blob: 8b65f289ee00802a54f3ed2e3d9718de5a9a0d65 [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 mutex_lock(&crypt_stat->keysig_list_mutex);
249 list_for_each_entry_safe(key_sig, key_sig_tmp,
250 &crypt_stat->keysig_list, crypt_stat_list) {
251 list_del(&key_sig->crypt_stat_list);
252 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
253 }
254 mutex_unlock(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700255 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
256}
257
Michael Halcrowfcd12832007-10-16 01:28:01 -0700258void ecryptfs_destroy_mount_crypt_stat(
Michael Halcrow237fead2006-10-04 02:16:22 -0700259 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
260{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700261 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
262
263 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
264 return;
265 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
266 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
267 &mount_crypt_stat->global_auth_tok_list,
268 mount_crypt_stat_list) {
269 list_del(&auth_tok->mount_crypt_stat_list);
270 mount_crypt_stat->num_global_auth_toks--;
271 if (auth_tok->global_auth_tok_key
272 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
273 key_put(auth_tok->global_auth_tok_key);
274 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
275 }
276 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700277 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
278}
279
280/**
281 * virt_to_scatterlist
282 * @addr: Virtual address
283 * @size: Size of data; should be an even multiple of the block size
284 * @sg: Pointer to scatterlist array; set to NULL to obtain only
285 * the number of scatterlist structs required in array
286 * @sg_size: Max array size
287 *
288 * Fills in a scatterlist array with page references for a passed
289 * virtual address.
290 *
291 * Returns the number of scatterlist structs in array used
292 */
293int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
294 int sg_size)
295{
296 int i = 0;
297 struct page *pg;
298 int offset;
299 int remainder_of_page;
300
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700301 sg_init_table(sg, sg_size);
302
Michael Halcrow237fead2006-10-04 02:16:22 -0700303 while (size > 0 && i < sg_size) {
304 pg = virt_to_page(addr);
305 offset = offset_in_page(addr);
Jens Axboe642f1492007-10-24 11:20:47 +0200306 if (sg)
307 sg_set_page(&sg[i], pg, 0, offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700308 remainder_of_page = PAGE_CACHE_SIZE - offset;
309 if (size >= remainder_of_page) {
310 if (sg)
311 sg[i].length = remainder_of_page;
312 addr += remainder_of_page;
313 size -= remainder_of_page;
314 } else {
315 if (sg)
316 sg[i].length = size;
317 addr += size;
318 size = 0;
319 }
320 i++;
321 }
322 if (size > 0)
323 return -ENOMEM;
324 return i;
325}
326
327/**
328 * encrypt_scatterlist
329 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
330 * @dest_sg: Destination of encrypted data
331 * @src_sg: Data to be encrypted
332 * @size: Length of data to be encrypted
333 * @iv: iv to use during encryption
334 *
335 * Returns the number of bytes encrypted; negative value on error
336 */
337static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
338 struct scatterlist *dest_sg,
339 struct scatterlist *src_sg, int size,
340 unsigned char *iv)
341{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800342 struct blkcipher_desc desc = {
343 .tfm = crypt_stat->tfm,
344 .info = iv,
345 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
346 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700347 int rc = 0;
348
349 BUG_ON(!crypt_stat || !crypt_stat->tfm
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800350 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
Michael Halcrow237fead2006-10-04 02:16:22 -0700351 if (unlikely(ecryptfs_verbosity > 0)) {
352 ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n",
353 crypt_stat->key_size);
354 ecryptfs_dump_hex(crypt_stat->key,
355 crypt_stat->key_size);
356 }
357 /* Consider doing this once, when the file is opened */
358 mutex_lock(&crypt_stat->cs_tfm_mutex);
Trevor Highland8e3a6f12008-02-06 01:38:33 -0800359 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
360 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
361 crypt_stat->key_size);
362 crypt_stat->flags |= ECRYPTFS_KEY_SET;
363 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700364 if (rc) {
365 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
366 rc);
367 mutex_unlock(&crypt_stat->cs_tfm_mutex);
368 rc = -EINVAL;
369 goto out;
370 }
371 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800372 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700373 mutex_unlock(&crypt_stat->cs_tfm_mutex);
374out:
375 return rc;
376}
377
Michael Halcrow237fead2006-10-04 02:16:22 -0700378/**
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700379 * ecryptfs_lower_offset_for_extent
380 *
381 * Convert an eCryptfs page index into a lower byte offset
382 */
Adrian Bunk7896b632008-02-06 01:38:32 -0800383static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
384 struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700385{
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800386 (*offset) = (crypt_stat->num_header_bytes_at_front
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700387 + (crypt_stat->extent_size * extent_num));
388}
389
390/**
391 * ecryptfs_encrypt_extent
392 * @enc_extent_page: Allocated page into which to encrypt the data in
393 * @page
394 * @crypt_stat: crypt_stat containing cryptographic context for the
395 * encryption operation
396 * @page: Page containing plaintext data extent to encrypt
397 * @extent_offset: Page extent offset for use in generating IV
398 *
399 * Encrypts one extent of data.
