blob: e5e29f8c920b18bc6959cdb16d2ee57fec7d45a6 [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
Herbert Xu3095e8e2016-01-25 10:29:33 +080026#include <crypto/hash.h>
27#include <crypto/skcipher.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070028#include <linux/fs.h>
29#include <linux/mount.h>
30#include <linux/pagemap.h>
31#include <linux/random.h>
32#include <linux/compiler.h>
33#include <linux/key.h>
34#include <linux/namei.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070035#include <linux/file.h>
36#include <linux/scatterlist.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090037#include <linux/slab.h>
Harvey Harrison29335c62008-07-23 21:30:06 -070038#include <asm/unaligned.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070039#include "ecryptfs_kernel.h"
40
Tyler Hicks00a69942013-04-05 23:26:22 -070041#define DECRYPT 0
42#define ENCRYPT 1
Michael Halcrow237fead2006-10-04 02:16:22 -070043
44/**
45 * ecryptfs_to_hex
46 * @dst: Buffer to take hex character representation of contents of
47 * src; must be at least of size (src_size * 2)
Wei Yuan5f9f2c22016-02-17 14:50:10 +080048 * @src: Buffer to be converted to a hex string representation
Michael Halcrow237fead2006-10-04 02:16:22 -070049 * @src_size: number of bytes to convert
50 */
51void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
52{
53 int x;
54
55 for (x = 0; x < src_size; x++)
56 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
57}
58
59/**
60 * ecryptfs_from_hex
61 * @dst: Buffer to take the bytes from src hex; must be at least of
62 * size (src_size / 2)
Wei Yuan5f9f2c22016-02-17 14:50:10 +080063 * @src: Buffer to be converted from a hex string representation to raw value
Michael Halcrow237fead2006-10-04 02:16:22 -070064 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
65 */
66void ecryptfs_from_hex(char *dst, char *src, int dst_size)
67{
68 int x;
69 char tmp[3] = { 0, };
70
71 for (x = 0; x < dst_size; x++) {
72 tmp[0] = src[x * 2];
73 tmp[1] = src[x * 2 + 1];
74 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
75 }
76}
77
Herbert Xu3095e8e2016-01-25 10:29:33 +080078static int ecryptfs_hash_digest(struct crypto_shash *tfm,
79 char *src, int len, char *dst)
80{
81 SHASH_DESC_ON_STACK(desc, tfm);
82 int err;
83
84 desc->tfm = tfm;
85 desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
86 err = crypto_shash_digest(desc, src, len, dst);
87 shash_desc_zero(desc);
88 return err;
89}
90
Michael Halcrow237fead2006-10-04 02:16:22 -070091/**
92 * ecryptfs_calculate_md5 - calculates the md5 of @src
93 * @dst: Pointer to 16 bytes of allocated memory
94 * @crypt_stat: Pointer to crypt_stat struct for the current inode
95 * @src: Data to be md5'd
96 * @len: Length of @src
97 *
98 * Uses the allocated crypto context that crypt_stat references to
99 * generate the MD5 sum of the contents of src.
100 */
101static int ecryptfs_calculate_md5(char *dst,
102 struct ecryptfs_crypt_stat *crypt_stat,
103 char *src, int len)
104{
Herbert Xu3095e8e2016-01-25 10:29:33 +0800105 struct crypto_shash *tfm;
Michael Halcrow565d97242006-10-30 22:07:17 -0800106 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700107
Herbert Xu3095e8e2016-01-25 10:29:33 +0800108 tfm = crypt_stat->hash_tfm;
Herbert Xu3095e8e2016-01-25 10:29:33 +0800109 rc = ecryptfs_hash_digest(tfm, src, len, dst);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800110 if (rc) {
111 printk(KERN_ERR
Herbert Xu3095e8e2016-01-25 10:29:33 +0800112 "%s: Error computing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700113 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800114 goto out;
115 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700116out:
117 return rc;
118}
119
Michael Halcrowcd9d67d2007-10-16 01:28:04 -0700120static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
121 char *cipher_name,
122 char *chaining_modifier)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800123{
124 int cipher_name_len = strlen(cipher_name);
125 int chaining_modifier_len = strlen(chaining_modifier);
126 int algified_name_len;
127 int rc;
128
129 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
130 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
Michael Halcrow7bd473f2006-11-02 22:06:56 -0800131 if (!(*algified_name)) {
Michael Halcrow8bba0662006-10-30 22:07:18 -0800132 rc = -ENOMEM;
133 goto out;
134 }
135 snprintf((*algified_name), algified_name_len, "%s(%s)",
136 chaining_modifier, cipher_name);
137 rc = 0;
138out:
139 return rc;
140}
141
Michael Halcrow237fead2006-10-04 02:16:22 -0700142/**
143 * ecryptfs_derive_iv
144 * @iv: destination for the derived iv vale
145 * @crypt_stat: Pointer to crypt_stat struct for the current inode
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700146 * @offset: Offset of the extent whose IV we are to derive
Michael Halcrow237fead2006-10-04 02:16:22 -0700147 *
148 * Generate the initialization vector from the given root IV and page
149 * offset.
150 *
151 * Returns zero on success; non-zero on error.
152 */
Michael Halcrowa34f60f2009-01-06 14:41:58 -0800153int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
154 loff_t offset)
Michael Halcrow237fead2006-10-04 02:16:22 -0700155{
156 int rc = 0;
157 char dst[MD5_DIGEST_SIZE];
158 char src[ECRYPTFS_MAX_IV_BYTES + 16];
159
160 if (unlikely(ecryptfs_verbosity > 0)) {
161 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
162 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
163 }
164 /* TODO: It is probably secure to just cast the least
165 * significant bits of the root IV into an unsigned long and
166 * add the offset to that rather than go through all this
167 * hashing business. -Halcrow */
168 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
169 memset((src + crypt_stat->iv_bytes), 0, 16);
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700170 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700171 if (unlikely(ecryptfs_verbosity > 0)) {
172 ecryptfs_printk(KERN_DEBUG, "source:\n");
173 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
174 }
175 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
176 (crypt_stat->iv_bytes + 16));
177 if (rc) {
178 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
179 "MD5 while generating IV for a page\n");
180 goto out;
181 }
182 memcpy(iv, dst, crypt_stat->iv_bytes);
183 if (unlikely(ecryptfs_verbosity > 0)) {
184 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
185 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
186 }
187out:
188 return rc;
189}
190
191/**
192 * ecryptfs_init_crypt_stat
193 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
194 *
195 * Initialize the crypt_stat structure.
196 */
Herbert Xue81f3342016-04-16 15:01:09 +0800197int ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -0700198{
Herbert Xue81f3342016-04-16 15:01:09 +0800199 struct crypto_shash *tfm;
200 int rc;
201
202 tfm = crypto_alloc_shash(ECRYPTFS_DEFAULT_HASH, 0, 0);
203 if (IS_ERR(tfm)) {
204 rc = PTR_ERR(tfm);
205 ecryptfs_printk(KERN_ERR, "Error attempting to "
206 "allocate crypto context; rc = [%d]\n",
207 rc);
208 return rc;
209 }
210
Michael Halcrow237fead2006-10-04 02:16:22 -0700211 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
Michael Halcrowf4aad162007-10-16 01:27:53 -0700212 INIT_LIST_HEAD(&crypt_stat->keysig_list);
213 mutex_init(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700214 mutex_init(&crypt_stat->cs_mutex);
215 mutex_init(&crypt_stat->cs_tfm_mutex);
Herbert Xue81f3342016-04-16 15:01:09 +0800216 crypt_stat->hash_tfm = tfm;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800217 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
Herbert Xue81f3342016-04-16 15:01:09 +0800218
219 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700220}
221
222/**
Michael Halcrowfcd12832007-10-16 01:28:01 -0700223 * ecryptfs_destroy_crypt_stat
Michael Halcrow237fead2006-10-04 02:16:22 -0700224 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
225 *
226 * Releases all memory associated with a crypt_stat struct.
227 */
Michael Halcrowfcd12832007-10-16 01:28:01 -0700228void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -0700229{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700230 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
231
Herbert Xu3095e8e2016-01-25 10:29:33 +0800232 crypto_free_skcipher(crypt_stat->tfm);
233 crypto_free_shash(crypt_stat->hash_tfm);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700234 list_for_each_entry_safe(key_sig, key_sig_tmp,
235 &crypt_stat->keysig_list, crypt_stat_list) {
236 list_del(&key_sig->crypt_stat_list);
237 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
238 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700239 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
240}
241
Michael Halcrowfcd12832007-10-16 01:28:01 -0700242void ecryptfs_destroy_mount_crypt_stat(
Michael Halcrow237fead2006-10-04 02:16:22 -0700243 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
244{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700245 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
246
247 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
248 return;
249 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
250 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
251 &mount_crypt_stat->global_auth_tok_list,
252 mount_crypt_stat_list) {
253 list_del(&auth_tok->mount_crypt_stat_list);
Markus Elfring0dad87f2015-06-26 18:18:54 +0200254 if (!(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
Michael Halcrowf4aad162007-10-16 01:27:53 -0700255 key_put(auth_tok->global_auth_tok_key);
256 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
257 }
258 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700259 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
260}
261
262/**
263 * virt_to_scatterlist
264 * @addr: Virtual address
265 * @size: Size of data; should be an even multiple of the block size
266 * @sg: Pointer to scatterlist array; set to NULL to obtain only
267 * the number of scatterlist structs required in array
268 * @sg_size: Max array size
269 *
270 * Fills in a scatterlist array with page references for a passed
271 * virtual address.
