
Tyler Hicks4a266202011-11-05 13:45:08 -04001865static size_t ecryptfs_max_decoded_size(size_t encoded_size)
1866{
1867 /* Not exact; conservatively long. Every block of 4
1868 * encoded characters decodes into a block of 3
1869 * decoded characters. This segment of code provides
1870 * the caller with the maximum amount of allocated
1871 * space that @dst will need to point to in a
1872 * subsequent call. */
1873 return ((encoded_size + 1) * 3) / 4;
1874}
1875
Michael Halcrow71c11c32009-01-06 14:42:05 -08001876/**
1877 * ecryptfs_decode_from_filename
1878 * @dst: If NULL, this function only sets @dst_size and returns. If
1879 * non-NULL, this function decodes the encoded octets in @src
1880 * into the memory that @dst points to.
1881 * @dst_size: Set to the size of the decoded string.
1882 * @src: The encoded set of octets to decode.
1883 * @src_size: The size of the encoded set of octets to decode.
1884 */
1885static void
1886ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
1887 const unsigned char *src, size_t src_size)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001888{
1889 u8 current_bit_offset = 0;
1890 size_t src_byte_offset = 0;
1891 size_t dst_byte_offset = 0;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001892
1893 if (dst == NULL) {
Tyler Hicks4a266202011-11-05 13:45:08 -04001894 (*dst_size) = ecryptfs_max_decoded_size(src_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001895 goto out;
1896 }
1897 while (src_byte_offset < src_size) {
1898 unsigned char src_byte =
1899 filename_rev_map[(int)src[src_byte_offset]];
1900
1901 switch (current_bit_offset) {
1902 case 0:
1903 dst[dst_byte_offset] = (src_byte << 2);
1904 current_bit_offset = 6;
1905 break;
1906 case 6:
1907 dst[dst_byte_offset++] |= (src_byte >> 4);
1908 dst[dst_byte_offset] = ((src_byte & 0xF)
1909 << 4);
1910 current_bit_offset = 4;
1911 break;
1912 case 4:
1913 dst[dst_byte_offset++] |= (src_byte >> 2);
1914 dst[dst_byte_offset] = (src_byte << 6);
1915 current_bit_offset = 2;
1916 break;
1917 case 2:
1918 dst[dst_byte_offset++] |= (src_byte);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001919 current_bit_offset = 0;
1920 break;
1921 }
1922 src_byte_offset++;
1923 }
1924 (*dst_size) = dst_byte_offset;
1925out:
Michael Halcrow71c11c32009-01-06 14:42:05 -08001926 return;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001927}
1928
1929/**
1930 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
1931 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1932 * @name: The plaintext name
1933 * @length: The length of the plaintext
1934 * @encoded_name: The encypted name
1935 *
1936 * Encrypts and encodes a filename into something that constitutes a
1937 * valid filename for a filesystem, with printable characters.
1938 *
1939 * We assume that we have a properly initialized crypto context,
1940 * pointed to by crypt_stat->tfm.
1941 *
1942 * Returns zero on success; non-zero on otherwise
1943 */
1944int ecryptfs_encrypt_and_encode_filename(
1945 char **encoded_name,
1946 size_t *encoded_name_size,
1947 struct ecryptfs_crypt_stat *crypt_stat,
1948 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1949 const char *name, size_t name_size)
1950{
1951 size_t encoded_name_no_prefix_size;
1952 int rc = 0;
1953
1954 (*encoded_name) = NULL;
1955 (*encoded_name_size) = 0;
1956 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
1957 || (mount_crypt_stat && (mount_crypt_stat->flags
1958 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
1959 struct ecryptfs_filename *filename;
1960
1961 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
1962 if (!filename) {
1963 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08001964 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001965 sizeof(*filename));
1966 rc = -ENOMEM;
1967 goto out;
1968 }
1969 filename->filename = (char *)name;
1970 filename->filename_size = name_size;
1971 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
1972 mount_crypt_stat);
1973 if (rc) {
1974 printk(KERN_ERR "%s: Error attempting to encrypt "
1975 "filename; rc = [%d]\n", __func__, rc);
1976 kfree(filename);
1977 goto out;
1978 }
1979 ecryptfs_encode_for_filename(
1980 NULL, &encoded_name_no_prefix_size,
1981 filename->encrypted_filename,
1982 filename->encrypted_filename_size);
1983 if ((crypt_stat && (crypt_stat->flags
1984 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1985 || (mount_crypt_stat
1986 && (mount_crypt_stat->flags
1987 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
1988 (*encoded_name_size) =
1989 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1990 + encoded_name_no_prefix_size);
1991 else
1992 (*encoded_name_size) =
1993 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1994 + encoded_name_no_prefix_size);
1995 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
1996 if (!(*encoded_name)) {
1997 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08001998 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001999 (*encoded_name_size));
2000 rc = -ENOMEM;
2001 kfree(filename->encrypted_filename);
2002 kfree(filename);
2003 goto out;
2004 }
2005 if ((crypt_stat && (crypt_stat->flags
2006 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2007 || (mount_crypt_stat
2008 && (mount_crypt_stat->flags
2009 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2010 memcpy((*encoded_name),
2011 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2012 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2013 ecryptfs_encode_for_filename(