400 *
401 * Return zero on success; non-zero otherwise
402 */
403static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
404 struct ecryptfs_crypt_stat *crypt_stat,
405 struct page *page,
406 unsigned long extent_offset)
407{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700408 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700409 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
410 int rc;
411
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700412 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700413 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
414 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
415 (extent_base + extent_offset));
416 if (rc) {
417 ecryptfs_printk(KERN_ERR, "Error attempting to "
418 "derive IV for extent [0x%.16x]; "
419 "rc = [%d]\n", (extent_base + extent_offset),
420 rc);
421 goto out;
422 }
423 if (unlikely(ecryptfs_verbosity > 0)) {
424 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
425 "with iv:\n");
426 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
427 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
428 "encryption:\n");
429 ecryptfs_dump_hex((char *)
430 (page_address(page)
431 + (extent_offset * crypt_stat->extent_size)),
432 8);
433 }
434 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
435 page, (extent_offset
436 * crypt_stat->extent_size),
437 crypt_stat->extent_size, extent_iv);
438 if (rc < 0) {
439 printk(KERN_ERR "%s: Error attempting to encrypt page with "
440 "page->index = [%ld], extent_offset = [%ld]; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700441 "rc = [%d]\n", __func__, page->index, extent_offset,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700442 rc);
443 goto out;
444 }
445 rc = 0;
446 if (unlikely(ecryptfs_verbosity > 0)) {
447 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
448 "rc = [%d]\n", (extent_base + extent_offset),
449 rc);
450 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
451 "encryption:\n");
452 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
453 }
454out:
455 return rc;
456}
457
458/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700459 * ecryptfs_encrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700460 * @page: Page mapped from the eCryptfs inode for the file; contains
461 * decrypted content that needs to be encrypted (to a temporary
462 * page; not in place) and written out to the lower file
Michael Halcrow237fead2006-10-04 02:16:22 -0700463 *
464 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
465 * that eCryptfs pages may straddle the lower pages -- for instance,
466 * if the file was created on a machine with an 8K page size
467 * (resulting in an 8K header), and then the file is copied onto a
468 * host with a 32K page size, then when reading page 0 of the eCryptfs
469 * file, 24K of page 0 of the lower file will be read and decrypted,
470 * and then 8K of page 1 of the lower file will be read and decrypted.
471 *
Michael Halcrow237fead2006-10-04 02:16:22 -0700472 * Returns zero on success; negative on error
473 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700474int ecryptfs_encrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700475{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700476 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700477 struct ecryptfs_crypt_stat *crypt_stat;
Eric Sandeen7fcba052008-07-28 15:46:39 -0700478 char *enc_extent_virt;
479 struct page *enc_extent_page = NULL;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700480 loff_t extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700481 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700482
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700483 ecryptfs_inode = page->mapping->host;
484 crypt_stat =
485 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800486 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700487 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
488 0, PAGE_CACHE_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -0700489 if (rc)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700490 printk(KERN_ERR "%s: Error attempting to copy "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700491 "page at index [%ld]\n", __func__,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700492 page->index);
Michael Halcrow237fead2006-10-04 02:16:22 -0700493 goto out;
494 }
Eric Sandeen7fcba052008-07-28 15:46:39 -0700495 enc_extent_page = alloc_page(GFP_USER);
496 if (!enc_extent_page) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700497 rc = -ENOMEM;
498 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
499 "encrypted extent\n");
500 goto out;
501 }
Eric Sandeen7fcba052008-07-28 15:46:39 -0700502 enc_extent_virt = kmap(enc_extent_page);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700503 for (extent_offset = 0;
504 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
505 extent_offset++) {
506 loff_t offset;
507
508 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
509 extent_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700510 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700511 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700512 "rc = [%d]\n", __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700513 goto out;
514 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700515 ecryptfs_lower_offset_for_extent(
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700516 &offset, ((((loff_t)page->index)
517 * (PAGE_CACHE_SIZE
518 / crypt_stat->extent_size))
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700519 + extent_offset), crypt_stat);