272 *
273 * Returns the number of scatterlist structs in array used
274 */
275int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
276 int sg_size)
277{
278 int i = 0;
279 struct page *pg;
280 int offset;
281 int remainder_of_page;
282
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700283 sg_init_table(sg, sg_size);
284
Michael Halcrow237fead2006-10-04 02:16:22 -0700285 while (size > 0 && i < sg_size) {
286 pg = virt_to_page(addr);
287 offset = offset_in_page(addr);
Dan Carpentera07c48a2013-01-26 10:48:42 +0300288 sg_set_page(&sg[i], pg, 0, offset);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300289 remainder_of_page = PAGE_SIZE - offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700290 if (size >= remainder_of_page) {
Dan Carpentera07c48a2013-01-26 10:48:42 +0300291 sg[i].length = remainder_of_page;
Michael Halcrow237fead2006-10-04 02:16:22 -0700292 addr += remainder_of_page;
293 size -= remainder_of_page;
294 } else {
Dan Carpentera07c48a2013-01-26 10:48:42 +0300295 sg[i].length = size;
Michael Halcrow237fead2006-10-04 02:16:22 -0700296 addr += size;
297 size = 0;
298 }
299 i++;
300 }
301 if (size > 0)
302 return -ENOMEM;
303 return i;
304}
305
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700306struct extent_crypt_result {
307 struct completion completion;
308 int rc;
309};
310
311static void extent_crypt_complete(struct crypto_async_request *req, int rc)
312{
313 struct extent_crypt_result *ecr = req->data;
314
315 if (rc == -EINPROGRESS)
316 return;
317
318 ecr->rc = rc;
319 complete(&ecr->completion);
320}
321
Michael Halcrow237fead2006-10-04 02:16:22 -0700322/**
Tyler Hicks00a69942013-04-05 23:26:22 -0700323 * crypt_scatterlist
Michael Halcrow237fead2006-10-04 02:16:22 -0700324 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700325 * @dst_sg: Destination of the data after performing the crypto operation
Tyler Hicks00a69942013-04-05 23:26:22 -0700326 * @src_sg: Data to be encrypted or decrypted
327 * @size: Length of data
328 * @iv: IV to use
329 * @op: ENCRYPT or DECRYPT to indicate the desired operation
Michael Halcrow237fead2006-10-04 02:16:22 -0700330 *
Tyler Hicks00a69942013-04-05 23:26:22 -0700331 * Returns the number of bytes encrypted or decrypted; negative value on error
Michael Halcrow237fead2006-10-04 02:16:22 -0700332 */
Tyler Hicks00a69942013-04-05 23:26:22 -0700333static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700334 struct scatterlist *dst_sg,
Tyler Hicks00a69942013-04-05 23:26:22 -0700335 struct scatterlist *src_sg, int size,
336 unsigned char *iv, int op)
Michael Halcrow237fead2006-10-04 02:16:22 -0700337{
Herbert Xu3095e8e2016-01-25 10:29:33 +0800338 struct skcipher_request *req = NULL;
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700339 struct extent_crypt_result ecr;
Michael Halcrow237fead2006-10-04 02:16:22 -0700340 int rc = 0;
341
342 BUG_ON(!crypt_stat || !crypt_stat->tfm
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800343 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
Michael Halcrow237fead2006-10-04 02:16:22 -0700344 if (unlikely(ecryptfs_verbosity > 0)) {
Tyler Hicksf24b3882010-11-15 17:36:38 -0600345 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700346 crypt_stat->key_size);
347 ecryptfs_dump_hex(crypt_stat->key,
348 crypt_stat->key_size);
349 }
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700350
351 init_completion(&ecr.completion);
352
Michael Halcrow237fead2006-10-04 02:16:22 -0700353 mutex_lock(&crypt_stat->cs_tfm_mutex);
Herbert Xu3095e8e2016-01-25 10:29:33 +0800354 req = skcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700355 if (!req) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700356 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700357 rc = -ENOMEM;
Michael Halcrow237fead2006-10-04 02:16:22 -0700358 goto out;
359 }
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700360
Herbert Xu3095e8e2016-01-25 10:29:33 +0800361 skcipher_request_set_callback(req,
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700362 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
363 extent_crypt_complete, &ecr);
364 /* Consider doing this once, when the file is opened */
365 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
Herbert Xu3095e8e2016-01-25 10:29:33 +0800366 rc = crypto_skcipher_setkey(crypt_stat->tfm, crypt_stat->key,
367 crypt_stat->key_size);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700368 if (rc) {
369 ecryptfs_printk(KERN_ERR,
370 "Error setting key; rc = [%d]\n",
371 rc);
372 mutex_unlock(&crypt_stat->cs_tfm_mutex);
373 rc = -EINVAL;
374 goto out;
375 }
376 crypt_stat->flags |= ECRYPTFS_KEY_SET;
377 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700378 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Herbert Xu3095e8e2016-01-25 10:29:33 +0800379 skcipher_request_set_crypt(req, src_sg, dst_sg, size, iv);
380 rc = op == ENCRYPT ? crypto_skcipher_encrypt(req) :
381 crypto_skcipher_decrypt(req);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700382 if (rc == -EINPROGRESS || rc == -EBUSY) {
383 struct extent_crypt_result *ecr = req->base.data;
384
385 wait_for_completion(&ecr->completion);
386 rc = ecr->rc;
Wolfram Sang16735d02013-11-14 14:32:02 -0800387 reinit_completion(&ecr->completion);
Tyler Hicks4dfea4f2013-05-09 16:55:07 -0700388 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700389out:
Herbert Xu3095e8e2016-01-25 10:29:33 +0800390 skcipher_request_free(req);
Michael Halcrow237fead2006-10-04 02:16:22 -0700391 return rc;
392}
393
Michael Halcrow237fead2006-10-04 02:16:22 -0700394/**
Tyler Hicks24d15262013-04-15 17:28:09 -0700395 * lower_offset_for_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700396 *
397 * Convert an eCryptfs page index into a lower byte offset
398 */
Tyler Hicks24d15262013-04-15 17:28:09 -0700399static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
400 struct page *page)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700401{
Tyler Hicks24d15262013-04-15 17:28:09 -0700402 return ecryptfs_lower_header_size(crypt_stat) +
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300403 ((loff_t)page->index << PAGE_SHIFT);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700404}
405
406/**
Tyler Hicksd78de612013-04-06 00:08:48 -0700407 * crypt_extent
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700408 * @crypt_stat: crypt_stat containing cryptographic context for the
409 * encryption operation
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700410 * @dst_page: The page to write the result into
Tyler Hicksd78de612013-04-06 00:08:48 -0700411 * @src_page: The page to read from
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700412 * @extent_offset: Page extent offset for use in generating IV
Tyler Hicksd78de612013-04-06 00:08:48 -0700413 * @op: ENCRYPT or DECRYPT to indicate the desired operation
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700414 *
Tyler Hicksd78de612013-04-06 00:08:48 -0700415 * Encrypts or decrypts one extent of data.
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700416 *
417 * Return zero on success; non-zero otherwise
418 */
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700419static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat,
420 struct page *dst_page,
Tyler Hicksd78de612013-04-06 00:08:48 -0700421 struct page *src_page,
422 unsigned long extent_offset, int op)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700423{
Tyler Hicksd78de612013-04-06 00:08:48 -0700424 pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index;
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700425 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700426 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
Tyler Hicks406c93d2013-04-15 17:49:31 -0700427 struct scatterlist src_sg, dst_sg;
428 size_t extent_size = crypt_stat->extent_size;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700429 int rc;
430
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300431 extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size));
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700432 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
433 (extent_base + extent_offset));
434 if (rc) {
Joe Perches888d57b2010-11-10 15:46:16 -0800435 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
436 "extent [0x%.16llx]; rc = [%d]\n",
437 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700438 goto out;
439 }
Tyler Hicks406c93d2013-04-15 17:49:31 -0700440
441 sg_init_table(&src_sg, 1);
442 sg_init_table(&dst_sg, 1);
443
444 sg_set_page(&src_sg, src_page, extent_size,
445 extent_offset * extent_size);
446 sg_set_page(&dst_sg, dst_page, extent_size,
447 extent_offset * extent_size);
448
449 rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size,
450 extent_iv, op);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700451 if (rc < 0) {
Tyler Hicksd78de612013-04-06 00:08:48 -0700452 printk(KERN_ERR "%s: Error attempting to crypt page with "
453 "page_index = [%ld], extent_offset = [%ld]; "
454 "rc = [%d]\n", __func__, page_index, extent_offset, rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700455 goto out;
456 }
457 rc = 0;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700458out:
459 return rc;
460}
461
462/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700463 * ecryptfs_encrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700464 * @page: Page mapped from the eCryptfs inode for the file; contains
465 * decrypted content that needs to be encrypted (to a temporary
466 * page; not in place) and written out to the lower file
Michael Halcrow237fead2006-10-04 02:16:22 -0700467 *
468 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
469 * that eCryptfs pages may straddle the lower pages -- for instance,
470 * if the file was created on a machine with an 8K page size
471 * (resulting in an 8K header), and then the file is copied onto a
472 * host with a 32K page size, then when reading page 0 of the eCryptfs
473 * file, 24K of page 0 of the lower file will be read and decrypted,
474 * and then 8K of page 1 of the lower file will be read and decrypted.
