blob: 2a834255c75de911b7e1f8eb10026972913e14b4 [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 Halcrow565d9722006-10-30 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 Halcrow565d9722006-10-30 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 Halcrow565d9722006-10-30 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 Halcrow565d9722006-10-30 22:07:17 -0800114 "allocate crypto context; rc = [%d]\n",
115 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700116 goto out;
117 }
Michael Halcrow565d9722006-10-30 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 Halcrow565d9722006-10-30 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 Halcrow565d9722006-10-30 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
Tyler Hicksb59db432011-11-21 17:31:02 -0600970 * @ecryptfs_inode: The eCryptfs inode
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 */
Tyler Hicksb59db432011-11-21 17:31:02 -0600987int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
Michael Halcrow237fead2006-10-04 02:16:22 -0700988{
Michael Halcrow237fead2006-10-04 02:16:22 -0700989 struct ecryptfs_crypt_stat *crypt_stat =
Tyler Hicksb59db432011-11-21 17:31:02 -0600990 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700991 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
992 &ecryptfs_superblock_to_private(
Tyler Hicksb59db432011-11-21 17:31:02 -0600993 ecryptfs_inode->i_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700994 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/**
Tyler Hicks7a866172011-05-02 00:39:54 -05001027 * ecryptfs_validate_marker - check for the ecryptfs marker
Michael Halcrow237fead2006-10-04 02:16:22 -07001028 * @data: The data block in which to check
1029 *
Tyler Hicks7a866172011-05-02 00:39:54 -05001030 * Returns zero if marker found; -EINVAL if not found
Michael Halcrow237fead2006-10-04 02:16:22 -07001031 */
Tyler Hicks7a866172011-05-02 00:39:54 -05001032static int ecryptfs_validate_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)
Tyler Hicks7a866172011-05-02 00:39:54 -05001039 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001040 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));
Tyler Hicks7a866172011-05-02 00:39:54 -05001045 return -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001046}
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
Tyler Hicks778aeb42011-05-24 04:56:23 -05001204int ecryptfs_read_and_validate_header_region(struct inode *inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001205{
Tyler Hicks778aeb42011-05-24 04:56:23 -05001206 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1207 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001208 int rc;
1209
Tyler Hicks778aeb42011-05-24 04:56:23 -05001210 rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
1211 inode);
1212 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1213 return rc >= 0 ? -EINVAL : rc;
1214 rc = ecryptfs_validate_marker(marker);
1215 if (!rc)
1216 ecryptfs_i_size_init(file_size, inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001217 return rc;
1218}
1219
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001220void
1221ecryptfs_write_header_metadata(char *virt,
1222 struct ecryptfs_crypt_stat *crypt_stat,
1223 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001224{
1225 u32 header_extent_size;
1226 u16 num_header_extents_at_front;
1227
Michael Halcrow45eaab72007-10-16 01:28:05 -07001228 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001229 num_header_extents_at_front =
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001230 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
Harvey Harrison29335c62008-07-23 21:30:06 -07001231 put_unaligned_be32(header_extent_size, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001232 virt += 4;
Harvey Harrison29335c62008-07-23 21:30:06 -07001233 put_unaligned_be16(num_header_extents_at_front, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001234 (*written) = 6;
1235}
1236
Tyler Hicks30632872011-05-24 05:11:12 -05001237struct kmem_cache *ecryptfs_header_cache;
Michael Halcrow237fead2006-10-04 02:16:22 -07001238
1239/**
1240 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001241 * @page_virt: The virtual address to write the headers to
Eric Sandeen87b811c2008-10-29 14:01:08 -07001242 * @max: The size of memory allocated at page_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001243 * @size: Set to the number of bytes written by this function
1244 * @crypt_stat: The cryptographic context
1245 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001246 *
1247 * Format version: 1
1248 *
1249 * Header Extent:
1250 * Octets 0-7: Unencrypted file size (big-endian)
1251 * Octets 8-15: eCryptfs special marker
1252 * Octets 16-19: Flags
1253 * Octet 16: File format version number (between 0 and 255)
1254 * Octets 17-18: Reserved
1255 * Octet 19: Bit 1 (lsb): Reserved
1256 * Bit 2: Encrypted?
1257 * Bits 3-8: Reserved
1258 * Octets 20-23: Header extent size (big-endian)
1259 * Octets 24-25: Number of header extents at front of file
1260 * (big-endian)
1261 * Octet 26: Begin RFC 2440 authentication token packet set
1262 * Data Extent 0:
1263 * Lower data (CBC encrypted)
1264 * Data Extent 1:
1265 * Lower data (CBC encrypted)
1266 * ...
