blob: fbb6e5eed6971a5a3b68e0e6c55bfa26fc8ec623 [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>
Harvey Harrison29335c62008-07-23 21:30:06 -070036#include <asm/unaligned.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070037#include "ecryptfs_kernel.h"
38
39static int
40ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
41 struct page *dst_page, int dst_offset,
42 struct page *src_page, int src_offset, int size,
43 unsigned char *iv);
44static int
45ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
46 struct page *dst_page, int dst_offset,
47 struct page *src_page, int src_offset, int size,
48 unsigned char *iv);
49
50/**
51 * ecryptfs_to_hex
52 * @dst: Buffer to take hex character representation of contents of
53 * src; must be at least of size (src_size * 2)
54 * @src: Buffer to be converted to a hex string respresentation
55 * @src_size: number of bytes to convert
56 */
57void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
58{
59 int x;
60
61 for (x = 0; x < src_size; x++)
62 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
63}
64
65/**
66 * ecryptfs_from_hex
67 * @dst: Buffer to take the bytes from src hex; must be at least of
68 * size (src_size / 2)
69 * @src: Buffer to be converted from a hex string respresentation to raw value
70 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
71 */
72void ecryptfs_from_hex(char *dst, char *src, int dst_size)
73{
74 int x;
75 char tmp[3] = { 0, };
76
77 for (x = 0; x < dst_size; x++) {
78 tmp[0] = src[x * 2];
79 tmp[1] = src[x * 2 + 1];
80 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
81 }
82}
83
84/**
85 * ecryptfs_calculate_md5 - calculates the md5 of @src
86 * @dst: Pointer to 16 bytes of allocated memory
87 * @crypt_stat: Pointer to crypt_stat struct for the current inode
88 * @src: Data to be md5'd
89 * @len: Length of @src
90 *
91 * Uses the allocated crypto context that crypt_stat references to
92 * generate the MD5 sum of the contents of src.
93 */
94static int ecryptfs_calculate_md5(char *dst,
95 struct ecryptfs_crypt_stat *crypt_stat,
96 char *src, int len)
97{
Michael Halcrow237fead2006-10-04 02:16:22 -070098 struct scatterlist sg;
Michael Halcrow565d97242006-10-30 22:07:17 -080099 struct hash_desc desc = {
100 .tfm = crypt_stat->hash_tfm,
101 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
102 };
103 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700104
Michael Halcrow565d97242006-10-30 22:07:17 -0800105 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700106 sg_init_one(&sg, (u8 *)src, len);
Michael Halcrow565d97242006-10-30 22:07:17 -0800107 if (!desc.tfm) {
108 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
109 CRYPTO_ALG_ASYNC);
110 if (IS_ERR(desc.tfm)) {
111 rc = PTR_ERR(desc.tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700112 ecryptfs_printk(KERN_ERR, "Error attempting to "
Michael Halcrow565d97242006-10-30 22:07:17 -0800113 "allocate crypto context; rc = [%d]\n",
114 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700115 goto out;
116 }
Michael Halcrow565d97242006-10-30 22:07:17 -0800117 crypt_stat->hash_tfm = desc.tfm;
Michael Halcrow237fead2006-10-04 02:16:22 -0700118 }
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800119 rc = crypto_hash_init(&desc);
120 if (rc) {
121 printk(KERN_ERR
122 "%s: Error initializing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700123 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800124 goto out;
125 }
126 rc = crypto_hash_update(&desc, &sg, len);
127 if (rc) {
128 printk(KERN_ERR
129 "%s: Error updating crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700130 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800131 goto out;
132 }
133 rc = crypto_hash_final(&desc, dst);
134 if (rc) {
135 printk(KERN_ERR
136 "%s: Error finalizing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700137 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800138 goto out;
139 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700140out:
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800141 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700142 return rc;
143}
144
Michael Halcrowcd9d67d2007-10-16 01:28:04 -0700145static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
146 char *cipher_name,
147 char *chaining_modifier)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800148{
149 int cipher_name_len = strlen(cipher_name);
150 int chaining_modifier_len = strlen(chaining_modifier);
151 int algified_name_len;
152 int rc;
153
154 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
155 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
Michael Halcrow7bd473f2006-11-02 22:06:56 -0800156 if (!(*algified_name)) {
Michael Halcrow8bba0662006-10-30 22:07:18 -0800157 rc = -ENOMEM;
158 goto out;
159 }
160 snprintf((*algified_name), algified_name_len, "%s(%s)",
161 chaining_modifier, cipher_name);
162 rc = 0;
163out:
164 return rc;
165}
166
Michael Halcrow237fead2006-10-04 02:16:22 -0700167/**
168 * ecryptfs_derive_iv
169 * @iv: destination for the derived iv vale
170 * @crypt_stat: Pointer to crypt_stat struct for the current inode
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700171 * @offset: Offset of the extent whose IV we are to derive
Michael Halcrow237fead2006-10-04 02:16:22 -0700172 *
173 * Generate the initialization vector from the given root IV and page
174 * offset.
175 *
176 * Returns zero on success; non-zero on error.
177 */
Michael Halcrowa34f60f2009-01-06 14:41:58 -0800178int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
179 loff_t offset)
Michael Halcrow237fead2006-10-04 02:16:22 -0700180{
181 int rc = 0;
182 char dst[MD5_DIGEST_SIZE];
183 char src[ECRYPTFS_MAX_IV_BYTES + 16];
184
185 if (unlikely(ecryptfs_verbosity > 0)) {
186 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
187 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
188 }
189 /* TODO: It is probably secure to just cast the least
190 * significant bits of the root IV into an unsigned long and
191 * add the offset to that rather than go through all this
192 * hashing business. -Halcrow */
193 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
194 memset((src + crypt_stat->iv_bytes), 0, 16);
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700195 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700196 if (unlikely(ecryptfs_verbosity > 0)) {
197 ecryptfs_printk(KERN_DEBUG, "source:\n");
198 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
199 }
200 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
201 (crypt_stat->iv_bytes + 16));
202 if (rc) {
203 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
204 "MD5 while generating IV for a page\n");
205 goto out;
206 }
207 memcpy(iv, dst, crypt_stat->iv_bytes);
208 if (unlikely(ecryptfs_verbosity > 0)) {
209 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
210 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
211 }
212out:
213 return rc;
214}
215
216/**
217 * ecryptfs_init_crypt_stat
218 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
219 *
220 * Initialize the crypt_stat structure.
221 */
222void
223ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
224{
225 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
Michael Halcrowf4aad162007-10-16 01:27:53 -0700226 INIT_LIST_HEAD(&crypt_stat->keysig_list);
227 mutex_init(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700228 mutex_init(&crypt_stat->cs_mutex);
229 mutex_init(&crypt_stat->cs_tfm_mutex);
Michael Halcrow565d97242006-10-30 22:07:17 -0800230 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800231 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
Michael Halcrow237fead2006-10-04 02:16:22 -0700232}
233
234/**
Michael Halcrowfcd12832007-10-16 01:28:01 -0700235 * ecryptfs_destroy_crypt_stat
Michael Halcrow237fead2006-10-04 02:16:22 -0700236 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
237 *
238 * Releases all memory associated with a crypt_stat struct.
239 */
Michael Halcrowfcd12832007-10-16 01:28:01 -0700240void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -0700241{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700242 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
243
Michael Halcrow237fead2006-10-04 02:16:22 -0700244 if (crypt_stat->tfm)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800245 crypto_free_blkcipher(crypt_stat->tfm);
Michael Halcrow565d97242006-10-30 22:07:17 -0800246 if (crypt_stat->hash_tfm)
247 crypto_free_hash(crypt_stat->hash_tfm);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700248 list_for_each_entry_safe(key_sig, key_sig_tmp,
249 &crypt_stat->keysig_list, crypt_stat_list) {
250 list_del(&key_sig->crypt_stat_list);
251 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
252 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700253 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
254}
255
Michael Halcrowfcd12832007-10-16 01:28:01 -0700256void ecryptfs_destroy_mount_crypt_stat(
Michael Halcrow237fead2006-10-04 02:16:22 -0700257 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
258{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700259 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
260
261 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
262 return;
263 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
264 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
265 &mount_crypt_stat->global_auth_tok_list,
266 mount_crypt_stat_list) {
267 list_del(&auth_tok->mount_crypt_stat_list);
268 mount_crypt_stat->num_global_auth_toks--;
269 if (auth_tok->global_auth_tok_key
270 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
271 key_put(auth_tok->global_auth_tok_key);
272 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
273 }
274 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700275 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
276}
277
278/**
279 * virt_to_scatterlist
280 * @addr: Virtual address
281 * @size: Size of data; should be an even multiple of the block size
282 * @sg: Pointer to scatterlist array; set to NULL to obtain only
283 * the number of scatterlist structs required in array
284 * @sg_size: Max array size
285 *
286 * Fills in a scatterlist array with page references for a passed
287 * virtual address.