475 *
Michael Halcrow237fead2006-10-04 02:16:22 -0700476 * Returns zero on success; negative on error
477 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700478int ecryptfs_encrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700479{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700480 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700481 struct ecryptfs_crypt_stat *crypt_stat;
Eric Sandeen7fcba052008-07-28 15:46:39 -0700482 char *enc_extent_virt;
483 struct page *enc_extent_page = NULL;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700484 loff_t extent_offset;
Tyler Hicks0f896172013-04-15 16:16:24 -0700485 loff_t lower_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700486 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700487
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700488 ecryptfs_inode = page->mapping->host;
489 crypt_stat =
490 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500491 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Eric Sandeen7fcba052008-07-28 15:46:39 -0700492 enc_extent_page = alloc_page(GFP_USER);
493 if (!enc_extent_page) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700494 rc = -ENOMEM;
495 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
496 "encrypted extent\n");
497 goto out;
498 }
Tyler Hicks0f896172013-04-15 16:16:24 -0700499
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700500 for (extent_offset = 0;
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300501 extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700502 extent_offset++) {
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700503 rc = crypt_extent(crypt_stat, enc_extent_page, page,
Tyler Hicksd78de612013-04-06 00:08:48 -0700504 extent_offset, ENCRYPT);
Michael Halcrow237fead2006-10-04 02:16:22 -0700505 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700506 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700507 "rc = [%d]\n", __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700508 goto out;
509 }
Tyler Hicks0f896172013-04-15 16:16:24 -0700510 }
511
Tyler Hicks24d15262013-04-15 17:28:09 -0700512 lower_offset = lower_offset_for_page(crypt_stat, page);
Tyler Hicks0f896172013-04-15 16:16:24 -0700513 enc_extent_virt = kmap(enc_extent_page);
514 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300515 PAGE_SIZE);
Tyler Hicks0f896172013-04-15 16:16:24 -0700516 kunmap(enc_extent_page);
517 if (rc < 0) {
518 ecryptfs_printk(KERN_ERR,
519 "Error attempting to write lower page; rc = [%d]\n",
520 rc);
521 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700522 }
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500523 rc = 0;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700524out:
Eric Sandeen7fcba052008-07-28 15:46:39 -0700525 if (enc_extent_page) {
Eric Sandeen7fcba052008-07-28 15:46:39 -0700526 __free_page(enc_extent_page);
527 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700528 return rc;
529}
530
Michael Halcrow237fead2006-10-04 02:16:22 -0700531/**
532 * ecryptfs_decrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700533 * @page: Page mapped from the eCryptfs inode for the file; data read
534 * and decrypted from the lower file will be written into this
535 * page
Michael Halcrow237fead2006-10-04 02:16:22 -0700536 *
537 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
538 * that eCryptfs pages may straddle the lower pages -- for instance,
539 * if the file was created on a machine with an 8K page size
540 * (resulting in an 8K header), and then the file is copied onto a
541 * host with a 32K page size, then when reading page 0 of the eCryptfs
542 * file, 24K of page 0 of the lower file will be read and decrypted,
543 * and then 8K of page 1 of the lower file will be read and decrypted.
544 *
545 * Returns zero on success; negative on error
546 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700547int ecryptfs_decrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700548{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700549 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700550 struct ecryptfs_crypt_stat *crypt_stat;
Tyler Hicks9c6043f2013-04-06 00:41:48 -0700551 char *page_virt;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700552 unsigned long extent_offset;
Tyler Hicks0f896172013-04-15 16:16:24 -0700553 loff_t lower_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700554 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700555
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700556 ecryptfs_inode = page->mapping->host;
557 crypt_stat =
558 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500559 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Tyler Hicks0f896172013-04-15 16:16:24 -0700560
Tyler Hicks24d15262013-04-15 17:28:09 -0700561 lower_offset = lower_offset_for_page(crypt_stat, page);
Tyler Hicks9c6043f2013-04-06 00:41:48 -0700562 page_virt = kmap(page);
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300563 rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE,
Tyler Hicks0f896172013-04-15 16:16:24 -0700564 ecryptfs_inode);
Tyler Hicks9c6043f2013-04-06 00:41:48 -0700565 kunmap(page);
Tyler Hicks0f896172013-04-15 16:16:24 -0700566 if (rc < 0) {
567 ecryptfs_printk(KERN_ERR,
568 "Error attempting to read lower page; rc = [%d]\n",
569 rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700570 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700571 }
Tyler Hicks0f896172013-04-15 16:16:24 -0700572
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700573 for (extent_offset = 0;
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300574 extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700575 extent_offset++) {
Tyler Hicks0df5ed62013-05-23 12:08:40 -0700576 rc = crypt_extent(crypt_stat, page, page,
Tyler Hicksd78de612013-04-06 00:08:48 -0700577 extent_offset, DECRYPT);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700578 if (rc) {
579 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700580 "rc = [%d]\n", __func__, rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700581 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700582 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700583 }
584out:
Michael Halcrow237fead2006-10-04 02:16:22 -0700585 return rc;
586}
587
Michael Halcrow237fead2006-10-04 02:16:22 -0700588#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
589
590/**
591 * ecryptfs_init_crypt_ctx
Uwe Kleine-König421f91d2010-06-11 12:17:00 +0200592 * @crypt_stat: Uninitialized crypt stats structure
Michael Halcrow237fead2006-10-04 02:16:22 -0700593 *
594 * Initialize the crypto context.
595 *
596 * TODO: Performance: Keep a cache of initialized cipher contexts;
597 * only init if needed
598 */
599int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
600{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800601 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700602 int rc = -EINVAL;
603
Michael Halcrow237fead2006-10-04 02:16:22 -0700604 ecryptfs_printk(KERN_DEBUG,
605 "Initializing cipher [%s]; strlen = [%d]; "
Tyler Hicksf24b3882010-11-15 17:36:38 -0600606 "key_size_bits = [%zd]\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700607 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
608 crypt_stat->key_size << 3);
Kees Cookcb69f362013-08-13 15:02:27 -0700609 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700610 if (crypt_stat->tfm) {
611 rc = 0;
Kees Cookcb69f362013-08-13 15:02:27 -0700612 goto out_unlock;
Michael Halcrow237fead2006-10-04 02:16:22 -0700613 }
Michael Halcrow8bba0662006-10-30 22:07:18 -0800614 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
615 crypt_stat->cipher, "cbc");
616 if (rc)
Eric Sandeenc8161f62007-12-22 14:03:26 -0800617 goto out_unlock;
Herbert Xu3095e8e2016-01-25 10:29:33 +0800618 crypt_stat->tfm = crypto_alloc_skcipher(full_alg_name, 0, 0);
Akinobu Mitade887772006-11-28 12:29:49 -0800619 if (IS_ERR(crypt_stat->tfm)) {
620 rc = PTR_ERR(crypt_stat->tfm);
Tyler Hicksb0105ea2009-08-11 00:36:32 -0500621 crypt_stat->tfm = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -0700622 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
623 "Error initializing cipher [%s]\n",
Kees Cookcb69f362013-08-13 15:02:27 -0700624 full_alg_name);
625 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -0700626 }
Herbert Xu3095e8e2016-01-25 10:29:33 +0800627 crypto_skcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow237fead2006-10-04 02:16:22 -0700628 rc = 0;
Kees Cookcb69f362013-08-13 15:02:27 -0700629out_free:
630 kfree(full_alg_name);
Eric Sandeenc8161f62007-12-22 14:03:26 -0800631out_unlock:
632 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700633 return rc;
634}
635
636static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
637{
638 int extent_size_tmp;
639
640 crypt_stat->extent_mask = 0xFFFFFFFF;
641 crypt_stat->extent_shift = 0;
642 if (crypt_stat->extent_size == 0)
643 return;
644 extent_size_tmp = crypt_stat->extent_size;
645 while ((extent_size_tmp & 0x01) == 0) {
646 extent_size_tmp >>= 1;
647 crypt_stat->extent_mask <<= 1;
648 crypt_stat->extent_shift++;
649 }
650}
651
652void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
653{
654 /* Default values; may be overwritten as we are parsing the
655 * packets. */
656 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
657 set_extent_mask_and_shift(crypt_stat);
658 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800659 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600660 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700661 else {
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300662 if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600663 crypt_stat->metadata_size =
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800664 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700665 else
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300666 crypt_stat->metadata_size = PAGE_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700667 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700668}
669
670/**
671 * ecryptfs_compute_root_iv
672 * @crypt_stats
673 *
674 * On error, sets the root IV to all 0's.
675 */
676int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
677{
678 int rc = 0;
679 char dst[MD5_DIGEST_SIZE];
680
681 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
682 BUG_ON(crypt_stat->iv_bytes <= 0);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800683 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700684 rc = -EINVAL;
685 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
686 "cannot generate root IV\n");
687 goto out;
688 }
689 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
690 crypt_stat->key_size);
691 if (rc) {
692 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
693 "MD5 while generating root IV\n");
694 goto out;
695 }
696 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
697out:
698 if (rc) {
699 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800700 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
Michael Halcrow237fead2006-10-04 02:16:22 -0700701 }
702 return rc;
703}
704
705static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
706{
707 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800708 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
Michael Halcrow237fead2006-10-04 02:16:22 -0700709 ecryptfs_compute_root_iv(crypt_stat);
710 if (unlikely(ecryptfs_verbosity > 0)) {
711 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
712 ecryptfs_dump_hex(crypt_stat->key,
713 crypt_stat->key_size);
714 }
715}
716
717/**
Michael Halcrow17398952007-02-12 00:53:45 -0800718 * ecryptfs_copy_mount_wide_flags_to_inode_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700719 * @crypt_stat: The inode's cryptographic context
720 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow17398952007-02-12 00:53:45 -0800721 *
722 * This function propagates the mount-wide flags to individual inode
723 * flags.