1267 *
1268 * Returns zero on success
1269 */
Eric Sandeen87b811c2008-10-29 14:01:08 -07001270static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1271 size_t *size,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001272 struct ecryptfs_crypt_stat *crypt_stat,
1273 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001274{
1275 int rc;
1276 size_t written;
1277 size_t offset;
1278
1279 offset = ECRYPTFS_FILE_SIZE_BYTES;
1280 write_ecryptfs_marker((page_virt + offset), &written);
1281 offset += written;
Tyler Hicksf4e60e62010-02-11 00:02:32 -06001282 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1283 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001284 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001285 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1286 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001287 offset += written;
1288 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1289 ecryptfs_dentry, &written,
Eric Sandeen87b811c2008-10-29 14:01:08 -07001290 max - offset);
Michael Halcrow237fead2006-10-04 02:16:22 -07001291 if (rc)
1292 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1293 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001294 if (size) {
1295 offset += written;
1296 *size = offset;
1297 }
1298 return rc;
1299}
1300
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001301static int
Tyler Hicksb59db432011-11-21 17:31:02 -06001302ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
Tyler Hicks8faece52009-03-20 01:25:09 -05001303 char *virt, size_t virt_len)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001304{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001305 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001306
Tyler Hicksb59db432011-11-21 17:31:02 -06001307 rc = ecryptfs_write_lower(ecryptfs_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001308 0, virt_len);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001309 if (rc < 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001310 printk(KERN_ERR "%s: Error attempting to write header "
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001311 "information to lower file; rc = [%d]\n", __func__, rc);
1312 else
1313 rc = 0;
Michael Halcrow70456602007-02-12 00:53:48 -08001314 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001315}
1316
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001317static int
1318ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001319 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001320{
1321 int rc;
1322
1323 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1324 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001325 return rc;
1326}
1327
Tyler Hicks8faece52009-03-20 01:25:09 -05001328static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1329 unsigned int order)
1330{
1331 struct page *page;
1332
1333 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1334 if (page)
1335 return (unsigned long) page_address(page);
1336 return 0;
1337}
1338
Michael Halcrow237fead2006-10-04 02:16:22 -07001339/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001340 * ecryptfs_write_metadata
Tyler Hicksb59db432011-11-21 17:31:02 -06001341 * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1342 * @ecryptfs_inode: The newly created eCryptfs inode
Michael Halcrow237fead2006-10-04 02:16:22 -07001343 *
1344 * Write the file headers out. This will likely involve a userspace
1345 * callout, in which the session key is encrypted with one or more
1346 * public keys and/or the passphrase necessary to do the encryption is
1347 * retrieved via a prompt. Exactly what happens at this point should
1348 * be policy-dependent.
1349 *
1350 * Returns zero on success; non-zero on error
1351 */
Tyler Hicksb59db432011-11-21 17:31:02 -06001352int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1353 struct inode *ecryptfs_inode)
Michael Halcrow237fead2006-10-04 02:16:22 -07001354{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001355 struct ecryptfs_crypt_stat *crypt_stat =
Tyler Hicksb59db432011-11-21 17:31:02 -06001356 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Tyler Hicks8faece52009-03-20 01:25:09 -05001357 unsigned int order;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001358 char *virt;
Tyler Hicks8faece52009-03-20 01:25:09 -05001359 size_t virt_len;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001360 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001361 int rc = 0;
1362
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001363 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1364 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001365 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001366 rc = -EINVAL;
1367 goto out;
1368 }
1369 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001370 printk(KERN_WARNING "%s: Encrypted flag not set\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001371 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001372 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001373 goto out;
1374 }
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001375 virt_len = crypt_stat->metadata_size;
Tyler Hicks8faece52009-03-20 01:25:09 -05001376 order = get_order(virt_len);
Michael Halcrow237fead2006-10-04 02:16:22 -07001377 /* Released in this function */
Tyler Hicks8faece52009-03-20 01:25:09 -05001378 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001379 if (!virt) {
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001380 printk(KERN_ERR "%s: Out of memory\n", __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001381 rc = -ENOMEM;
1382 goto out;
1383 }
Tyler Hicksbd4f0fe2011-02-23 00:14:19 -06001384 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
Tyler Hicks8faece52009-03-20 01:25:09 -05001385 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1386 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001387 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001388 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001389 __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001390 goto out_free;
