blob: d2a70a4561f91257fe44d7cb867e9d14ec1ff908 [file] [log] [blame]
Michael Halcrow237fead2006-10-04 02:16:22 -07001/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08006 * Copyright (C) 2004-2007 International Business Machines Corp.
Michael Halcrow237fead2006-10-04 02:16:22 -07007 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 * 02111-1307, USA.
24 */
25
26#include <linux/fs.h>
27#include <linux/mount.h>
28#include <linux/pagemap.h>
29#include <linux/random.h>
30#include <linux/compiler.h>
31#include <linux/key.h>
32#include <linux/namei.h>
33#include <linux/crypto.h>
34#include <linux/file.h>
35#include <linux/scatterlist.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090036#include <linux/slab.h>
Harvey Harrison29335c62008-07-23 21:30:06 -070037#include <asm/unaligned.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070038#include "ecryptfs_kernel.h"
39
40static int
41ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
42 struct page *dst_page, int dst_offset,
43 struct page *src_page, int src_offset, int size,
44 unsigned char *iv);
45static int
46ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
47 struct page *dst_page, int dst_offset,
48 struct page *src_page, int src_offset, int size,
49 unsigned char *iv);
50
51/**
52 * ecryptfs_to_hex
53 * @dst: Buffer to take hex character representation of contents of
54 * src; must be at least of size (src_size * 2)
55 * @src: Buffer to be converted to a hex string respresentation
56 * @src_size: number of bytes to convert
57 */
58void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
59{
60 int x;
61
62 for (x = 0; x < src_size; x++)
63 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
64}
65
66/**
67 * ecryptfs_from_hex
68 * @dst: Buffer to take the bytes from src hex; must be at least of
69 * size (src_size / 2)
70 * @src: Buffer to be converted from a hex string respresentation to raw value
71 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
72 */
73void ecryptfs_from_hex(char *dst, char *src, int dst_size)
74{
75 int x;
76 char tmp[3] = { 0, };
77
78 for (x = 0; x < dst_size; x++) {
79 tmp[0] = src[x * 2];
80 tmp[1] = src[x * 2 + 1];
81 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
82 }
83}
84
85/**
86 * ecryptfs_calculate_md5 - calculates the md5 of @src
87 * @dst: Pointer to 16 bytes of allocated memory
88 * @crypt_stat: Pointer to crypt_stat struct for the current inode
89 * @src: Data to be md5'd
90 * @len: Length of @src
91 *
92 * Uses the allocated crypto context that crypt_stat references to
93 * generate the MD5 sum of the contents of src.
94 */
95static int ecryptfs_calculate_md5(char *dst,
96 struct ecryptfs_crypt_stat *crypt_stat,
97 char *src, int len)
98{
Michael Halcrow237fead2006-10-04 02:16:22 -070099 struct scatterlist sg;
Michael Halcrow565d97242006-10-30 22:07:17 -0800100 struct hash_desc desc = {
101 .tfm = crypt_stat->hash_tfm,
102 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
103 };
104 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700105
Michael Halcrow565d97242006-10-30 22:07:17 -0800106 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700107 sg_init_one(&sg, (u8 *)src, len);
Michael Halcrow565d97242006-10-30 22:07:17 -0800108 if (!desc.tfm) {
109 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
110 CRYPTO_ALG_ASYNC);
111 if (IS_ERR(desc.tfm)) {
112 rc = PTR_ERR(desc.tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700113 ecryptfs_printk(KERN_ERR, "Error attempting to "
Michael Halcrow565d97242006-10-30 22:07:17 -0800114 "allocate crypto context; rc = [%d]\n",
115 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700116 goto out;
117 }
Michael Halcrow565d97242006-10-30 22:07:17 -0800118 crypt_stat->hash_tfm = desc.tfm;
Michael Halcrow237fead2006-10-04 02:16:22 -0700119 }
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800120 rc = crypto_hash_init(&desc);
121 if (rc) {
122 printk(KERN_ERR
123 "%s: Error initializing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700124 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800125 goto out;
126 }
127 rc = crypto_hash_update(&desc, &sg, len);
128 if (rc) {
129 printk(KERN_ERR
130 "%s: Error updating crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700131 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800132 goto out;
133 }
134 rc = crypto_hash_final(&desc, dst);
135 if (rc) {
136 printk(KERN_ERR
137 "%s: Error finalizing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700138 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800139 goto out;
140 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700141out:
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800142 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700143 return rc;
144}
145
Michael Halcrowcd9d67d2007-10-16 01:28:04 -0700146static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
147 char *cipher_name,
148 char *chaining_modifier)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800149{
150 int cipher_name_len = strlen(cipher_name);
151 int chaining_modifier_len = strlen(chaining_modifier);
152 int algified_name_len;
153 int rc;
154
155 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
156 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
Michael Halcrow7bd473f2006-11-02 22:06:56 -0800157 if (!(*algified_name)) {
Michael Halcrow8bba0662006-10-30 22:07:18 -0800158 rc = -ENOMEM;
159 goto out;
160 }
161 snprintf((*algified_name), algified_name_len, "%s(%s)",
162 chaining_modifier, cipher_name);
163 rc = 0;
164out:
165 return rc;
166}
167
Michael Halcrow237fead2006-10-04 02:16:22 -0700168/**
169 * ecryptfs_derive_iv
170 * @iv: destination for the derived iv vale
171 * @crypt_stat: Pointer to crypt_stat struct for the current inode
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700172 * @offset: Offset of the extent whose IV we are to derive
Michael Halcrow237fead2006-10-04 02:16:22 -0700173 *
174 * Generate the initialization vector from the given root IV and page
175 * offset.
176 *
177 * Returns zero on success; non-zero on error.
178 */
Michael Halcrowa34f60f2009-01-06 14:41:58 -0800179int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
180 loff_t offset)
Michael Halcrow237fead2006-10-04 02:16:22 -0700181{
182 int rc = 0;
183 char dst[MD5_DIGEST_SIZE];
184 char src[ECRYPTFS_MAX_IV_BYTES + 16];
185
186 if (unlikely(ecryptfs_verbosity > 0)) {
187 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
188 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
189 }
190 /* TODO: It is probably secure to just cast the least
191 * significant bits of the root IV into an unsigned long and
192 * add the offset to that rather than go through all this
193 * hashing business. -Halcrow */
194 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
195 memset((src + crypt_stat->iv_bytes), 0, 16);
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700196 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700197 if (unlikely(ecryptfs_verbosity > 0)) {
198 ecryptfs_printk(KERN_DEBUG, "source:\n");
199 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
200 }
201 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
202 (crypt_stat->iv_bytes + 16));
203 if (rc) {
204 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
205 "MD5 while generating IV for a page\n");
206 goto out;
207 }
208 memcpy(iv, dst, crypt_stat->iv_bytes);
209 if (unlikely(ecryptfs_verbosity > 0)) {
210 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
211 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
212 }
213out:
214 return rc;
215}
216
217/**
218 * ecryptfs_init_crypt_stat
219 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
220 *
221 * Initialize the crypt_stat structure.
222 */
223void
224ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
225{
226 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
Michael Halcrowf4aad162007-10-16 01:27:53 -0700227 INIT_LIST_HEAD(&crypt_stat->keysig_list);
228 mutex_init(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700229 mutex_init(&crypt_stat->cs_mutex);
230 mutex_init(&crypt_stat->cs_tfm_mutex);
Michael Halcrow565d97242006-10-30 22:07:17 -0800231 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800232 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
Michael Halcrow237fead2006-10-04 02:16:22 -0700233}
234
235/**
Michael Halcrowfcd12832007-10-16 01:28:01 -0700236 * ecryptfs_destroy_crypt_stat
Michael Halcrow237fead2006-10-04 02:16:22 -0700237 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
238 *
239 * Releases all memory associated with a crypt_stat struct.
240 */
Michael Halcrowfcd12832007-10-16 01:28:01 -0700241void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -0700242{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700243 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
244
Michael Halcrow237fead2006-10-04 02:16:22 -0700245 if (crypt_stat->tfm)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800246 crypto_free_blkcipher(crypt_stat->tfm);
Michael Halcrow565d97242006-10-30 22:07:17 -0800247 if (crypt_stat->hash_tfm)
248 crypto_free_hash(crypt_stat->hash_tfm);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700249 list_for_each_entry_safe(key_sig, key_sig_tmp,
250 &crypt_stat->keysig_list, crypt_stat_list) {
251 list_del(&key_sig->crypt_stat_list);
252 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
253 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700254 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
255}
256
Michael Halcrowfcd12832007-10-16 01:28:01 -0700257void ecryptfs_destroy_mount_crypt_stat(
Michael Halcrow237fead2006-10-04 02:16:22 -0700258 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
259{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700260 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
261
262 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
263 return;
264 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
265 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
266 &mount_crypt_stat->global_auth_tok_list,
267 mount_crypt_stat_list) {
268 list_del(&auth_tok->mount_crypt_stat_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700269 if (auth_tok->global_auth_tok_key
270 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
271 key_put(auth_tok->global_auth_tok_key);
272 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
273 }
274 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700275 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
276}
277
278/**
279 * virt_to_scatterlist
280 * @addr: Virtual address
281 * @size: Size of data; should be an even multiple of the block size
282 * @sg: Pointer to scatterlist array; set to NULL to obtain only
283 * the number of scatterlist structs required in array
284 * @sg_size: Max array size
285 *
286 * Fills in a scatterlist array with page references for a passed
287 * virtual address.