724 */
725static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
726 struct ecryptfs_crypt_stat *crypt_stat,
727 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
728{
729 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
730 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
731 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
732 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800733 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
734 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
735 if (mount_crypt_stat->flags
736 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
737 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
738 else if (mount_crypt_stat->flags
739 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
740 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
741 }
Michael Halcrow17398952007-02-12 00:53:45 -0800742}
743
Michael Halcrowf4aad162007-10-16 01:27:53 -0700744static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
745 struct ecryptfs_crypt_stat *crypt_stat,
746 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
747{
748 struct ecryptfs_global_auth_tok *global_auth_tok;
749 int rc = 0;
750
Roland Dreieraa061172009-07-01 15:48:18 -0700751 mutex_lock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700752 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
Roland Dreieraa061172009-07-01 15:48:18 -0700753
Michael Halcrowf4aad162007-10-16 01:27:53 -0700754 list_for_each_entry(global_auth_tok,
755 &mount_crypt_stat->global_auth_tok_list,
756 mount_crypt_stat_list) {
Tyler Hicks84814d62009-03-13 13:51:59 -0700757 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
758 continue;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700759 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
760 if (rc) {
761 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700762 goto out;
763 }
764 }
Roland Dreieraa061172009-07-01 15:48:18 -0700765
Michael Halcrowf4aad162007-10-16 01:27:53 -0700766out:
Roland Dreieraa061172009-07-01 15:48:18 -0700767 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
768 mutex_unlock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700769 return rc;
770}
771
Michael Halcrow17398952007-02-12 00:53:45 -0800772/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700773 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700774 * @crypt_stat: The inode's cryptographic context
775 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700776 *
777 * Default values in the event that policy does not override them.
778 */
779static void ecryptfs_set_default_crypt_stat_vals(
780 struct ecryptfs_crypt_stat *crypt_stat,
781 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
782{
Michael Halcrow17398952007-02-12 00:53:45 -0800783 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
784 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700785 ecryptfs_set_default_sizes(crypt_stat);
786 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
787 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800788 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -0700789 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
790 crypt_stat->mount_crypt_stat = mount_crypt_stat;
791}
792
793/**
794 * ecryptfs_new_file_context
Tyler Hicksb59db432011-11-21 17:31:02 -0600795 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrow237fead2006-10-04 02:16:22 -0700796 *
797 * If the crypto context for the file has not yet been established,
798 * this is where we do that. Establishing a new crypto context
799 * involves the following decisions:
800 * - What cipher to use?
801 * - What set of authentication tokens to use?
802 * Here we just worry about getting enough information into the
803 * authentication tokens so that we know that they are available.
804 * We associate the available authentication tokens with the new file
805 * via the set of signatures in the crypt_stat struct. Later, when
806 * the headers are actually written out, we may again defer to
807 * userspace to perform the encryption of the session key; for the
808 * foreseeable future, this will be the case with public key packets.
809 *
810 * Returns zero on success; non-zero otherwise
811 */
Tyler Hicksb59db432011-11-21 17:31:02 -0600812int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
Michael Halcrow237fead2006-10-04 02:16:22 -0700813{
Michael Halcrow237fead2006-10-04 02:16:22 -0700814 struct ecryptfs_crypt_stat *crypt_stat =
Tyler Hicksb59db432011-11-21 17:31:02 -0600815 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700816 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
817 &ecryptfs_superblock_to_private(
Tyler Hicksb59db432011-11-21 17:31:02 -0600818 ecryptfs_inode->i_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700819 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700820 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700821
822 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -0700823 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700824 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
825 mount_crypt_stat);
826 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
827 mount_crypt_stat);
828 if (rc) {
829 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
830 "to the inode key sigs; rc = [%d]\n", rc);
831 goto out;
832 }
833 cipher_name_len =
834 strlen(mount_crypt_stat->global_default_cipher_name);
835 memcpy(crypt_stat->cipher,
836 mount_crypt_stat->global_default_cipher_name,
837 cipher_name_len);
838 crypt_stat->cipher[cipher_name_len] = '\0';
839 crypt_stat->key_size =
840 mount_crypt_stat->global_default_cipher_key_size;
841 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700842 rc = ecryptfs_init_crypt_ctx(crypt_stat);
843 if (rc)
844 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
845 "context for cipher [%s]: rc = [%d]\n",
846 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700847out:
Michael Halcrow237fead2006-10-04 02:16:22 -0700848 return rc;
849}
850
851/**
Tyler Hicks7a866172011-05-02 00:39:54 -0500852 * ecryptfs_validate_marker - check for the ecryptfs marker
Michael Halcrow237fead2006-10-04 02:16:22 -0700853 * @data: The data block in which to check
854 *
Tyler Hicks7a866172011-05-02 00:39:54 -0500855 * Returns zero if marker found; -EINVAL if not found
Michael Halcrow237fead2006-10-04 02:16:22 -0700856 */
Tyler Hicks7a866172011-05-02 00:39:54 -0500857static int ecryptfs_validate_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -0700858{
859 u32 m_1, m_2;
860
Harvey Harrison29335c62008-07-23 21:30:06 -0700861 m_1 = get_unaligned_be32(data);
862 m_2 = get_unaligned_be32(data + 4);
Michael Halcrow237fead2006-10-04 02:16:22 -0700863 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
Tyler Hicks7a866172011-05-02 00:39:54 -0500864 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700865 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
866 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
867 MAGIC_ECRYPTFS_MARKER);
868 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
869 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
Tyler Hicks7a866172011-05-02 00:39:54 -0500870 return -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -0700871}
872
873struct ecryptfs_flag_map_elem {
874 u32 file_flag;
875 u32 local_flag;
876};
877
878/* Add support for additional flags by adding elements here. */
879static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
880 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800881 {0x00000002, ECRYPTFS_ENCRYPTED},
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800882 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
883 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
Michael Halcrow237fead2006-10-04 02:16:22 -0700884};
885
886/**
887 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700888 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700889 * @page_virt: Source data to be parsed
890 * @bytes_read: Updated with the number of bytes read
891 *
892 * Returns zero on success; non-zero if the flag set is invalid
893 */
894static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
895 char *page_virt, int *bytes_read)
896{
897 int rc = 0;
898 int i;
899 u32 flags;
900
Harvey Harrison29335c62008-07-23 21:30:06 -0700901 flags = get_unaligned_be32(page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700902 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
903 / sizeof(struct ecryptfs_flag_map_elem))); i++)
904 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800905 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -0700906 } else
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800907 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
Michael Halcrow237fead2006-10-04 02:16:22 -0700908 /* Version is in top 8 bits of the 32-bit flag vector */
909 crypt_stat->file_version = ((flags >> 24) & 0xFF);
910 (*bytes_read) = 4;
911 return rc;
912}
913
914/**
915 * write_ecryptfs_marker
916 * @page_virt: The pointer to in a page to begin writing the marker
917 * @written: Number of bytes written
918 *
919 * Marker = 0x3c81b7f5
920 */
921static void write_ecryptfs_marker(char *page_virt, size_t *written)
922{
923 u32 m_1, m_2;
924
925 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
926 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
Harvey Harrison29335c62008-07-23 21:30:06 -0700927 put_unaligned_be32(m_1, page_virt);
928 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
929 put_unaligned_be32(m_2, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700930 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
931}
932
Tyler Hicksf4e60e62010-02-11 00:02:32 -0600933void ecryptfs_write_crypt_stat_flags(char *page_virt,
934 struct ecryptfs_crypt_stat *crypt_stat,
935 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -0700936{
937 u32 flags = 0;
938 int i;
939
940 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
941 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800942 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -0700943 flags |= ecryptfs_flag_map[i].file_flag;
944 /* Version is in top 8 bits of the 32-bit flag vector */
945 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
Harvey Harrison29335c62008-07-23 21:30:06 -0700946 put_unaligned_be32(flags, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700947 (*written) = 4;
948}
949
950struct ecryptfs_cipher_code_str_map_elem {
951 char cipher_str[16];
Trevor Highland19e66a62008-02-06 01:38:36 -0800952 u8 cipher_code;
Michael Halcrow237fead2006-10-04 02:16:22 -0700953};
954
955/* Add support for additional ciphers by adding elements here. The
Chris J Arges40f0fd32016-06-09 15:31:29 -0500956 * cipher_code is whatever OpenPGP applications use to identify the
Michael Halcrow237fead2006-10-04 02:16:22 -0700957 * ciphers. List in order of probability. */
958static struct ecryptfs_cipher_code_str_map_elem
959ecryptfs_cipher_code_str_map[] = {
960 {"aes",RFC2440_CIPHER_AES_128 },
961 {"blowfish", RFC2440_CIPHER_BLOWFISH},
962 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
963 {"cast5", RFC2440_CIPHER_CAST_5},
964 {"twofish", RFC2440_CIPHER_TWOFISH},
965 {"cast6", RFC2440_CIPHER_CAST_6},
966 {"aes", RFC2440_CIPHER_AES_192},
967 {"aes", RFC2440_CIPHER_AES_256}
968};
969
970/**
971 * ecryptfs_code_for_cipher_string
Michael Halcrow9c79f342009-01-06 14:41:57 -0800972 * @cipher_name: The string alias for the cipher
973 * @key_bytes: Length of key in bytes; used for AES code selection
Michael Halcrow237fead2006-10-04 02:16:22 -0700974 *
975 * Returns zero on no match, or the cipher code on match
976 */
Michael Halcrow9c79f342009-01-06 14:41:57 -0800977u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
Michael Halcrow237fead2006-10-04 02:16:22 -0700978{
979 int i;
Trevor Highland19e66a62008-02-06 01:38:36 -0800980 u8 code = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700981 struct ecryptfs_cipher_code_str_map_elem *map =
982 ecryptfs_cipher_code_str_map;
983
Michael Halcrow9c79f342009-01-06 14:41:57 -0800984 if (strcmp(cipher_name, "aes") == 0) {
985 switch (key_bytes) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700986 case 16:
987 code = RFC2440_CIPHER_AES_128;
988 break;
989 case 24:
990 code = RFC2440_CIPHER_AES_192;
991 break;
992 case 32:
993 code = RFC2440_CIPHER_AES_256;
994 }
995 } else {
996 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
Michael Halcrow9c79f342009-01-06 14:41:57 -0800997 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700998 code = map[i].cipher_code;
999 break;
1000 }
1001 }
1002 return code;
1003}
1004
1005/**