520 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
521 offset, crypt_stat->extent_size);
522 if (rc) {
523 ecryptfs_printk(KERN_ERR, "Error attempting "
524 "to write lower page; rc = [%d]"
525 "\n", rc);
526 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700527 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700528 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700529out:
Eric Sandeen7fcba052008-07-28 15:46:39 -0700530 if (enc_extent_page) {
531 kunmap(enc_extent_page);
532 __free_page(enc_extent_page);
533 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700534 return rc;
535}
536
537static int ecryptfs_decrypt_extent(struct page *page,
538 struct ecryptfs_crypt_stat *crypt_stat,
539 struct page *enc_extent_page,
540 unsigned long extent_offset)
541{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700542 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700543 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
544 int rc;
545
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700546 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700547 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
548 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
549 (extent_base + extent_offset));
Michael Halcrow237fead2006-10-04 02:16:22 -0700550 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700551 ecryptfs_printk(KERN_ERR, "Error attempting to "
552 "derive IV for extent [0x%.16x]; "
553 "rc = [%d]\n", (extent_base + extent_offset),
554 rc);
555 goto out;
556 }
557 if (unlikely(ecryptfs_verbosity > 0)) {
558 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
559 "with iv:\n");
560 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
561 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
562 "decryption:\n");
563 ecryptfs_dump_hex((char *)
564 (page_address(enc_extent_page)
565 + (extent_offset * crypt_stat->extent_size)),
566 8);
567 }
568 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
569 (extent_offset
570 * crypt_stat->extent_size),
571 enc_extent_page, 0,
572 crypt_stat->extent_size, extent_iv);
573 if (rc < 0) {
574 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
575 "page->index = [%ld], extent_offset = [%ld]; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700576 "rc = [%d]\n", __func__, page->index, extent_offset,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700577 rc);
578 goto out;
579 }
580 rc = 0;
581 if (unlikely(ecryptfs_verbosity > 0)) {
582 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
583 "rc = [%d]\n", (extent_base + extent_offset),
584 rc);
585 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
586 "decryption:\n");
587 ecryptfs_dump_hex((char *)(page_address(page)
588 + (extent_offset
589 * crypt_stat->extent_size)), 8);
Michael Halcrow237fead2006-10-04 02:16:22 -0700590 }
591out:
592 return rc;
593}
594
595/**
596 * ecryptfs_decrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700597 * @page: Page mapped from the eCryptfs inode for the file; data read
598 * and decrypted from the lower file will be written into this
599 * page
Michael Halcrow237fead2006-10-04 02:16:22 -0700600 *
601 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
602 * that eCryptfs pages may straddle the lower pages -- for instance,
603 * if the file was created on a machine with an 8K page size
604 * (resulting in an 8K header), and then the file is copied onto a
605 * host with a 32K page size, then when reading page 0 of the eCryptfs
606 * file, 24K of page 0 of the lower file will be read and decrypted,
607 * and then 8K of page 1 of the lower file will be read and decrypted.
608 *
609 * Returns zero on success; negative on error
610 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700611int ecryptfs_decrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700612{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700613 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700614 struct ecryptfs_crypt_stat *crypt_stat;
Eric Sandeen7fcba052008-07-28 15:46:39 -0700615 char *enc_extent_virt;
616 struct page *enc_extent_page = NULL;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700617 unsigned long extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700618 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700619
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700620 ecryptfs_inode = page->mapping->host;
621 crypt_stat =
622 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800623 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700624 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
625 PAGE_CACHE_SIZE,
626 ecryptfs_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700627 if (rc)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700628 printk(KERN_ERR "%s: Error attempting to copy "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700629 "page at index [%ld]\n", __func__,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700630 page->index);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700631 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700632 }
Eric Sandeen7fcba052008-07-28 15:46:39 -0700633 enc_extent_page = alloc_page(GFP_USER);
634 if (!enc_extent_page) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700635 rc = -ENOMEM;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700636 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
637 "encrypted extent\n");
Michael Halcrow16a72c42007-10-16 01:28:14 -0700638 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700639 }
