blob: bfd8b680e6481a205dd07d89f3ec401e057abf31 [file] [log] [blame]
Michael Halcrow237fead2006-10-04 02:16:22 -07001/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08006 * Copyright (C) 2004-2007 International Business Machines Corp.
Michael Halcrow237fead2006-10-04 02:16:22 -07007 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 * 02111-1307, USA.
24 */
25
26#include <linux/fs.h>
27#include <linux/mount.h>
28#include <linux/pagemap.h>
29#include <linux/random.h>
30#include <linux/compiler.h>
31#include <linux/key.h>
32#include <linux/namei.h>
33#include <linux/crypto.h>
34#include <linux/file.h>
35#include <linux/scatterlist.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090036#include <linux/slab.h>
Harvey Harrison29335c62008-07-23 21:30:06 -070037#include <asm/unaligned.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070038#include "ecryptfs_kernel.h"
39
40static int
41ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
42 struct page *dst_page, int dst_offset,
43 struct page *src_page, int src_offset, int size,
44 unsigned char *iv);
45static int
46ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
47 struct page *dst_page, int dst_offset,
48 struct page *src_page, int src_offset, int size,
49 unsigned char *iv);
50
51/**
52 * ecryptfs_to_hex
53 * @dst: Buffer to take hex character representation of contents of
54 * src; must be at least of size (src_size * 2)
55 * @src: Buffer to be converted to a hex string respresentation
56 * @src_size: number of bytes to convert
57 */
58void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
59{
60 int x;
61
62 for (x = 0; x < src_size; x++)
63 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
64}
65
66/**
67 * ecryptfs_from_hex
68 * @dst: Buffer to take the bytes from src hex; must be at least of
69 * size (src_size / 2)
70 * @src: Buffer to be converted from a hex string respresentation to raw value
71 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
72 */
73void ecryptfs_from_hex(char *dst, char *src, int dst_size)
74{
75 int x;
76 char tmp[3] = { 0, };
77
78 for (x = 0; x < dst_size; x++) {
79 tmp[0] = src[x * 2];
80 tmp[1] = src[x * 2 + 1];
81 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
82 }
83}
84
85/**
86 * ecryptfs_calculate_md5 - calculates the md5 of @src
87 * @dst: Pointer to 16 bytes of allocated memory
88 * @crypt_stat: Pointer to crypt_stat struct for the current inode
89 * @src: Data to be md5'd
90 * @len: Length of @src
91 *
92 * Uses the allocated crypto context that crypt_stat references to
93 * generate the MD5 sum of the contents of src.
94 */
95static int ecryptfs_calculate_md5(char *dst,
96 struct ecryptfs_crypt_stat *crypt_stat,
97 char *src, int len)
98{
Michael Halcrow237fead2006-10-04 02:16:22 -070099 struct scatterlist sg;
Michael Halcrow565d97242006-10-30 22:07:17 -0800100 struct hash_desc desc = {
101 .tfm = crypt_stat->hash_tfm,
102 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
103 };
104 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700105
Michael Halcrow565d97242006-10-30 22:07:17 -0800106 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700107 sg_init_one(&sg, (u8 *)src, len);
Michael Halcrow565d97242006-10-30 22:07:17 -0800108 if (!desc.tfm) {
109 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
110 CRYPTO_ALG_ASYNC);
111 if (IS_ERR(desc.tfm)) {
112 rc = PTR_ERR(desc.tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700113 ecryptfs_printk(KERN_ERR, "Error attempting to "
Michael Halcrow565d97242006-10-30 22:07:17 -0800114 "allocate crypto context; rc = [%d]\n",
115 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700116 goto out;
117 }
Michael Halcrow565d97242006-10-30 22:07:17 -0800118 crypt_stat->hash_tfm = desc.tfm;
Michael Halcrow237fead2006-10-04 02:16:22 -0700119 }
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800120 rc = crypto_hash_init(&desc);
121 if (rc) {
122 printk(KERN_ERR
123 "%s: Error initializing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700124 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800125 goto out;
126 }
127 rc = crypto_hash_update(&desc, &sg, len);
128 if (rc) {
129 printk(KERN_ERR
130 "%s: Error updating crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700131 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800132 goto out;
133 }
134 rc = crypto_hash_final(&desc, dst);
135 if (rc) {
136 printk(KERN_ERR
137 "%s: Error finalizing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700138 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800139 goto out;
140 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700141out:
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800142 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700143 return rc;
144}
145
Michael Halcrowcd9d67d2007-10-16 01:28:04 -0700146static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
147 char *cipher_name,
148 char *chaining_modifier)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800149{
150 int cipher_name_len = strlen(cipher_name);
151 int chaining_modifier_len = strlen(chaining_modifier);
152 int algified_name_len;
153 int rc;
154
155 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
156 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
Michael Halcrow7bd473f2006-11-02 22:06:56 -0800157 if (!(*algified_name)) {
Michael Halcrow8bba0662006-10-30 22:07:18 -0800158 rc = -ENOMEM;
159 goto out;
160 }
161 snprintf((*algified_name), algified_name_len, "%s(%s)",
162 chaining_modifier, cipher_name);
163 rc = 0;
164out:
165 return rc;
166}
167
Michael Halcrow237fead2006-10-04 02:16:22 -0700168/**
169 * ecryptfs_derive_iv
170 * @iv: destination for the derived iv vale
171 * @crypt_stat: Pointer to crypt_stat struct for the current inode
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700172 * @offset: Offset of the extent whose IV we are to derive
Michael Halcrow237fead2006-10-04 02:16:22 -0700173 *
174 * Generate the initialization vector from the given root IV and page
175 * offset.
176 *
177 * Returns zero on success; non-zero on error.
178 */
Michael Halcrowa34f60f2009-01-06 14:41:58 -0800179int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
180 loff_t offset)
Michael Halcrow237fead2006-10-04 02:16:22 -0700181{
182 int rc = 0;
183 char dst[MD5_DIGEST_SIZE];
184 char src[ECRYPTFS_MAX_IV_BYTES + 16];
185
186 if (unlikely(ecryptfs_verbosity > 0)) {
187 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
188 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
189 }
190 /* TODO: It is probably secure to just cast the least
191 * significant bits of the root IV into an unsigned long and
192 * add the offset to that rather than go through all this
193 * hashing business. -Halcrow */
194 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
195 memset((src + crypt_stat->iv_bytes), 0, 16);
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700196 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700197 if (unlikely(ecryptfs_verbosity > 0)) {
198 ecryptfs_printk(KERN_DEBUG, "source:\n");
199 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
200 }
201 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
202 (crypt_stat->iv_bytes + 16));
203 if (rc) {
204 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
205 "MD5 while generating IV for a page\n");
206 goto out;
207 }
208 memcpy(iv, dst, crypt_stat->iv_bytes);
209 if (unlikely(ecryptfs_verbosity > 0)) {
210 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
211 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
212 }
213out:
214 return rc;
215}
216
217/**
218 * ecryptfs_init_crypt_stat
219 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
220 *
221 * Initialize the crypt_stat structure.
222 */
223void
224ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
225{
226 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
Michael Halcrowf4aad162007-10-16 01:27:53 -0700227 INIT_LIST_HEAD(&crypt_stat->keysig_list);
228 mutex_init(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700229 mutex_init(&crypt_stat->cs_mutex);
230 mutex_init(&crypt_stat->cs_tfm_mutex);
Michael Halcrow565d97242006-10-30 22:07:17 -0800231 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800232 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
Michael Halcrow237fead2006-10-04 02:16:22 -0700233}
234
235/**
Michael Halcrowfcd12832007-10-16 01:28:01 -0700236 * ecryptfs_destroy_crypt_stat
Michael Halcrow237fead2006-10-04 02:16:22 -0700237 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
238 *
239 * Releases all memory associated with a crypt_stat struct.
240 */
Michael Halcrowfcd12832007-10-16 01:28:01 -0700241void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -0700242{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700243 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
244
Michael Halcrow237fead2006-10-04 02:16:22 -0700245 if (crypt_stat->tfm)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800246 crypto_free_blkcipher(crypt_stat->tfm);
Michael Halcrow565d97242006-10-30 22:07:17 -0800247 if (crypt_stat->hash_tfm)
248 crypto_free_hash(crypt_stat->hash_tfm);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700249 list_for_each_entry_safe(key_sig, key_sig_tmp,
250 &crypt_stat->keysig_list, crypt_stat_list) {
251 list_del(&key_sig->crypt_stat_list);
252 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
253 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700254 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
255}
256
Michael Halcrowfcd12832007-10-16 01:28:01 -0700257void ecryptfs_destroy_mount_crypt_stat(
Michael Halcrow237fead2006-10-04 02:16:22 -0700258 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
259{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700260 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
261
262 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
263 return;
264 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
265 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
266 &mount_crypt_stat->global_auth_tok_list,
267 mount_crypt_stat_list) {
268 list_del(&auth_tok->mount_crypt_stat_list);
269 mount_crypt_stat->num_global_auth_toks--;
270 if (auth_tok->global_auth_tok_key
271 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
272 key_put(auth_tok->global_auth_tok_key);
273 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
274 }
275 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700276 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
277}
278
279/**
280 * virt_to_scatterlist
281 * @addr: Virtual address
282 * @size: Size of data; should be an even multiple of the block size
283 * @sg: Pointer to scatterlist array; set to NULL to obtain only
284 * the number of scatterlist structs required in array
285 * @sg_size: Max array size
286 *
287 * Fills in a scatterlist array with page references for a passed
288 * virtual address.