1006 * ecryptfs_cipher_code_to_string
1007 * @str: Destination to write out the cipher name
1008 * @cipher_code: The code to convert to cipher name string
1009 *
1010 * Returns zero on success
1011 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001012int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
Michael Halcrow237fead2006-10-04 02:16:22 -07001013{
1014 int rc = 0;
1015 int i;
1016
1017 str[0] = '\0';
1018 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1019 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1020 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1021 if (str[0] == '\0') {
1022 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1023 "[%d]\n", cipher_code);
1024 rc = -EINVAL;
1025 }
1026 return rc;
1027}
1028
Tyler Hicks778aeb42011-05-24 04:56:23 -05001029int ecryptfs_read_and_validate_header_region(struct inode *inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001030{
Tyler Hicks778aeb42011-05-24 04:56:23 -05001031 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1032 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001033 int rc;
1034
Tyler Hicks778aeb42011-05-24 04:56:23 -05001035 rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
1036 inode);
1037 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1038 return rc >= 0 ? -EINVAL : rc;
1039 rc = ecryptfs_validate_marker(marker);
1040 if (!rc)
1041 ecryptfs_i_size_init(file_size, inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001042 return rc;
1043}
1044
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001045void
1046ecryptfs_write_header_metadata(char *virt,
1047 struct ecryptfs_crypt_stat *crypt_stat,
1048 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001049{
1050 u32 header_extent_size;
1051 u16 num_header_extents_at_front;
1052
Michael Halcrow45eaab72007-10-16 01:28:05 -07001053 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001054 num_header_extents_at_front =
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001055 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
Harvey Harrison29335c62008-07-23 21:30:06 -07001056 put_unaligned_be32(header_extent_size, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001057 virt += 4;
Harvey Harrison29335c62008-07-23 21:30:06 -07001058 put_unaligned_be16(num_header_extents_at_front, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001059 (*written) = 6;
1060}
1061
Tyler Hicks30632872011-05-24 05:11:12 -05001062struct kmem_cache *ecryptfs_header_cache;
Michael Halcrow237fead2006-10-04 02:16:22 -07001063
1064/**
1065 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001066 * @page_virt: The virtual address to write the headers to
Eric Sandeen87b811c2008-10-29 14:01:08 -07001067 * @max: The size of memory allocated at page_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001068 * @size: Set to the number of bytes written by this function
1069 * @crypt_stat: The cryptographic context
1070 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001071 *
1072 * Format version: 1
1073 *
1074 * Header Extent:
1075 * Octets 0-7: Unencrypted file size (big-endian)
1076 * Octets 8-15: eCryptfs special marker
1077 * Octets 16-19: Flags
1078 * Octet 16: File format version number (between 0 and 255)
1079 * Octets 17-18: Reserved
1080 * Octet 19: Bit 1 (lsb): Reserved
1081 * Bit 2: Encrypted?
1082 * Bits 3-8: Reserved
1083 * Octets 20-23: Header extent size (big-endian)
1084 * Octets 24-25: Number of header extents at front of file
1085 * (big-endian)
1086 * Octet 26: Begin RFC 2440 authentication token packet set
1087 * Data Extent 0:
1088 * Lower data (CBC encrypted)
1089 * Data Extent 1:
1090 * Lower data (CBC encrypted)
1091 * ...
1092 *
1093 * Returns zero on success
1094 */
Eric Sandeen87b811c2008-10-29 14:01:08 -07001095static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1096 size_t *size,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001097 struct ecryptfs_crypt_stat *crypt_stat,
1098 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001099{
1100 int rc;
1101 size_t written;
1102 size_t offset;
1103
1104 offset = ECRYPTFS_FILE_SIZE_BYTES;
1105 write_ecryptfs_marker((page_virt + offset), &written);
1106 offset += written;
Tyler Hicksf4e60e62010-02-11 00:02:32 -06001107 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1108 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001109 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001110 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1111 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001112 offset += written;
1113 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1114 ecryptfs_dentry, &written,
Eric Sandeen87b811c2008-10-29 14:01:08 -07001115 max - offset);
Michael Halcrow237fead2006-10-04 02:16:22 -07001116 if (rc)
1117 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1118 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001119 if (size) {
1120 offset += written;
1121 *size = offset;
1122 }
1123 return rc;
1124}
1125
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001126static int
Tyler Hicksb59db432011-11-21 17:31:02 -06001127ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
Tyler Hicks8faece52009-03-20 01:25:09 -05001128 char *virt, size_t virt_len)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001129{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001130 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001131
Tyler Hicksb59db432011-11-21 17:31:02 -06001132 rc = ecryptfs_write_lower(ecryptfs_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001133 0, virt_len);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001134 if (rc < 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001135 printk(KERN_ERR "%s: Error attempting to write header "
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001136 "information to lower file; rc = [%d]\n", __func__, rc);
1137 else
1138 rc = 0;
Michael Halcrow70456602007-02-12 00:53:48 -08001139 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001140}
1141
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001142static int
1143ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
Al Viro3767e252016-05-27 11:06:05 -04001144 struct inode *ecryptfs_inode,
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001145 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001146{
1147 int rc;
1148
Al Viro3767e252016-05-27 11:06:05 -04001149 rc = ecryptfs_setxattr(ecryptfs_dentry, ecryptfs_inode,
1150 ECRYPTFS_XATTR_NAME, page_virt, size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001151 return rc;
1152}
1153
Tyler Hicks8faece52009-03-20 01:25:09 -05001154static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1155 unsigned int order)
1156{
1157 struct page *page;
1158
1159 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1160 if (page)
1161 return (unsigned long) page_address(page);
1162 return 0;
1163}
1164
Michael Halcrow237fead2006-10-04 02:16:22 -07001165/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001166 * ecryptfs_write_metadata
Tyler Hicksb59db432011-11-21 17:31:02 -06001167 * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1168 * @ecryptfs_inode: The newly created eCryptfs inode
Michael Halcrow237fead2006-10-04 02:16:22 -07001169 *
1170 * Write the file headers out. This will likely involve a userspace
1171 * callout, in which the session key is encrypted with one or more
1172 * public keys and/or the passphrase necessary to do the encryption is
1173 * retrieved via a prompt. Exactly what happens at this point should
1174 * be policy-dependent.
1175 *
1176 * Returns zero on success; non-zero on error
1177 */
Tyler Hicksb59db432011-11-21 17:31:02 -06001178int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1179 struct inode *ecryptfs_inode)
Michael Halcrow237fead2006-10-04 02:16:22 -07001180{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001181 struct ecryptfs_crypt_stat *crypt_stat =
Tyler Hicksb59db432011-11-21 17:31:02 -06001182 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Tyler Hicks8faece52009-03-20 01:25:09 -05001183 unsigned int order;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001184 char *virt;
Tyler Hicks8faece52009-03-20 01:25:09 -05001185 size_t virt_len;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001186 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001187 int rc = 0;
1188
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001189 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1190 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001191 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001192 rc = -EINVAL;
1193 goto out;
1194 }
1195 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001196 printk(KERN_WARNING "%s: Encrypted flag not set\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001197 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001198 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001199 goto out;
1200 }
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001201 virt_len = crypt_stat->metadata_size;
Tyler Hicks8faece52009-03-20 01:25:09 -05001202 order = get_order(virt_len);
Michael Halcrow237fead2006-10-04 02:16:22 -07001203 /* Released in this function */
Tyler Hicks8faece52009-03-20 01:25:09 -05001204 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001205 if (!virt) {
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001206 printk(KERN_ERR "%s: Out of memory\n", __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001207 rc = -ENOMEM;
1208 goto out;
1209 }
Tyler Hicksbd4f0fe2011-02-23 00:14:19 -06001210 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
Tyler Hicks8faece52009-03-20 01:25:09 -05001211 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1212 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001213 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001214 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001215 __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001216 goto out_free;
1217 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001218 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Al Viro3767e252016-05-27 11:06:05 -04001219 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode,
1220 virt, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001221 else
Tyler Hicksb59db432011-11-21 17:31:02 -06001222 rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001223 virt_len);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001224 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001225 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001226 "rc = [%d]\n", __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001227 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001228 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001229out_free:
Tyler Hicks8faece52009-03-20 01:25:09 -05001230 free_pages((unsigned long)virt, order);
Michael Halcrow237fead2006-10-04 02:16:22 -07001231out:
1232 return rc;
1233}
1234
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001235#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1236#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001237static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001238 char *virt, int *bytes_read,
1239 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001240{
1241 int rc = 0;
1242 u32 header_extent_size;
1243 u16 num_header_extents_at_front;
1244
Harvey Harrison29335c62008-07-23 21:30:06 -07001245 header_extent_size = get_unaligned_be32(virt);
1246 virt += sizeof(__be32);
1247 num_header_extents_at_front = get_unaligned_be16(virt);
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001248 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1249 * (size_t)header_extent_size));
Harvey Harrison29335c62008-07-23 21:30:06 -07001250 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001251 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001252 && (crypt_stat->metadata_size
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001253 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001254 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001255 printk(KERN_WARNING "Invalid header size: [%zd]\n",
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001256 crypt_stat->metadata_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001257 }
1258 return rc;
1259}
1260
1261/**
1262 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001263 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001264 *
1265 * For version 0 file format; this function is only for backwards
1266 * compatibility for files created with the prior versions of
1267 * eCryptfs.