1391 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001392 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicks8faece52009-03-20 01:25:09 -05001393 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1394 size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001395 else
Tyler Hicksb59db432011-11-21 17:31:02 -06001396 rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001397 virt_len);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001398 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001399 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001400 "rc = [%d]\n", __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001401 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001402 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001403out_free:
Tyler Hicks8faece52009-03-20 01:25:09 -05001404 free_pages((unsigned long)virt, order);
Michael Halcrow237fead2006-10-04 02:16:22 -07001405out:
1406 return rc;
1407}
1408
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001409#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1410#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001411static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001412 char *virt, int *bytes_read,
1413 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001414{
1415 int rc = 0;
1416 u32 header_extent_size;
1417 u16 num_header_extents_at_front;
1418
Harvey Harrison29335c62008-07-23 21:30:06 -07001419 header_extent_size = get_unaligned_be32(virt);
1420 virt += sizeof(__be32);
1421 num_header_extents_at_front = get_unaligned_be16(virt);
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001422 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1423 * (size_t)header_extent_size));
Harvey Harrison29335c62008-07-23 21:30:06 -07001424 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001425 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001426 && (crypt_stat->metadata_size
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001427 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001428 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001429 printk(KERN_WARNING "Invalid header size: [%zd]\n",
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001430 crypt_stat->metadata_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001431 }
1432 return rc;
1433}
1434
1435/**
1436 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001437 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001438 *
1439 * For version 0 file format; this function is only for backwards
1440 * compatibility for files created with the prior versions of
1441 * eCryptfs.
1442 */
1443static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1444{
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001445 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001446}
1447
Tyler Hicks3aeb86e2011-03-15 14:54:00 -05001448void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1449{
1450 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1451 struct ecryptfs_crypt_stat *crypt_stat;
1452 u64 file_size;
1453
1454 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1455 mount_crypt_stat =
1456 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1457 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1458 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1459 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1460 file_size += crypt_stat->metadata_size;
1461 } else
1462 file_size = get_unaligned_be64(page_virt);
1463 i_size_write(inode, (loff_t)file_size);
1464 crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1465}
1466
Michael Halcrow237fead2006-10-04 02:16:22 -07001467/**
1468 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001469 * @page_virt: The virtual address into which to read the headers
1470 * @crypt_stat: The cryptographic context
1471 * @ecryptfs_dentry: The eCryptfs dentry
1472 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001473 *
1474 * Read/parse the header data. The header format is detailed in the
1475 * comment block for the ecryptfs_write_headers_virt() function.
1476 *
1477 * Returns zero on success
1478 */
1479static int ecryptfs_read_headers_virt(char *page_virt,
1480 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001481 struct dentry *ecryptfs_dentry,
1482 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001483{
1484 int rc = 0;
1485 int offset;
1486 int bytes_read;
1487
1488 ecryptfs_set_default_sizes(crypt_stat);
1489 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1490 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1491 offset = ECRYPTFS_FILE_SIZE_BYTES;
Tyler Hicks7a866172011-05-02 00:39:54 -05001492 rc = ecryptfs_validate_marker(page_virt + offset);
1493 if (rc)
Michael Halcrow237fead2006-10-04 02:16:22 -07001494 goto out;
Tyler Hicks3aeb86e2011-03-15 14:54:00 -05001495 if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1496 ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -07001497 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1498 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1499 &bytes_read);
1500 if (rc) {
1501 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1502 goto out;
1503 }
1504 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1505 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1506 "file version [%d] is supported by this "
1507 "version of eCryptfs\n",
1508 crypt_stat->file_version,
1509 ECRYPTFS_SUPPORTED_FILE_VERSION);
1510 rc = -EINVAL;
1511 goto out;
1512 }
1513 offset += bytes_read;
1514 if (crypt_stat->file_version >= 1) {
1515 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001516 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001517 if (rc) {
1518 ecryptfs_printk(KERN_WARNING, "Error reading header "
1519 "metadata; rc = [%d]\n", rc);
1520 }
1521 offset += bytes_read;
1522 } else
1523 set_default_header_data(crypt_stat);
1524 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1525 ecryptfs_dentry);