288 *
289 * Returns the number of scatterlist structs in array used
290 */
291int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
292 int sg_size)
293{
294 int i = 0;
295 struct page *pg;
296 int offset;
297 int remainder_of_page;
298
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700299 sg_init_table(sg, sg_size);
300
Michael Halcrow237fead2006-10-04 02:16:22 -0700301 while (size > 0 && i < sg_size) {
302 pg = virt_to_page(addr);
303 offset = offset_in_page(addr);
Jens Axboe642f1492007-10-24 11:20:47 +0200304 if (sg)
305 sg_set_page(&sg[i], pg, 0, offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700306 remainder_of_page = PAGE_CACHE_SIZE - offset;
307 if (size >= remainder_of_page) {
308 if (sg)
309 sg[i].length = remainder_of_page;
310 addr += remainder_of_page;
311 size -= remainder_of_page;
312 } else {
313 if (sg)
314 sg[i].length = size;
315 addr += size;
316 size = 0;
317 }
318 i++;
319 }
320 if (size > 0)
321 return -ENOMEM;
322 return i;
323}
324
325/**
326 * encrypt_scatterlist
327 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
328 * @dest_sg: Destination of encrypted data
329 * @src_sg: Data to be encrypted
330 * @size: Length of data to be encrypted
331 * @iv: iv to use during encryption
332 *
333 * Returns the number of bytes encrypted; negative value on error
334 */
335static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
336 struct scatterlist *dest_sg,
337 struct scatterlist *src_sg, int size,
338 unsigned char *iv)
339{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800340 struct blkcipher_desc desc = {
341 .tfm = crypt_stat->tfm,
342 .info = iv,
343 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
344 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700345 int rc = 0;
346
347 BUG_ON(!crypt_stat || !crypt_stat->tfm
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800348 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
Michael Halcrow237fead2006-10-04 02:16:22 -0700349 if (unlikely(ecryptfs_verbosity > 0)) {
Tyler Hicksf24b3882010-11-15 17:36:38 -0600350 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700351 crypt_stat->key_size);
352 ecryptfs_dump_hex(crypt_stat->key,
353 crypt_stat->key_size);
354 }
355 /* Consider doing this once, when the file is opened */
356 mutex_lock(&crypt_stat->cs_tfm_mutex);
Trevor Highland8e3a6f12008-02-06 01:38:33 -0800357 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
358 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
359 crypt_stat->key_size);
360 crypt_stat->flags |= ECRYPTFS_KEY_SET;
361 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700362 if (rc) {
363 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
364 rc);
365 mutex_unlock(&crypt_stat->cs_tfm_mutex);
366 rc = -EINVAL;
367 goto out;
368 }
369 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800370 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700371 mutex_unlock(&crypt_stat->cs_tfm_mutex);
372out:
373 return rc;
374}
375
Michael Halcrow237fead2006-10-04 02:16:22 -0700376/**
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700377 * ecryptfs_lower_offset_for_extent
378 *
379 * Convert an eCryptfs page index into a lower byte offset
380 */
Adrian Bunk7896b632008-02-06 01:38:32 -0800381static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
382 struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700383{
Tyler Hicks157f1072010-02-11 07:10:38 -0600384 (*offset) = ecryptfs_lower_header_size(crypt_stat)
385 + (crypt_stat->extent_size * extent_num);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700386}
387
388/**
389 * ecryptfs_encrypt_extent
390 * @enc_extent_page: Allocated page into which to encrypt the data in
391 * @page
392 * @crypt_stat: crypt_stat containing cryptographic context for the
393 * encryption operation
394 * @page: Page containing plaintext data extent to encrypt
395 * @extent_offset: Page extent offset for use in generating IV
396 *
397 * Encrypts one extent of data.
398 *
399 * Return zero on success; non-zero otherwise
400 */
401static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
402 struct ecryptfs_crypt_stat *crypt_stat,
403 struct page *page,
404 unsigned long extent_offset)
405{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700406 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700407 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
408 int rc;
409
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700410 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700411 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
412 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
413 (extent_base + extent_offset));
414 if (rc) {
Joe Perches888d57b2010-11-10 15:46:16 -0800415 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
416 "extent [0x%.16llx]; rc = [%d]\n",
417 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700418 goto out;
419 }
420 if (unlikely(ecryptfs_verbosity > 0)) {
421 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
422 "with iv:\n");
423 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
424 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
425 "encryption:\n");
426 ecryptfs_dump_hex((char *)
427 (page_address(page)
428 + (extent_offset * crypt_stat->extent_size)),
429 8);
430 }
431 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
432 page, (extent_offset
433 * crypt_stat->extent_size),
434 crypt_stat->extent_size, extent_iv);
435 if (rc < 0) {
436 printk(KERN_ERR "%s: Error attempting to encrypt page with "
437 "page->index = [%ld], extent_offset = [%ld]; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700438 "rc = [%d]\n", __func__, page->index, extent_offset,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700439 rc);
440 goto out;
441 }
442 rc = 0;
443 if (unlikely(ecryptfs_verbosity > 0)) {
Joe Perches888d57b2010-11-10 15:46:16 -0800444 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16llx]; "
445 "rc = [%d]\n",
446 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700447 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
448 "encryption:\n");
449 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
450 }
451out:
452 return rc;
453}
454
455/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700456 * ecryptfs_encrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700457 * @page: Page mapped from the eCryptfs inode for the file; contains
458 * decrypted content that needs to be encrypted (to a temporary
459 * page; not in place) and written out to the lower file
Michael Halcrow237fead2006-10-04 02:16:22 -0700460 *
461 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
462 * that eCryptfs pages may straddle the lower pages -- for instance,
463 * if the file was created on a machine with an 8K page size
464 * (resulting in an 8K header), and then the file is copied onto a
465 * host with a 32K page size, then when reading page 0 of the eCryptfs
466 * file, 24K of page 0 of the lower file will be read and decrypted,
467 * and then 8K of page 1 of the lower file will be read and decrypted.
468 *
Michael Halcrow237fead2006-10-04 02:16:22 -0700469 * Returns zero on success; negative on error
470 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700471int ecryptfs_encrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700472{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700473 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700474 struct ecryptfs_crypt_stat *crypt_stat;
Eric Sandeen7fcba052008-07-28 15:46:39 -0700475 char *enc_extent_virt;
476 struct page *enc_extent_page = NULL;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700477 loff_t extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700478 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700479
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700480 ecryptfs_inode = page->mapping->host;
481 crypt_stat =
482 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500483 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Eric Sandeen7fcba052008-07-28 15:46:39 -0700484 enc_extent_page = alloc_page(GFP_USER);
485 if (!enc_extent_page) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700486 rc = -ENOMEM;
487 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
488 "encrypted extent\n");
489 goto out;
490 }
Eric Sandeen7fcba052008-07-28 15:46:39 -0700491 enc_extent_virt = kmap(enc_extent_page);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700492 for (extent_offset = 0;
493 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
494 extent_offset++) {
495 loff_t offset;
496
497 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
498 extent_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700499 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700500 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700501 "rc = [%d]\n", __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700502 goto out;
503 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700504 ecryptfs_lower_offset_for_extent(
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700505 &offset, ((((loff_t)page->index)
506 * (PAGE_CACHE_SIZE
507 / crypt_stat->extent_size))
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700508 + extent_offset), crypt_stat);
509 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
510 offset, crypt_stat->extent_size);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500511 if (rc < 0) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700512 ecryptfs_printk(KERN_ERR, "Error attempting "
513 "to write lower page; rc = [%d]"
514 "\n", rc);
515 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700516 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700517 }
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500518 rc = 0;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700519out:
Eric Sandeen7fcba052008-07-28 15:46:39 -0700520 if (enc_extent_page) {
521 kunmap(enc_extent_page);
522 __free_page(enc_extent_page);
523 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700524 return rc;
525}
526
527static int ecryptfs_decrypt_extent(struct page *page,
528 struct ecryptfs_crypt_stat *crypt_stat,
529 struct page *enc_extent_page,
530 unsigned long extent_offset)
531{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700532 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700533 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
534 int rc;
535
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700536 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700537 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
538 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
539 (extent_base + extent_offset));
Michael Halcrow237fead2006-10-04 02:16:22 -0700540 if (rc) {
Joe Perches888d57b2010-11-10 15:46:16 -0800541 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
542 "extent [0x%.16llx]; rc = [%d]\n",
543 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700544 goto out;
545 }
546 if (unlikely(ecryptfs_verbosity > 0)) {
547 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
548 "with iv:\n");
549 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
550 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
551 "decryption:\n");
552 ecryptfs_dump_hex((char *)
553 (page_address(enc_extent_page)
554 + (extent_offset * crypt_stat->extent_size)),
555 8);
556 }
557 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
558 (extent_offset
559 * crypt_stat->extent_size),
560 enc_extent_page, 0,
561 crypt_stat->extent_size, extent_iv);
562 if (rc < 0) {
563 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
564 "page->index = [%ld], extent_offset = [%ld]; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700565 "rc = [%d]\n", __func__, page->index, extent_offset,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700566 rc);
567 goto out;
568 }
569 rc = 0;
570 if (unlikely(ecryptfs_verbosity > 0)) {
Joe Perches888d57b2010-11-10 15:46:16 -0800571 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16llx]; "
572 "rc = [%d]\n",
573 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700574 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
575 "decryption:\n");
576 ecryptfs_dump_hex((char *)(page_address(page)
577 + (extent_offset
578 * crypt_stat->extent_size)), 8);
Michael Halcrow237fead2006-10-04 02:16:22 -0700579 }
580out:
581 return rc;
582}
583
584/**
585 * ecryptfs_decrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700586 * @page: Page mapped from the eCryptfs inode for the file; data read
587 * and decrypted from the lower file will be written into this
588 * page
Michael Halcrow237fead2006-10-04 02:16:22 -0700589 *
590 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
591 * that eCryptfs pages may straddle the lower pages -- for instance,
592 * if the file was created on a machine with an 8K page size
593 * (resulting in an 8K header), and then the file is copied onto a
594 * host with a 32K page size, then when reading page 0 of the eCryptfs
595 * file, 24K of page 0 of the lower file will be read and decrypted,
596 * and then 8K of page 1 of the lower file will be read and decrypted.