1268 */
1269static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1270{
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001271 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001272}
1273
Tyler Hicks3aeb86e2011-03-15 14:54:00 -05001274void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1275{
1276 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1277 struct ecryptfs_crypt_stat *crypt_stat;
1278 u64 file_size;
1279
1280 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1281 mount_crypt_stat =
1282 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1283 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1284 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1285 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1286 file_size += crypt_stat->metadata_size;
1287 } else
1288 file_size = get_unaligned_be64(page_virt);
1289 i_size_write(inode, (loff_t)file_size);
1290 crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1291}
1292
Michael Halcrow237fead2006-10-04 02:16:22 -07001293/**
1294 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001295 * @page_virt: The virtual address into which to read the headers
1296 * @crypt_stat: The cryptographic context
1297 * @ecryptfs_dentry: The eCryptfs dentry
1298 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001299 *
1300 * Read/parse the header data. The header format is detailed in the
1301 * comment block for the ecryptfs_write_headers_virt() function.
1302 *
1303 * Returns zero on success
1304 */
1305static int ecryptfs_read_headers_virt(char *page_virt,
1306 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001307 struct dentry *ecryptfs_dentry,
1308 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001309{
1310 int rc = 0;
1311 int offset;
1312 int bytes_read;
1313
1314 ecryptfs_set_default_sizes(crypt_stat);
1315 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1316 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1317 offset = ECRYPTFS_FILE_SIZE_BYTES;
Tyler Hicks7a866172011-05-02 00:39:54 -05001318 rc = ecryptfs_validate_marker(page_virt + offset);
1319 if (rc)
Michael Halcrow237fead2006-10-04 02:16:22 -07001320 goto out;
Tyler Hicks3aeb86e2011-03-15 14:54:00 -05001321 if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
David Howells2b0143b2015-03-17 22:25:59 +00001322 ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry));
Michael Halcrow237fead2006-10-04 02:16:22 -07001323 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1324 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1325 &bytes_read);
1326 if (rc) {
1327 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1328 goto out;
1329 }
1330 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1331 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1332 "file version [%d] is supported by this "
1333 "version of eCryptfs\n",
1334 crypt_stat->file_version,
1335 ECRYPTFS_SUPPORTED_FILE_VERSION);
1336 rc = -EINVAL;
1337 goto out;
1338 }
1339 offset += bytes_read;
1340 if (crypt_stat->file_version >= 1) {
1341 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001342 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001343 if (rc) {
1344 ecryptfs_printk(KERN_WARNING, "Error reading header "
1345 "metadata; rc = [%d]\n", rc);
1346 }
1347 offset += bytes_read;
1348 } else
1349 set_default_header_data(crypt_stat);
1350 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1351 ecryptfs_dentry);
1352out:
1353 return rc;
1354}
1355
1356/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001357 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001358 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001359 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001360 *
1361 * Attempts to read the crypto metadata from the extended attribute
1362 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001363 *
1364 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001365 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001366int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001367{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001368 struct dentry *lower_dentry =
Al Virob5830432014-10-31 01:22:04 -04001369 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001370 ssize_t size;
1371 int rc = 0;
1372
Al Viroce23e642016-04-11 00:48:00 -04001373 size = ecryptfs_getxattr_lower(lower_dentry,
1374 ecryptfs_inode_to_lower(ecryptfs_inode),
1375 ECRYPTFS_XATTR_NAME,
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001376 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001377 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001378 if (unlikely(ecryptfs_verbosity > 0))
1379 printk(KERN_INFO "Error attempting to read the [%s] "
1380 "xattr from the lower file; return value = "
1381 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001382 rc = -EINVAL;
1383 goto out;
1384 }
1385out:
1386 return rc;
1387}
1388
Tyler Hicks778aeb42011-05-24 04:56:23 -05001389int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
Tyler Hicks3b06b3e2011-05-24 03:49:02 -05001390 struct inode *inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001391{
Tyler Hicks778aeb42011-05-24 04:56:23 -05001392 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1393 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001394 int rc;
1395
Tyler Hicks778aeb42011-05-24 04:56:23 -05001396 rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
Al Viroce23e642016-04-11 00:48:00 -04001397 ecryptfs_inode_to_lower(inode),
Tyler Hicks778aeb42011-05-24 04:56:23 -05001398 ECRYPTFS_XATTR_NAME, file_size,
1399 ECRYPTFS_SIZE_AND_MARKER_BYTES);
1400 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1401 return rc >= 0 ? -EINVAL : rc;
1402 rc = ecryptfs_validate_marker(marker);
1403 if (!rc)
1404 ecryptfs_i_size_init(file_size, inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001405 return rc;
1406}
1407
1408/**
1409 * ecryptfs_read_metadata
1410 *
1411 * Common entry point for reading file metadata. From here, we could
1412 * retrieve the header information from the header region of the file,
Chris J Arges40f0fd32016-06-09 15:31:29 -05001413 * the xattr region of the file, or some other repository that is
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001414 * stored separately from the file itself. The current implementation
1415 * supports retrieving the metadata information from the file contents
1416 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001417 *
1418 * Returns zero if valid headers found and parsed; non-zero otherwise
1419 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001420int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001421{
Tim Gardnerbb450362012-01-12 16:31:55 +01001422 int rc;
1423 char *page_virt;
David Howells2b0143b2015-03-17 22:25:59 +00001424 struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001425 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001426 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001427 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1428 &ecryptfs_superblock_to_private(
1429 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001430
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001431 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1432 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001433 /* Read the first page from the underlying file */
Tyler Hicks30632872011-05-24 05:11:12 -05001434 page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001435 if (!page_virt) {
1436 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001437 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001438 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001439 goto out;
1440 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001441 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1442 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001443 if (rc >= 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001444 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1445 ecryptfs_dentry,
1446 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001447 if (rc) {
Tim Gardnerbb450362012-01-12 16:31:55 +01001448 /* metadata is not in the file header, so try xattrs */
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +03001449 memset(page_virt, 0, PAGE_SIZE);
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001450 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001451 if (rc) {
1452 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
Tim Gardner30373dc2012-01-12 16:31:55 +01001453 "file header region or xattr region, inode %lu\n",
1454 ecryptfs_inode->i_ino);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001455 rc = -EINVAL;
1456 goto out;
1457 }
1458 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1459 ecryptfs_dentry,
1460 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1461 if (rc) {
1462 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
Tim Gardner30373dc2012-01-12 16:31:55 +01001463 "file xattr region either, inode %lu\n",
1464 ecryptfs_inode->i_ino);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001465 rc = -EINVAL;
1466 }
1467 if (crypt_stat->mount_crypt_stat->flags
1468 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1469 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1470 } else {
1471 printk(KERN_WARNING "Attempt to access file with "
1472 "crypto metadata only in the extended attribute "
1473 "region, but eCryptfs was mounted without "
1474 "xattr support enabled. eCryptfs will not treat "
Tim Gardner30373dc2012-01-12 16:31:55 +01001475 "this like an encrypted file, inode %lu\n",
1476 ecryptfs_inode->i_ino);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001477 rc = -EINVAL;
1478 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001479 }
1480out:
1481 if (page_virt) {
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +03001482 memset(page_virt, 0, PAGE_SIZE);
Tyler Hicks30632872011-05-24 05:11:12 -05001483 kmem_cache_free(ecryptfs_header_cache, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001484 }
1485 return rc;
1486}
1487
1488/**
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001489 * ecryptfs_encrypt_filename - encrypt filename
1490 *
1491 * CBC-encrypts the filename. We do not want to encrypt the same
1492 * filename with the same key and IV, which may happen with hard
1493 * links, so we prepend random bits to each filename.
1494 *
1495 * Returns zero on success; non-zero otherwise
1496 */
1497static int
1498ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001499 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1500{
1501 int rc = 0;
1502
1503 filename->encrypted_filename = NULL;
1504 filename->encrypted_filename_size = 0;
Al Viro97c31602016-02-22 18:14:25 -05001505 if (mount_crypt_stat && (mount_crypt_stat->flags
1506 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001507 size_t packet_size;
1508 size_t remaining_bytes;
1509
1510 rc = ecryptfs_write_tag_70_packet(
1511 NULL, NULL,
1512 &filename->encrypted_filename_size,
1513 mount_crypt_stat, NULL,
1514 filename->filename_size);
1515 if (rc) {
1516 printk(KERN_ERR "%s: Error attempting to get packet "
1517 "size for tag 72; rc = [%d]\n", __func__,
1518 rc);
1519 filename->encrypted_filename_size = 0;
1520 goto out;
1521 }
1522 filename->encrypted_filename =
1523 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1524 if (!filename->encrypted_filename) {
1525 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08001526 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001527 filename->encrypted_filename_size);
1528 rc = -ENOMEM;
1529 goto out;
1530 }
1531 remaining_bytes = filename->encrypted_filename_size;
1532 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1533 &remaining_bytes,
1534 &packet_size,
1535 mount_crypt_stat,
1536 filename->filename,
1537 filename->filename_size);
1538 if (rc) {
1539 printk(KERN_ERR "%s: Error attempting to generate "
1540 "tag 70 packet; rc = [%d]\n", __func__,
1541 rc);
1542 kfree(filename->encrypted_filename);
1543 filename->encrypted_filename = NULL;
1544 filename->encrypted_filename_size = 0;
1545 goto out;
1546 }
1547 filename->encrypted_filename_size = packet_size;
1548 } else {
1549 printk(KERN_ERR "%s: No support for requested filename "
1550 "encryption method in this release\n", __func__);
Tyler Hicksdf6ad332009-08-21 04:27:46 -05001551 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001552 goto out;
1553 }
1554out:
1555 return rc;
1556}
1557
1558static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1559 const char *name, size_t name_size)
1560{
1561 int rc = 0;
1562
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001563 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001564 if (!(*copied_name)) {
1565 rc = -ENOMEM;
1566 goto out;
1567 }
1568 memcpy((void *)(*copied_name), (void *)name, name_size);
1569 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1570 * in printing out the
1571 * string in debug
1572 * messages */
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001573 (*copied_name_size) = name_size;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001574out:
1575 return rc;
1576}
1577
1578/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001579 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001580 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001581 * @cipher_name: Name of the cipher
1582 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001583 *
1584 * Returns zero on success. Any crypto_tfm structs allocated here
1585 * should be released by other functions, such as on a superblock put
1586 * event, regardless of whether this function succeeds for fails.