1526out:
1527 return rc;
1528}
1529
1530/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001531 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001532 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001533 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001534 *
1535 * Attempts to read the crypto metadata from the extended attribute
1536 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001537 *
1538 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001539 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001540int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001541{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001542 struct dentry *lower_dentry =
1543 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001544 ssize_t size;
1545 int rc = 0;
1546
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001547 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1548 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001549 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001550 if (unlikely(ecryptfs_verbosity > 0))
1551 printk(KERN_INFO "Error attempting to read the [%s] "
1552 "xattr from the lower file; return value = "
1553 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001554 rc = -EINVAL;
1555 goto out;
1556 }
1557out:
1558 return rc;
1559}
1560
Tyler Hicks778aeb42011-05-24 04:56:23 -05001561int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
Tyler Hicks3b06b3e2011-05-24 03:49:02 -05001562 struct inode *inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001563{
Tyler Hicks778aeb42011-05-24 04:56:23 -05001564 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1565 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001566 int rc;
1567
Tyler Hicks778aeb42011-05-24 04:56:23 -05001568 rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1569 ECRYPTFS_XATTR_NAME, file_size,
1570 ECRYPTFS_SIZE_AND_MARKER_BYTES);
1571 if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1572 return rc >= 0 ? -EINVAL : rc;
1573 rc = ecryptfs_validate_marker(marker);
1574 if (!rc)
1575 ecryptfs_i_size_init(file_size, inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001576 return rc;
1577}
1578
1579/**
1580 * ecryptfs_read_metadata
1581 *
1582 * Common entry point for reading file metadata. From here, we could
1583 * retrieve the header information from the header region of the file,
1584 * the xattr region of the file, or some other repostory that is
1585 * stored separately from the file itself. The current implementation
1586 * supports retrieving the metadata information from the file contents
1587 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001588 *
1589 * Returns zero if valid headers found and parsed; non-zero otherwise
1590 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001591int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001592{
1593 int rc = 0;
1594 char *page_virt = NULL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001595 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -07001596 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001597 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001598 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1599 &ecryptfs_superblock_to_private(
1600 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001601
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001602 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1603 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001604 /* Read the first page from the underlying file */
Tyler Hicks30632872011-05-24 05:11:12 -05001605 page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001606 if (!page_virt) {
1607 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001608 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001609 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001610 goto out;
1611 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001612 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1613 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001614 if (rc >= 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001615 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1616 ecryptfs_dentry,
1617 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001618 if (rc) {
Tyler Hicks1984c232010-02-10 23:17:44 -06001619 memset(page_virt, 0, PAGE_CACHE_SIZE);
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001620 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001621 if (rc) {
1622 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1623 "file header region or xattr region\n");
1624 rc = -EINVAL;
1625 goto out;
1626 }
1627 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1628 ecryptfs_dentry,
1629 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1630 if (rc) {
1631 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1632 "file xattr region either\n");
1633 rc = -EINVAL;
1634 }
1635 if (crypt_stat->mount_crypt_stat->flags
1636 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1637 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1638 } else {
1639 printk(KERN_WARNING "Attempt to access file with "
1640 "crypto metadata only in the extended attribute "
1641 "region, but eCryptfs was mounted without "
1642 "xattr support enabled. eCryptfs will not treat "
1643 "this like an encrypted file.\n");
1644 rc = -EINVAL;
1645 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001646 }
1647out:
1648 if (page_virt) {
1649 memset(page_virt, 0, PAGE_CACHE_SIZE);
Tyler Hicks30632872011-05-24 05:11:12 -05001650 kmem_cache_free(ecryptfs_header_cache, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001651 }
1652 return rc;
1653}
1654
1655/**
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001656 * ecryptfs_encrypt_filename - encrypt filename
1657 *
1658 * CBC-encrypts the filename. We do not want to encrypt the same
1659 * filename with the same key and IV, which may happen with hard
1660 * links, so we prepend random bits to each filename.