597 *
598 * Returns zero on success; negative on error
599 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700600int ecryptfs_decrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700601{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700602 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700603 struct ecryptfs_crypt_stat *crypt_stat;
Eric Sandeen7fcba052008-07-28 15:46:39 -0700604 char *enc_extent_virt;
605 struct page *enc_extent_page = NULL;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700606 unsigned long extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700607 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700608
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700609 ecryptfs_inode = page->mapping->host;
610 crypt_stat =
611 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500612 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Eric Sandeen7fcba052008-07-28 15:46:39 -0700613 enc_extent_page = alloc_page(GFP_USER);
614 if (!enc_extent_page) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700615 rc = -ENOMEM;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700616 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
617 "encrypted extent\n");
Michael Halcrow16a72c42007-10-16 01:28:14 -0700618 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700619 }
Eric Sandeen7fcba052008-07-28 15:46:39 -0700620 enc_extent_virt = kmap(enc_extent_page);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700621 for (extent_offset = 0;
622 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
623 extent_offset++) {
624 loff_t offset;
625
626 ecryptfs_lower_offset_for_extent(
627 &offset, ((page->index * (PAGE_CACHE_SIZE
628 / crypt_stat->extent_size))
629 + extent_offset), crypt_stat);
630 rc = ecryptfs_read_lower(enc_extent_virt, offset,
631 crypt_stat->extent_size,
632 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500633 if (rc < 0) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700634 ecryptfs_printk(KERN_ERR, "Error attempting "
635 "to read lower page; rc = [%d]"
636 "\n", rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700637 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700638 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700639 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
640 extent_offset);
641 if (rc) {
642 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700643 "rc = [%d]\n", __func__, rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700644 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700645 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700646 }
647out:
Eric Sandeen7fcba052008-07-28 15:46:39 -0700648 if (enc_extent_page) {
649 kunmap(enc_extent_page);
650 __free_page(enc_extent_page);
651 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700652 return rc;
653}
654
655/**
656 * decrypt_scatterlist
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700657 * @crypt_stat: Cryptographic context
658 * @dest_sg: The destination scatterlist to decrypt into
659 * @src_sg: The source scatterlist to decrypt from
660 * @size: The number of bytes to decrypt
661 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700662 *
663 * Returns the number of bytes decrypted; negative value on error
664 */
665static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
666 struct scatterlist *dest_sg,
667 struct scatterlist *src_sg, int size,
668 unsigned char *iv)
669{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800670 struct blkcipher_desc desc = {
671 .tfm = crypt_stat->tfm,
672 .info = iv,
673 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
674 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700675 int rc = 0;
676
677 /* Consider doing this once, when the file is opened */
678 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800679 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
680 crypt_stat->key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700681 if (rc) {
682 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
683 rc);
684 mutex_unlock(&crypt_stat->cs_tfm_mutex);
685 rc = -EINVAL;
686 goto out;
687 }
688 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800689 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700690 mutex_unlock(&crypt_stat->cs_tfm_mutex);
691 if (rc) {
692 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
693 rc);
694 goto out;
695 }
696 rc = size;
697out:
698 return rc;
699}
700
701/**
702 * ecryptfs_encrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700703 * @crypt_stat: The cryptographic context
704 * @dst_page: The page to encrypt into
705 * @dst_offset: The offset in the page to encrypt into
706 * @src_page: The page to encrypt from
707 * @src_offset: The offset in the page to encrypt from
708 * @size: The number of bytes to encrypt
709 * @iv: The initialization vector to use for the encryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700710 *
711 * Returns the number of bytes encrypted
712 */
713static int
714ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
715 struct page *dst_page, int dst_offset,
716 struct page *src_page, int src_offset, int size,
717 unsigned char *iv)
718{
719 struct scatterlist src_sg, dst_sg;
720
Jens Axboe60c74f82007-10-22 19:43:30 +0200721 sg_init_table(&src_sg, 1);
722 sg_init_table(&dst_sg, 1);
723
Jens Axboe642f1492007-10-24 11:20:47 +0200724 sg_set_page(&src_sg, src_page, size, src_offset);
725 sg_set_page(&dst_sg, dst_page, size, dst_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700726 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
727}
728
729/**
730 * ecryptfs_decrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700731 * @crypt_stat: The cryptographic context
732 * @dst_page: The page to decrypt into
733 * @dst_offset: The offset in the page to decrypt into
734 * @src_page: The page to decrypt from
735 * @src_offset: The offset in the page to decrypt from
736 * @size: The number of bytes to decrypt
737 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700738 *
739 * Returns the number of bytes decrypted
740 */
741static int
742ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
743 struct page *dst_page, int dst_offset,
744 struct page *src_page, int src_offset, int size,
745 unsigned char *iv)
746{
747 struct scatterlist src_sg, dst_sg;
748
Jens Axboe60c74f82007-10-22 19:43:30 +0200749 sg_init_table(&src_sg, 1);
Jens Axboe642f1492007-10-24 11:20:47 +0200750 sg_set_page(&src_sg, src_page, size, src_offset);
Jens Axboe60c74f82007-10-22 19:43:30 +0200751
Jens Axboe642f1492007-10-24 11:20:47 +0200752 sg_init_table(&dst_sg, 1);
753 sg_set_page(&dst_sg, dst_page, size, dst_offset);
754
Michael Halcrow237fead2006-10-04 02:16:22 -0700755 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
756}
757
758#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
759
760/**
761 * ecryptfs_init_crypt_ctx
Uwe Kleine-König421f91d2010-06-11 12:17:00 +0200762 * @crypt_stat: Uninitialized crypt stats structure
Michael Halcrow237fead2006-10-04 02:16:22 -0700763 *
764 * Initialize the crypto context.