1587 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001588static int
Herbert Xu3095e8e2016-01-25 10:29:33 +08001589ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm,
Michael Halcrowf4aad162007-10-16 01:27:53 -07001590 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001591{
1592 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Dan Carpenterece550f2010-01-19 12:34:32 +03001593 char *full_alg_name = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001594 int rc;
1595
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001596 *key_tfm = NULL;
1597 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001598 rc = -EINVAL;
Michael Halcrowdf261c52009-01-06 14:42:02 -08001599 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001600 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001601 goto out;
1602 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001603 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1604 "ecb");
1605 if (rc)
1606 goto out;
Herbert Xu3095e8e2016-01-25 10:29:33 +08001607 *key_tfm = crypto_alloc_skcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001608 if (IS_ERR(*key_tfm)) {
1609 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001610 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Dave Hansen38268492009-08-27 09:47:07 -07001611 "[%s]; rc = [%d]\n", full_alg_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001612 goto out;
1613 }
Herbert Xu3095e8e2016-01-25 10:29:33 +08001614 crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1615 if (*key_size == 0)
1616 *key_size = crypto_skcipher_default_keysize(*key_tfm);
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001617 get_random_bytes(dummy_key, *key_size);
Herbert Xu3095e8e2016-01-25 10:29:33 +08001618 rc = crypto_skcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001619 if (rc) {
Michael Halcrowdf261c52009-01-06 14:42:02 -08001620 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
Dave Hansen38268492009-08-27 09:47:07 -07001621 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1622 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001623 rc = -EINVAL;
1624 goto out;
1625 }
1626out:
Dan Carpenterece550f2010-01-19 12:34:32 +03001627 kfree(full_alg_name);
Michael Halcrow237fead2006-10-04 02:16:22 -07001628 return rc;
1629}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001630
1631struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001632static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001633struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001634
Jerome Marchand7371a382010-08-17 17:24:05 +02001635int __init ecryptfs_init_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001636{
1637 mutex_init(&key_tfm_list_mutex);
1638 INIT_LIST_HEAD(&key_tfm_list);
1639 return 0;
1640}
1641
Eric Sandeenaf440f52008-02-06 01:38:37 -08001642/**
1643 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1644 *
1645 * Called only at module unload time
1646 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001647int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001648{
1649 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1650
1651 mutex_lock(&key_tfm_list_mutex);
1652 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1653 key_tfm_list) {
1654 list_del(&key_tfm->key_tfm_list);
Herbert Xu3095e8e2016-01-25 10:29:33 +08001655 crypto_free_skcipher(key_tfm->key_tfm);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001656 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1657 }
1658 mutex_unlock(&key_tfm_list_mutex);
1659 return 0;
1660}
1661
1662int
1663ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1664 size_t key_size)
1665{
1666 struct ecryptfs_key_tfm *tmp_tfm;
1667 int rc = 0;
1668
Eric Sandeenaf440f52008-02-06 01:38:37 -08001669 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1670
Michael Halcrowf4aad162007-10-16 01:27:53 -07001671 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1672 if (key_tfm != NULL)
1673 (*key_tfm) = tmp_tfm;
1674 if (!tmp_tfm) {
1675 rc = -ENOMEM;
1676 printk(KERN_ERR "Error attempting to allocate from "
1677 "ecryptfs_key_tfm_cache\n");
1678 goto out;
1679 }
1680 mutex_init(&tmp_tfm->key_tfm_mutex);
1681 strncpy(tmp_tfm->cipher_name, cipher_name,
1682 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001683 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001684 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001685 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1686 tmp_tfm->cipher_name,
1687 &tmp_tfm->key_size);
1688 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001689 printk(KERN_ERR "Error attempting to initialize key TFM "
1690 "cipher with name = [%s]; rc = [%d]\n",
1691 tmp_tfm->cipher_name, rc);
1692 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1693 if (key_tfm != NULL)
1694 (*key_tfm) = NULL;
1695 goto out;
1696 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001697 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001698out:
1699 return rc;
1700}
1701
Eric Sandeenaf440f52008-02-06 01:38:37 -08001702/**
1703 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1704 * @cipher_name: the name of the cipher to search for
1705 * @key_tfm: set to corresponding tfm if found
1706 *
1707 * Searches for cached key_tfm matching @cipher_name
1708 * Must be called with &key_tfm_list_mutex held
1709 * Returns 1 if found, with @key_tfm set
1710 * Returns 0 if not found, with @key_tfm set to NULL
1711 */
1712int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1713{
1714 struct ecryptfs_key_tfm *tmp_key_tfm;
1715
1716 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1717
1718 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1719 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1720 if (key_tfm)
1721 (*key_tfm) = tmp_key_tfm;
1722 return 1;
1723 }
1724 }
1725 if (key_tfm)
1726 (*key_tfm) = NULL;
1727 return 0;
1728}
1729
1730/**
1731 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1732 *
1733 * @tfm: set to cached tfm found, or new tfm created
1734 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1735 * @cipher_name: the name of the cipher to search for and/or add
1736 *
1737 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1738 * Searches for cached item first, and creates new if not found.
1739 * Returns 0 on success, non-zero if adding new cipher failed
1740 */
Herbert Xu3095e8e2016-01-25 10:29:33 +08001741int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm,
Michael Halcrowf4aad162007-10-16 01:27:53 -07001742 struct mutex **tfm_mutex,
1743 char *cipher_name)
1744{
1745 struct ecryptfs_key_tfm *key_tfm;
1746 int rc = 0;
1747
1748 (*tfm) = NULL;
1749 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001750
Michael Halcrowf4aad162007-10-16 01:27:53 -07001751 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001752 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1753 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1754 if (rc) {
1755 printk(KERN_ERR "Error adding new key_tfm to list; "
1756 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001757 goto out;
1758 }
1759 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001760 (*tfm) = key_tfm->key_tfm;
1761 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1762out:
Cyrill Gorcunov71fd5172008-05-23 13:04:20 -07001763 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001764 return rc;
1765}
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001766
1767/* 64 characters forming a 6-bit target field */
1768static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1769 "EFGHIJKLMNOPQRST"
1770 "UVWXYZabcdefghij"
1771 "klmnopqrstuvwxyz");
1772
1773/* We could either offset on every reverse map or just pad some 0x00's
1774 * at the front here */
Tyler Hicks0f751e62011-11-23 11:31:24 -06001775static const unsigned char filename_rev_map[256] = {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001776 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1777 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1778 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1779 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1780 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1781 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1782 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1783 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1784 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1785 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1786 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1787 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1788 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1789 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1790 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
Tyler Hicks0f751e62011-11-23 11:31:24 -06001791 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001792};
1793
1794/**
1795 * ecryptfs_encode_for_filename
1796 * @dst: Destination location for encoded filename
1797 * @dst_size: Size of the encoded filename in bytes
1798 * @src: Source location for the filename to encode
1799 * @src_size: Size of the source in bytes
1800 */
Cong Ding37028752012-12-07 22:21:56 +00001801static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001802 unsigned char *src, size_t src_size)
1803{
1804 size_t num_blocks;
1805 size_t block_num = 0;
1806 size_t dst_offset = 0;
1807 unsigned char last_block[3];
1808
1809 if (src_size == 0) {
1810 (*dst_size) = 0;
1811 goto out;
1812 }
1813 num_blocks = (src_size / 3);
1814 if ((src_size % 3) == 0) {
1815 memcpy(last_block, (&src[src_size - 3]), 3);
1816 } else {
1817 num_blocks++;
1818 last_block[2] = 0x00;
1819 switch (src_size % 3) {
1820 case 1:
1821 last_block[0] = src[src_size - 1];
1822 last_block[1] = 0x00;
1823 break;
1824 case 2:
1825 last_block[0] = src[src_size - 2];
1826 last_block[1] = src[src_size - 1];
1827 }
1828 }
1829 (*dst_size) = (num_blocks * 4);
1830 if (!dst)
1831 goto out;
1832 while (block_num < num_blocks) {
1833 unsigned char *src_block;
1834 unsigned char dst_block[4];
1835
1836 if (block_num == (num_blocks - 1))
1837 src_block = last_block;
1838 else
1839 src_block = &src[block_num * 3];
1840 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
1841 dst_block[1] = (((src_block[0] << 4) & 0x30)
1842 | ((src_block[1] >> 4) & 0x0F));
1843 dst_block[2] = (((src_block[1] << 2) & 0x3C)
1844 | ((src_block[2] >> 6) & 0x03));
1845 dst_block[3] = (src_block[2] & 0x3F);
1846 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
1847 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
1848 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
1849 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
1850 block_num++;
1851 }
1852out:
1853 return;
1854}
1855
Tyler Hicks4a266202011-11-05 13:45:08 -04001856static size_t ecryptfs_max_decoded_size(size_t encoded_size)
1857{
1858 /* Not exact; conservatively long. Every block of 4
1859 * encoded characters decodes into a block of 3
1860 * decoded characters. This segment of code provides
1861 * the caller with the maximum amount of allocated
1862 * space that @dst will need to point to in a
1863 * subsequent call. */
1864 return ((encoded_size + 1) * 3) / 4;
1865}
1866
Michael Halcrow71c11c32009-01-06 14:42:05 -08001867/**
1868 * ecryptfs_decode_from_filename
1869 * @dst: If NULL, this function only sets @dst_size and returns. If
1870 * non-NULL, this function decodes the encoded octets in @src
1871 * into the memory that @dst points to.