288 *
289 * Returns the number of scatterlist structs in array used
290 */
291int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
292 int sg_size)
293{
294 int i = 0;
295 struct page *pg;
296 int offset;
297 int remainder_of_page;
298
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700299 sg_init_table(sg, sg_size);
300
Michael Halcrow237fead2006-10-04 02:16:22 -0700301 while (size > 0 && i < sg_size) {
302 pg = virt_to_page(addr);
303 offset = offset_in_page(addr);
Jens Axboe642f1492007-10-24 11:20:47 +0200304 if (sg)
305 sg_set_page(&sg[i], pg, 0, offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700306 remainder_of_page = PAGE_CACHE_SIZE - offset;
307 if (size >= remainder_of_page) {
308 if (sg)
309 sg[i].length = remainder_of_page;
310 addr += remainder_of_page;
311 size -= remainder_of_page;
312 } else {
313 if (sg)
314 sg[i].length = size;
315 addr += size;
316 size = 0;
317 }
318 i++;
319 }
320 if (size > 0)
321 return -ENOMEM;
322 return i;
323}
324
325/**
326 * encrypt_scatterlist
327 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
328 * @dest_sg: Destination of encrypted data
329 * @src_sg: Data to be encrypted
330 * @size: Length of data to be encrypted
331 * @iv: iv to use during encryption
332 *
333 * Returns the number of bytes encrypted; negative value on error
334 */
335static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
336 struct scatterlist *dest_sg,
337 struct scatterlist *src_sg, int size,
338 unsigned char *iv)
339{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800340 struct blkcipher_desc desc = {
341 .tfm = crypt_stat->tfm,
342 .info = iv,
343 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
344 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700345 int rc = 0;
346
347 BUG_ON(!crypt_stat || !crypt_stat->tfm
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800348 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
Michael Halcrow237fead2006-10-04 02:16:22 -0700349 if (unlikely(ecryptfs_verbosity > 0)) {
350 ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n",
351 crypt_stat->key_size);
352 ecryptfs_dump_hex(crypt_stat->key,
353 crypt_stat->key_size);
354 }
355 /* Consider doing this once, when the file is opened */
356 mutex_lock(&crypt_stat->cs_tfm_mutex);
Trevor Highland8e3a6f12008-02-06 01:38:33 -0800357 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
358 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
359 crypt_stat->key_size);
360 crypt_stat->flags |= ECRYPTFS_KEY_SET;
361 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700362 if (rc) {
363 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
364 rc);
365 mutex_unlock(&crypt_stat->cs_tfm_mutex);
366 rc = -EINVAL;
367 goto out;
368 }
369 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800370 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700371 mutex_unlock(&crypt_stat->cs_tfm_mutex);
372out:
373 return rc;
374}
375
Michael Halcrow237fead2006-10-04 02:16:22 -0700376/**
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700377 * ecryptfs_lower_offset_for_extent
378 *
379 * Convert an eCryptfs page index into a lower byte offset
380 */
Adrian Bunk7896b632008-02-06 01:38:32 -0800381static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
382 struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700383{
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800384 (*offset) = (crypt_stat->num_header_bytes_at_front
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700385 + (crypt_stat->extent_size * extent_num));
386}
387
388/**
389 * ecryptfs_encrypt_extent
390 * @enc_extent_page: Allocated page into which to encrypt the data in
391 * @page
392 * @crypt_stat: crypt_stat containing cryptographic context for the
393 * encryption operation
394 * @page: Page containing plaintext data extent to encrypt
395 * @extent_offset: Page extent offset for use in generating IV
396 *
397 * Encrypts one extent of data.
398 *
399 * Return zero on success; non-zero otherwise
400 */
401static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
402 struct ecryptfs_crypt_stat *crypt_stat,
403 struct page *page,
404 unsigned long extent_offset)
405{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700406 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700407 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
408 int rc;
409
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700410 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700411 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
412 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
413 (extent_base + extent_offset));
414 if (rc) {
415 ecryptfs_printk(KERN_ERR, "Error attempting to "
416 "derive IV for extent [0x%.16x]; "
417 "rc = [%d]\n", (extent_base + extent_offset),
418 rc);
419 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)) {
445 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
446 "rc = [%d]\n", (extent_base + extent_offset),
447 rc);
448 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) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700542 ecryptfs_printk(KERN_ERR, "Error attempting to "
543 "derive IV for extent [0x%.16x]; "
544 "rc = [%d]\n", (extent_base + extent_offset),
545 rc);
546 goto out;
547 }
548 if (unlikely(ecryptfs_verbosity > 0)) {
549 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
550 "with iv:\n");
551 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
552 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
553 "decryption:\n");
554 ecryptfs_dump_hex((char *)
555 (page_address(enc_extent_page)
556 + (extent_offset * crypt_stat->extent_size)),
557 8);
558 }
559 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
560 (extent_offset
561 * crypt_stat->extent_size),
562 enc_extent_page, 0,
563 crypt_stat->extent_size, extent_iv);
564 if (rc < 0) {
565 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
566 "page->index = [%ld], extent_offset = [%ld]; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700567 "rc = [%d]\n", __func__, page->index, extent_offset,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700568 rc);
569 goto out;
570 }
571 rc = 0;
572 if (unlikely(ecryptfs_verbosity > 0)) {
573 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
574 "rc = [%d]\n", (extent_base + extent_offset),
575 rc);
576 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
577 "decryption:\n");
578 ecryptfs_dump_hex((char *)(page_address(page)
579 + (extent_offset
580 * crypt_stat->extent_size)), 8);
Michael Halcrow237fead2006-10-04 02:16:22 -0700581 }
582out:
583 return rc;
584}
585
586/**
587 * ecryptfs_decrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700588 * @page: Page mapped from the eCryptfs inode for the file; data read
589 * and decrypted from the lower file will be written into this
590 * page
Michael Halcrow237fead2006-10-04 02:16:22 -0700591 *
592 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
593 * that eCryptfs pages may straddle the lower pages -- for instance,
594 * if the file was created on a machine with an 8K page size
595 * (resulting in an 8K header), and then the file is copied onto a
596 * host with a 32K page size, then when reading page 0 of the eCryptfs
597 * file, 24K of page 0 of the lower file will be read and decrypted,
598 * and then 8K of page 1 of the lower file will be read and decrypted.