765 *
766 * TODO: Performance: Keep a cache of initialized cipher contexts;
767 * only init if needed
768 */
769int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
770{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800771 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700772 int rc = -EINVAL;
773
774 if (!crypt_stat->cipher) {
775 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
776 goto out;
777 }
778 ecryptfs_printk(KERN_DEBUG,
779 "Initializing cipher [%s]; strlen = [%d]; "
Tyler Hicksf24b3882010-11-15 17:36:38 -0600780 "key_size_bits = [%zd]\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700781 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
782 crypt_stat->key_size << 3);
783 if (crypt_stat->tfm) {
784 rc = 0;
785 goto out;
786 }
787 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800788 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
789 crypt_stat->cipher, "cbc");
790 if (rc)
Eric Sandeenc8161f62007-12-22 14:03:26 -0800791 goto out_unlock;
Michael Halcrow8bba0662006-10-30 22:07:18 -0800792 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
793 CRYPTO_ALG_ASYNC);
794 kfree(full_alg_name);
Akinobu Mitade887772006-11-28 12:29:49 -0800795 if (IS_ERR(crypt_stat->tfm)) {
796 rc = PTR_ERR(crypt_stat->tfm);
Tyler Hicksb0105ea2009-08-11 00:36:32 -0500797 crypt_stat->tfm = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -0700798 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
799 "Error initializing cipher [%s]\n",
800 crypt_stat->cipher);
Eric Sandeenc8161f62007-12-22 14:03:26 -0800801 goto out_unlock;
Michael Halcrow237fead2006-10-04 02:16:22 -0700802 }
Herbert Xuf1ddcaf2007-01-27 10:05:15 +1100803 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow237fead2006-10-04 02:16:22 -0700804 rc = 0;
Eric Sandeenc8161f62007-12-22 14:03:26 -0800805out_unlock:
806 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700807out:
808 return rc;
809}
810
811static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
812{
813 int extent_size_tmp;
814
815 crypt_stat->extent_mask = 0xFFFFFFFF;
816 crypt_stat->extent_shift = 0;
817 if (crypt_stat->extent_size == 0)
818 return;
819 extent_size_tmp = crypt_stat->extent_size;
820 while ((extent_size_tmp & 0x01) == 0) {
821 extent_size_tmp >>= 1;
822 crypt_stat->extent_mask <<= 1;
823 crypt_stat->extent_shift++;
824 }
825}
826
827void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
828{
829 /* Default values; may be overwritten as we are parsing the
830 * packets. */
831 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
832 set_extent_mask_and_shift(crypt_stat);
833 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800834 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600835 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700836 else {
837 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600838 crypt_stat->metadata_size =
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800839 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700840 else
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600841 crypt_stat->metadata_size = PAGE_CACHE_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700842 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700843}
844
845/**
846 * ecryptfs_compute_root_iv
847 * @crypt_stats
848 *
849 * On error, sets the root IV to all 0's.
850 */
851int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
852{
853 int rc = 0;
854 char dst[MD5_DIGEST_SIZE];
855
856 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
857 BUG_ON(crypt_stat->iv_bytes <= 0);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800858 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700859 rc = -EINVAL;
860 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
861 "cannot generate root IV\n");
862 goto out;
863 }
864 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
865 crypt_stat->key_size);
866 if (rc) {
867 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
868 "MD5 while generating root IV\n");
869 goto out;
870 }
871 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
872out:
873 if (rc) {
874 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800875 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
Michael Halcrow237fead2006-10-04 02:16:22 -0700876 }
877 return rc;
878}
879
880static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
881{
882 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800883 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
Michael Halcrow237fead2006-10-04 02:16:22 -0700884 ecryptfs_compute_root_iv(crypt_stat);
885 if (unlikely(ecryptfs_verbosity > 0)) {
886 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
887 ecryptfs_dump_hex(crypt_stat->key,
888 crypt_stat->key_size);
889 }
890}
891
892/**
Michael Halcrow17398952007-02-12 00:53:45 -0800893 * ecryptfs_copy_mount_wide_flags_to_inode_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700894 * @crypt_stat: The inode's cryptographic context
895 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow17398952007-02-12 00:53:45 -0800896 *
897 * This function propagates the mount-wide flags to individual inode
898 * flags.
899 */
900static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
901 struct ecryptfs_crypt_stat *crypt_stat,
902 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
903{
904 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
905 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
906 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
907 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800908 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
909 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
910 if (mount_crypt_stat->flags
911 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
912 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
913 else if (mount_crypt_stat->flags
914 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
915 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
916 }
Michael Halcrow17398952007-02-12 00:53:45 -0800917}
918
Michael Halcrowf4aad162007-10-16 01:27:53 -0700919static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
920 struct ecryptfs_crypt_stat *crypt_stat,
921 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
922{
923 struct ecryptfs_global_auth_tok *global_auth_tok;
924 int rc = 0;
925
Roland Dreieraa061172009-07-01 15:48:18 -0700926 mutex_lock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700927 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
Roland Dreieraa061172009-07-01 15:48:18 -0700928
Michael Halcrowf4aad162007-10-16 01:27:53 -0700929 list_for_each_entry(global_auth_tok,
930 &mount_crypt_stat->global_auth_tok_list,
931 mount_crypt_stat_list) {
Tyler Hicks84814d62009-03-13 13:51:59 -0700932 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
933 continue;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700934 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
935 if (rc) {
936 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700937 goto out;
938 }
939 }
Roland Dreieraa061172009-07-01 15:48:18 -0700940
Michael Halcrowf4aad162007-10-16 01:27:53 -0700941out:
Roland Dreieraa061172009-07-01 15:48:18 -0700942 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
943 mutex_unlock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700944 return rc;
945}
946
Michael Halcrow17398952007-02-12 00:53:45 -0800947/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700948 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700949 * @crypt_stat: The inode's cryptographic context
950 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700951 *
952 * Default values in the event that policy does not override them.
953 */
954static void ecryptfs_set_default_crypt_stat_vals(
955 struct ecryptfs_crypt_stat *crypt_stat,
956 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
957{
Michael Halcrow17398952007-02-12 00:53:45 -0800958 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
959 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700960 ecryptfs_set_default_sizes(crypt_stat);
961 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
962 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800963 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -0700964 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
965 crypt_stat->mount_crypt_stat = mount_crypt_stat;
966}
967
968/**
969 * ecryptfs_new_file_context
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700970 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -0700971 *
972 * If the crypto context for the file has not yet been established,
973 * this is where we do that. Establishing a new crypto context
974 * involves the following decisions:
975 * - What cipher to use?
976 * - What set of authentication tokens to use?
977 * Here we just worry about getting enough information into the
978 * authentication tokens so that we know that they are available.
979 * We associate the available authentication tokens with the new file
980 * via the set of signatures in the crypt_stat struct. Later, when
981 * the headers are actually written out, we may again defer to
982 * userspace to perform the encryption of the session key; for the
983 * foreseeable future, this will be the case with public key packets.
984 *
985 * Returns zero on success; non-zero otherwise
986 */
Michael Halcrow237fead2006-10-04 02:16:22 -0700987int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
988{
Michael Halcrow237fead2006-10-04 02:16:22 -0700989 struct ecryptfs_crypt_stat *crypt_stat =
990 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
991 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
992 &ecryptfs_superblock_to_private(
993 ecryptfs_dentry->d_sb)->mount_crypt_stat;
994 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700995 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700996
997 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -0700998 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700999 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1000 mount_crypt_stat);
1001 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1002 mount_crypt_stat);
1003 if (rc) {
1004 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1005 "to the inode key sigs; rc = [%d]\n", rc);
1006 goto out;
1007 }
1008 cipher_name_len =
1009 strlen(mount_crypt_stat->global_default_cipher_name);
1010 memcpy(crypt_stat->cipher,
1011 mount_crypt_stat->global_default_cipher_name,
1012 cipher_name_len);
1013 crypt_stat->cipher[cipher_name_len] = '\0';
1014 crypt_stat->key_size =
1015 mount_crypt_stat->global_default_cipher_key_size;
1016 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001017 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1018 if (rc)
1019 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1020 "context for cipher [%s]: rc = [%d]\n",
1021 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001022out:
Michael Halcrow237fead2006-10-04 02:16:22 -07001023 return rc;
1024}
1025
1026/**
1027 * contains_ecryptfs_marker - check for the ecryptfs marker
1028 * @data: The data block in which to check
1029 *
1030 * Returns one if marker found; zero if not found
1031 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001032static int contains_ecryptfs_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -07001033{
1034 u32 m_1, m_2;
1035
Harvey Harrison29335c62008-07-23 21:30:06 -07001036 m_1 = get_unaligned_be32(data);
1037 m_2 = get_unaligned_be32(data + 4);
Michael Halcrow237fead2006-10-04 02:16:22 -07001038 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1039 return 1;
1040 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1041 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1042 MAGIC_ECRYPTFS_MARKER);
1043 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1044 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1045 return 0;
1046}
1047
1048struct ecryptfs_flag_map_elem {
1049 u32 file_flag;
1050 u32 local_flag;
1051};
1052
1053/* Add support for additional flags by adding elements here. */
1054static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1055 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001056 {0x00000002, ECRYPTFS_ENCRYPTED},
Michael Halcrowaddd65ad2009-01-06 14:42:00 -08001057 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1058 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
Michael Halcrow237fead2006-10-04 02:16:22 -07001059};
1060
1061/**