289 *
290 * Returns the number of scatterlist structs in array used
291 */
292int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
293 int sg_size)
294{
295 int i = 0;
296 struct page *pg;
297 int offset;
298 int remainder_of_page;
299
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700300 sg_init_table(sg, sg_size);
301
Michael Halcrow237fead2006-10-04 02:16:22 -0700302 while (size > 0 && i < sg_size) {
303 pg = virt_to_page(addr);
304 offset = offset_in_page(addr);
Jens Axboe642f1492007-10-24 11:20:47 +0200305 if (sg)
306 sg_set_page(&sg[i], pg, 0, offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700307 remainder_of_page = PAGE_CACHE_SIZE - offset;
308 if (size >= remainder_of_page) {
309 if (sg)
310 sg[i].length = remainder_of_page;
311 addr += remainder_of_page;
312 size -= remainder_of_page;
313 } else {
314 if (sg)
315 sg[i].length = size;
316 addr += size;
317 size = 0;
318 }
319 i++;
320 }
321 if (size > 0)
322 return -ENOMEM;
323 return i;
324}
325
326/**
327 * encrypt_scatterlist
328 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
329 * @dest_sg: Destination of encrypted data
330 * @src_sg: Data to be encrypted
331 * @size: Length of data to be encrypted
332 * @iv: iv to use during encryption
333 *
334 * Returns the number of bytes encrypted; negative value on error
335 */
336static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
337 struct scatterlist *dest_sg,
338 struct scatterlist *src_sg, int size,
339 unsigned char *iv)
340{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800341 struct blkcipher_desc desc = {
342 .tfm = crypt_stat->tfm,
343 .info = iv,
344 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
345 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700346 int rc = 0;
347
348 BUG_ON(!crypt_stat || !crypt_stat->tfm
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800349 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
Michael Halcrow237fead2006-10-04 02:16:22 -0700350 if (unlikely(ecryptfs_verbosity > 0)) {
Tyler Hicksf24b3882010-11-15 17:36:38 -0600351 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700352 crypt_stat->key_size);
353 ecryptfs_dump_hex(crypt_stat->key,
354 crypt_stat->key_size);
355 }
356 /* Consider doing this once, when the file is opened */
357 mutex_lock(&crypt_stat->cs_tfm_mutex);
Trevor Highland8e3a6f12008-02-06 01:38:33 -0800358 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
359 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
360 crypt_stat->key_size);
361 crypt_stat->flags |= ECRYPTFS_KEY_SET;
362 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700363 if (rc) {
364 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
365 rc);
366 mutex_unlock(&crypt_stat->cs_tfm_mutex);
367 rc = -EINVAL;
368 goto out;
369 }
370 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800371 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700372 mutex_unlock(&crypt_stat->cs_tfm_mutex);
373out:
374 return rc;
375}
376
Michael Halcrow237fead2006-10-04 02:16:22 -0700377/**
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700378 * ecryptfs_lower_offset_for_extent
379 *
380 * Convert an eCryptfs page index into a lower byte offset
381 */
Adrian Bunk7896b632008-02-06 01:38:32 -0800382static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
383 struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700384{
Tyler Hicks157f1072010-02-11 07:10:38 -0600385 (*offset) = ecryptfs_lower_header_size(crypt_stat)
386 + (crypt_stat->extent_size * extent_num);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700387}
388
389/**
390 * ecryptfs_encrypt_extent
391 * @enc_extent_page: Allocated page into which to encrypt the data in
392 * @page
393 * @crypt_stat: crypt_stat containing cryptographic context for the
394 * encryption operation
395 * @page: Page containing plaintext data extent to encrypt
396 * @extent_offset: Page extent offset for use in generating IV
397 *
398 * Encrypts one extent of data.
399 *
400 * Return zero on success; non-zero otherwise
401 */
402static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
403 struct ecryptfs_crypt_stat *crypt_stat,
404 struct page *page,
405 unsigned long extent_offset)
406{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700407 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700408 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
409 int rc;
410
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700411 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700412 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
413 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
414 (extent_base + extent_offset));
415 if (rc) {
Joe Perches888d57b2010-11-10 15:46:16 -0800416 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
417 "extent [0x%.16llx]; rc = [%d]\n",
418 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700419 goto out;
420 }
421 if (unlikely(ecryptfs_verbosity > 0)) {
422 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
423 "with iv:\n");
424 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
425 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
426 "encryption:\n");
427 ecryptfs_dump_hex((char *)
428 (page_address(page)
429 + (extent_offset * crypt_stat->extent_size)),
430 8);
431 }
432 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
433 page, (extent_offset
434 * crypt_stat->extent_size),
435 crypt_stat->extent_size, extent_iv);
436 if (rc < 0) {
437 printk(KERN_ERR "%s: Error attempting to encrypt page with "
438 "page->index = [%ld], extent_offset = [%ld]; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700439 "rc = [%d]\n", __func__, page->index, extent_offset,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700440 rc);
441 goto out;
442 }
443 rc = 0;
444 if (unlikely(ecryptfs_verbosity > 0)) {
Joe Perches888d57b2010-11-10 15:46:16 -0800445 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16llx]; "
446 "rc = [%d]\n",
447 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700448 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
449 "encryption:\n");
450 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
451 }
452out:
453 return rc;
454}
455
456/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700457 * ecryptfs_encrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700458 * @page: Page mapped from the eCryptfs inode for the file; contains
459 * decrypted content that needs to be encrypted (to a temporary
460 * page; not in place) and written out to the lower file
Michael Halcrow237fead2006-10-04 02:16:22 -0700461 *
462 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
463 * that eCryptfs pages may straddle the lower pages -- for instance,
464 * if the file was created on a machine with an 8K page size
465 * (resulting in an 8K header), and then the file is copied onto a
466 * host with a 32K page size, then when reading page 0 of the eCryptfs
467 * file, 24K of page 0 of the lower file will be read and decrypted,
468 * and then 8K of page 1 of the lower file will be read and decrypted.
469 *
Michael Halcrow237fead2006-10-04 02:16:22 -0700470 * Returns zero on success; negative on error
471 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700472int ecryptfs_encrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700473{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700474 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700475 struct ecryptfs_crypt_stat *crypt_stat;
Eric Sandeen7fcba052008-07-28 15:46:39 -0700476 char *enc_extent_virt;
477 struct page *enc_extent_page = NULL;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700478 loff_t extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700479 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700480
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700481 ecryptfs_inode = page->mapping->host;
482 crypt_stat =
483 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500484 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Eric Sandeen7fcba052008-07-28 15:46:39 -0700485 enc_extent_page = alloc_page(GFP_USER);
486 if (!enc_extent_page) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700487 rc = -ENOMEM;
488 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
489 "encrypted extent\n");
490 goto out;
491 }
Eric Sandeen7fcba052008-07-28 15:46:39 -0700492 enc_extent_virt = kmap(enc_extent_page);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700493 for (extent_offset = 0;
494 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
495 extent_offset++) {
496 loff_t offset;
497
498 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
499 extent_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700500 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700501 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700502 "rc = [%d]\n", __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700503 goto out;
504 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700505 ecryptfs_lower_offset_for_extent(
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700506 &offset, ((((loff_t)page->index)
507 * (PAGE_CACHE_SIZE
508 / crypt_stat->extent_size))
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700509 + extent_offset), crypt_stat);
510 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
511 offset, crypt_stat->extent_size);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500512 if (rc < 0) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700513 ecryptfs_printk(KERN_ERR, "Error attempting "
514 "to write lower page; rc = [%d]"
515 "\n", rc);
516 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700517 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700518 }
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500519 rc = 0;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700520out:
Eric Sandeen7fcba052008-07-28 15:46:39 -0700521 if (enc_extent_page) {
522 kunmap(enc_extent_page);
523 __free_page(enc_extent_page);
524 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700525 return rc;
526}
527
528static int ecryptfs_decrypt_extent(struct page *page,
529 struct ecryptfs_crypt_stat *crypt_stat,
530 struct page *enc_extent_page,
531 unsigned long extent_offset)
532{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700533 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700534 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
535 int rc;
536
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700537 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700538 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
539 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
540 (extent_base + extent_offset));
Michael Halcrow237fead2006-10-04 02:16:22 -0700541 if (rc) {
Joe Perches888d57b2010-11-10 15:46:16 -0800542 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
543 "extent [0x%.16llx]; rc = [%d]\n",
544 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700545 goto out;
546 }
547 if (unlikely(ecryptfs_verbosity > 0)) {
548 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
549 "with iv:\n");
550 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
551 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
552 "decryption:\n");
553 ecryptfs_dump_hex((char *)
554 (page_address(enc_extent_page)
555 + (extent_offset * crypt_stat->extent_size)),
556 8);
557 }
558 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
559 (extent_offset
560 * crypt_stat->extent_size),
561 enc_extent_page, 0,
562 crypt_stat->extent_size, extent_iv);
563 if (rc < 0) {
564 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
565 "page->index = [%ld], extent_offset = [%ld]; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700566 "rc = [%d]\n", __func__, page->index, extent_offset,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700567 rc);
568 goto out;
569 }
570 rc = 0;
571 if (unlikely(ecryptfs_verbosity > 0)) {
Joe Perches888d57b2010-11-10 15:46:16 -0800572 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16llx]; "
573 "rc = [%d]\n",
574 (unsigned long long)(extent_base + extent_offset), rc);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700575 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
576 "decryption:\n");
577 ecryptfs_dump_hex((char *)(page_address(page)
578 + (extent_offset
579 * crypt_stat->extent_size)), 8);
Michael Halcrow237fead2006-10-04 02:16:22 -0700580 }
581out:
582 return rc;
583}
584
585/**
586 * ecryptfs_decrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700587 * @page: Page mapped from the eCryptfs inode for the file; data read
588 * and decrypted from the lower file will be written into this
589 * page
Michael Halcrow237fead2006-10-04 02:16:22 -0700590 *
591 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
592 * that eCryptfs pages may straddle the lower pages -- for instance,
593 * if the file was created on a machine with an 8K page size
594 * (resulting in an 8K header), and then the file is copied onto a
595 * host with a 32K page size, then when reading page 0 of the eCryptfs
596 * file, 24K of page 0 of the lower file will be read and decrypted,
597 * and then 8K of page 1 of the lower file will be read and decrypted.