Eric Sandeen7fcba052008-07-28 15:46:39 -0700640 enc_extent_virt = kmap(enc_extent_page);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700641 for (extent_offset = 0;
642 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
643 extent_offset++) {
644 loff_t offset;
645
646 ecryptfs_lower_offset_for_extent(
647 &offset, ((page->index * (PAGE_CACHE_SIZE
648 / crypt_stat->extent_size))
649 + extent_offset), crypt_stat);
650 rc = ecryptfs_read_lower(enc_extent_virt, offset,
651 crypt_stat->extent_size,
652 ecryptfs_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700653 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700654 ecryptfs_printk(KERN_ERR, "Error attempting "
655 "to read lower page; rc = [%d]"
656 "\n", rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700657 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700658 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700659 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
660 extent_offset);
661 if (rc) {
662 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700663 "rc = [%d]\n", __func__, rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700664 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700665 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700666 }
667out:
Eric Sandeen7fcba052008-07-28 15:46:39 -0700668 if (enc_extent_page) {
669 kunmap(enc_extent_page);
670 __free_page(enc_extent_page);
671 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700672 return rc;
673}
674
675/**
676 * decrypt_scatterlist
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700677 * @crypt_stat: Cryptographic context
678 * @dest_sg: The destination scatterlist to decrypt into
679 * @src_sg: The source scatterlist to decrypt from
680 * @size: The number of bytes to decrypt
681 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700682 *
683 * Returns the number of bytes decrypted; negative value on error
684 */
685static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
686 struct scatterlist *dest_sg,
687 struct scatterlist *src_sg, int size,
688 unsigned char *iv)
689{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800690 struct blkcipher_desc desc = {
691 .tfm = crypt_stat->tfm,
692 .info = iv,
693 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
694 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700695 int rc = 0;
696
697 /* Consider doing this once, when the file is opened */
698 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800699 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
700 crypt_stat->key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700701 if (rc) {
702 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
703 rc);
704 mutex_unlock(&crypt_stat->cs_tfm_mutex);
705 rc = -EINVAL;
706 goto out;
707 }
708 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800709 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700710 mutex_unlock(&crypt_stat->cs_tfm_mutex);
711 if (rc) {
712 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
713 rc);
714 goto out;
715 }
716 rc = size;
717out:
718 return rc;
719}
720
721/**
722 * ecryptfs_encrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700723 * @crypt_stat: The cryptographic context
724 * @dst_page: The page to encrypt into
725 * @dst_offset: The offset in the page to encrypt into
726 * @src_page: The page to encrypt from
727 * @src_offset: The offset in the page to encrypt from
728 * @size: The number of bytes to encrypt
729 * @iv: The initialization vector to use for the encryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700730 *
731 * Returns the number of bytes encrypted
732 */
733static int
734ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
735 struct page *dst_page, int dst_offset,
736 struct page *src_page, int src_offset, int size,
737 unsigned char *iv)
738{
739 struct scatterlist src_sg, dst_sg;
740
Jens Axboe60c74f82007-10-22 19:43:30 +0200741 sg_init_table(&src_sg, 1);
742 sg_init_table(&dst_sg, 1);
743
Jens Axboe642f1492007-10-24 11:20:47 +0200744 sg_set_page(&src_sg, src_page, size, src_offset);
745 sg_set_page(&dst_sg, dst_page, size, dst_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700746 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
747}
748
749/**
750 * ecryptfs_decrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700751 * @crypt_stat: The cryptographic context
752 * @dst_page: The page to decrypt into
753 * @dst_offset: The offset in the page to decrypt into
754 * @src_page: The page to decrypt from
755 * @src_offset: The offset in the page to decrypt from
756 * @size: The number of bytes to decrypt
757 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700758 *
759 * Returns the number of bytes decrypted
760 */
761static int
762ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
763 struct page *dst_page, int dst_offset,
764 struct page *src_page, int src_offset, int size,
765 unsigned char *iv)
766{
767 struct scatterlist src_sg, dst_sg;
768
Jens Axboe60c74f82007-10-22 19:43:30 +0200769 sg_init_table(&src_sg, 1);
Jens Axboe642f1492007-10-24 11:20:47 +0200770 sg_set_page(&src_sg, src_page, size, src_offset);
Jens Axboe60c74f82007-10-22 19:43:30 +0200771
Jens Axboe642f1492007-10-24 11:20:47 +0200772 sg_init_table(&dst_sg, 1);
773 sg_set_page(&dst_sg, dst_page, size, dst_offset);
774
Michael Halcrow237fead2006-10-04 02:16:22 -0700775 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
776}
777
778#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
779
780/**
781 * ecryptfs_init_crypt_ctx
782 * @crypt_stat: Uninitilized crypt stats structure
783 *
784 * Initialize the crypto context.