1062 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001063 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001064 * @page_virt: Source data to be parsed
1065 * @bytes_read: Updated with the number of bytes read
1066 *
1067 * Returns zero on success; non-zero if the flag set is invalid
1068 */
1069static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1070 char *page_virt, int *bytes_read)
1071{
1072 int rc = 0;
1073 int i;
1074 u32 flags;
1075
Harvey Harrison29335c62008-07-23 21:30:06 -07001076 flags = get_unaligned_be32(page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001077 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1078 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1079 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001080 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -07001081 } else
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001082 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
Michael Halcrow237fead2006-10-04 02:16:22 -07001083 /* Version is in top 8 bits of the 32-bit flag vector */
1084 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1085 (*bytes_read) = 4;
1086 return rc;
1087}
1088
1089/**
1090 * write_ecryptfs_marker
1091 * @page_virt: The pointer to in a page to begin writing the marker
1092 * @written: Number of bytes written
1093 *
1094 * Marker = 0x3c81b7f5
1095 */
1096static void write_ecryptfs_marker(char *page_virt, size_t *written)
1097{
1098 u32 m_1, m_2;
1099
1100 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1101 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
Harvey Harrison29335c62008-07-23 21:30:06 -07001102 put_unaligned_be32(m_1, page_virt);
1103 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1104 put_unaligned_be32(m_2, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001105 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1106}
1107
Tyler Hicksf4e60e62010-02-11 00:02:32 -06001108void ecryptfs_write_crypt_stat_flags(char *page_virt,
1109 struct ecryptfs_crypt_stat *crypt_stat,
1110 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001111{
1112 u32 flags = 0;
1113 int i;
1114
1115 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1116 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001117 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -07001118 flags |= ecryptfs_flag_map[i].file_flag;
1119 /* Version is in top 8 bits of the 32-bit flag vector */
1120 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
Harvey Harrison29335c62008-07-23 21:30:06 -07001121 put_unaligned_be32(flags, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001122 (*written) = 4;
1123}
1124
1125struct ecryptfs_cipher_code_str_map_elem {
1126 char cipher_str[16];
Trevor Highland19e66a62008-02-06 01:38:36 -08001127 u8 cipher_code;
Michael Halcrow237fead2006-10-04 02:16:22 -07001128};
1129
1130/* Add support for additional ciphers by adding elements here. The
1131 * cipher_code is whatever OpenPGP applicatoins use to identify the
1132 * ciphers. List in order of probability. */
1133static struct ecryptfs_cipher_code_str_map_elem
1134ecryptfs_cipher_code_str_map[] = {
1135 {"aes",RFC2440_CIPHER_AES_128 },
1136 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1137 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1138 {"cast5", RFC2440_CIPHER_CAST_5},
1139 {"twofish", RFC2440_CIPHER_TWOFISH},
1140 {"cast6", RFC2440_CIPHER_CAST_6},
1141 {"aes", RFC2440_CIPHER_AES_192},
1142 {"aes", RFC2440_CIPHER_AES_256}
1143};
1144
1145/**
1146 * ecryptfs_code_for_cipher_string
Michael Halcrow9c79f342009-01-06 14:41:57 -08001147 * @cipher_name: The string alias for the cipher
1148 * @key_bytes: Length of key in bytes; used for AES code selection
Michael Halcrow237fead2006-10-04 02:16:22 -07001149 *
1150 * Returns zero on no match, or the cipher code on match
1151 */
Michael Halcrow9c79f342009-01-06 14:41:57 -08001152u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
Michael Halcrow237fead2006-10-04 02:16:22 -07001153{
1154 int i;
Trevor Highland19e66a62008-02-06 01:38:36 -08001155 u8 code = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001156 struct ecryptfs_cipher_code_str_map_elem *map =
1157 ecryptfs_cipher_code_str_map;
1158
Michael Halcrow9c79f342009-01-06 14:41:57 -08001159 if (strcmp(cipher_name, "aes") == 0) {
1160 switch (key_bytes) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001161 case 16:
1162 code = RFC2440_CIPHER_AES_128;
1163 break;
1164 case 24:
1165 code = RFC2440_CIPHER_AES_192;
1166 break;
1167 case 32:
1168 code = RFC2440_CIPHER_AES_256;
1169 }
1170 } else {
1171 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
Michael Halcrow9c79f342009-01-06 14:41:57 -08001172 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001173 code = map[i].cipher_code;
1174 break;
1175 }
1176 }
1177 return code;
1178}
1179
1180/**
1181 * ecryptfs_cipher_code_to_string
1182 * @str: Destination to write out the cipher name
1183 * @cipher_code: The code to convert to cipher name string
1184 *
1185 * Returns zero on success
1186 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001187int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
Michael Halcrow237fead2006-10-04 02:16:22 -07001188{
1189 int rc = 0;
1190 int i;
1191
1192 str[0] = '\0';
1193 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1194 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1195 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1196 if (str[0] == '\0') {
1197 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1198 "[%d]\n", cipher_code);
1199 rc = -EINVAL;
1200 }
1201 return rc;
1202}
1203
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001204int ecryptfs_read_and_validate_header_region(char *data,
1205 struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001206{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001207 struct ecryptfs_crypt_stat *crypt_stat =
1208 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001209 int rc;
1210
Michael Halcrowaddd65ad2009-01-06 14:42:00 -08001211 if (crypt_stat->extent_size == 0)
1212 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001213 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1214 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001215 if (rc < 0) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001216 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001217 __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001218 goto out;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001219 }
1220 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001221 rc = -EINVAL;
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001222 } else
1223 rc = 0;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001224out:
1225 return rc;
1226}
1227
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001228void
1229ecryptfs_write_header_metadata(char *virt,
1230 struct ecryptfs_crypt_stat *crypt_stat,
1231 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001232{
1233 u32 header_extent_size;
1234 u16 num_header_extents_at_front;
1235
Michael Halcrow45eaab72007-10-16 01:28:05 -07001236 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001237 num_header_extents_at_front =
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001238 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
Harvey Harrison29335c62008-07-23 21:30:06 -07001239 put_unaligned_be32(header_extent_size, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001240 virt += 4;
Harvey Harrison29335c62008-07-23 21:30:06 -07001241 put_unaligned_be16(num_header_extents_at_front, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001242 (*written) = 6;
1243}
1244
Michael Halcrow237fead2006-10-04 02:16:22 -07001245struct kmem_cache *ecryptfs_header_cache_1;
1246struct kmem_cache *ecryptfs_header_cache_2;
1247
1248/**
1249 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001250 * @page_virt: The virtual address to write the headers to
Eric Sandeen87b811c2008-10-29 14:01:08 -07001251 * @max: The size of memory allocated at page_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001252 * @size: Set to the number of bytes written by this function
1253 * @crypt_stat: The cryptographic context
1254 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001255 *
1256 * Format version: 1
1257 *
1258 * Header Extent:
1259 * Octets 0-7: Unencrypted file size (big-endian)
1260 * Octets 8-15: eCryptfs special marker
1261 * Octets 16-19: Flags
1262 * Octet 16: File format version number (between 0 and 255)
1263 * Octets 17-18: Reserved
1264 * Octet 19: Bit 1 (lsb): Reserved
1265 * Bit 2: Encrypted?
1266 * Bits 3-8: Reserved
1267 * Octets 20-23: Header extent size (big-endian)
1268 * Octets 24-25: Number of header extents at front of file
1269 * (big-endian)
1270 * Octet 26: Begin RFC 2440 authentication token packet set
1271 * Data Extent 0:
1272 * Lower data (CBC encrypted)
1273 * Data Extent 1:
1274 * Lower data (CBC encrypted)
1275 * ...
1276 *
1277 * Returns zero on success
1278 */
Eric Sandeen87b811c2008-10-29 14:01:08 -07001279static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1280 size_t *size,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001281 struct ecryptfs_crypt_stat *crypt_stat,
1282 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001283{
1284 int rc;
1285 size_t written;
1286 size_t offset;
1287
1288 offset = ECRYPTFS_FILE_SIZE_BYTES;
1289 write_ecryptfs_marker((page_virt + offset), &written);
1290 offset += written;
Tyler Hicksf4e60e62010-02-11 00:02:32 -06001291 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1292 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001293 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001294 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1295 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001296 offset += written;
1297 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1298 ecryptfs_dentry, &written,
Eric Sandeen87b811c2008-10-29 14:01:08 -07001299 max - offset);
Michael Halcrow237fead2006-10-04 02:16:22 -07001300 if (rc)
1301 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1302 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001303 if (size) {
1304 offset += written;
1305 *size = offset;
1306 }
1307 return rc;
1308}
1309
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001310static int
Tyler Hicks8faece52009-03-20 01:25:09 -05001311ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
1312 char *virt, size_t virt_len)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001313{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001314 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001315
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001316 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001317 0, virt_len);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001318 if (rc < 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001319 printk(KERN_ERR "%s: Error attempting to write header "
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001320 "information to lower file; rc = [%d]\n", __func__, rc);
1321 else
1322 rc = 0;
Michael Halcrow70456602007-02-12 00:53:48 -08001323 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001324}
1325
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001326static int
1327ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001328 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001329{
1330 int rc;
1331
1332 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1333 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001334 return rc;
1335}
1336
Tyler Hicks8faece52009-03-20 01:25:09 -05001337static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1338 unsigned int order)
1339{
1340 struct page *page;
1341
1342 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1343 if (page)
1344 return (unsigned long) page_address(page);
1345 return 0;
1346}
1347
Michael Halcrow237fead2006-10-04 02:16:22 -07001348/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001349 * ecryptfs_write_metadata
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001350 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001351 *
1352 * Write the file headers out. This will likely involve a userspace
1353 * callout, in which the session key is encrypted with one or more
1354 * public keys and/or the passphrase necessary to do the encryption is
1355 * retrieved via a prompt. Exactly what happens at this point should
1356 * be policy-dependent.