599 *
600 * Returns zero on success; negative on error
601 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700602int ecryptfs_decrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700603{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700604 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700605 struct ecryptfs_crypt_stat *crypt_stat;
Eric Sandeen7fcba052008-07-28 15:46:39 -0700606 char *enc_extent_virt;
607 struct page *enc_extent_page = NULL;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700608 unsigned long extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700609 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700610
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700611 ecryptfs_inode = page->mapping->host;
612 crypt_stat =
613 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500614 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Eric Sandeen7fcba052008-07-28 15:46:39 -0700615 enc_extent_page = alloc_page(GFP_USER);
616 if (!enc_extent_page) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700617 rc = -ENOMEM;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700618 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
619 "encrypted extent\n");
Michael Halcrow16a72c42007-10-16 01:28:14 -0700620 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700621 }
Eric Sandeen7fcba052008-07-28 15:46:39 -0700622 enc_extent_virt = kmap(enc_extent_page);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700623 for (extent_offset = 0;
624 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
625 extent_offset++) {
626 loff_t offset;
627
628 ecryptfs_lower_offset_for_extent(
629 &offset, ((page->index * (PAGE_CACHE_SIZE
630 / crypt_stat->extent_size))
631 + extent_offset), crypt_stat);
632 rc = ecryptfs_read_lower(enc_extent_virt, offset,
633 crypt_stat->extent_size,
634 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500635 if (rc < 0) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700636 ecryptfs_printk(KERN_ERR, "Error attempting "
637 "to read lower page; rc = [%d]"
638 "\n", rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700639 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700640 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700641 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
642 extent_offset);
643 if (rc) {
644 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700645 "rc = [%d]\n", __func__, rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700646 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700647 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700648 }
649out:
Eric Sandeen7fcba052008-07-28 15:46:39 -0700650 if (enc_extent_page) {
651 kunmap(enc_extent_page);
652 __free_page(enc_extent_page);
653 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700654 return rc;
655}
656
657/**
658 * decrypt_scatterlist
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700659 * @crypt_stat: Cryptographic context
660 * @dest_sg: The destination scatterlist to decrypt into
661 * @src_sg: The source scatterlist to decrypt from
662 * @size: The number of bytes to decrypt
663 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700664 *
665 * Returns the number of bytes decrypted; negative value on error
666 */
667static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
668 struct scatterlist *dest_sg,
669 struct scatterlist *src_sg, int size,
670 unsigned char *iv)
671{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800672 struct blkcipher_desc desc = {
673 .tfm = crypt_stat->tfm,
674 .info = iv,
675 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
676 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700677 int rc = 0;
678
679 /* Consider doing this once, when the file is opened */
680 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800681 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
682 crypt_stat->key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700683 if (rc) {
684 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
685 rc);
686 mutex_unlock(&crypt_stat->cs_tfm_mutex);
687 rc = -EINVAL;
688 goto out;
689 }
690 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800691 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700692 mutex_unlock(&crypt_stat->cs_tfm_mutex);
693 if (rc) {
694 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
695 rc);
696 goto out;
697 }
698 rc = size;
699out:
700 return rc;
701}
702
703/**
704 * ecryptfs_encrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700705 * @crypt_stat: The cryptographic context
706 * @dst_page: The page to encrypt into
707 * @dst_offset: The offset in the page to encrypt into
708 * @src_page: The page to encrypt from
709 * @src_offset: The offset in the page to encrypt from
710 * @size: The number of bytes to encrypt
711 * @iv: The initialization vector to use for the encryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700712 *
713 * Returns the number of bytes encrypted
714 */
715static int
716ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
717 struct page *dst_page, int dst_offset,
718 struct page *src_page, int src_offset, int size,
719 unsigned char *iv)
720{
721 struct scatterlist src_sg, dst_sg;
722
Jens Axboe60c74f82007-10-22 19:43:30 +0200723 sg_init_table(&src_sg, 1);
724 sg_init_table(&dst_sg, 1);
725
Jens Axboe642f1492007-10-24 11:20:47 +0200726 sg_set_page(&src_sg, src_page, size, src_offset);
727 sg_set_page(&dst_sg, dst_page, size, dst_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700728 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
729}
730
731/**
732 * ecryptfs_decrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700733 * @crypt_stat: The cryptographic context
734 * @dst_page: The page to decrypt into
735 * @dst_offset: The offset in the page to decrypt into
736 * @src_page: The page to decrypt from
737 * @src_offset: The offset in the page to decrypt from
738 * @size: The number of bytes to decrypt
739 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700740 *
741 * Returns the number of bytes decrypted
742 */
743static int
744ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
745 struct page *dst_page, int dst_offset,
746 struct page *src_page, int src_offset, int size,
747 unsigned char *iv)
748{
749 struct scatterlist src_sg, dst_sg;
750
Jens Axboe60c74f82007-10-22 19:43:30 +0200751 sg_init_table(&src_sg, 1);
Jens Axboe642f1492007-10-24 11:20:47 +0200752 sg_set_page(&src_sg, src_page, size, src_offset);
Jens Axboe60c74f82007-10-22 19:43:30 +0200753
Jens Axboe642f1492007-10-24 11:20:47 +0200754 sg_init_table(&dst_sg, 1);
755 sg_set_page(&dst_sg, dst_page, size, dst_offset);
756
Michael Halcrow237fead2006-10-04 02:16:22 -0700757 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
758}
759
760#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
761
762/**
763 * ecryptfs_init_crypt_ctx
764 * @crypt_stat: Uninitilized crypt stats structure
765 *
766 * Initialize the crypto context.
767 *
768 * TODO: Performance: Keep a cache of initialized cipher contexts;
769 * only init if needed
770 */
771int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
772{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800773 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700774 int rc = -EINVAL;
775
776 if (!crypt_stat->cipher) {
777 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
778 goto out;
779 }
780 ecryptfs_printk(KERN_DEBUG,
781 "Initializing cipher [%s]; strlen = [%d]; "
782 "key_size_bits = [%d]\n",
783 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
784 crypt_stat->key_size << 3);
785 if (crypt_stat->tfm) {
786 rc = 0;
787 goto out;
788 }
789 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800790 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
791 crypt_stat->cipher, "cbc");
792 if (rc)
Eric Sandeenc8161f62007-12-22 14:03:26 -0800793 goto out_unlock;
Michael Halcrow8bba0662006-10-30 22:07:18 -0800794 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
795 CRYPTO_ALG_ASYNC);
796 kfree(full_alg_name);
Akinobu Mitade887772006-11-28 12:29:49 -0800797 if (IS_ERR(crypt_stat->tfm)) {
798 rc = PTR_ERR(crypt_stat->tfm);
Tyler Hicksb0105ea2009-08-11 00:36:32 -0500799 crypt_stat->tfm = NULL;
Michael Halcrow237fead2006-10-04 02:16:22 -0700800 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
801 "Error initializing cipher [%s]\n",
802 crypt_stat->cipher);
Eric Sandeenc8161f62007-12-22 14:03:26 -0800803 goto out_unlock;
Michael Halcrow237fead2006-10-04 02:16:22 -0700804 }
Herbert Xuf1ddcaf2007-01-27 10:05:15 +1100805 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow237fead2006-10-04 02:16:22 -0700806 rc = 0;
Eric Sandeenc8161f62007-12-22 14:03:26 -0800807out_unlock:
808 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700809out:
810 return rc;
811}
812
813static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
814{
815 int extent_size_tmp;
816
817 crypt_stat->extent_mask = 0xFFFFFFFF;
818 crypt_stat->extent_shift = 0;
819 if (crypt_stat->extent_size == 0)
820 return;
821 extent_size_tmp = crypt_stat->extent_size;
822 while ((extent_size_tmp & 0x01) == 0) {
823 extent_size_tmp >>= 1;
824 crypt_stat->extent_mask <<= 1;
825 crypt_stat->extent_shift++;
826 }
827}
828
829void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
830{
831 /* Default values; may be overwritten as we are parsing the
832 * packets. */
833 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
834 set_extent_mask_and_shift(crypt_stat);
835 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800836 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800837 crypt_stat->num_header_bytes_at_front = 0;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700838 else {
839 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800840 crypt_stat->num_header_bytes_at_front =
841 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700842 else
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800843 crypt_stat->num_header_bytes_at_front = PAGE_CACHE_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700844 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700845}
846
847/**
848 * ecryptfs_compute_root_iv
849 * @crypt_stats
850 *
851 * On error, sets the root IV to all 0's.
852 */
853int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
854{
855 int rc = 0;
856 char dst[MD5_DIGEST_SIZE];
857
858 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
859 BUG_ON(crypt_stat->iv_bytes <= 0);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800860 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700861 rc = -EINVAL;
862 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
863 "cannot generate root IV\n");
864 goto out;
865 }
866 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
867 crypt_stat->key_size);
868 if (rc) {
869 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
870 "MD5 while generating root IV\n");
871 goto out;
872 }
873 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
874out:
875 if (rc) {
876 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800877 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
Michael Halcrow237fead2006-10-04 02:16:22 -0700878 }
879 return rc;
880}
881
882static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
883{
884 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800885 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
Michael Halcrow237fead2006-10-04 02:16:22 -0700886 ecryptfs_compute_root_iv(crypt_stat);
887 if (unlikely(ecryptfs_verbosity > 0)) {
888 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
889 ecryptfs_dump_hex(crypt_stat->key,
890 crypt_stat->key_size);
891 }
892}
893
894/**
Michael Halcrow17398952007-02-12 00:53:45 -0800895 * ecryptfs_copy_mount_wide_flags_to_inode_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700896 * @crypt_stat: The inode's cryptographic context
897 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow17398952007-02-12 00:53:45 -0800898 *
899 * This function propagates the mount-wide flags to individual inode
900 * flags.