598 *
599 * Returns zero on success; negative on error
600 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700601int ecryptfs_decrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700602{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700603 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700604 struct ecryptfs_crypt_stat *crypt_stat;
Eric Sandeen7fcba052008-07-28 15:46:39 -0700605 char *enc_extent_virt;
606 struct page *enc_extent_page = NULL;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700607 unsigned long extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700608 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700609
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700610 ecryptfs_inode = page->mapping->host;
611 crypt_stat =
612 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500613 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Eric Sandeen7fcba052008-07-28 15:46:39 -0700614 enc_extent_page = alloc_page(GFP_USER);
615 if (!enc_extent_page) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700616 rc = -ENOMEM;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700617 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
618 "encrypted extent\n");
Michael Halcrow16a72c42007-10-16 01:28:14 -0700619 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700620 }
Eric Sandeen7fcba052008-07-28 15:46:39 -0700621 enc_extent_virt = kmap(enc_extent_page);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700622 for (extent_offset = 0;
623 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
624 extent_offset++) {
625 loff_t offset;
626
627 ecryptfs_lower_offset_for_extent(
628 &offset, ((page->index * (PAGE_CACHE_SIZE
629 / crypt_stat->extent_size))
630 + extent_offset), crypt_stat);
631 rc = ecryptfs_read_lower(enc_extent_virt, offset,
632 crypt_stat->extent_size,
633 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500634 if (rc < 0) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700635 ecryptfs_printk(KERN_ERR, "Error attempting "
636 "to read lower page; rc = [%d]"
637 "\n", rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700638 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700639 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700640 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
641 extent_offset);
642 if (rc) {
643 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700644 "rc = [%d]\n", __func__, rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700645 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700646 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700647 }
648out:
Eric Sandeen7fcba052008-07-28 15:46:39 -0700649 if (enc_extent_page) {
650 kunmap(enc_extent_page);
651 __free_page(enc_extent_page);
652 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700653 return rc;
654}
655
656/**
657 * decrypt_scatterlist
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700658 * @crypt_stat: Cryptographic context
659 * @dest_sg: The destination scatterlist to decrypt into
660 * @src_sg: The source scatterlist to decrypt from
661 * @size: The number of bytes to decrypt
662 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700663 *
664 * Returns the number of bytes decrypted; negative value on error
665 */
666static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
667 struct scatterlist *dest_sg,
668 struct scatterlist *src_sg, int size,
669 unsigned char *iv)
670{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800671 struct blkcipher_desc desc = {
672 .tfm = crypt_stat->tfm,
673 .info = iv,
674 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
675 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700676 int rc = 0;
677
678 /* Consider doing this once, when the file is opened */
679 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800680 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
681 crypt_stat->key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700682 if (rc) {
683 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
684 rc);
685 mutex_unlock(&crypt_stat->cs_tfm_mutex);
686 rc = -EINVAL;
687 goto out;
688 }
689 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800690 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700691 mutex_unlock(&crypt_stat->cs_tfm_mutex);
692 if (rc) {
693 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
694 rc);
695 goto out;
696 }
697 rc = size;
698out:
699 return rc;
700}
701
702/**
703 * ecryptfs_encrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700704 * @crypt_stat: The cryptographic context
705 * @dst_page: The page to encrypt into
706 * @dst_offset: The offset in the page to encrypt into
707 * @src_page: The page to encrypt from
708 * @src_offset: The offset in the page to encrypt from
709 * @size: The number of bytes to encrypt
710 * @iv: The initialization vector to use for the encryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700711 *
712 * Returns the number of bytes encrypted
713 */
714static int
715ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
716 struct page *dst_page, int dst_offset,
717 struct page *src_page, int src_offset, int size,
718 unsigned char *iv)
719{
720 struct scatterlist src_sg, dst_sg;
721
Jens Axboe60c74f82007-10-22 19:43:30 +0200722 sg_init_table(&src_sg, 1);
723 sg_init_table(&dst_sg, 1);
724
Jens Axboe642f1492007-10-24 11:20:47 +0200725 sg_set_page(&src_sg, src_page, size, src_offset);
726 sg_set_page(&dst_sg, dst_page, size, dst_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700727 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
728}
729
730/**
731 * ecryptfs_decrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700732 * @crypt_stat: The cryptographic context
733 * @dst_page: The page to decrypt into
734 * @dst_offset: The offset in the page to decrypt into
735 * @src_page: The page to decrypt from
736 * @src_offset: The offset in the page to decrypt from
737 * @size: The number of bytes to decrypt
738 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700739 *
740 * Returns the number of bytes decrypted
741 */
742static int
743ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
744 struct page *dst_page, int dst_offset,
745 struct page *src_page, int src_offset, int size,
746 unsigned char *iv)
747{
748 struct scatterlist src_sg, dst_sg;
749
Jens Axboe60c74f82007-10-22 19:43:30 +0200750 sg_init_table(&src_sg, 1);
Jens Axboe642f1492007-10-24 11:20:47 +0200751 sg_set_page(&src_sg, src_page, size, src_offset);
Jens Axboe60c74f82007-10-22 19:43:30 +0200752
Jens Axboe642f1492007-10-24 11:20:47 +0200753 sg_init_table(&dst_sg, 1);
754 sg_set_page(&dst_sg, dst_page, size, dst_offset);
755
Michael Halcrow237fead2006-10-04 02:16:22 -0700756 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
757}
758
759#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
760
761/**
762 * ecryptfs_init_crypt_ctx
Uwe Kleine-König421f91d2010-06-11 12:17:00 +0200763 * @crypt_stat: Uninitialized crypt stats structure
Michael Halcrow237fead2006-10-04 02:16:22 -0700764 *
765 * Initialize the crypto context.