1357 *
1358 * Returns zero on success; non-zero on error
1359 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001360int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001361{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001362 struct ecryptfs_crypt_stat *crypt_stat =
1363 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
Tyler Hicks8faece52009-03-20 01:25:09 -05001364 unsigned int order;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001365 char *virt;
Tyler Hicks8faece52009-03-20 01:25:09 -05001366 size_t virt_len;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001367 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001368 int rc = 0;
1369
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001370 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1371 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001372 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001373 rc = -EINVAL;
1374 goto out;
1375 }
1376 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001377 printk(KERN_WARNING "%s: Encrypted flag not set\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001378 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001379 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001380 goto out;
1381 }
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001382 virt_len = crypt_stat->metadata_size;
Tyler Hicks8faece52009-03-20 01:25:09 -05001383 order = get_order(virt_len);
Michael Halcrow237fead2006-10-04 02:16:22 -07001384 /* Released in this function */
Tyler Hicks8faece52009-03-20 01:25:09 -05001385 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001386 if (!virt) {
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001387 printk(KERN_ERR "%s: Out of memory\n", __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001388 rc = -ENOMEM;
1389 goto out;
1390 }
Tyler Hicksbd4f0fe2011-02-23 00:14:19 -06001391 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
Tyler Hicks8faece52009-03-20 01:25:09 -05001392 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1393 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001394 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001395 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001396 __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001397 goto out_free;
1398 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001399 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicks8faece52009-03-20 01:25:09 -05001400 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1401 size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001402 else
Tyler Hicks8faece52009-03-20 01:25:09 -05001403 rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
1404 virt_len);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001405 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001406 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001407 "rc = [%d]\n", __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001408 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001409 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001410out_free:
Tyler Hicks8faece52009-03-20 01:25:09 -05001411 free_pages((unsigned long)virt, order);
Michael Halcrow237fead2006-10-04 02:16:22 -07001412out:
1413 return rc;
1414}
1415
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001416#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1417#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001418static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001419 char *virt, int *bytes_read,
1420 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001421{
1422 int rc = 0;
1423 u32 header_extent_size;
1424 u16 num_header_extents_at_front;
1425
Harvey Harrison29335c62008-07-23 21:30:06 -07001426 header_extent_size = get_unaligned_be32(virt);
1427 virt += sizeof(__be32);
1428 num_header_extents_at_front = get_unaligned_be16(virt);
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001429 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1430 * (size_t)header_extent_size));
Harvey Harrison29335c62008-07-23 21:30:06 -07001431 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001432 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001433 && (crypt_stat->metadata_size
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001434 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001435 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001436 printk(KERN_WARNING "Invalid header size: [%zd]\n",
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001437 crypt_stat->metadata_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001438 }
1439 return rc;
1440}
1441
1442/**
1443 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001444 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001445 *
1446 * For version 0 file format; this function is only for backwards
1447 * compatibility for files created with the prior versions of
1448 * eCryptfs.
1449 */
1450static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1451{
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001452 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001453}
1454
1455/**
1456 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001457 * @page_virt: The virtual address into which to read the headers
1458 * @crypt_stat: The cryptographic context
1459 * @ecryptfs_dentry: The eCryptfs dentry
1460 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001461 *
1462 * Read/parse the header data. The header format is detailed in the
1463 * comment block for the ecryptfs_write_headers_virt() function.
1464 *
1465 * Returns zero on success
1466 */
1467static int ecryptfs_read_headers_virt(char *page_virt,
1468 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001469 struct dentry *ecryptfs_dentry,
1470 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001471{
1472 int rc = 0;
1473 int offset;
1474 int bytes_read;
1475
1476 ecryptfs_set_default_sizes(crypt_stat);
1477 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1478 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1479 offset = ECRYPTFS_FILE_SIZE_BYTES;
1480 rc = contains_ecryptfs_marker(page_virt + offset);
1481 if (rc == 0) {
1482 rc = -EINVAL;
1483 goto out;
1484 }
1485 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1486 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1487 &bytes_read);
1488 if (rc) {
1489 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1490 goto out;
1491 }
1492 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1493 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1494 "file version [%d] is supported by this "
1495 "version of eCryptfs\n",
1496 crypt_stat->file_version,
1497 ECRYPTFS_SUPPORTED_FILE_VERSION);
1498 rc = -EINVAL;
1499 goto out;
1500 }
1501 offset += bytes_read;
1502 if (crypt_stat->file_version >= 1) {
1503 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001504 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001505 if (rc) {
1506 ecryptfs_printk(KERN_WARNING, "Error reading header "
1507 "metadata; rc = [%d]\n", rc);
1508 }
1509 offset += bytes_read;
1510 } else
1511 set_default_header_data(crypt_stat);
1512 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1513 ecryptfs_dentry);
1514out:
1515 return rc;
1516}
1517
1518/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001519 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001520 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001521 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001522 *
1523 * Attempts to read the crypto metadata from the extended attribute
1524 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001525 *
1526 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001527 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001528int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001529{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001530 struct dentry *lower_dentry =
1531 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001532 ssize_t size;
1533 int rc = 0;
1534
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001535 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1536 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001537 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001538 if (unlikely(ecryptfs_verbosity > 0))
1539 printk(KERN_INFO "Error attempting to read the [%s] "
1540 "xattr from the lower file; return value = "
1541 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001542 rc = -EINVAL;
1543 goto out;
1544 }
1545out:
1546 return rc;
1547}
1548
1549int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1550 struct dentry *ecryptfs_dentry)
1551{
1552 int rc;
1553
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001554 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001555 if (rc)
1556 goto out;
1557 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1558 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1559 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1560 rc = -EINVAL;
1561 }
1562out:
1563 return rc;
1564}
1565
1566/**
1567 * ecryptfs_read_metadata
1568 *
1569 * Common entry point for reading file metadata. From here, we could
1570 * retrieve the header information from the header region of the file,
1571 * the xattr region of the file, or some other repostory that is
1572 * stored separately from the file itself. The current implementation
1573 * supports retrieving the metadata information from the file contents
1574 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001575 *
1576 * Returns zero if valid headers found and parsed; non-zero otherwise
1577 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001578int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001579{
1580 int rc = 0;
1581 char *page_virt = NULL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001582 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -07001583 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001584 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001585 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1586 &ecryptfs_superblock_to_private(
1587 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001588
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001589 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1590 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001591 /* Read the first page from the underlying file */
Christoph Lameterf7267c02006-12-06 20:33:15 -08001592 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001593 if (!page_virt) {
1594 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001595 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001596 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001597 goto out;
1598 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001599 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1600 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001601 if (rc >= 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001602 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1603 ecryptfs_dentry,
1604 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001605 if (rc) {
Tyler Hicks1984c232010-02-10 23:17:44 -06001606 memset(page_virt, 0, PAGE_CACHE_SIZE);
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001607 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001608 if (rc) {
1609 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1610 "file header region or xattr region\n");
1611 rc = -EINVAL;
1612 goto out;
1613 }
1614 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1615 ecryptfs_dentry,
1616 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1617 if (rc) {
1618 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1619 "file xattr region either\n");
1620 rc = -EINVAL;
1621 }
1622 if (crypt_stat->mount_crypt_stat->flags
1623 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1624 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1625 } else {
1626 printk(KERN_WARNING "Attempt to access file with "
1627 "crypto metadata only in the extended attribute "
1628 "region, but eCryptfs was mounted without "
1629 "xattr support enabled. eCryptfs will not treat "
1630 "this like an encrypted file.\n");
1631 rc = -EINVAL;
1632 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001633 }
1634out:
1635 if (page_virt) {
1636 memset(page_virt, 0, PAGE_CACHE_SIZE);
1637 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1638 }
1639 return rc;
1640}
1641
1642/**
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001643 * ecryptfs_encrypt_filename - encrypt filename
1644 *
1645 * CBC-encrypts the filename. We do not want to encrypt the same
1646 * filename with the same key and IV, which may happen with hard
1647 * links, so we prepend random bits to each filename.