1661 *
1662 * Returns zero on success; non-zero otherwise
1663 */
1664static int
1665ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1666 struct ecryptfs_crypt_stat *crypt_stat,
1667 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1668{
1669 int rc = 0;
1670
1671 filename->encrypted_filename = NULL;
1672 filename->encrypted_filename_size = 0;
1673 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1674 || (mount_crypt_stat && (mount_crypt_stat->flags
1675 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1676 size_t packet_size;
1677 size_t remaining_bytes;
1678
1679 rc = ecryptfs_write_tag_70_packet(
1680 NULL, NULL,
1681 &filename->encrypted_filename_size,
1682 mount_crypt_stat, NULL,
1683 filename->filename_size);
1684 if (rc) {
1685 printk(KERN_ERR "%s: Error attempting to get packet "
1686 "size for tag 72; rc = [%d]\n", __func__,
1687 rc);
1688 filename->encrypted_filename_size = 0;
1689 goto out;
1690 }
1691 filename->encrypted_filename =
1692 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1693 if (!filename->encrypted_filename) {
1694 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08001695 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001696 filename->encrypted_filename_size);
1697 rc = -ENOMEM;
1698 goto out;
1699 }
1700 remaining_bytes = filename->encrypted_filename_size;
1701 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1702 &remaining_bytes,
1703 &packet_size,
1704 mount_crypt_stat,
1705 filename->filename,
1706 filename->filename_size);
1707 if (rc) {
1708 printk(KERN_ERR "%s: Error attempting to generate "
1709 "tag 70 packet; rc = [%d]\n", __func__,
1710 rc);
1711 kfree(filename->encrypted_filename);
1712 filename->encrypted_filename = NULL;
1713 filename->encrypted_filename_size = 0;
1714 goto out;
1715 }
1716 filename->encrypted_filename_size = packet_size;
1717 } else {
1718 printk(KERN_ERR "%s: No support for requested filename "
1719 "encryption method in this release\n", __func__);
Tyler Hicksdf6ad332009-08-21 04:27:46 -05001720 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001721 goto out;
1722 }
1723out:
1724 return rc;
1725}
1726
1727static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1728 const char *name, size_t name_size)
1729{
1730 int rc = 0;
1731
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001732 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001733 if (!(*copied_name)) {
1734 rc = -ENOMEM;
1735 goto out;
1736 }
1737 memcpy((void *)(*copied_name), (void *)name, name_size);
1738 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1739 * in printing out the
1740 * string in debug
1741 * messages */
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001742 (*copied_name_size) = name_size;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001743out:
1744 return rc;
1745}
1746
1747/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001748 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001749 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001750 * @cipher_name: Name of the cipher
1751 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001752 *
1753 * Returns zero on success. Any crypto_tfm structs allocated here
1754 * should be released by other functions, such as on a superblock put
1755 * event, regardless of whether this function succeeds for fails.
1756 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001757static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001758ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1759 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001760{
1761 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Dan Carpenterece550f2010-01-19 12:34:32 +03001762 char *full_alg_name = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001763 int rc;
1764
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001765 *key_tfm = NULL;
1766 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001767 rc = -EINVAL;
Michael Halcrowdf261c52009-01-06 14:42:02 -08001768 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001769 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001770 goto out;
1771 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001772 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1773 "ecb");
1774 if (rc)
1775 goto out;
1776 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001777 if (IS_ERR(*key_tfm)) {
1778 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001779 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Dave Hansen38268492009-08-27 09:47:07 -07001780 "[%s]; rc = [%d]\n", full_alg_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001781 goto out;
1782 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001783 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1784 if (*key_size == 0) {
1785 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1786
1787 *key_size = alg->max_keysize;
1788 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001789 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001790 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001791 if (rc) {
Michael Halcrowdf261c52009-01-06 14:42:02 -08001792 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
Dave Hansen38268492009-08-27 09:47:07 -07001793 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1794 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001795 rc = -EINVAL;
1796 goto out;
1797 }
1798out:
Dan Carpenterece550f2010-01-19 12:34:32 +03001799 kfree(full_alg_name);
Michael Halcrow237fead2006-10-04 02:16:22 -07001800 return rc;
1801}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001802
1803struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001804static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001805struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001806
Jerome Marchand7371a382010-08-17 17:24:05 +02001807int __init ecryptfs_init_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001808{
1809 mutex_init(&key_tfm_list_mutex);
1810 INIT_LIST_HEAD(&key_tfm_list);
1811 return 0;
1812}
1813
Eric Sandeenaf440f52008-02-06 01:38:37 -08001814/**
1815 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1816 *
1817 * Called only at module unload time
1818 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001819int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001820{
1821 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1822
1823 mutex_lock(&key_tfm_list_mutex);
1824 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1825 key_tfm_list) {
1826 list_del(&key_tfm->key_tfm_list);
1827 if (key_tfm->key_tfm)
1828 crypto_free_blkcipher(key_tfm->key_tfm);
1829 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1830 }
1831 mutex_unlock(&key_tfm_list_mutex);
1832 return 0;
1833}
1834
1835int
1836ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1837 size_t key_size)
1838{
1839 struct ecryptfs_key_tfm *tmp_tfm;
1840 int rc = 0;
1841
Eric Sandeenaf440f52008-02-06 01:38:37 -08001842 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1843