901 */
902static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
903 struct ecryptfs_crypt_stat *crypt_stat,
904 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
905{
906 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
907 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
908 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
909 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800910 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
911 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
912 if (mount_crypt_stat->flags
913 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
914 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
915 else if (mount_crypt_stat->flags
916 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
917 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
918 }
Michael Halcrow17398952007-02-12 00:53:45 -0800919}
920
Michael Halcrowf4aad162007-10-16 01:27:53 -0700921static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
922 struct ecryptfs_crypt_stat *crypt_stat,
923 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
924{
925 struct ecryptfs_global_auth_tok *global_auth_tok;
926 int rc = 0;
927
Roland Dreieraa061172009-07-01 15:48:18 -0700928 mutex_lock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700929 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
Roland Dreieraa061172009-07-01 15:48:18 -0700930
Michael Halcrowf4aad162007-10-16 01:27:53 -0700931 list_for_each_entry(global_auth_tok,
932 &mount_crypt_stat->global_auth_tok_list,
933 mount_crypt_stat_list) {
Tyler Hicks84814d62009-03-13 13:51:59 -0700934 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
935 continue;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700936 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
937 if (rc) {
938 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700939 goto out;
940 }
941 }
Roland Dreieraa061172009-07-01 15:48:18 -0700942
Michael Halcrowf4aad162007-10-16 01:27:53 -0700943out:
Roland Dreieraa061172009-07-01 15:48:18 -0700944 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
945 mutex_unlock(&crypt_stat->keysig_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700946 return rc;
947}
948
Michael Halcrow17398952007-02-12 00:53:45 -0800949/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700950 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700951 * @crypt_stat: The inode's cryptographic context
952 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700953 *
954 * Default values in the event that policy does not override them.
955 */
956static void ecryptfs_set_default_crypt_stat_vals(
957 struct ecryptfs_crypt_stat *crypt_stat,
958 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
959{
Michael Halcrow17398952007-02-12 00:53:45 -0800960 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
961 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700962 ecryptfs_set_default_sizes(crypt_stat);
963 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
964 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800965 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -0700966 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
967 crypt_stat->mount_crypt_stat = mount_crypt_stat;
968}
969
970/**
971 * ecryptfs_new_file_context
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700972 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -0700973 *
974 * If the crypto context for the file has not yet been established,
975 * this is where we do that. Establishing a new crypto context
976 * involves the following decisions:
977 * - What cipher to use?
978 * - What set of authentication tokens to use?
979 * Here we just worry about getting enough information into the
980 * authentication tokens so that we know that they are available.
981 * We associate the available authentication tokens with the new file
982 * via the set of signatures in the crypt_stat struct. Later, when
983 * the headers are actually written out, we may again defer to
984 * userspace to perform the encryption of the session key; for the
985 * foreseeable future, this will be the case with public key packets.
986 *
987 * Returns zero on success; non-zero otherwise
988 */
Michael Halcrow237fead2006-10-04 02:16:22 -0700989int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
990{
Michael Halcrow237fead2006-10-04 02:16:22 -0700991 struct ecryptfs_crypt_stat *crypt_stat =
992 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
993 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
994 &ecryptfs_superblock_to_private(
995 ecryptfs_dentry->d_sb)->mount_crypt_stat;
996 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700997 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700998
999 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -07001000 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001001 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1002 mount_crypt_stat);
1003 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1004 mount_crypt_stat);
1005 if (rc) {
1006 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1007 "to the inode key sigs; rc = [%d]\n", rc);
1008 goto out;
1009 }
1010 cipher_name_len =
1011 strlen(mount_crypt_stat->global_default_cipher_name);
1012 memcpy(crypt_stat->cipher,
1013 mount_crypt_stat->global_default_cipher_name,
1014 cipher_name_len);
1015 crypt_stat->cipher[cipher_name_len] = '\0';
1016 crypt_stat->key_size =
1017 mount_crypt_stat->global_default_cipher_key_size;
1018 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001019 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1020 if (rc)
1021 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1022 "context for cipher [%s]: rc = [%d]\n",
1023 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001024out:
Michael Halcrow237fead2006-10-04 02:16:22 -07001025 return rc;
1026}
1027
1028/**
1029 * contains_ecryptfs_marker - check for the ecryptfs marker
1030 * @data: The data block in which to check
1031 *
1032 * Returns one if marker found; zero if not found
1033 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001034static int contains_ecryptfs_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -07001035{
1036 u32 m_1, m_2;
1037
Harvey Harrison29335c62008-07-23 21:30:06 -07001038 m_1 = get_unaligned_be32(data);
1039 m_2 = get_unaligned_be32(data + 4);
Michael Halcrow237fead2006-10-04 02:16:22 -07001040 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1041 return 1;
1042 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1043 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1044 MAGIC_ECRYPTFS_MARKER);
1045 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1046 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1047 return 0;
1048}
1049
1050struct ecryptfs_flag_map_elem {
1051 u32 file_flag;
1052 u32 local_flag;
1053};
1054
1055/* Add support for additional flags by adding elements here. */
1056static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1057 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001058 {0x00000002, ECRYPTFS_ENCRYPTED},
Michael Halcrowaddd65ad2009-01-06 14:42:00 -08001059 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1060 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
Michael Halcrow237fead2006-10-04 02:16:22 -07001061};
1062
1063/**
1064 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001065 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001066 * @page_virt: Source data to be parsed
1067 * @bytes_read: Updated with the number of bytes read
1068 *
1069 * Returns zero on success; non-zero if the flag set is invalid
1070 */
1071static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1072 char *page_virt, int *bytes_read)
1073{
1074 int rc = 0;
1075 int i;
1076 u32 flags;
1077
Harvey Harrison29335c62008-07-23 21:30:06 -07001078 flags = get_unaligned_be32(page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001079 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1080 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1081 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001082 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -07001083 } else
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001084 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
Michael Halcrow237fead2006-10-04 02:16:22 -07001085 /* Version is in top 8 bits of the 32-bit flag vector */
1086 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1087 (*bytes_read) = 4;
1088 return rc;
1089}
1090
1091/**
1092 * write_ecryptfs_marker
1093 * @page_virt: The pointer to in a page to begin writing the marker
1094 * @written: Number of bytes written
1095 *
1096 * Marker = 0x3c81b7f5
1097 */
1098static void write_ecryptfs_marker(char *page_virt, size_t *written)
1099{
1100 u32 m_1, m_2;
1101
1102 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1103 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
Harvey Harrison29335c62008-07-23 21:30:06 -07001104 put_unaligned_be32(m_1, page_virt);
1105 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1106 put_unaligned_be32(m_2, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001107 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1108}
1109
1110static void
1111write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1112 size_t *written)
1113{
1114 u32 flags = 0;
1115 int i;
1116
1117 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1118 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001119 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -07001120 flags |= ecryptfs_flag_map[i].file_flag;
1121 /* Version is in top 8 bits of the 32-bit flag vector */
1122 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
Harvey Harrison29335c62008-07-23 21:30:06 -07001123 put_unaligned_be32(flags, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001124 (*written) = 4;
1125}
1126
1127struct ecryptfs_cipher_code_str_map_elem {
1128 char cipher_str[16];
Trevor Highland19e66a62008-02-06 01:38:36 -08001129 u8 cipher_code;
Michael Halcrow237fead2006-10-04 02:16:22 -07001130};
1131
1132/* Add support for additional ciphers by adding elements here. The
1133 * cipher_code is whatever OpenPGP applicatoins use to identify the
1134 * ciphers. List in order of probability. */
1135static struct ecryptfs_cipher_code_str_map_elem
1136ecryptfs_cipher_code_str_map[] = {
1137 {"aes",RFC2440_CIPHER_AES_128 },
1138 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1139 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1140 {"cast5", RFC2440_CIPHER_CAST_5},
1141 {"twofish", RFC2440_CIPHER_TWOFISH},
1142 {"cast6", RFC2440_CIPHER_CAST_6},
1143 {"aes", RFC2440_CIPHER_AES_192},
1144 {"aes", RFC2440_CIPHER_AES_256}
1145};
1146
1147/**
1148 * ecryptfs_code_for_cipher_string
Michael Halcrow9c79f342009-01-06 14:41:57 -08001149 * @cipher_name: The string alias for the cipher
1150 * @key_bytes: Length of key in bytes; used for AES code selection
Michael Halcrow237fead2006-10-04 02:16:22 -07001151 *
1152 * Returns zero on no match, or the cipher code on match
1153 */
Michael Halcrow9c79f342009-01-06 14:41:57 -08001154u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
Michael Halcrow237fead2006-10-04 02:16:22 -07001155{
1156 int i;
Trevor Highland19e66a62008-02-06 01:38:36 -08001157 u8 code = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001158 struct ecryptfs_cipher_code_str_map_elem *map =
1159 ecryptfs_cipher_code_str_map;
1160
Michael Halcrow9c79f342009-01-06 14:41:57 -08001161 if (strcmp(cipher_name, "aes") == 0) {
1162 switch (key_bytes) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001163 case 16:
1164 code = RFC2440_CIPHER_AES_128;
1165 break;
1166 case 24:
1167 code = RFC2440_CIPHER_AES_192;
1168 break;
1169 case 32:
1170 code = RFC2440_CIPHER_AES_256;
1171 }
1172 } else {
1173 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
Michael Halcrow9c79f342009-01-06 14:41:57 -08001174 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001175 code = map[i].cipher_code;
1176 break;
1177 }
1178 }
1179 return code;
1180}
1181
1182/**
1183 * ecryptfs_cipher_code_to_string
1184 * @str: Destination to write out the cipher name
1185 * @cipher_code: The code to convert to cipher name string