1648 *
1649 * Returns zero on success; non-zero otherwise
1650 */
1651static int
1652ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1653 struct ecryptfs_crypt_stat *crypt_stat,
1654 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1655{
1656 int rc = 0;
1657
1658 filename->encrypted_filename = NULL;
1659 filename->encrypted_filename_size = 0;
1660 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1661 || (mount_crypt_stat && (mount_crypt_stat->flags
1662 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1663 size_t packet_size;
1664 size_t remaining_bytes;
1665
1666 rc = ecryptfs_write_tag_70_packet(
1667 NULL, NULL,
1668 &filename->encrypted_filename_size,
1669 mount_crypt_stat, NULL,
1670 filename->filename_size);
1671 if (rc) {
1672 printk(KERN_ERR "%s: Error attempting to get packet "
1673 "size for tag 72; rc = [%d]\n", __func__,
1674 rc);
1675 filename->encrypted_filename_size = 0;
1676 goto out;
1677 }
1678 filename->encrypted_filename =
1679 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1680 if (!filename->encrypted_filename) {
1681 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08001682 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001683 filename->encrypted_filename_size);
1684 rc = -ENOMEM;
1685 goto out;
1686 }
1687 remaining_bytes = filename->encrypted_filename_size;
1688 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1689 &remaining_bytes,
1690 &packet_size,
1691 mount_crypt_stat,
1692 filename->filename,
1693 filename->filename_size);
1694 if (rc) {
1695 printk(KERN_ERR "%s: Error attempting to generate "
1696 "tag 70 packet; rc = [%d]\n", __func__,
1697 rc);
1698 kfree(filename->encrypted_filename);
1699 filename->encrypted_filename = NULL;
1700 filename->encrypted_filename_size = 0;
1701 goto out;
1702 }
1703 filename->encrypted_filename_size = packet_size;
1704 } else {
1705 printk(KERN_ERR "%s: No support for requested filename "
1706 "encryption method in this release\n", __func__);
Tyler Hicksdf6ad332009-08-21 04:27:46 -05001707 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001708 goto out;
1709 }
1710out:
1711 return rc;
1712}
1713
1714static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1715 const char *name, size_t name_size)
1716{
1717 int rc = 0;
1718
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001719 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001720 if (!(*copied_name)) {
1721 rc = -ENOMEM;
1722 goto out;
1723 }
1724 memcpy((void *)(*copied_name), (void *)name, name_size);
1725 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1726 * in printing out the
1727 * string in debug
1728 * messages */
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001729 (*copied_name_size) = name_size;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001730out:
1731 return rc;
1732}
1733
1734/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001735 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001736 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001737 * @cipher_name: Name of the cipher
1738 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001739 *
1740 * Returns zero on success. Any crypto_tfm structs allocated here
1741 * should be released by other functions, such as on a superblock put
1742 * event, regardless of whether this function succeeds for fails.
1743 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001744static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001745ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1746 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001747{
1748 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Dan Carpenterece550f2010-01-19 12:34:32 +03001749 char *full_alg_name = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001750 int rc;
1751
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001752 *key_tfm = NULL;
1753 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001754 rc = -EINVAL;
Michael Halcrowdf261c52009-01-06 14:42:02 -08001755 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001756 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001757 goto out;
1758 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001759 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1760 "ecb");
1761 if (rc)
1762 goto out;
1763 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001764 if (IS_ERR(*key_tfm)) {
1765 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001766 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Dave Hansen38268492009-08-27 09:47:07 -07001767 "[%s]; rc = [%d]\n", full_alg_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001768 goto out;
1769 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001770 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1771 if (*key_size == 0) {
1772 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1773
1774 *key_size = alg->max_keysize;
1775 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001776 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001777 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001778 if (rc) {
Michael Halcrowdf261c52009-01-06 14:42:02 -08001779 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
Dave Hansen38268492009-08-27 09:47:07 -07001780 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1781 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001782 rc = -EINVAL;
1783 goto out;
1784 }
1785out:
Dan Carpenterece550f2010-01-19 12:34:32 +03001786 kfree(full_alg_name);
Michael Halcrow237fead2006-10-04 02:16:22 -07001787 return rc;
1788}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001789
1790struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001791static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001792struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001793
Jerome Marchand7371a382010-08-17 17:24:05 +02001794int __init ecryptfs_init_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001795{
1796 mutex_init(&key_tfm_list_mutex);
1797 INIT_LIST_HEAD(&key_tfm_list);
1798 return 0;
1799}
1800
Eric Sandeenaf440f52008-02-06 01:38:37 -08001801/**
1802 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1803 *
1804 * Called only at module unload time
1805 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001806int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001807{
1808 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1809
1810 mutex_lock(&key_tfm_list_mutex);
1811 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1812 key_tfm_list) {
1813 list_del(&key_tfm->key_tfm_list);
1814 if (key_tfm->key_tfm)
1815 crypto_free_blkcipher(key_tfm->key_tfm);
1816 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1817 }
1818 mutex_unlock(&key_tfm_list_mutex);
1819 return 0;
1820}
1821
1822int
1823ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1824 size_t key_size)
1825{
1826 struct ecryptfs_key_tfm *tmp_tfm;
1827 int rc = 0;
1828
Eric Sandeenaf440f52008-02-06 01:38:37 -08001829 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1830
Michael Halcrowf4aad162007-10-16 01:27:53 -07001831 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1832 if (key_tfm != NULL)
1833 (*key_tfm) = tmp_tfm;
1834 if (!tmp_tfm) {
1835 rc = -ENOMEM;
1836 printk(KERN_ERR "Error attempting to allocate from "
1837 "ecryptfs_key_tfm_cache\n");
1838 goto out;
1839 }
1840 mutex_init(&tmp_tfm->key_tfm_mutex);
1841 strncpy(tmp_tfm->cipher_name, cipher_name,
1842 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001843 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001844 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001845 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1846 tmp_tfm->cipher_name,
1847 &tmp_tfm->key_size);
1848 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001849 printk(KERN_ERR "Error attempting to initialize key TFM "
1850 "cipher with name = [%s]; rc = [%d]\n",
1851 tmp_tfm->cipher_name, rc);
1852 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1853 if (key_tfm != NULL)
1854 (*key_tfm) = NULL;
1855 goto out;
1856 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001857 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001858out:
1859 return rc;
1860}
1861
Eric Sandeenaf440f52008-02-06 01:38:37 -08001862/**
1863 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1864 * @cipher_name: the name of the cipher to search for
1865 * @key_tfm: set to corresponding tfm if found
1866 *
1867 * Searches for cached key_tfm matching @cipher_name
1868 * Must be called with &key_tfm_list_mutex held
1869 * Returns 1 if found, with @key_tfm set
1870 * Returns 0 if not found, with @key_tfm set to NULL
1871 */
1872int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1873{
1874 struct ecryptfs_key_tfm *tmp_key_tfm;
1875
1876 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1877
1878 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1879 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1880 if (key_tfm)
1881 (*key_tfm) = tmp_key_tfm;
1882 return 1;
1883 }
1884 }
1885 if (key_tfm)
1886 (*key_tfm) = NULL;
1887 return 0;
1888}
1889
1890/**
1891 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1892 *
1893 * @tfm: set to cached tfm found, or new tfm created
1894 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1895 * @cipher_name: the name of the cipher to search for and/or add
1896 *
1897 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1898 * Searches for cached item first, and creates new if not found.
1899 * Returns 0 on success, non-zero if adding new cipher failed
1900 */
Michael Halcrowf4aad162007-10-16 01:27:53 -07001901int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1902 struct mutex **tfm_mutex,
1903 char *cipher_name)
1904{
1905 struct ecryptfs_key_tfm *key_tfm;
1906 int rc = 0;
1907
1908 (*tfm) = NULL;
1909 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001910
Michael Halcrowf4aad162007-10-16 01:27:53 -07001911 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001912 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1913 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1914 if (rc) {
1915 printk(KERN_ERR "Error adding new key_tfm to list; "
1916 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001917 goto out;
1918 }
1919 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001920 (*tfm) = key_tfm->key_tfm;
1921 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1922out:
Cyrill Gorcunov71fd5172008-05-23 13:04:20 -07001923 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001924 return rc;
1925}
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001926
1927/* 64 characters forming a 6-bit target field */
1928static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1929 "EFGHIJKLMNOPQRST"
1930 "UVWXYZabcdefghij"
1931 "klmnopqrstuvwxyz");
1932
1933/* We could either offset on every reverse map or just pad some 0x00's
1934 * at the front here */
Michael Halcrow71c11c32009-01-06 14:42:05 -08001935static const unsigned char filename_rev_map[] = {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001936 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1937 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1938 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1939 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1940 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1941 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1942 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1943 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1944 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1945 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1946 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1947 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1948 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1949 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1950 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1951 0x3D, 0x3E, 0x3F
1952};
1953
1954/**
1955 * ecryptfs_encode_for_filename
1956 * @dst: Destination location for encoded filename
1957 * @dst_size: Size of the encoded filename in bytes
1958 * @src: Source location for the filename to encode
1959 * @src_size: Size of the source in bytes
1960 */
1961void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1962 unsigned char *src, size_t src_size)
1963{
1964 size_t num_blocks;
1965 size_t block_num = 0;
1966 size_t dst_offset = 0;
1967 unsigned char last_block[3];
1968
1969 if (src_size == 0) {
1970 (*dst_size) = 0;
1971 goto out;
1972 }
1973 num_blocks = (src_size / 3);
1974 if ((src_size % 3) == 0) {
1975 memcpy(last_block, (&src[src_size - 3]), 3);
1976 } else {
1977 num_blocks++;
1978 last_block[2] = 0x00;
1979 switch (src_size % 3) {
1980 case 1:
1981 last_block[0] = src[src_size - 1];
1982 last_block[1] = 0x00;
1983 break;
1984 case 2:
1985 last_block[0] = src[src_size - 2];
1986 last_block[1] = src[src_size - 1];
1987 }
1988 }
1989 (*dst_size) = (num_blocks * 4);
1990 if (!dst)
1991 goto out;
1992 while (block_num < num_blocks) {
1993 unsigned char *src_block;
1994 unsigned char dst_block[4];
1995
1996 if (block_num == (num_blocks - 1))
1997 src_block = last_block;
1998 else
1999 src_block = &src[block_num * 3];
2000 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2001 dst_block[1] = (((src_block[0] << 4) & 0x30)
2002 | ((src_block[1] >> 4) & 0x0F));
2003 dst_block[2] = (((src_block[1] << 2) & 0x3C)
2004 | ((src_block[2] >> 6) & 0x03));
2005 dst_block[3] = (src_block[2] & 0x3F);
2006 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2007 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2008 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2009 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2010 block_num++;
2011 }
2012out:
2013 return;
2014}
2015
Michael Halcrow71c11c32009-01-06 14:42:05 -08002016/**
2017 * ecryptfs_decode_from_filename
2018 * @dst: If NULL, this function only sets @dst_size and returns. If
2019 * non-NULL, this function decodes the encoded octets in @src
2020 * into the memory that @dst points to.