766 *
767 * TODO: Performance: Keep a cache of initialized cipher contexts;
768 * only init if needed
769 */
770int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
771{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800772 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700773 int rc = -EINVAL;
774
775 if (!crypt_stat->cipher) {
776 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
777 goto out;
778 }
779 ecryptfs_printk(KERN_DEBUG,
780 "Initializing cipher [%s]; strlen = [%d]; "
Tyler Hicksf24b3882010-11-15 17:36:38 -0600781 "key_size_bits = [%zd]\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700782 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
783 crypt_stat->key_size << 3);
784 if (crypt_stat->tfm) {
785 rc = 0;
786 goto out;
787 }
788 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800789 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
790 crypt_stat->cipher, "cbc");
791 if (rc)
Eric Sandeenc8161f62007-12-22 14:03:26 -0800792 goto out_unlock;
Michael Halcrow8bba0662006-10-30 22:07:18 -0800793 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
794 CRYPTO_ALG_ASYNC);
795 kfree(full_alg_name);
Akinobu Mitade887772006-11-28 12:29:49 -0800796 if (IS_ERR(crypt_stat->tfm)) {
797 rc = PTR_ERR(crypt_stat->tfm);
Tyler Hicksb0105ea2009-08-11 00:36:32 -0500798 crypt_stat->tfm = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -0700799 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
800 "Error initializing cipher [%s]\n",
801 crypt_stat->cipher);
Eric Sandeenc8161f62007-12-22 14:03:26 -0800802 goto out_unlock;
Michael Halcrow237fead2006-10-04 02:16:22 -0700803 }
Herbert Xuf1ddcaf2007-01-27 10:05:15 +1100804 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow237fead2006-10-04 02:16:22 -0700805 rc = 0;
Eric Sandeenc8161f62007-12-22 14:03:26 -0800806out_unlock:
807 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700808out:
809 return rc;
810}
811
812static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
813{
814 int extent_size_tmp;
815
816 crypt_stat->extent_mask = 0xFFFFFFFF;
817 crypt_stat->extent_shift = 0;
818 if (crypt_stat->extent_size == 0)
819 return;
820 extent_size_tmp = crypt_stat->extent_size;
821 while ((extent_size_tmp & 0x01) == 0) {
822 extent_size_tmp >>= 1;
823 crypt_stat->extent_mask <<= 1;
824 crypt_stat->extent_shift++;
825 }
826}
827
828void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
829{
830 /* Default values; may be overwritten as we are parsing the
831 * packets. */
832 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
833 set_extent_mask_and_shift(crypt_stat);
834 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800835 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600836 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700837 else {
838 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600839 crypt_stat->metadata_size =
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800840 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700841 else
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600842 crypt_stat->metadata_size = PAGE_CACHE_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700843 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700844}
845
846/**
847 * ecryptfs_compute_root_iv
848 * @crypt_stats
849 *
850 * On error, sets the root IV to all 0's.
851 */
852int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
853{
854 int rc = 0;
855 char dst[MD5_DIGEST_SIZE];
856
857 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
858 BUG_ON(crypt_stat->iv_bytes <= 0);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800859 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700860 rc = -EINVAL;
861 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
862 "cannot generate root IV\n");
863 goto out;
864 }
865 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
866 crypt_stat->key_size);
867 if (rc) {
868 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
869 "MD5 while generating root IV\n");
870 goto out;
871 }
872 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
873out:
874 if (rc) {
875 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800876 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
Michael Halcrow237fead2006-10-04 02:16:22 -0700877 }
878 return rc;
879}
880
881static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
882{
883 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800884 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
Michael Halcrow237fead2006-10-04 02:16:22 -0700885 ecryptfs_compute_root_iv(crypt_stat);
886 if (unlikely(ecryptfs_verbosity > 0)) {
887 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
888 ecryptfs_dump_hex(crypt_stat->key,
889 crypt_stat->key_size);
890 }
891}
892
893/**
Michael Halcrow17398952007-02-12 00:53:45 -0800894 * ecryptfs_copy_mount_wide_flags_to_inode_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700895 * @crypt_stat: The inode's cryptographic context
896 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow17398952007-02-12 00:53:45 -0800897 *
898 * This function propagates the mount-wide flags to individual inode
899 * flags.
900 */
901static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
902 struct ecryptfs_crypt_stat *crypt_stat,
903 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
904{
905 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
906 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
907 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
908 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800909 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
910 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
911 if (mount_crypt_stat->flags
912 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
913 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
914 else if (mount_crypt_stat->flags
915 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
916 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
917 }
Michael Halcrow17398952007-02-12 00:53:45 -0800918}
919
Michael Halcrowf4aad162007-10-16 01:27:53 -0700920static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
921 struct ecryptfs_crypt_stat *crypt_stat,
922 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
923{
924 struct ecryptfs_global_auth_tok *global_auth_tok;
925 int rc = 0;
926
Roland Dreieraa061172009-07-01 15:48:18 -0700927 mutex_lock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700928 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
Roland Dreieraa061172009-07-01 15:48:18 -0700929
Michael Halcrowf4aad162007-10-16 01:27:53 -0700930 list_for_each_entry(global_auth_tok,
931 &mount_crypt_stat->global_auth_tok_list,
932 mount_crypt_stat_list) {
Tyler Hicks84814d62009-03-13 13:51:59 -0700933 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
934 continue;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700935 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
936 if (rc) {
937 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700938 goto out;
939 }
940 }
Roland Dreieraa061172009-07-01 15:48:18 -0700941
Michael Halcrowf4aad162007-10-16 01:27:53 -0700942out:
Roland Dreieraa061172009-07-01 15:48:18 -0700943 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
944 mutex_unlock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700945 return rc;
946}
947
Michael Halcrow17398952007-02-12 00:53:45 -0800948/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700949 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700950 * @crypt_stat: The inode's cryptographic context
951 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700952 *
953 * Default values in the event that policy does not override them.
954 */
955static void ecryptfs_set_default_crypt_stat_vals(
956 struct ecryptfs_crypt_stat *crypt_stat,
957 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
958{
Michael Halcrow17398952007-02-12 00:53:45 -0800959 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
960 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700961 ecryptfs_set_default_sizes(crypt_stat);
962 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
963 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800964 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -0700965 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
966 crypt_stat->mount_crypt_stat = mount_crypt_stat;
967}
968
969/**
970 * ecryptfs_new_file_context
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700971 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -0700972 *
973 * If the crypto context for the file has not yet been established,
974 * this is where we do that. Establishing a new crypto context
975 * involves the following decisions:
976 * - What cipher to use?
977 * - What set of authentication tokens to use?
978 * Here we just worry about getting enough information into the
979 * authentication tokens so that we know that they are available.
980 * We associate the available authentication tokens with the new file
981 * via the set of signatures in the crypt_stat struct. Later, when
982 * the headers are actually written out, we may again defer to
983 * userspace to perform the encryption of the session key; for the
984 * foreseeable future, this will be the case with public key packets.
985 *
986 * Returns zero on success; non-zero otherwise
987 */
Michael Halcrow237fead2006-10-04 02:16:22 -0700988int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
989{
Michael Halcrow237fead2006-10-04 02:16:22 -0700990 struct ecryptfs_crypt_stat *crypt_stat =
991 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
992 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
993 &ecryptfs_superblock_to_private(
994 ecryptfs_dentry->d_sb)->mount_crypt_stat;
995 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700996 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700997
998 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -0700999 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001000 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1001 mount_crypt_stat);
1002 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1003 mount_crypt_stat);
1004 if (rc) {
1005 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1006 "to the inode key sigs; rc = [%d]\n", rc);
1007 goto out;
1008 }
1009 cipher_name_len =
1010 strlen(mount_crypt_stat->global_default_cipher_name);
1011 memcpy(crypt_stat->cipher,
1012 mount_crypt_stat->global_default_cipher_name,
1013 cipher_name_len);
1014 crypt_stat->cipher[cipher_name_len] = '\0';
1015 crypt_stat->key_size =
1016 mount_crypt_stat->global_default_cipher_key_size;
1017 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001018 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1019 if (rc)
1020 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1021 "context for cipher [%s]: rc = [%d]\n",
1022 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001023out:
Michael Halcrow237fead2006-10-04 02:16:22 -07001024 return rc;
1025}
1026
1027/**
1028 * contains_ecryptfs_marker - check for the ecryptfs marker
1029 * @data: The data block in which to check
1030 *
1031 * Returns one if marker found; zero if not found
1032 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001033static int contains_ecryptfs_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -07001034{
1035 u32 m_1, m_2;
1036
Harvey Harrison29335c62008-07-23 21:30:06 -07001037 m_1 = get_unaligned_be32(data);
1038 m_2 = get_unaligned_be32(data + 4);
Michael Halcrow237fead2006-10-04 02:16:22 -07001039 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1040 return 1;
1041 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1042 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1043 MAGIC_ECRYPTFS_MARKER);
1044 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1045 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1046 return 0;
1047}
1048
1049struct ecryptfs_flag_map_elem {
1050 u32 file_flag;
1051 u32 local_flag;
1052};
1053
1054/* Add support for additional flags by adding elements here. */
1055static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1056 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001057 {0x00000002, ECRYPTFS_ENCRYPTED},
Michael Halcrowaddd65ad2009-01-06 14:42:00 -08001058 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1059 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
Michael Halcrow237fead2006-10-04 02:16:22 -07001060};
1061
1062/**