Michael Halcrowf4aad162007-10-16 01:27:53 -07001844 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1845 if (key_tfm != NULL)
1846 (*key_tfm) = tmp_tfm;
1847 if (!tmp_tfm) {
1848 rc = -ENOMEM;
1849 printk(KERN_ERR "Error attempting to allocate from "
1850 "ecryptfs_key_tfm_cache\n");
1851 goto out;
1852 }
1853 mutex_init(&tmp_tfm->key_tfm_mutex);
1854 strncpy(tmp_tfm->cipher_name, cipher_name,
1855 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001856 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001857 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001858 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1859 tmp_tfm->cipher_name,
1860 &tmp_tfm->key_size);
1861 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001862 printk(KERN_ERR "Error attempting to initialize key TFM "
1863 "cipher with name = [%s]; rc = [%d]\n",
1864 tmp_tfm->cipher_name, rc);
1865 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1866 if (key_tfm != NULL)
1867 (*key_tfm) = NULL;
1868 goto out;
1869 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001870 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001871out:
1872 return rc;
1873}
1874
Eric Sandeenaf440f52008-02-06 01:38:37 -08001875/**
1876 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1877 * @cipher_name: the name of the cipher to search for
1878 * @key_tfm: set to corresponding tfm if found
1879 *
1880 * Searches for cached key_tfm matching @cipher_name
1881 * Must be called with &key_tfm_list_mutex held
1882 * Returns 1 if found, with @key_tfm set
1883 * Returns 0 if not found, with @key_tfm set to NULL
1884 */
1885int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1886{
1887 struct ecryptfs_key_tfm *tmp_key_tfm;
1888
1889 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1890
1891 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1892 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1893 if (key_tfm)
1894 (*key_tfm) = tmp_key_tfm;
1895 return 1;
1896 }
1897 }
1898 if (key_tfm)
1899 (*key_tfm) = NULL;
1900 return 0;
1901}
1902
1903/**
1904 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1905 *
1906 * @tfm: set to cached tfm found, or new tfm created
1907 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1908 * @cipher_name: the name of the cipher to search for and/or add
1909 *
1910 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1911 * Searches for cached item first, and creates new if not found.
1912 * Returns 0 on success, non-zero if adding new cipher failed
1913 */
Michael Halcrowf4aad162007-10-16 01:27:53 -07001914int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1915 struct mutex **tfm_mutex,
1916 char *cipher_name)
1917{
1918 struct ecryptfs_key_tfm *key_tfm;
1919 int rc = 0;
1920
1921 (*tfm) = NULL;
1922 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001923
Michael Halcrowf4aad162007-10-16 01:27:53 -07001924 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001925 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1926 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1927 if (rc) {
1928 printk(KERN_ERR "Error adding new key_tfm to list; "
1929 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001930 goto out;
1931 }
1932 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001933 (*tfm) = key_tfm->key_tfm;
1934 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1935out:
Cyrill Gorcunov71fd5172008-05-23 13:04:20 -07001936 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001937 return rc;
1938}
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001939
1940/* 64 characters forming a 6-bit target field */
1941static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1942 "EFGHIJKLMNOPQRST"
1943 "UVWXYZabcdefghij"
1944 "klmnopqrstuvwxyz");
1945
1946/* We could either offset on every reverse map or just pad some 0x00's
1947 * at the front here */
Tyler Hicks0f751e62011-11-23 11:31:24 -06001948static const unsigned char filename_rev_map[256] = {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001949 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1950 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1951 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1952 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1953 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1954 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1955 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1956 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1957 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1958 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1959 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1960 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1961 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1962 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1963 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
Tyler Hicks0f751e62011-11-23 11:31:24 -06001964 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001965};
1966
1967/**
1968 * ecryptfs_encode_for_filename
1969 * @dst: Destination location for encoded filename
1970 * @dst_size: Size of the encoded filename in bytes
1971 * @src: Source location for the filename to encode
1972 * @src_size: Size of the source in bytes
1973 */
1974void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1975 unsigned char *src, size_t src_size)
1976{
1977 size_t num_blocks;
1978 size_t block_num = 0;
1979 size_t dst_offset = 0;
1980 unsigned char last_block[3];
1981
1982 if (src_size == 0) {
1983 (*dst_size) = 0;
1984 goto out;
1985 }
1986 num_blocks = (src_size / 3);
1987 if ((src_size % 3) == 0) {
1988 memcpy(last_block, (&src[src_size - 3]), 3);
1989 } else {
1990 num_blocks++;
1991 last_block[2] = 0x00;
1992 switch (src_size % 3) {
1993 case 1:
1994 last_block[0] = src[src_size - 1];
1995 last_block[1] = 0x00;
1996 break;
1997 case 2:
1998 last_block[0] = src[src_size - 2];
1999 last_block[1] = src[src_size - 1];
2000 }
2001 }
2002 (*dst_size) = (num_blocks * 4);
2003 if (!dst)
2004 goto out;
2005 while (block_num < num_blocks) {
2006 unsigned char *src_block;
2007 unsigned char dst_block[4];
2008
2009 if (block_num == (num_blocks - 1))
2010 src_block = last_block;
2011 else
2012 src_block = &src[block_num * 3];
2013 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2014 dst_block[1] = (((src_block[0] << 4) & 0x30)
2015 | ((src_block[1] >> 4) & 0x0F));
2016 dst_block[2] = (((src_block[1] << 2) & 0x3C)
2017 | ((src_block[2] >> 6) & 0x03));
2018 dst_block[3] = (src_block[2] & 0x3F);
2019 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2020 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2021 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2022 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2023 block_num++;
2024 }
2025out:
2026 return;
2027}
2028
Michael Halcrow71c11c32009-01-06 14:42:05 -08002029/**
2030 * ecryptfs_decode_from_filename
2031 * @dst: If NULL, this function only sets @dst_size and returns. If
2032 * non-NULL, this function decodes the encoded octets in @src
2033 * into the memory that @dst points to.