1186 *
1187 * Returns zero on success
1188 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001189int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
Michael Halcrow237fead2006-10-04 02:16:22 -07001190{
1191 int rc = 0;
1192 int i;
1193
1194 str[0] = '\0';
1195 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1196 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1197 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1198 if (str[0] == '\0') {
1199 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1200 "[%d]\n", cipher_code);
1201 rc = -EINVAL;
1202 }
1203 return rc;
1204}
1205
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001206int ecryptfs_read_and_validate_header_region(char *data,
1207 struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001208{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001209 struct ecryptfs_crypt_stat *crypt_stat =
1210 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001211 int rc;
1212
Michael Halcrowaddd65ad2009-01-06 14:42:00 -08001213 if (crypt_stat->extent_size == 0)
1214 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001215 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1216 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001217 if (rc < 0) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001218 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001219 __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001220 goto out;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001221 }
1222 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001223 rc = -EINVAL;
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001224 } else
1225 rc = 0;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001226out:
1227 return rc;
1228}
1229
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001230void
1231ecryptfs_write_header_metadata(char *virt,
1232 struct ecryptfs_crypt_stat *crypt_stat,
1233 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001234{
1235 u32 header_extent_size;
1236 u16 num_header_extents_at_front;
1237
Michael Halcrow45eaab72007-10-16 01:28:05 -07001238 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001239 num_header_extents_at_front =
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001240 (u16)(crypt_stat->num_header_bytes_at_front
1241 / crypt_stat->extent_size);
Harvey Harrison29335c62008-07-23 21:30:06 -07001242 put_unaligned_be32(header_extent_size, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001243 virt += 4;
Harvey Harrison29335c62008-07-23 21:30:06 -07001244 put_unaligned_be16(num_header_extents_at_front, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001245 (*written) = 6;
1246}
1247
Michael Halcrow237fead2006-10-04 02:16:22 -07001248struct kmem_cache *ecryptfs_header_cache_1;
1249struct kmem_cache *ecryptfs_header_cache_2;
1250
1251/**
1252 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001253 * @page_virt: The virtual address to write the headers to
Eric Sandeen87b811c2008-10-29 14:01:08 -07001254 * @max: The size of memory allocated at page_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001255 * @size: Set to the number of bytes written by this function
1256 * @crypt_stat: The cryptographic context
1257 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001258 *
1259 * Format version: 1
1260 *
1261 * Header Extent:
1262 * Octets 0-7: Unencrypted file size (big-endian)
1263 * Octets 8-15: eCryptfs special marker
1264 * Octets 16-19: Flags
1265 * Octet 16: File format version number (between 0 and 255)
1266 * Octets 17-18: Reserved
1267 * Octet 19: Bit 1 (lsb): Reserved
1268 * Bit 2: Encrypted?
1269 * Bits 3-8: Reserved
1270 * Octets 20-23: Header extent size (big-endian)
1271 * Octets 24-25: Number of header extents at front of file
1272 * (big-endian)
1273 * Octet 26: Begin RFC 2440 authentication token packet set
1274 * Data Extent 0:
1275 * Lower data (CBC encrypted)
1276 * Data Extent 1:
1277 * Lower data (CBC encrypted)
1278 * ...
1279 *
1280 * Returns zero on success
1281 */
Eric Sandeen87b811c2008-10-29 14:01:08 -07001282static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1283 size_t *size,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001284 struct ecryptfs_crypt_stat *crypt_stat,
1285 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001286{
1287 int rc;
1288 size_t written;
1289 size_t offset;
1290
1291 offset = ECRYPTFS_FILE_SIZE_BYTES;
1292 write_ecryptfs_marker((page_virt + offset), &written);
1293 offset += written;
1294 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1295 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001296 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1297 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001298 offset += written;
1299 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1300 ecryptfs_dentry, &written,
Eric Sandeen87b811c2008-10-29 14:01:08 -07001301 max - offset);
Michael Halcrow237fead2006-10-04 02:16:22 -07001302 if (rc)
1303 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1304 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001305 if (size) {
1306 offset += written;
1307 *size = offset;
1308 }
1309 return rc;
1310}
1311
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001312static int
Tyler Hicks8faece52009-03-20 01:25:09 -05001313ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
1314 char *virt, size_t virt_len)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001315{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001316 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001317
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001318 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001319 0, virt_len);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001320 if (rc < 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001321 printk(KERN_ERR "%s: Error attempting to write header "
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001322 "information to lower file; rc = [%d]\n", __func__, rc);
1323 else
1324 rc = 0;
Michael Halcrow70456602007-02-12 00:53:48 -08001325 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001326}
1327
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001328static int
1329ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001330 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001331{
1332 int rc;
1333
1334 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1335 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001336 return rc;
1337}
1338
Tyler Hicks8faece52009-03-20 01:25:09 -05001339static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1340 unsigned int order)
1341{
1342 struct page *page;
1343
1344 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1345 if (page)
1346 return (unsigned long) page_address(page);
1347 return 0;
1348}
1349
Michael Halcrow237fead2006-10-04 02:16:22 -07001350/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001351 * ecryptfs_write_metadata
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001352 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001353 *
1354 * Write the file headers out. This will likely involve a userspace
1355 * callout, in which the session key is encrypted with one or more
1356 * public keys and/or the passphrase necessary to do the encryption is
1357 * retrieved via a prompt. Exactly what happens at this point should
1358 * be policy-dependent.
1359 *
1360 * Returns zero on success; non-zero on error
1361 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001362int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001363{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001364 struct ecryptfs_crypt_stat *crypt_stat =
1365 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
Tyler Hicks8faece52009-03-20 01:25:09 -05001366 unsigned int order;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001367 char *virt;
Tyler Hicks8faece52009-03-20 01:25:09 -05001368 size_t virt_len;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001369 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001370 int rc = 0;
1371
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001372 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1373 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001374 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001375 rc = -EINVAL;
1376 goto out;
1377 }
1378 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001379 printk(KERN_WARNING "%s: Encrypted flag not set\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001380 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001381 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001382 goto out;
1383 }
Tyler Hicks8faece52009-03-20 01:25:09 -05001384 virt_len = crypt_stat->num_header_bytes_at_front;
1385 order = get_order(virt_len);
Michael Halcrow237fead2006-10-04 02:16:22 -07001386 /* Released in this function */
Tyler Hicks8faece52009-03-20 01:25:09 -05001387 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001388 if (!virt) {
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001389 printk(KERN_ERR "%s: Out of memory\n", __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001390 rc = -ENOMEM;
1391 goto out;
1392 }
Tyler Hicks8faece52009-03-20 01:25:09 -05001393 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1394 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001395 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001396 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001397 __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001398 goto out_free;
1399 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001400 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicks8faece52009-03-20 01:25:09 -05001401 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1402 size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001403 else
Tyler Hicks8faece52009-03-20 01:25:09 -05001404 rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
1405 virt_len);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001406 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001407 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001408 "rc = [%d]\n", __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001409 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001410 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001411out_free:
Tyler Hicks8faece52009-03-20 01:25:09 -05001412 free_pages((unsigned long)virt, order);
Michael Halcrow237fead2006-10-04 02:16:22 -07001413out:
1414 return rc;
1415}
1416
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001417#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1418#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001419static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001420 char *virt, int *bytes_read,
1421 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001422{
1423 int rc = 0;
1424 u32 header_extent_size;
1425 u16 num_header_extents_at_front;
1426
Harvey Harrison29335c62008-07-23 21:30:06 -07001427 header_extent_size = get_unaligned_be32(virt);
1428 virt += sizeof(__be32);
1429 num_header_extents_at_front = get_unaligned_be16(virt);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001430 crypt_stat->num_header_bytes_at_front =
1431 (((size_t)num_header_extents_at_front
1432 * (size_t)header_extent_size));
Harvey Harrison29335c62008-07-23 21:30:06 -07001433 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001434 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001435 && (crypt_stat->num_header_bytes_at_front
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001436 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001437 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001438 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1439 crypt_stat->num_header_bytes_at_front);
Michael Halcrow237fead2006-10-04 02:16:22 -07001440 }
1441 return rc;
1442}
1443
1444/**
1445 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001446 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001447 *
1448 * For version 0 file format; this function is only for backwards
1449 * compatibility for files created with the prior versions of
1450 * eCryptfs.