1063 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001064 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001065 * @page_virt: Source data to be parsed
1066 * @bytes_read: Updated with the number of bytes read
1067 *
1068 * Returns zero on success; non-zero if the flag set is invalid
1069 */
1070static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1071 char *page_virt, int *bytes_read)
1072{
1073 int rc = 0;
1074 int i;
1075 u32 flags;
1076
Harvey Harrison29335c62008-07-23 21:30:06 -07001077 flags = get_unaligned_be32(page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001078 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1079 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1080 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001081 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -07001082 } else
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001083 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
Michael Halcrow237fead2006-10-04 02:16:22 -07001084 /* Version is in top 8 bits of the 32-bit flag vector */
1085 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1086 (*bytes_read) = 4;
1087 return rc;
1088}
1089
1090/**
1091 * write_ecryptfs_marker
1092 * @page_virt: The pointer to in a page to begin writing the marker
1093 * @written: Number of bytes written
1094 *
1095 * Marker = 0x3c81b7f5
1096 */
1097static void write_ecryptfs_marker(char *page_virt, size_t *written)
1098{
1099 u32 m_1, m_2;
1100
1101 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1102 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
Harvey Harrison29335c62008-07-23 21:30:06 -07001103 put_unaligned_be32(m_1, page_virt);
1104 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1105 put_unaligned_be32(m_2, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001106 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1107}
1108
Tyler Hicksf4e60e62010-02-11 00:02:32 -06001109void ecryptfs_write_crypt_stat_flags(char *page_virt,
1110 struct ecryptfs_crypt_stat *crypt_stat,
1111 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001112{
1113 u32 flags = 0;
1114 int i;
1115
1116 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1117 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001118 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -07001119 flags |= ecryptfs_flag_map[i].file_flag;
1120 /* Version is in top 8 bits of the 32-bit flag vector */
1121 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
Harvey Harrison29335c62008-07-23 21:30:06 -07001122 put_unaligned_be32(flags, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001123 (*written) = 4;
1124}
1125
1126struct ecryptfs_cipher_code_str_map_elem {
1127 char cipher_str[16];
Trevor Highland19e66a62008-02-06 01:38:36 -08001128 u8 cipher_code;
Michael Halcrow237fead2006-10-04 02:16:22 -07001129};
1130
1131/* Add support for additional ciphers by adding elements here. The
1132 * cipher_code is whatever OpenPGP applicatoins use to identify the
1133 * ciphers. List in order of probability. */
1134static struct ecryptfs_cipher_code_str_map_elem
1135ecryptfs_cipher_code_str_map[] = {
1136 {"aes",RFC2440_CIPHER_AES_128 },
1137 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1138 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1139 {"cast5", RFC2440_CIPHER_CAST_5},
1140 {"twofish", RFC2440_CIPHER_TWOFISH},
1141 {"cast6", RFC2440_CIPHER_CAST_6},
1142 {"aes", RFC2440_CIPHER_AES_192},
1143 {"aes", RFC2440_CIPHER_AES_256}
1144};
1145
1146/**
1147 * ecryptfs_code_for_cipher_string
Michael Halcrow9c79f342009-01-06 14:41:57 -08001148 * @cipher_name: The string alias for the cipher
1149 * @key_bytes: Length of key in bytes; used for AES code selection
Michael Halcrow237fead2006-10-04 02:16:22 -07001150 *
1151 * Returns zero on no match, or the cipher code on match
1152 */
Michael Halcrow9c79f342009-01-06 14:41:57 -08001153u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
Michael Halcrow237fead2006-10-04 02:16:22 -07001154{
1155 int i;
Trevor Highland19e66a62008-02-06 01:38:36 -08001156 u8 code = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001157 struct ecryptfs_cipher_code_str_map_elem *map =
1158 ecryptfs_cipher_code_str_map;
1159
Michael Halcrow9c79f342009-01-06 14:41:57 -08001160 if (strcmp(cipher_name, "aes") == 0) {
1161 switch (key_bytes) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001162 case 16:
1163 code = RFC2440_CIPHER_AES_128;
1164 break;
1165 case 24:
1166 code = RFC2440_CIPHER_AES_192;
1167 break;
1168 case 32:
1169 code = RFC2440_CIPHER_AES_256;
1170 }
1171 } else {
1172 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
Michael Halcrow9c79f342009-01-06 14:41:57 -08001173 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001174 code = map[i].cipher_code;
1175 break;
1176 }
1177 }
1178 return code;
1179}
1180
1181/**
1182 * ecryptfs_cipher_code_to_string
1183 * @str: Destination to write out the cipher name
1184 * @cipher_code: The code to convert to cipher name string
1185 *
1186 * Returns zero on success
1187 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001188int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
Michael Halcrow237fead2006-10-04 02:16:22 -07001189{
1190 int rc = 0;
1191 int i;
1192
1193 str[0] = '\0';
1194 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1195 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1196 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1197 if (str[0] == '\0') {
1198 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1199 "[%d]\n", cipher_code);
1200 rc = -EINVAL;
1201 }
1202 return rc;
1203}
1204
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001205int ecryptfs_read_and_validate_header_region(char *data,
1206 struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001207{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001208 struct ecryptfs_crypt_stat *crypt_stat =
1209 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001210 int rc;
1211
Michael Halcrowaddd65ad2009-01-06 14:42:00 -08001212 if (crypt_stat->extent_size == 0)
1213 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001214 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1215 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001216 if (rc < 0) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001217 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001218 __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001219 goto out;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001220 }
1221 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001222 rc = -EINVAL;
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001223 } else
1224 rc = 0;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001225out:
1226 return rc;
1227}
1228
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001229void
1230ecryptfs_write_header_metadata(char *virt,
1231 struct ecryptfs_crypt_stat *crypt_stat,
1232 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001233{
1234 u32 header_extent_size;
1235 u16 num_header_extents_at_front;
1236
Michael Halcrow45eaab72007-10-16 01:28:05 -07001237 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001238 num_header_extents_at_front =
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001239 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
Harvey Harrison29335c62008-07-23 21:30:06 -07001240 put_unaligned_be32(header_extent_size, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001241 virt += 4;
Harvey Harrison29335c62008-07-23 21:30:06 -07001242 put_unaligned_be16(num_header_extents_at_front, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001243 (*written) = 6;
1244}
1245
Michael Halcrow237fead2006-10-04 02:16:22 -07001246struct kmem_cache *ecryptfs_header_cache_1;
1247struct kmem_cache *ecryptfs_header_cache_2;
1248
1249/**
1250 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001251 * @page_virt: The virtual address to write the headers to
Eric Sandeen87b811c2008-10-29 14:01:08 -07001252 * @max: The size of memory allocated at page_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001253 * @size: Set to the number of bytes written by this function
1254 * @crypt_stat: The cryptographic context
1255 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001256 *
1257 * Format version: 1
1258 *
1259 * Header Extent:
1260 * Octets 0-7: Unencrypted file size (big-endian)
1261 * Octets 8-15: eCryptfs special marker
1262 * Octets 16-19: Flags
1263 * Octet 16: File format version number (between 0 and 255)
1264 * Octets 17-18: Reserved
1265 * Octet 19: Bit 1 (lsb): Reserved
1266 * Bit 2: Encrypted?
1267 * Bits 3-8: Reserved
1268 * Octets 20-23: Header extent size (big-endian)
1269 * Octets 24-25: Number of header extents at front of file
1270 * (big-endian)
1271 * Octet 26: Begin RFC 2440 authentication token packet set
1272 * Data Extent 0:
1273 * Lower data (CBC encrypted)
1274 * Data Extent 1:
1275 * Lower data (CBC encrypted)
1276 * ...
1277 *
1278 * Returns zero on success
1279 */
Eric Sandeen87b811c2008-10-29 14:01:08 -07001280static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1281 size_t *size,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001282 struct ecryptfs_crypt_stat *crypt_stat,
1283 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001284{
1285 int rc;
1286 size_t written;
1287 size_t offset;
1288
1289 offset = ECRYPTFS_FILE_SIZE_BYTES;
1290 write_ecryptfs_marker((page_virt + offset), &written);
1291 offset += written;
Tyler Hicksf4e60e62010-02-11 00:02:32 -06001292 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1293 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001294 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001295 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1296 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001297 offset += written;
1298 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1299 ecryptfs_dentry, &written,
Eric Sandeen87b811c2008-10-29 14:01:08 -07001300 max - offset);
Michael Halcrow237fead2006-10-04 02:16:22 -07001301 if (rc)
1302 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1303 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001304 if (size) {
1305 offset += written;
1306 *size = offset;
1307 }
1308 return rc;
1309}
1310
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001311static int
Tyler Hicks8faece52009-03-20 01:25:09 -05001312ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
1313 char *virt, size_t virt_len)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001314{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001315 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001316
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001317 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001318 0, virt_len);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001319 if (rc < 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001320 printk(KERN_ERR "%s: Error attempting to write header "
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001321 "information to lower file; rc = [%d]\n", __func__, rc);
1322 else
1323 rc = 0;
Michael Halcrow70456602007-02-12 00:53:48 -08001324 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001325}
1326
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001327static int
1328ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001329 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001330{
1331 int rc;
1332
1333 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1334 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001335 return rc;
1336}
1337
Tyler Hicks8faece52009-03-20 01:25:09 -05001338static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1339 unsigned int order)
1340{
1341 struct page *page;
1342
1343 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1344 if (page)
1345 return (unsigned long) page_address(page);
1346 return 0;
1347}
1348
Michael Halcrow237fead2006-10-04 02:16:22 -07001349/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001350 * ecryptfs_write_metadata
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001351 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001352 *
1353 * Write the file headers out. This will likely involve a userspace
1354 * callout, in which the session key is encrypted with one or more
1355 * public keys and/or the passphrase necessary to do the encryption is
1356 * retrieved via a prompt. Exactly what happens at this point should
1357 * be policy-dependent.