2034 * @dst_size: Set to the size of the decoded string.
2035 * @src: The encoded set of octets to decode.
2036 * @src_size: The size of the encoded set of octets to decode.
2037 */
2038static void
2039ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2040 const unsigned char *src, size_t src_size)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002041{
2042 u8 current_bit_offset = 0;
2043 size_t src_byte_offset = 0;
2044 size_t dst_byte_offset = 0;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002045
2046 if (dst == NULL) {
Michael Halcrow71c11c32009-01-06 14:42:05 -08002047 /* Not exact; conservatively long. Every block of 4
2048 * encoded characters decodes into a block of 3
2049 * decoded characters. This segment of code provides
2050 * the caller with the maximum amount of allocated
2051 * space that @dst will need to point to in a
2052 * subsequent call. */
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002053 (*dst_size) = (((src_size + 1) * 3) / 4);
2054 goto out;
2055 }
2056 while (src_byte_offset < src_size) {
2057 unsigned char src_byte =
2058 filename_rev_map[(int)src[src_byte_offset]];
2059
2060 switch (current_bit_offset) {
2061 case 0:
2062 dst[dst_byte_offset] = (src_byte << 2);
2063 current_bit_offset = 6;
2064 break;
2065 case 6:
2066 dst[dst_byte_offset++] |= (src_byte >> 4);
2067 dst[dst_byte_offset] = ((src_byte & 0xF)
2068 << 4);
2069 current_bit_offset = 4;
2070 break;
2071 case 4:
2072 dst[dst_byte_offset++] |= (src_byte >> 2);
2073 dst[dst_byte_offset] = (src_byte << 6);
2074 current_bit_offset = 2;
2075 break;
2076 case 2:
2077 dst[dst_byte_offset++] |= (src_byte);
2078 dst[dst_byte_offset] = 0;
2079 current_bit_offset = 0;
2080 break;
2081 }
2082 src_byte_offset++;
2083 }
2084 (*dst_size) = dst_byte_offset;
2085out:
Michael Halcrow71c11c32009-01-06 14:42:05 -08002086 return;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002087}
2088
2089/**
2090 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2091 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2092 * @name: The plaintext name
2093 * @length: The length of the plaintext
2094 * @encoded_name: The encypted name
2095 *
2096 * Encrypts and encodes a filename into something that constitutes a
2097 * valid filename for a filesystem, with printable characters.
2098 *
2099 * We assume that we have a properly initialized crypto context,
2100 * pointed to by crypt_stat->tfm.