1872 * @dst_size: Set to the size of the decoded string.
1873 * @src: The encoded set of octets to decode.
1874 * @src_size: The size of the encoded set of octets to decode.
1875 */
1876static void
1877ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
1878 const unsigned char *src, size_t src_size)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001879{
1880 u8 current_bit_offset = 0;
1881 size_t src_byte_offset = 0;
1882 size_t dst_byte_offset = 0;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001883
1884 if (dst == NULL) {
Tyler Hicks4a266202011-11-05 13:45:08 -04001885 (*dst_size) = ecryptfs_max_decoded_size(src_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001886 goto out;
1887 }
1888 while (src_byte_offset < src_size) {
1889 unsigned char src_byte =
1890 filename_rev_map[(int)src[src_byte_offset]];
1891
1892 switch (current_bit_offset) {
1893 case 0:
1894 dst[dst_byte_offset] = (src_byte << 2);
1895 current_bit_offset = 6;
1896 break;
1897 case 6:
1898 dst[dst_byte_offset++] |= (src_byte >> 4);
1899 dst[dst_byte_offset] = ((src_byte & 0xF)
1900 << 4);
1901 current_bit_offset = 4;
1902 break;
1903 case 4:
1904 dst[dst_byte_offset++] |= (src_byte >> 2);
1905 dst[dst_byte_offset] = (src_byte << 6);
1906 current_bit_offset = 2;
1907 break;
1908 case 2:
1909 dst[dst_byte_offset++] |= (src_byte);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001910 current_bit_offset = 0;
1911 break;
1912 }
1913 src_byte_offset++;
1914 }
1915 (*dst_size) = dst_byte_offset;
1916out:
Michael Halcrow71c11c32009-01-06 14:42:05 -08001917 return;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001918}
1919
1920/**
1921 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
1922 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1923 * @name: The plaintext name
1924 * @length: The length of the plaintext
1925 * @encoded_name: The encypted name
1926 *
1927 * Encrypts and encodes a filename into something that constitutes a
1928 * valid filename for a filesystem, with printable characters.
1929 *
1930 * We assume that we have a properly initialized crypto context,
1931 * pointed to by crypt_stat->tfm.
1932 *
1933 * Returns zero on success; non-zero on otherwise
1934 */
1935int ecryptfs_encrypt_and_encode_filename(
1936 char **encoded_name,
1937 size_t *encoded_name_size,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001938 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1939 const char *name, size_t name_size)
1940{
1941 size_t encoded_name_no_prefix_size;
1942 int rc = 0;
1943
1944 (*encoded_name) = NULL;
1945 (*encoded_name_size) = 0;
Al Viro97c31602016-02-22 18:14:25 -05001946 if (mount_crypt_stat && (mount_crypt_stat->flags
1947 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001948 struct ecryptfs_filename *filename;
1949
1950 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
1951 if (!filename) {
1952 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08001953 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001954 sizeof(*filename));
1955 rc = -ENOMEM;
1956 goto out;
1957 }
1958 filename->filename = (char *)name;
1959 filename->filename_size = name_size;
Al Viro97c31602016-02-22 18:14:25 -05001960 rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001961 if (rc) {
1962 printk(KERN_ERR "%s: Error attempting to encrypt "
1963 "filename; rc = [%d]\n", __func__, rc);
1964 kfree(filename);
1965 goto out;
1966 }
1967 ecryptfs_encode_for_filename(
1968 NULL, &encoded_name_no_prefix_size,
1969 filename->encrypted_filename,
1970 filename->encrypted_filename_size);
Al Viro97c31602016-02-22 18:14:25 -05001971 if (mount_crypt_stat
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001972 && (mount_crypt_stat->flags
Al Viro97c31602016-02-22 18:14:25 -05001973 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001974 (*encoded_name_size) =
1975 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1976 + encoded_name_no_prefix_size);
1977 else
1978 (*encoded_name_size) =
1979 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1980 + encoded_name_no_prefix_size);
1981 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
1982 if (!(*encoded_name)) {
1983 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08001984 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001985 (*encoded_name_size));
1986 rc = -ENOMEM;
1987 kfree(filename->encrypted_filename);
1988 kfree(filename);
1989 goto out;
1990 }
Al Viro97c31602016-02-22 18:14:25 -05001991 if (mount_crypt_stat
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001992 && (mount_crypt_stat->flags
Al Viro97c31602016-02-22 18:14:25 -05001993 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001994 memcpy((*encoded_name),
1995 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
1996 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
1997 ecryptfs_encode_for_filename(
1998 ((*encoded_name)
1999 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2000 &encoded_name_no_prefix_size,
2001 filename->encrypted_filename,
2002 filename->encrypted_filename_size);
2003 (*encoded_name_size) =
2004 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2005 + encoded_name_no_prefix_size);
2006 (*encoded_name)[(*encoded_name_size)] = '\0';
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002007 } else {
Tyler Hicksdf6ad332009-08-21 04:27:46 -05002008 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002009 }
2010 if (rc) {
2011 printk(KERN_ERR "%s: Error attempting to encode "
2012 "encrypted filename; rc = [%d]\n", __func__,
2013 rc);
2014 kfree((*encoded_name));
2015 (*encoded_name) = NULL;
2016 (*encoded_name_size) = 0;
2017 }
2018 kfree(filename->encrypted_filename);
2019 kfree(filename);
2020 } else {
2021 rc = ecryptfs_copy_filename(encoded_name,
2022 encoded_name_size,
2023 name, name_size);
2024 }
2025out:
2026 return rc;
2027}
2028
2029/**
2030 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2031 * @plaintext_name: The plaintext name
2032 * @plaintext_name_size: The plaintext name size
2033 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2034 * @name: The filename in cipher text
2035 * @name_size: The cipher text name size
2036 *
2037 * Decrypts and decodes the filename.
2038 *
2039 * Returns zero on error; non-zero otherwise
2040 */
2041int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2042 size_t *plaintext_name_size,
Al Viro0747fdb2013-06-16 20:05:38 +04002043 struct super_block *sb,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002044 const char *name, size_t name_size)
2045{
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002046 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
Al Viro0747fdb2013-06-16 20:05:38 +04002047 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002048 char *decoded_name;
2049 size_t decoded_name_size;
2050 size_t packet_size;
2051 int rc = 0;
2052
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002053 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2054 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2055 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002056 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2057 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002058 const char *orig_name = name;
2059 size_t orig_name_size = name_size;
2060
2061 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2062 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
Michael Halcrow71c11c32009-01-06 14:42:05 -08002063 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2064 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002065 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2066 if (!decoded_name) {
2067 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08002068 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002069 decoded_name_size);
2070 rc = -ENOMEM;
2071 goto out;
2072 }
Michael Halcrow71c11c32009-01-06 14:42:05 -08002073 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2074 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002075 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2076 plaintext_name_size,
2077 &packet_size,
2078 mount_crypt_stat,
2079 decoded_name,
2080 decoded_name_size);
2081 if (rc) {
2082 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2083 "from filename; copying through filename "
2084 "as-is\n", __func__);
2085 rc = ecryptfs_copy_filename(plaintext_name,
2086 plaintext_name_size,
2087 orig_name, orig_name_size);
2088 goto out_free;
2089 }
2090 } else {
2091 rc = ecryptfs_copy_filename(plaintext_name,
2092 plaintext_name_size,
2093 name, name_size);
2094 goto out;
2095 }
2096out_free:
2097 kfree(decoded_name);
2098out:
2099 return rc;
2100}
Tyler Hicks4a266202011-11-05 13:45:08 -04002101
2102#define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
2103
2104int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
2105 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
2106{
Herbert Xu3095e8e2016-01-25 10:29:33 +08002107 struct crypto_skcipher *tfm;
Tyler Hicks4a266202011-11-05 13:45:08 -04002108 struct mutex *tfm_mutex;
2109 size_t cipher_blocksize;
2110 int rc;
2111
2112 if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
2113 (*namelen) = lower_namelen;
2114 return 0;
2115 }
2116
Herbert Xu3095e8e2016-01-25 10:29:33 +08002117 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
Tyler Hicks4a266202011-11-05 13:45:08 -04002118 mount_crypt_stat->global_default_fn_cipher_name);
2119 if (unlikely(rc)) {
2120 (*namelen) = 0;
2121 return rc;
2122 }
2123
2124 mutex_lock(tfm_mutex);
Herbert Xu3095e8e2016-01-25 10:29:33 +08002125 cipher_blocksize = crypto_skcipher_blocksize(tfm);
Tyler Hicks4a266202011-11-05 13:45:08 -04002126 mutex_unlock(tfm_mutex);
2127
2128 /* Return an exact amount for the common cases */
2129 if (lower_namelen == NAME_MAX
2130 && (cipher_blocksize == 8 || cipher_blocksize == 16)) {
2131 (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
2132 return 0;
2133 }
2134
2135 /* Return a safe estimate for the uncommon cases */
2136 (*namelen) = lower_namelen;
2137 (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2138 /* Since this is the max decoded size, subtract 1 "decoded block" len */
2139 (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3;
2140 (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
2141 (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
2142 /* Worst case is that the filename is padded nearly a full block size */
2143 (*namelen) -= cipher_blocksize - 1;
2144
2145 if ((*namelen) < 0)
2146 (*namelen) = 0;
2147
2148 return 0;
2149}