1358 *
1359 * Returns zero on success; non-zero on error
1360 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001361int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001362{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001363 struct ecryptfs_crypt_stat *crypt_stat =
1364 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
Tyler Hicks8faece52009-03-20 01:25:09 -05001365 unsigned int order;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001366 char *virt;
Tyler Hicks8faece52009-03-20 01:25:09 -05001367 size_t virt_len;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001368 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001369 int rc = 0;
1370
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001371 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1372 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001373 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001374 rc = -EINVAL;
1375 goto out;
1376 }
1377 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001378 printk(KERN_WARNING "%s: Encrypted flag not set\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001379 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001380 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001381 goto out;
1382 }
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001383 virt_len = crypt_stat->metadata_size;
Tyler Hicks8faece52009-03-20 01:25:09 -05001384 order = get_order(virt_len);
Michael Halcrow237fead2006-10-04 02:16:22 -07001385 /* Released in this function */
Tyler Hicks8faece52009-03-20 01:25:09 -05001386 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001387 if (!virt) {
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001388 printk(KERN_ERR "%s: Out of memory\n", __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001389 rc = -ENOMEM;
1390 goto out;
1391 }
Tyler Hicks8faece52009-03-20 01:25:09 -05001392 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1393 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001394 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001395 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001396 __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001397 goto out_free;
1398 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001399 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicks8faece52009-03-20 01:25:09 -05001400 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1401 size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001402 else
Tyler Hicks8faece52009-03-20 01:25:09 -05001403 rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
1404 virt_len);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001405 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001406 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001407 "rc = [%d]\n", __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001408 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001409 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001410out_free:
Tyler Hicks8faece52009-03-20 01:25:09 -05001411 free_pages((unsigned long)virt, order);
Michael Halcrow237fead2006-10-04 02:16:22 -07001412out:
1413 return rc;
1414}
1415
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001416#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1417#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001418static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001419 char *virt, int *bytes_read,
1420 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001421{
1422 int rc = 0;
1423 u32 header_extent_size;
1424 u16 num_header_extents_at_front;
1425
Harvey Harrison29335c62008-07-23 21:30:06 -07001426 header_extent_size = get_unaligned_be32(virt);
1427 virt += sizeof(__be32);
1428 num_header_extents_at_front = get_unaligned_be16(virt);
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001429 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1430 * (size_t)header_extent_size));
Harvey Harrison29335c62008-07-23 21:30:06 -07001431 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001432 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001433 && (crypt_stat->metadata_size
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001434 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001435 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001436 printk(KERN_WARNING "Invalid header size: [%zd]\n",
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001437 crypt_stat->metadata_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001438 }
1439 return rc;
1440}
1441
1442/**
1443 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001444 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001445 *
1446 * For version 0 file format; this function is only for backwards
1447 * compatibility for files created with the prior versions of
1448 * eCryptfs.
1449 */
1450static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1451{
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -06001452 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001453}
1454
1455/**
1456 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001457 * @page_virt: The virtual address into which to read the headers
1458 * @crypt_stat: The cryptographic context
1459 * @ecryptfs_dentry: The eCryptfs dentry
1460 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001461 *
1462 * Read/parse the header data. The header format is detailed in the
1463 * comment block for the ecryptfs_write_headers_virt() function.
1464 *
1465 * Returns zero on success
1466 */
1467static int ecryptfs_read_headers_virt(char *page_virt,
1468 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001469 struct dentry *ecryptfs_dentry,
1470 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001471{
1472 int rc = 0;
1473 int offset;
1474 int bytes_read;
1475
1476 ecryptfs_set_default_sizes(crypt_stat);
1477 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1478 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1479 offset = ECRYPTFS_FILE_SIZE_BYTES;
1480 rc = contains_ecryptfs_marker(page_virt + offset);
1481 if (rc == 0) {
1482 rc = -EINVAL;
1483 goto out;
1484 }
1485 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1486 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1487 &bytes_read);
1488 if (rc) {
1489 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1490 goto out;
1491 }
1492 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1493 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1494 "file version [%d] is supported by this "
1495 "version of eCryptfs\n",
1496 crypt_stat->file_version,
1497 ECRYPTFS_SUPPORTED_FILE_VERSION);
1498 rc = -EINVAL;
1499 goto out;
1500 }
1501 offset += bytes_read;
1502 if (crypt_stat->file_version >= 1) {
1503 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001504 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001505 if (rc) {
1506 ecryptfs_printk(KERN_WARNING, "Error reading header "
1507 "metadata; rc = [%d]\n", rc);
1508 }
1509 offset += bytes_read;
1510 } else
1511 set_default_header_data(crypt_stat);
1512 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1513 ecryptfs_dentry);
1514out:
1515 return rc;
1516}
1517
1518/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001519 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001520 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001521 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001522 *
1523 * Attempts to read the crypto metadata from the extended attribute
1524 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001525 *
1526 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001527 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001528int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001529{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001530 struct dentry *lower_dentry =
1531 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001532 ssize_t size;
1533 int rc = 0;
1534
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001535 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1536 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001537 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001538 if (unlikely(ecryptfs_verbosity > 0))
1539 printk(KERN_INFO "Error attempting to read the [%s] "
1540 "xattr from the lower file; return value = "
1541 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001542 rc = -EINVAL;
1543 goto out;
1544 }
1545out:
1546 return rc;
1547}
1548
1549int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1550 struct dentry *ecryptfs_dentry)
1551{
1552 int rc;
1553
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001554 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001555 if (rc)
1556 goto out;
1557 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1558 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1559 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1560 rc = -EINVAL;
1561 }
1562out:
1563 return rc;
1564}
1565
1566/**
1567 * ecryptfs_read_metadata
1568 *
1569 * Common entry point for reading file metadata. From here, we could
1570 * retrieve the header information from the header region of the file,
1571 * the xattr region of the file, or some other repostory that is
1572 * stored separately from the file itself. The current implementation
1573 * supports retrieving the metadata information from the file contents
1574 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001575 *
1576 * Returns zero if valid headers found and parsed; non-zero otherwise
1577 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001578int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001579{
1580 int rc = 0;
1581 char *page_virt = NULL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001582 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -07001583 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001584 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001585 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1586 &ecryptfs_superblock_to_private(
1587 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001588
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001589 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1590 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001591 /* Read the first page from the underlying file */
Christoph Lameterf7267c02006-12-06 20:33:15 -08001592 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001593 if (!page_virt) {
1594 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001595 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001596 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001597 goto out;
1598 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001599 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1600 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001601 if (rc >= 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001602 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1603 ecryptfs_dentry,
1604 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001605 if (rc) {
Tyler Hicks1984c232010-02-10 23:17:44 -06001606 memset(page_virt, 0, PAGE_CACHE_SIZE);
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001607 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001608 if (rc) {
1609 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1610 "file header region or xattr region\n");
1611 rc = -EINVAL;
1612 goto out;
1613 }
1614 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1615 ecryptfs_dentry,
1616 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1617 if (rc) {
1618 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1619 "file xattr region either\n");
1620 rc = -EINVAL;
1621 }
1622 if (crypt_stat->mount_crypt_stat->flags
1623 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1624 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1625 } else {
1626 printk(KERN_WARNING "Attempt to access file with "
1627 "crypto metadata only in the extended attribute "
1628 "region, but eCryptfs was mounted without "
1629 "xattr support enabled. eCryptfs will not treat "
1630 "this like an encrypted file.\n");
1631 rc = -EINVAL;
1632 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001633 }
1634out:
1635 if (page_virt) {
1636 memset(page_virt, 0, PAGE_CACHE_SIZE);
1637 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1638 }
1639 return rc;
1640}
1641
1642/**
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001643 * ecryptfs_encrypt_filename - encrypt filename
1644 *
1645 * CBC-encrypts the filename. We do not want to encrypt the same
1646 * filename with the same key and IV, which may happen with hard
1647 * links, so we prepend random bits to each filename.