2101 *
2102 * Returns zero on success; non-zero on otherwise
2103 */
2104int ecryptfs_encrypt_and_encode_filename(
2105 char **encoded_name,
2106 size_t *encoded_name_size,
2107 struct ecryptfs_crypt_stat *crypt_stat,
2108 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2109 const char *name, size_t name_size)
2110{
2111 size_t encoded_name_no_prefix_size;
2112 int rc = 0;
2113
2114 (*encoded_name) = NULL;
2115 (*encoded_name_size) = 0;
2116 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2117 || (mount_crypt_stat && (mount_crypt_stat->flags
2118 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2119 struct ecryptfs_filename *filename;
2120
2121 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2122 if (!filename) {
2123 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002124 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002125 sizeof(*filename));
2126 rc = -ENOMEM;
2127 goto out;
2128 }
2129 filename->filename = (char *)name;
2130 filename->filename_size = name_size;
2131 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2132 mount_crypt_stat);
2133 if (rc) {
2134 printk(KERN_ERR "%s: Error attempting to encrypt "
2135 "filename; rc = [%d]\n", __func__, rc);
2136 kfree(filename);
2137 goto out;
2138 }
2139 ecryptfs_encode_for_filename(
2140 NULL, &encoded_name_no_prefix_size,
2141 filename->encrypted_filename,
2142 filename->encrypted_filename_size);
2143 if ((crypt_stat && (crypt_stat->flags
2144 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2145 || (mount_crypt_stat
2146 && (mount_crypt_stat->flags
2147 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2148 (*encoded_name_size) =
2149 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2150 + encoded_name_no_prefix_size);
2151 else
2152 (*encoded_name_size) =
2153 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2154 + encoded_name_no_prefix_size);
2155 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2156 if (!(*encoded_name)) {
2157 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002158 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002159 (*encoded_name_size));
2160 rc = -ENOMEM;
2161 kfree(filename->encrypted_filename);
2162 kfree(filename);
2163 goto out;
2164 }
2165 if ((crypt_stat && (crypt_stat->flags
2166 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2167 || (mount_crypt_stat
2168 && (mount_crypt_stat->flags
2169 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2170 memcpy((*encoded_name),
2171 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2172 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2173 ecryptfs_encode_for_filename(
2174 ((*encoded_name)
2175 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2176 &encoded_name_no_prefix_size,
2177 filename->encrypted_filename,
2178 filename->encrypted_filename_size);
2179 (*encoded_name_size) =
2180 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2181 + encoded_name_no_prefix_size);
2182 (*encoded_name)[(*encoded_name_size)] = '\0';
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002183 } else {
Tyler Hicksdf6ad332009-08-21 04:27:46 -05002184 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002185 }
2186 if (rc) {
2187 printk(KERN_ERR "%s: Error attempting to encode "
2188 "encrypted filename; rc = [%d]\n", __func__,
2189 rc);
2190 kfree((*encoded_name));
2191 (*encoded_name) = NULL;
2192 (*encoded_name_size) = 0;
2193 }
2194 kfree(filename->encrypted_filename);
2195 kfree(filename);
2196 } else {
2197 rc = ecryptfs_copy_filename(encoded_name,
2198 encoded_name_size,
2199 name, name_size);
2200 }
2201out:
2202 return rc;
2203}
2204
2205/**
2206 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2207 * @plaintext_name: The plaintext name
2208 * @plaintext_name_size: The plaintext name size
2209 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2210 * @name: The filename in cipher text
2211 * @name_size: The cipher text name size
2212 *
2213 * Decrypts and decodes the filename.
2214 *
2215 * Returns zero on error; non-zero otherwise
2216 */
2217int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2218 size_t *plaintext_name_size,
2219 struct dentry *ecryptfs_dir_dentry,
2220 const char *name, size_t name_size)
2221{
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002222 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2223 &ecryptfs_superblock_to_private(
2224 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002225 char *decoded_name;
2226 size_t decoded_name_size;
2227 size_t packet_size;
2228 int rc = 0;
2229
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002230 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2231 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2232 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002233 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2234 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002235 const char *orig_name = name;
2236 size_t orig_name_size = name_size;
2237
2238 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2239 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
Michael Halcrow71c11c32009-01-06 14:42:05 -08002240 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2241 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002242 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2243 if (!decoded_name) {
2244 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08002245 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002246 decoded_name_size);
2247 rc = -ENOMEM;
2248 goto out;
2249 }
Michael Halcrow71c11c32009-01-06 14:42:05 -08002250 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2251 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002252 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2253 plaintext_name_size,
2254 &packet_size,
2255 mount_crypt_stat,
2256 decoded_name,
2257 decoded_name_size);
2258 if (rc) {
2259 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2260 "from filename; copying through filename "
2261 "as-is\n", __func__);
2262 rc = ecryptfs_copy_filename(plaintext_name,
2263 plaintext_name_size,
2264 orig_name, orig_name_size);
2265 goto out_free;
2266 }
2267 } else {
2268 rc = ecryptfs_copy_filename(plaintext_name,
2269 plaintext_name_size,
2270 name, name_size);
2271 goto out;
2272 }
2273out_free:
2274 kfree(decoded_name);
2275out:
2276 return rc;
2277}