1451 */
1452static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1453{
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001454 crypt_stat->num_header_bytes_at_front =
1455 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001456}
1457
1458/**
1459 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001460 * @page_virt: The virtual address into which to read the headers
1461 * @crypt_stat: The cryptographic context
1462 * @ecryptfs_dentry: The eCryptfs dentry
1463 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001464 *
1465 * Read/parse the header data. The header format is detailed in the
1466 * comment block for the ecryptfs_write_headers_virt() function.
1467 *
1468 * Returns zero on success
1469 */
1470static int ecryptfs_read_headers_virt(char *page_virt,
1471 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001472 struct dentry *ecryptfs_dentry,
1473 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001474{
1475 int rc = 0;
1476 int offset;
1477 int bytes_read;
1478
1479 ecryptfs_set_default_sizes(crypt_stat);
1480 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1481 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1482 offset = ECRYPTFS_FILE_SIZE_BYTES;
1483 rc = contains_ecryptfs_marker(page_virt + offset);
1484 if (rc == 0) {
1485 rc = -EINVAL;
1486 goto out;
1487 }
1488 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1489 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1490 &bytes_read);
1491 if (rc) {
1492 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1493 goto out;
1494 }
1495 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1496 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1497 "file version [%d] is supported by this "
1498 "version of eCryptfs\n",
1499 crypt_stat->file_version,
1500 ECRYPTFS_SUPPORTED_FILE_VERSION);
1501 rc = -EINVAL;
1502 goto out;
1503 }
1504 offset += bytes_read;
1505 if (crypt_stat->file_version >= 1) {
1506 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001507 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001508 if (rc) {
1509 ecryptfs_printk(KERN_WARNING, "Error reading header "
1510 "metadata; rc = [%d]\n", rc);
1511 }
1512 offset += bytes_read;
1513 } else
1514 set_default_header_data(crypt_stat);
1515 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1516 ecryptfs_dentry);
1517out:
1518 return rc;
1519}
1520
1521/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001522 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001523 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001524 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001525 *
1526 * Attempts to read the crypto metadata from the extended attribute
1527 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001528 *
1529 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001530 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001531int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001532{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001533 struct dentry *lower_dentry =
1534 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001535 ssize_t size;
1536 int rc = 0;
1537
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001538 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1539 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001540 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001541 if (unlikely(ecryptfs_verbosity > 0))
1542 printk(KERN_INFO "Error attempting to read the [%s] "
1543 "xattr from the lower file; return value = "
1544 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001545 rc = -EINVAL;
1546 goto out;
1547 }
1548out:
1549 return rc;
1550}
1551
1552int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1553 struct dentry *ecryptfs_dentry)
1554{
1555 int rc;
1556
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001557 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001558 if (rc)
1559 goto out;
1560 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1561 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1562 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1563 rc = -EINVAL;
1564 }
1565out:
1566 return rc;
1567}
1568
1569/**
1570 * ecryptfs_read_metadata
1571 *
1572 * Common entry point for reading file metadata. From here, we could
1573 * retrieve the header information from the header region of the file,
1574 * the xattr region of the file, or some other repostory that is
1575 * stored separately from the file itself. The current implementation
1576 * supports retrieving the metadata information from the file contents
1577 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001578 *
1579 * Returns zero if valid headers found and parsed; non-zero otherwise
1580 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001581int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001582{
1583 int rc = 0;
1584 char *page_virt = NULL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001585 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -07001586 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001587 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001588 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1589 &ecryptfs_superblock_to_private(
1590 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001591
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001592 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1593 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001594 /* Read the first page from the underlying file */
Christoph Lameterf7267c02006-12-06 20:33:15 -08001595 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001596 if (!page_virt) {
1597 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001598 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001599 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001600 goto out;
1601 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001602 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1603 ecryptfs_inode);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -05001604 if (rc >= 0)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001605 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1606 ecryptfs_dentry,
1607 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001608 if (rc) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001609 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001610 if (rc) {
1611 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1612 "file header region or xattr region\n");
1613 rc = -EINVAL;
1614 goto out;
1615 }
1616 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1617 ecryptfs_dentry,
1618 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1619 if (rc) {
1620 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1621 "file xattr region either\n");
1622 rc = -EINVAL;
1623 }
1624 if (crypt_stat->mount_crypt_stat->flags
1625 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1626 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1627 } else {
1628 printk(KERN_WARNING "Attempt to access file with "
1629 "crypto metadata only in the extended attribute "
1630 "region, but eCryptfs was mounted without "
1631 "xattr support enabled. eCryptfs will not treat "
1632 "this like an encrypted file.\n");
1633 rc = -EINVAL;
1634 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001635 }
1636out:
1637 if (page_virt) {
1638 memset(page_virt, 0, PAGE_CACHE_SIZE);
1639 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1640 }
1641 return rc;
1642}
1643
1644/**
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001645 * ecryptfs_encrypt_filename - encrypt filename
1646 *
1647 * CBC-encrypts the filename. We do not want to encrypt the same
1648 * filename with the same key and IV, which may happen with hard
1649 * links, so we prepend random bits to each filename.
1650 *
1651 * Returns zero on success; non-zero otherwise
1652 */
1653static int
1654ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1655 struct ecryptfs_crypt_stat *crypt_stat,
1656 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1657{
1658 int rc = 0;
1659
1660 filename->encrypted_filename = NULL;
1661 filename->encrypted_filename_size = 0;
1662 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1663 || (mount_crypt_stat && (mount_crypt_stat->flags
1664 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1665 size_t packet_size;
1666 size_t remaining_bytes;
1667
1668 rc = ecryptfs_write_tag_70_packet(
1669 NULL, NULL,
1670 &filename->encrypted_filename_size,
1671 mount_crypt_stat, NULL,
1672 filename->filename_size);
1673 if (rc) {
1674 printk(KERN_ERR "%s: Error attempting to get packet "
1675 "size for tag 72; rc = [%d]\n", __func__,
1676 rc);
1677 filename->encrypted_filename_size = 0;
1678 goto out;
1679 }
1680 filename->encrypted_filename =
1681 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1682 if (!filename->encrypted_filename) {
1683 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08001684 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001685 filename->encrypted_filename_size);
1686 rc = -ENOMEM;
1687 goto out;
1688 }
1689 remaining_bytes = filename->encrypted_filename_size;
1690 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1691 &remaining_bytes,
1692 &packet_size,
1693 mount_crypt_stat,
1694 filename->filename,
1695 filename->filename_size);
1696 if (rc) {
1697 printk(KERN_ERR "%s: Error attempting to generate "
1698 "tag 70 packet; rc = [%d]\n", __func__,
1699 rc);
1700 kfree(filename->encrypted_filename);
1701 filename->encrypted_filename = NULL;
1702 filename->encrypted_filename_size = 0;
1703 goto out;
1704 }
1705 filename->encrypted_filename_size = packet_size;
1706 } else {
1707 printk(KERN_ERR "%s: No support for requested filename "
1708 "encryption method in this release\n", __func__);
Tyler Hicksdf6ad332009-08-21 04:27:46 -05001709 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001710 goto out;
1711 }
1712out:
1713 return rc;
1714}
1715
1716static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1717 const char *name, size_t name_size)
1718{
1719 int rc = 0;
1720
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001721 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001722 if (!(*copied_name)) {
1723 rc = -ENOMEM;
1724 goto out;
1725 }
1726 memcpy((void *)(*copied_name), (void *)name, name_size);
1727 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1728 * in printing out the
1729 * string in debug
1730 * messages */
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001731 (*copied_name_size) = name_size;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001732out:
1733 return rc;
1734}
1735
1736/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001737 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001738 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001739 * @cipher_name: Name of the cipher
1740 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001741 *
1742 * Returns zero on success. Any crypto_tfm structs allocated here
1743 * should be released by other functions, such as on a superblock put
1744 * event, regardless of whether this function succeeds for fails.