1648 *
1649 * Returns zero on success; non-zero otherwise
1650 */
1651static int
1652ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1653 struct ecryptfs_crypt_stat *crypt_stat,
1654 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1655{
1656 int rc = 0;
1657
1658 filename->encrypted_filename = NULL;
1659 filename->encrypted_filename_size = 0;
1660 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1661 || (mount_crypt_stat && (mount_crypt_stat->flags
1662 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1663 size_t packet_size;
1664 size_t remaining_bytes;
1665
1666 rc = ecryptfs_write_tag_70_packet(
1667 NULL, NULL,
1668 &filename->encrypted_filename_size,
1669 mount_crypt_stat, NULL,
1670 filename->filename_size);
1671 if (rc) {
1672 printk(KERN_ERR "%s: Error attempting to get packet "
1673 "size for tag 72; rc = [%d]\n", __func__,
1674 rc);
1675 filename->encrypted_filename_size = 0;
1676 goto out;
1677 }
1678 filename->encrypted_filename =
1679 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1680 if (!filename->encrypted_filename) {
1681 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08001682 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001683 filename->encrypted_filename_size);
1684 rc = -ENOMEM;
1685 goto out;
1686 }
1687 remaining_bytes = filename->encrypted_filename_size;
1688 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1689 &remaining_bytes,
1690 &packet_size,
1691 mount_crypt_stat,
1692 filename->filename,
1693 filename->filename_size);
1694 if (rc) {
1695 printk(KERN_ERR "%s: Error attempting to generate "
1696 "tag 70 packet; rc = [%d]\n", __func__,
1697 rc);
1698 kfree(filename->encrypted_filename);
1699 filename->encrypted_filename = NULL;
1700 filename->encrypted_filename_size = 0;
1701 goto out;
1702 }
1703 filename->encrypted_filename_size = packet_size;
1704 } else {
1705 printk(KERN_ERR "%s: No support for requested filename "
1706 "encryption method in this release\n", __func__);
Tyler Hicksdf6ad332009-08-21 04:27:46 -05001707 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001708 goto out;
1709 }
1710out:
1711 return rc;
1712}
1713
1714static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1715 const char *name, size_t name_size)
1716{
1717 int rc = 0;
1718
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001719 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001720 if (!(*copied_name)) {
1721 rc = -ENOMEM;
1722 goto out;
1723 }
1724 memcpy((void *)(*copied_name), (void *)name, name_size);
1725 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1726 * in printing out the
1727 * string in debug
1728 * messages */
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001729 (*copied_name_size) = name_size;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001730out:
1731 return rc;
1732}
1733
1734/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001735 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001736 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001737 * @cipher_name: Name of the cipher
1738 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001739 *
1740 * Returns zero on success. Any crypto_tfm structs allocated here
1741 * should be released by other functions, such as on a superblock put
1742 * event, regardless of whether this function succeeds for fails.
1743 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001744static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001745ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1746 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001747{
1748 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Dan Carpenterece550f2010-01-19 12:34:32 +03001749 char *full_alg_name = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001750 int rc;
1751
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001752 *key_tfm = NULL;
1753 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001754 rc = -EINVAL;
Michael Halcrowdf261c52009-01-06 14:42:02 -08001755 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001756 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001757 goto out;
1758 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001759 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1760 "ecb");
1761 if (rc)
1762 goto out;
1763 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001764 if (IS_ERR(*key_tfm)) {
1765 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001766 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Dave Hansen38268492009-08-27 09:47:07 -07001767 "[%s]; rc = [%d]\n", full_alg_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001768 goto out;
1769 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001770 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1771 if (*key_size == 0) {
1772 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1773
1774 *key_size = alg->max_keysize;
1775 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001776 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001777 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001778 if (rc) {
Michael Halcrowdf261c52009-01-06 14:42:02 -08001779 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
Dave Hansen38268492009-08-27 09:47:07 -07001780 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1781 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001782 rc = -EINVAL;
1783 goto out;
1784 }
1785out:
Dan Carpenterece550f2010-01-19 12:34:32 +03001786 kfree(full_alg_name);
Michael Halcrow237fead2006-10-04 02:16:22 -07001787 return rc;
1788}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001789
1790struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001791static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001792struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001793
Jerome Marchand7371a382010-08-17 17:24:05 +02001794int __init ecryptfs_init_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001795{
1796 mutex_init(&key_tfm_list_mutex);
1797 INIT_LIST_HEAD(&key_tfm_list);
1798 return 0;
1799}
1800
Eric Sandeenaf440f52008-02-06 01:38:37 -08001801/**
1802 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1803 *
1804 * Called only at module unload time
1805 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001806int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001807{
1808 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1809
1810 mutex_lock(&key_tfm_list_mutex);
1811 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1812 key_tfm_list) {
1813 list_del(&key_tfm->key_tfm_list);
1814 if (key_tfm->key_tfm)
1815 crypto_free_blkcipher(key_tfm->key_tfm);
1816 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1817 }
1818 mutex_unlock(&key_tfm_list_mutex);
1819 return 0;
1820}
1821
1822int
1823ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1824 size_t key_size)
1825{
1826 struct ecryptfs_key_tfm *tmp_tfm;
1827 int rc = 0;
1828
Eric Sandeenaf440f52008-02-06 01:38:37 -08001829 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1830
Michael Halcrowf4aad162007-10-16 01:27:53 -07001831 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1832 if (key_tfm != NULL)
1833 (*key_tfm) = tmp_tfm;
1834 if (!tmp_tfm) {
1835 rc = -ENOMEM;
1836 printk(KERN_ERR "Error attempting to allocate from "
1837 "ecryptfs_key_tfm_cache\n");
1838 goto out;
1839 }
1840 mutex_init(&tmp_tfm->key_tfm_mutex);
1841 strncpy(tmp_tfm->cipher_name, cipher_name,
1842 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001843 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001844 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001845 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1846 tmp_tfm->cipher_name,
1847 &tmp_tfm->key_size);
1848 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001849 printk(KERN_ERR "Error attempting to initialize key TFM "
1850 "cipher with name = [%s]; rc = [%d]\n",
1851 tmp_tfm->cipher_name, rc);
1852 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1853 if (key_tfm != NULL)
1854 (*key_tfm) = NULL;
1855 goto out;
1856 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001857 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001858out:
1859 return rc;
1860}
1861
Eric Sandeenaf440f52008-02-06 01:38:37 -08001862/**
1863 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1864 * @cipher_name: the name of the cipher to search for
1865 * @key_tfm: set to corresponding tfm if found
1866 *
1867 * Searches for cached key_tfm matching @cipher_name
1868 * Must be called with &key_tfm_list_mutex held
1869 * Returns 1 if found, with @key_tfm set
1870 * Returns 0 if not found, with @key_tfm set to NULL
1871 */
1872int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1873{
1874 struct ecryptfs_key_tfm *tmp_key_tfm;
1875
1876 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1877
1878 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1879 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1880 if (key_tfm)
1881 (*key_tfm) = tmp_key_tfm;
1882 return 1;
1883 }
1884 }
1885 if (key_tfm)
1886 (*key_tfm) = NULL;
1887 return 0;
1888}
1889
1890/**
1891 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1892 *
1893 * @tfm: set to cached tfm found, or new tfm created
1894 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1895 * @cipher_name: the name of the cipher to search for and/or add
1896 *
1897 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1898 * Searches for cached item first, and creates new if not found.
1899 * Returns 0 on success, non-zero if adding new cipher failed
1900 */
Michael Halcrowf4aad162007-10-16 01:27:53 -07001901int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1902 struct mutex **tfm_mutex,
1903 char *cipher_name)
1904{
1905 struct ecryptfs_key_tfm *key_tfm;
1906 int rc = 0;
1907
1908 (*tfm) = NULL;
1909 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001910
Michael Halcrowf4aad162007-10-16 01:27:53 -07001911 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001912 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1913 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1914 if (rc) {
1915 printk(KERN_ERR "Error adding new key_tfm to list; "
1916 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001917 goto out;
1918 }
1919 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001920 (*tfm) = key_tfm->key_tfm;
1921 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1922out:
Cyrill Gorcunov71fd5172008-05-23 13:04:20 -07001923 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001924 return rc;
1925}
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001926
1927/* 64 characters forming a 6-bit target field */
1928static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1929 "EFGHIJKLMNOPQRST"
1930 "UVWXYZabcdefghij"
1931 "klmnopqrstuvwxyz");
1932
1933/* We could either offset on every reverse map or just pad some 0x00's
1934 * at the front here */
Michael Halcrow71c11c32009-01-06 14:42:05 -08001935static const unsigned char filename_rev_map[] = {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001936 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1937 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1938 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1939 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1940 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1941 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1942 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1943 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1944 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1945 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1946 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1947 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1948 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1949 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1950 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1951 0x3D, 0x3E, 0x3F
1952};
1953
1954/**
1955 * ecryptfs_encode_for_filename
1956 * @dst: Destination location for encoded filename
1957 * @dst_size: Size of the encoded filename in bytes
1958 * @src: Source location for the filename to encode
1959 * @src_size: Size of the source in bytes
1960 */
1961void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1962 unsigned char *src, size_t src_size)
1963{
1964 size_t num_blocks;
1965 size_t block_num = 0;
1966 size_t dst_offset = 0;
1967 unsigned char last_block[3];
1968
1969 if (src_size == 0) {
1970 (*dst_size) = 0;
1971 goto out;
1972 }
1973 num_blocks = (src_size / 3);
1974 if ((src_size % 3) == 0) {
1975 memcpy(last_block, (&src[src_size - 3]), 3);
1976 } else {
1977 num_blocks++;
1978 last_block[2] = 0x00;
1979 switch (src_size % 3) {
1980 case 1:
1981 last_block[0] = src[src_size - 1];
1982 last_block[1] = 0x00;
1983 break;
1984 case 2:
1985 last_block[0] = src[src_size - 2];
1986 last_block[1] = src[src_size - 1];
1987 }
1988 }
1989 (*dst_size) = (num_blocks * 4);
1990 if (!dst)
1991 goto out;
1992 while (block_num < num_blocks) {
1993 unsigned char *src_block;
1994 unsigned char dst_block[4];
1995
1996 if (block_num == (num_blocks - 1))
1997 src_block = last_block;
1998 else
1999 src_block = &src[block_num * 3];
2000 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2001 dst_block[1] = (((src_block[0] << 4) & 0x30)
2002 | ((src_block[1] >> 4) & 0x0F));
2003 dst_block[2] = (((src_block[1] << 2) & 0x3C)
2004 | ((src_block[2] >> 6) & 0x03));
2005 dst_block[3] = (src_block[2] & 0x3F);
2006 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2007 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2008 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2009 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2010 block_num++;
2011 }
2012out:
2013 return;
2014}
2015
Michael Halcrow71c11c32009-01-06 14:42:05 -08002016/**
2017 * ecryptfs_decode_from_filename
2018 * @dst: If NULL, this function only sets @dst_size and returns. If
2019 * non-NULL, this function decodes the encoded octets in @src
2020 * into the memory that @dst points to.