2014 ((*encoded_name)
2015 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2016 &encoded_name_no_prefix_size,
2017 filename->encrypted_filename,
2018 filename->encrypted_filename_size);
2019 (*encoded_name_size) =
2020 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2021 + encoded_name_no_prefix_size);
2022 (*encoded_name)[(*encoded_name_size)] = '\0';
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002023 } else {
Tyler Hicksdf6ad332009-08-21 04:27:46 -05002024 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002025 }
2026 if (rc) {
2027 printk(KERN_ERR "%s: Error attempting to encode "
2028 "encrypted filename; rc = [%d]\n", __func__,
2029 rc);
2030 kfree((*encoded_name));
2031 (*encoded_name) = NULL;
2032 (*encoded_name_size) = 0;
2033 }
2034 kfree(filename->encrypted_filename);
2035 kfree(filename);
2036 } else {
2037 rc = ecryptfs_copy_filename(encoded_name,
2038 encoded_name_size,
2039 name, name_size);
2040 }
2041out:
2042 return rc;
2043}
2044
2045/**
2046 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2047 * @plaintext_name: The plaintext name
2048 * @plaintext_name_size: The plaintext name size
2049 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2050 * @name: The filename in cipher text
2051 * @name_size: The cipher text name size
2052 *
2053 * Decrypts and decodes the filename.
2054 *
2055 * Returns zero on error; non-zero otherwise
2056 */
2057int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2058 size_t *plaintext_name_size,
Al Viro0747fdb2013-06-16 20:05:38 +04002059 struct super_block *sb,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002060 const char *name, size_t name_size)
2061{
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002062 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
Al Viro0747fdb2013-06-16 20:05:38 +04002063 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002064 char *decoded_name;
2065 size_t decoded_name_size;
2066 size_t packet_size;
2067 int rc = 0;
2068
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002069 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2070 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2071 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002072 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2073 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002074 const char *orig_name = name;
2075 size_t orig_name_size = name_size;
2076
2077 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2078 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
Michael Halcrow71c11c32009-01-06 14:42:05 -08002079 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2080 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002081 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2082 if (!decoded_name) {
2083 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08002084 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002085 decoded_name_size);
2086 rc = -ENOMEM;
2087 goto out;
2088 }
Michael Halcrow71c11c32009-01-06 14:42:05 -08002089 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2090 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002091 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2092 plaintext_name_size,
2093 &packet_size,
2094 mount_crypt_stat,
2095 decoded_name,
2096 decoded_name_size);
2097 if (rc) {
2098 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2099 "from filename; copying through filename "
2100 "as-is\n", __func__);
2101 rc = ecryptfs_copy_filename(plaintext_name,
2102 plaintext_name_size,
2103 orig_name, orig_name_size);
2104 goto out_free;
2105 }
2106 } else {
2107 rc = ecryptfs_copy_filename(plaintext_name,
2108 plaintext_name_size,
2109 name, name_size);
2110 goto out;
2111 }
2112out_free:
2113 kfree(decoded_name);
2114out:
2115 return rc;
2116}
Tyler Hicks4a266202011-11-05 13:45:08 -04002117
2118#define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
2119
2120int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
2121 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
2122{
2123 struct blkcipher_desc desc;
2124 struct mutex *tfm_mutex;
2125 size_t cipher_blocksize;
2126 int rc;
2127
2128 if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
2129 (*namelen) = lower_namelen;
2130 return 0;
2131 }
2132
2133 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2134 mount_crypt_stat->global_default_fn_cipher_name);
2135 if (unlikely(rc)) {
2136 (*namelen) = 0;
2137 return rc;
2138 }
2139
2140 mutex_lock(tfm_mutex);
2141 cipher_blocksize = crypto_blkcipher_blocksize(desc.tfm);
2142 mutex_unlock(tfm_mutex);
2143
2144 /* Return an exact amount for the common cases */
2145 if (lower_namelen == NAME_MAX
2146 && (cipher_blocksize == 8 || cipher_blocksize == 16)) {
2147 (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
2148 return 0;
2149 }
2150
2151 /* Return a safe estimate for the uncommon cases */
2152 (*namelen) = lower_namelen;
2153 (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2154 /* Since this is the max decoded size, subtract 1 "decoded block" len */
2155 (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3;
2156 (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
2157 (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
2158 /* Worst case is that the filename is padded nearly a full block size */
2159 (*namelen) -= cipher_blocksize - 1;
2160
2161 if ((*namelen) < 0)
2162 (*namelen) = 0;
2163
2164 return 0;
2165}