1745 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001746static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001747ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1748 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001749{
1750 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Michael Halcrow8bba0662006-10-30 22:07:18 -08001751 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -07001752 int rc;
1753
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001754 *key_tfm = NULL;
1755 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001756 rc = -EINVAL;
Michael Halcrowdf261c52009-01-06 14:42:02 -08001757 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001758 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001759 goto out;
1760 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001761 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1762 "ecb");
1763 if (rc)
1764 goto out;
1765 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1766 kfree(full_alg_name);
1767 if (IS_ERR(*key_tfm)) {
1768 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001769 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Dave Hansen38268492009-08-27 09:47:07 -07001770 "[%s]; rc = [%d]\n", full_alg_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001771 goto out;
1772 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001773 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1774 if (*key_size == 0) {
1775 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1776
1777 *key_size = alg->max_keysize;
1778 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001779 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001780 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001781 if (rc) {
Michael Halcrowdf261c52009-01-06 14:42:02 -08001782 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
Dave Hansen38268492009-08-27 09:47:07 -07001783 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1784 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001785 rc = -EINVAL;
1786 goto out;
1787 }
1788out:
1789 return rc;
1790}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001791
1792struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001793static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001794struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001795
1796int ecryptfs_init_crypto(void)
1797{
1798 mutex_init(&key_tfm_list_mutex);
1799 INIT_LIST_HEAD(&key_tfm_list);
1800 return 0;
1801}
1802
Eric Sandeenaf440f52008-02-06 01:38:37 -08001803/**
1804 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1805 *
1806 * Called only at module unload time
1807 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001808int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001809{
1810 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1811
1812 mutex_lock(&key_tfm_list_mutex);
1813 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1814 key_tfm_list) {
1815 list_del(&key_tfm->key_tfm_list);
1816 if (key_tfm->key_tfm)
1817 crypto_free_blkcipher(key_tfm->key_tfm);
1818 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1819 }
1820 mutex_unlock(&key_tfm_list_mutex);
1821 return 0;
1822}
1823
1824int
1825ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1826 size_t key_size)
1827{
1828 struct ecryptfs_key_tfm *tmp_tfm;
1829 int rc = 0;
1830
Eric Sandeenaf440f52008-02-06 01:38:37 -08001831 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1832
Michael Halcrowf4aad162007-10-16 01:27:53 -07001833 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1834 if (key_tfm != NULL)
1835 (*key_tfm) = tmp_tfm;
1836 if (!tmp_tfm) {
1837 rc = -ENOMEM;
1838 printk(KERN_ERR "Error attempting to allocate from "
1839 "ecryptfs_key_tfm_cache\n");
1840 goto out;
1841 }
1842 mutex_init(&tmp_tfm->key_tfm_mutex);
1843 strncpy(tmp_tfm->cipher_name, cipher_name,
1844 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001845 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001846 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001847 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1848 tmp_tfm->cipher_name,
1849 &tmp_tfm->key_size);
1850 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001851 printk(KERN_ERR "Error attempting to initialize key TFM "
1852 "cipher with name = [%s]; rc = [%d]\n",
1853 tmp_tfm->cipher_name, rc);
1854 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1855 if (key_tfm != NULL)
1856 (*key_tfm) = NULL;
1857 goto out;
1858 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001859 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001860out:
1861 return rc;
1862}
1863
Eric Sandeenaf440f52008-02-06 01:38:37 -08001864/**
1865 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1866 * @cipher_name: the name of the cipher to search for
1867 * @key_tfm: set to corresponding tfm if found
1868 *
1869 * Searches for cached key_tfm matching @cipher_name
1870 * Must be called with &key_tfm_list_mutex held
1871 * Returns 1 if found, with @key_tfm set
1872 * Returns 0 if not found, with @key_tfm set to NULL
1873 */
1874int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1875{
1876 struct ecryptfs_key_tfm *tmp_key_tfm;
1877
1878 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1879
1880 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1881 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1882 if (key_tfm)
1883 (*key_tfm) = tmp_key_tfm;
1884 return 1;
1885 }
1886 }
1887 if (key_tfm)
1888 (*key_tfm) = NULL;
1889 return 0;
1890}
1891
1892/**
1893 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1894 *
1895 * @tfm: set to cached tfm found, or new tfm created
1896 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1897 * @cipher_name: the name of the cipher to search for and/or add
1898 *
1899 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1900 * Searches for cached item first, and creates new if not found.
1901 * Returns 0 on success, non-zero if adding new cipher failed
1902 */
Michael Halcrowf4aad162007-10-16 01:27:53 -07001903int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1904 struct mutex **tfm_mutex,
1905 char *cipher_name)
1906{
1907 struct ecryptfs_key_tfm *key_tfm;
1908 int rc = 0;
1909
1910 (*tfm) = NULL;
1911 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001912
Michael Halcrowf4aad162007-10-16 01:27:53 -07001913 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001914 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1915 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1916 if (rc) {
1917 printk(KERN_ERR "Error adding new key_tfm to list; "
1918 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001919 goto out;
1920 }
1921 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001922 (*tfm) = key_tfm->key_tfm;
1923 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1924out:
Cyrill Gorcunov71fd5172008-05-23 13:04:20 -07001925 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001926 return rc;
1927}
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001928
1929/* 64 characters forming a 6-bit target field */
1930static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1931 "EFGHIJKLMNOPQRST"
1932 "UVWXYZabcdefghij"
1933 "klmnopqrstuvwxyz");
1934
1935/* We could either offset on every reverse map or just pad some 0x00's
1936 * at the front here */
Michael Halcrow71c11c32009-01-06 14:42:05 -08001937static const unsigned char filename_rev_map[] = {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001938 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1939 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1940 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1941 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1942 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1943 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1944 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1945 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1946 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1947 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1948 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1949 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1950 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1951 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1952 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1953 0x3D, 0x3E, 0x3F
1954};
1955
1956/**
1957 * ecryptfs_encode_for_filename
1958 * @dst: Destination location for encoded filename
1959 * @dst_size: Size of the encoded filename in bytes
1960 * @src: Source location for the filename to encode
1961 * @src_size: Size of the source in bytes
1962 */
1963void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1964 unsigned char *src, size_t src_size)
1965{
1966 size_t num_blocks;
1967 size_t block_num = 0;
1968 size_t dst_offset = 0;
1969 unsigned char last_block[3];
1970
1971 if (src_size == 0) {
1972 (*dst_size) = 0;
1973 goto out;
1974 }
1975 num_blocks = (src_size / 3);
1976 if ((src_size % 3) == 0) {
1977 memcpy(last_block, (&src[src_size - 3]), 3);
1978 } else {
1979 num_blocks++;
1980 last_block[2] = 0x00;
1981 switch (src_size % 3) {
1982 case 1:
1983 last_block[0] = src[src_size - 1];
1984 last_block[1] = 0x00;
1985 break;
1986 case 2:
1987 last_block[0] = src[src_size - 2];
1988 last_block[1] = src[src_size - 1];
1989 }
1990 }
1991 (*dst_size) = (num_blocks * 4);
1992 if (!dst)
1993 goto out;
1994 while (block_num < num_blocks) {
1995 unsigned char *src_block;
1996 unsigned char dst_block[4];
1997
1998 if (block_num == (num_blocks - 1))
1999 src_block = last_block;
2000 else
2001 src_block = &src[block_num * 3];
2002 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2003 dst_block[1] = (((src_block[0] << 4) & 0x30)
2004 | ((src_block[1] >> 4) & 0x0F));
2005 dst_block[2] = (((src_block[1] << 2) & 0x3C)
2006 | ((src_block[2] >> 6) & 0x03));
2007 dst_block[3] = (src_block[2] & 0x3F);
2008 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2009 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2010 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2011 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2012 block_num++;
2013 }
2014out:
2015 return;
2016}
2017
Michael Halcrow71c11c32009-01-06 14:42:05 -08002018/**
2019 * ecryptfs_decode_from_filename
2020 * @dst: If NULL, this function only sets @dst_size and returns. If
2021 * non-NULL, this function decodes the encoded octets in @src
2022 * into the memory that @dst points to.