2021 * @dst_size: Set to the size of the decoded string.
2022 * @src: The encoded set of octets to decode.
2023 * @src_size: The size of the encoded set of octets to decode.
2024 */
2025static void
2026ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2027 const unsigned char *src, size_t src_size)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002028{
2029 u8 current_bit_offset = 0;
2030 size_t src_byte_offset = 0;
2031 size_t dst_byte_offset = 0;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002032
2033 if (dst == NULL) {
Michael Halcrow71c11c32009-01-06 14:42:05 -08002034 /* Not exact; conservatively long. Every block of 4
2035 * encoded characters decodes into a block of 3
2036 * decoded characters. This segment of code provides
2037 * the caller with the maximum amount of allocated
2038 * space that @dst will need to point to in a
2039 * subsequent call. */
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002040 (*dst_size) = (((src_size + 1) * 3) / 4);
2041 goto out;
2042 }
2043 while (src_byte_offset < src_size) {
2044 unsigned char src_byte =
2045 filename_rev_map[(int)src[src_byte_offset]];
2046
2047 switch (current_bit_offset) {
2048 case 0:
2049 dst[dst_byte_offset] = (src_byte << 2);
2050 current_bit_offset = 6;
2051 break;
2052 case 6:
2053 dst[dst_byte_offset++] |= (src_byte >> 4);
2054 dst[dst_byte_offset] = ((src_byte & 0xF)
2055 << 4);
2056 current_bit_offset = 4;
2057 break;
2058 case 4:
2059 dst[dst_byte_offset++] |= (src_byte >> 2);
2060 dst[dst_byte_offset] = (src_byte << 6);
2061 current_bit_offset = 2;
2062 break;
2063 case 2:
2064 dst[dst_byte_offset++] |= (src_byte);
2065 dst[dst_byte_offset] = 0;
2066 current_bit_offset = 0;
2067 break;
2068 }
2069 src_byte_offset++;
2070 }
2071 (*dst_size) = dst_byte_offset;
2072out:
Michael Halcrow71c11c32009-01-06 14:42:05 -08002073 return;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002074}
2075
2076/**
2077 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2078 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2079 * @name: The plaintext name
2080 * @length: The length of the plaintext
2081 * @encoded_name: The encypted name
2082 *
2083 * Encrypts and encodes a filename into something that constitutes a
2084 * valid filename for a filesystem, with printable characters.
2085 *
2086 * We assume that we have a properly initialized crypto context,
2087 * pointed to by crypt_stat->tfm.
2088 *
2089 * Returns zero on success; non-zero on otherwise
2090 */
2091int ecryptfs_encrypt_and_encode_filename(
2092 char **encoded_name,
2093 size_t *encoded_name_size,
2094 struct ecryptfs_crypt_stat *crypt_stat,
2095 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2096 const char *name, size_t name_size)
2097{
2098 size_t encoded_name_no_prefix_size;
2099 int rc = 0;
2100
2101 (*encoded_name) = NULL;
2102 (*encoded_name_size) = 0;
2103 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2104 || (mount_crypt_stat && (mount_crypt_stat->flags
2105 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2106 struct ecryptfs_filename *filename;
2107
2108 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2109 if (!filename) {
2110 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002111 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002112 sizeof(*filename));
2113 rc = -ENOMEM;
2114 goto out;
2115 }
2116 filename->filename = (char *)name;
2117 filename->filename_size = name_size;
2118 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2119 mount_crypt_stat);
2120 if (rc) {
2121 printk(KERN_ERR "%s: Error attempting to encrypt "
2122 "filename; rc = [%d]\n", __func__, rc);
2123 kfree(filename);
2124 goto out;
2125 }
2126 ecryptfs_encode_for_filename(
2127 NULL, &encoded_name_no_prefix_size,
2128 filename->encrypted_filename,
2129 filename->encrypted_filename_size);
2130 if ((crypt_stat && (crypt_stat->flags
2131 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2132 || (mount_crypt_stat
2133 && (mount_crypt_stat->flags
2134 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2135 (*encoded_name_size) =
2136 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2137 + encoded_name_no_prefix_size);
2138 else
2139 (*encoded_name_size) =
2140 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2141 + encoded_name_no_prefix_size);
2142 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2143 if (!(*encoded_name)) {
2144 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002145 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002146 (*encoded_name_size));
2147 rc = -ENOMEM;
2148 kfree(filename->encrypted_filename);
2149 kfree(filename);
2150 goto out;
2151 }
2152 if ((crypt_stat && (crypt_stat->flags
2153 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2154 || (mount_crypt_stat
2155 && (mount_crypt_stat->flags
2156 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2157 memcpy((*encoded_name),
2158 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2159 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2160 ecryptfs_encode_for_filename(
2161 ((*encoded_name)
2162 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2163 &encoded_name_no_prefix_size,
2164 filename->encrypted_filename,
2165 filename->encrypted_filename_size);
2166 (*encoded_name_size) =
2167 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2168 + encoded_name_no_prefix_size);
2169 (*encoded_name)[(*encoded_name_size)] = '\0';
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002170 } else {
Tyler Hicksdf6ad332009-08-21 04:27:46 -05002171 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002172 }
2173 if (rc) {
2174 printk(KERN_ERR "%s: Error attempting to encode "
2175 "encrypted filename; rc = [%d]\n", __func__,
2176 rc);
2177 kfree((*encoded_name));
2178 (*encoded_name) = NULL;
2179 (*encoded_name_size) = 0;
2180 }
2181 kfree(filename->encrypted_filename);
2182 kfree(filename);
2183 } else {
2184 rc = ecryptfs_copy_filename(encoded_name,
2185 encoded_name_size,
2186 name, name_size);
2187 }
2188out:
2189 return rc;
2190}
2191
2192/**
2193 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2194 * @plaintext_name: The plaintext name
2195 * @plaintext_name_size: The plaintext name size
2196 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2197 * @name: The filename in cipher text
2198 * @name_size: The cipher text name size
2199 *
2200 * Decrypts and decodes the filename.
2201 *
2202 * Returns zero on error; non-zero otherwise
2203 */
2204int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2205 size_t *plaintext_name_size,
2206 struct dentry *ecryptfs_dir_dentry,
2207 const char *name, size_t name_size)
2208{
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002209 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2210 &ecryptfs_superblock_to_private(
2211 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002212 char *decoded_name;
2213 size_t decoded_name_size;
2214 size_t packet_size;
2215 int rc = 0;
2216
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002217 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2218 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2219 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002220 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2221 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002222 const char *orig_name = name;
2223 size_t orig_name_size = name_size;
2224
2225 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2226 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
Michael Halcrow71c11c32009-01-06 14:42:05 -08002227 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2228 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002229 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2230 if (!decoded_name) {
2231 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08002232 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002233 decoded_name_size);
2234 rc = -ENOMEM;
2235 goto out;
2236 }
Michael Halcrow71c11c32009-01-06 14:42:05 -08002237 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2238 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002239 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2240 plaintext_name_size,
2241 &packet_size,
2242 mount_crypt_stat,
2243 decoded_name,
2244 decoded_name_size);
2245 if (rc) {
2246 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2247 "from filename; copying through filename "
2248 "as-is\n", __func__);
2249 rc = ecryptfs_copy_filename(plaintext_name,
2250 plaintext_name_size,
2251 orig_name, orig_name_size);
2252 goto out_free;
2253 }
2254 } else {
2255 rc = ecryptfs_copy_filename(plaintext_name,
2256 plaintext_name_size,
2257 name, name_size);
2258 goto out;
2259 }
2260out_free:
2261 kfree(decoded_name);
2262out:
2263 return rc;
2264}