2021 * @dst_size: Set to the size of the decoded string.
2022 * @src: The encoded set of octets to decode.
2023 * @src_size: The size of the encoded set of octets to decode.
2024 */
2025static void
2026ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2027 const unsigned char *src, size_t src_size)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002028{
2029 u8 current_bit_offset = 0;
2030 size_t src_byte_offset = 0;
2031 size_t dst_byte_offset = 0;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002032
2033 if (dst == NULL) {
Michael Halcrow71c11c32009-01-06 14:42:05 -08002034 /* Not exact; conservatively long. Every block of 4
2035 * encoded characters decodes into a block of 3
2036 * decoded characters. This segment of code provides
2037 * the caller with the maximum amount of allocated
2038 * space that @dst will need to point to in a
2039 * subsequent call. */
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002040 (*dst_size) = (((src_size + 1) * 3) / 4);
2041 goto out;
2042 }
2043 while (src_byte_offset < src_size) {
2044 unsigned char src_byte =
2045 filename_rev_map[(int)src[src_byte_offset]];
2046
2047 switch (current_bit_offset) {
2048 case 0:
2049 dst[dst_byte_offset] = (src_byte << 2);
2050 current_bit_offset = 6;
2051 break;
2052 case 6:
2053 dst[dst_byte_offset++] |= (src_byte >> 4);
2054 dst[dst_byte_offset] = ((src_byte & 0xF)
2055 << 4);
2056 current_bit_offset = 4;
2057 break;
2058 case 4:
2059 dst[dst_byte_offset++] |= (src_byte >> 2);
2060 dst[dst_byte_offset] = (src_byte << 6);
2061 current_bit_offset = 2;
2062 break;
2063 case 2:
2064 dst[dst_byte_offset++] |= (src_byte);
2065 dst[dst_byte_offset] = 0;
2066 current_bit_offset = 0;
2067 break;
2068 }
2069 src_byte_offset++;
2070 }
2071 (*dst_size) = dst_byte_offset;
2072out:
Michael Halcrow71c11c32009-01-06 14:42:05 -08002073 return;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002074}
2075
2076/**
2077 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2078 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2079 * @name: The plaintext name
2080 * @length: The length of the plaintext
2081 * @encoded_name: The encypted name
2082 *
2083 * Encrypts and encodes a filename into something that constitutes a
2084 * valid filename for a filesystem, with printable characters.
2085 *
2086 * We assume that we have a properly initialized crypto context,
2087 * pointed to by crypt_stat->tfm.
2088 *
2089 * Returns zero on success; non-zero on otherwise
2090 */
2091int ecryptfs_encrypt_and_encode_filename(
2092 char **encoded_name,
2093 size_t *encoded_name_size,
2094 struct ecryptfs_crypt_stat *crypt_stat,
2095 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2096 const char *name, size_t name_size)
2097{
2098 size_t encoded_name_no_prefix_size;
2099 int rc = 0;
2100
2101 (*encoded_name) = NULL;
2102 (*encoded_name_size) = 0;
2103 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2104 || (mount_crypt_stat && (mount_crypt_stat->flags
2105 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2106 struct ecryptfs_filename *filename;
2107
2108 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2109 if (!filename) {
2110 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002111 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002112 sizeof(*filename));
2113 rc = -ENOMEM;
2114 goto out;
2115 }
2116 filename->filename = (char *)name;
2117 filename->filename_size = name_size;
2118 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2119 mount_crypt_stat);
2120 if (rc) {
2121 printk(KERN_ERR "%s: Error attempting to encrypt "
2122 "filename; rc = [%d]\n", __func__, rc);
2123 kfree(filename);
2124 goto out;
2125 }
2126 ecryptfs_encode_for_filename(
2127 NULL, &encoded_name_no_prefix_size,
2128 filename->encrypted_filename,
2129 filename->encrypted_filename_size);
2130 if ((crypt_stat && (crypt_stat->flags
2131 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2132 || (mount_crypt_stat
2133 && (mount_crypt_stat->flags
2134 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2135 (*encoded_name_size) =
2136 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2137 + encoded_name_no_prefix_size);
2138 else
2139 (*encoded_name_size) =
2140 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2141 + encoded_name_no_prefix_size);
2142 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2143 if (!(*encoded_name)) {
2144 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002145 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002146 (*encoded_name_size));
2147 rc = -ENOMEM;
2148 kfree(filename->encrypted_filename);
2149 kfree(filename);
2150 goto out;
2151 }
2152 if ((crypt_stat && (crypt_stat->flags
2153 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2154 || (mount_crypt_stat
2155 && (mount_crypt_stat->flags
2156 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2157 memcpy((*encoded_name),
2158 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2159 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2160 ecryptfs_encode_for_filename(
2161 ((*encoded_name)
2162 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2163 &encoded_name_no_prefix_size,
2164 filename->encrypted_filename,
2165 filename->encrypted_filename_size);
2166 (*encoded_name_size) =
2167 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2168 + encoded_name_no_prefix_size);
2169 (*encoded_name)[(*encoded_name_size)] = '\0';
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002170 } else {
Tyler Hicksdf6ad332009-08-21 04:27:46 -05002171 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002172 }
2173 if (rc) {
2174 printk(KERN_ERR "%s: Error attempting to encode "
2175 "encrypted filename; rc = [%d]\n", __func__,
2176 rc);
2177 kfree((*encoded_name));
2178 (*encoded_name) = NULL;
2179 (*encoded_name_size) = 0;
2180 }
2181 kfree(filename->encrypted_filename);
2182 kfree(filename);
2183 } else {
2184 rc = ecryptfs_copy_filename(encoded_name,
2185 encoded_name_size,
2186 name, name_size);
2187 }
2188out:
2189 return rc;
2190}
2191
2192/**
2193 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2194 * @plaintext_name: The plaintext name
2195 * @plaintext_name_size: The plaintext name size
2196 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2197 * @name: The filename in cipher text
2198 * @name_size: The cipher text name size
2199 *
2200 * Decrypts and decodes the filename.
2201 *
2202 * Returns zero on error; non-zero otherwise
2203 */
2204int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2205 size_t *plaintext_name_size,
2206 struct dentry *ecryptfs_dir_dentry,
2207 const char *name, size_t name_size)
2208{
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002209 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2210 &ecryptfs_superblock_to_private(
2211 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002212 char *decoded_name;
2213 size_t decoded_name_size;
2214 size_t packet_size;
2215 int rc = 0;
2216
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002217 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2218 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2219 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002220 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2221 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002222 const char *orig_name = name;
2223 size_t orig_name_size = name_size;
2224
2225 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2226 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
Michael Halcrow71c11c32009-01-06 14:42:05 -08002227 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2228 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002229 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2230 if (!decoded_name) {
2231 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08002232 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002233 decoded_name_size);
2234 rc = -ENOMEM;
2235 goto out;
2236 }
Michael Halcrow71c11c32009-01-06 14:42:05 -08002237 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2238 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002239 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2240 plaintext_name_size,
2241 &packet_size,
2242 mount_crypt_stat,
2243 decoded_name,
2244 decoded_name_size);
2245 if (rc) {
2246 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2247 "from filename; copying through filename "
2248 "as-is\n", __func__);
2249 rc = ecryptfs_copy_filename(plaintext_name,
2250 plaintext_name_size,
2251 orig_name, orig_name_size);
2252 goto out_free;
2253 }
2254 } else {
2255 rc = ecryptfs_copy_filename(plaintext_name,
2256 plaintext_name_size,
2257 name, name_size);
2258 goto out;
2259 }
2260out_free:
2261 kfree(decoded_name);
2262out:
2263 return rc;
2264}