2023 * @dst_size: Set to the size of the decoded string.
2024 * @src: The encoded set of octets to decode.
2025 * @src_size: The size of the encoded set of octets to decode.
2026 */
2027static void
2028ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2029 const unsigned char *src, size_t src_size)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002030{
2031 u8 current_bit_offset = 0;
2032 size_t src_byte_offset = 0;
2033 size_t dst_byte_offset = 0;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002034
2035 if (dst == NULL) {
Michael Halcrow71c11c32009-01-06 14:42:05 -08002036 /* Not exact; conservatively long. Every block of 4
2037 * encoded characters decodes into a block of 3
2038 * decoded characters. This segment of code provides
2039 * the caller with the maximum amount of allocated
2040 * space that @dst will need to point to in a
2041 * subsequent call. */
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002042 (*dst_size) = (((src_size + 1) * 3) / 4);
2043 goto out;
2044 }
2045 while (src_byte_offset < src_size) {
2046 unsigned char src_byte =
2047 filename_rev_map[(int)src[src_byte_offset]];
2048
2049 switch (current_bit_offset) {
2050 case 0:
2051 dst[dst_byte_offset] = (src_byte << 2);
2052 current_bit_offset = 6;
2053 break;
2054 case 6:
2055 dst[dst_byte_offset++] |= (src_byte >> 4);
2056 dst[dst_byte_offset] = ((src_byte & 0xF)
2057 << 4);
2058 current_bit_offset = 4;
2059 break;
2060 case 4:
2061 dst[dst_byte_offset++] |= (src_byte >> 2);
2062 dst[dst_byte_offset] = (src_byte << 6);
2063 current_bit_offset = 2;
2064 break;
2065 case 2:
2066 dst[dst_byte_offset++] |= (src_byte);
2067 dst[dst_byte_offset] = 0;
2068 current_bit_offset = 0;
2069 break;
2070 }
2071 src_byte_offset++;
2072 }
2073 (*dst_size) = dst_byte_offset;
2074out:
Michael Halcrow71c11c32009-01-06 14:42:05 -08002075 return;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002076}
2077
2078/**
2079 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2080 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2081 * @name: The plaintext name
2082 * @length: The length of the plaintext
2083 * @encoded_name: The encypted name
2084 *
2085 * Encrypts and encodes a filename into something that constitutes a
2086 * valid filename for a filesystem, with printable characters.
2087 *
2088 * We assume that we have a properly initialized crypto context,
2089 * pointed to by crypt_stat->tfm.
2090 *
2091 * Returns zero on success; non-zero on otherwise
2092 */
2093int ecryptfs_encrypt_and_encode_filename(
2094 char **encoded_name,
2095 size_t *encoded_name_size,
2096 struct ecryptfs_crypt_stat *crypt_stat,
2097 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2098 const char *name, size_t name_size)
2099{
2100 size_t encoded_name_no_prefix_size;
2101 int rc = 0;
2102
2103 (*encoded_name) = NULL;
2104 (*encoded_name_size) = 0;
2105 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2106 || (mount_crypt_stat && (mount_crypt_stat->flags
2107 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2108 struct ecryptfs_filename *filename;
2109
2110 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2111 if (!filename) {
2112 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002113 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002114 sizeof(*filename));
2115 rc = -ENOMEM;
2116 goto out;
2117 }
2118 filename->filename = (char *)name;
2119 filename->filename_size = name_size;
2120 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2121 mount_crypt_stat);
2122 if (rc) {
2123 printk(KERN_ERR "%s: Error attempting to encrypt "
2124 "filename; rc = [%d]\n", __func__, rc);
2125 kfree(filename);
2126 goto out;
2127 }
2128 ecryptfs_encode_for_filename(
2129 NULL, &encoded_name_no_prefix_size,
2130 filename->encrypted_filename,
2131 filename->encrypted_filename_size);
2132 if ((crypt_stat && (crypt_stat->flags
2133 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2134 || (mount_crypt_stat
2135 && (mount_crypt_stat->flags
2136 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2137 (*encoded_name_size) =
2138 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2139 + encoded_name_no_prefix_size);
2140 else
2141 (*encoded_name_size) =
2142 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2143 + encoded_name_no_prefix_size);
2144 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2145 if (!(*encoded_name)) {
2146 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002147 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002148 (*encoded_name_size));
2149 rc = -ENOMEM;
2150 kfree(filename->encrypted_filename);
2151 kfree(filename);
2152 goto out;
2153 }
2154 if ((crypt_stat && (crypt_stat->flags
2155 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2156 || (mount_crypt_stat
2157 && (mount_crypt_stat->flags
2158 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2159 memcpy((*encoded_name),
2160 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2161 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2162 ecryptfs_encode_for_filename(
2163 ((*encoded_name)
2164 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2165 &encoded_name_no_prefix_size,
2166 filename->encrypted_filename,
2167 filename->encrypted_filename_size);
2168 (*encoded_name_size) =
2169 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2170 + encoded_name_no_prefix_size);
2171 (*encoded_name)[(*encoded_name_size)] = '\0';
2172 (*encoded_name_size)++;
2173 } else {
Tyler Hicksdf6ad332009-08-21 04:27:46 -05002174 rc = -EOPNOTSUPP;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002175 }
2176 if (rc) {
2177 printk(KERN_ERR "%s: Error attempting to encode "
2178 "encrypted filename; rc = [%d]\n", __func__,
2179 rc);
2180 kfree((*encoded_name));
2181 (*encoded_name) = NULL;
2182 (*encoded_name_size) = 0;
2183 }
2184 kfree(filename->encrypted_filename);
2185 kfree(filename);
2186 } else {
2187 rc = ecryptfs_copy_filename(encoded_name,
2188 encoded_name_size,
2189 name, name_size);
2190 }
2191out:
2192 return rc;
2193}
2194
2195/**
2196 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2197 * @plaintext_name: The plaintext name
2198 * @plaintext_name_size: The plaintext name size
2199 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2200 * @name: The filename in cipher text
2201 * @name_size: The cipher text name size
2202 *
2203 * Decrypts and decodes the filename.
2204 *
2205 * Returns zero on error; non-zero otherwise
2206 */
2207int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2208 size_t *plaintext_name_size,
2209 struct dentry *ecryptfs_dir_dentry,
2210 const char *name, size_t name_size)
2211{
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002212 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2213 &ecryptfs_superblock_to_private(
2214 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002215 char *decoded_name;
2216 size_t decoded_name_size;
2217 size_t packet_size;
2218 int rc = 0;
2219
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002220 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2221 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2222 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002223 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2224 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002225 const char *orig_name = name;
2226 size_t orig_name_size = name_size;
2227
2228 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2229 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
Michael Halcrow71c11c32009-01-06 14:42:05 -08002230 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2231 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002232 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2233 if (!decoded_name) {
2234 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08002235 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002236 decoded_name_size);
2237 rc = -ENOMEM;
2238 goto out;
2239 }
Michael Halcrow71c11c32009-01-06 14:42:05 -08002240 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2241 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002242 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2243 plaintext_name_size,
2244 &packet_size,
2245 mount_crypt_stat,
2246 decoded_name,
2247 decoded_name_size);
2248 if (rc) {
2249 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2250 "from filename; copying through filename "
2251 "as-is\n", __func__);
2252 rc = ecryptfs_copy_filename(plaintext_name,
2253 plaintext_name_size,
2254 orig_name, orig_name_size);
2255 goto out_free;
2256 }
2257 } else {
2258 rc = ecryptfs_copy_filename(plaintext_name,
2259 plaintext_name_size,
2260 name, name_size);
2261 goto out;
2262 }
2263out_free:
2264 kfree(decoded_name);
2265out:
2266 return rc;
2267}