785 *
786 * TODO: Performance: Keep a cache of initialized cipher contexts;
787 * only init if needed
788 */
789int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
790{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800791 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700792 int rc = -EINVAL;
793
794 if (!crypt_stat->cipher) {
795 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
796 goto out;
797 }
798 ecryptfs_printk(KERN_DEBUG,
799 "Initializing cipher [%s]; strlen = [%d]; "
800 "key_size_bits = [%d]\n",
801 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
802 crypt_stat->key_size << 3);
803 if (crypt_stat->tfm) {
804 rc = 0;
805 goto out;
806 }
807 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800808 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
809 crypt_stat->cipher, "cbc");
810 if (rc)
Eric Sandeenc8161f62007-12-22 14:03:26 -0800811 goto out_unlock;
Michael Halcrow8bba0662006-10-30 22:07:18 -0800812 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
813 CRYPTO_ALG_ASYNC);
814 kfree(full_alg_name);
Akinobu Mitade887772006-11-28 12:29:49 -0800815 if (IS_ERR(crypt_stat->tfm)) {
816 rc = PTR_ERR(crypt_stat->tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700817 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
818 "Error initializing cipher [%s]\n",
819 crypt_stat->cipher);
Eric Sandeenc8161f62007-12-22 14:03:26 -0800820 goto out_unlock;
Michael Halcrow237fead2006-10-04 02:16:22 -0700821 }
Herbert Xuf1ddcaf2007-01-27 10:05:15 +1100822 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow237fead2006-10-04 02:16:22 -0700823 rc = 0;
Eric Sandeenc8161f62007-12-22 14:03:26 -0800824out_unlock:
825 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700826out:
827 return rc;
828}
829
830static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
831{
832 int extent_size_tmp;
833
834 crypt_stat->extent_mask = 0xFFFFFFFF;
835 crypt_stat->extent_shift = 0;
836 if (crypt_stat->extent_size == 0)
837 return;
838 extent_size_tmp = crypt_stat->extent_size;
839 while ((extent_size_tmp & 0x01) == 0) {
840 extent_size_tmp >>= 1;
841 crypt_stat->extent_mask <<= 1;
842 crypt_stat->extent_shift++;
843 }
844}
845
846void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
847{
848 /* Default values; may be overwritten as we are parsing the
849 * packets. */
850 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
851 set_extent_mask_and_shift(crypt_stat);
852 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800853 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800854 crypt_stat->num_header_bytes_at_front = 0;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700855 else {
856 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800857 crypt_stat->num_header_bytes_at_front =
858 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700859 else
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800860 crypt_stat->num_header_bytes_at_front = PAGE_CACHE_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700861 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700862}
863
864/**
865 * ecryptfs_compute_root_iv
866 * @crypt_stats
867 *
868 * On error, sets the root IV to all 0's.
869 */
870int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
871{
872 int rc = 0;
873 char dst[MD5_DIGEST_SIZE];
874
875 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
876 BUG_ON(crypt_stat->iv_bytes <= 0);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800877 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700878 rc = -EINVAL;
879 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
880 "cannot generate root IV\n");
881 goto out;
882 }
883 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
884 crypt_stat->key_size);
885 if (rc) {
886 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
887 "MD5 while generating root IV\n");
888 goto out;
889 }
890 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
891out:
892 if (rc) {
893 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800894 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
Michael Halcrow237fead2006-10-04 02:16:22 -0700895 }
896 return rc;
897}
898
899static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
900{
901 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800902 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
Michael Halcrow237fead2006-10-04 02:16:22 -0700903 ecryptfs_compute_root_iv(crypt_stat);
904 if (unlikely(ecryptfs_verbosity > 0)) {
905 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
906 ecryptfs_dump_hex(crypt_stat->key,
907 crypt_stat->key_size);
908 }
909}
910
911/**
Michael Halcrow17398952007-02-12 00:53:45 -0800912 * ecryptfs_copy_mount_wide_flags_to_inode_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700913 * @crypt_stat: The inode's cryptographic context
914 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow17398952007-02-12 00:53:45 -0800915 *
916 * This function propagates the mount-wide flags to individual inode
917 * flags.
918 */
919static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
920 struct ecryptfs_crypt_stat *crypt_stat,
921 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
922{
923 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
924 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
925 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
926 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800927 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
928 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
929 if (mount_crypt_stat->flags
930 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
931 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
932 else if (mount_crypt_stat->flags
933 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
934 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
935 }
Michael Halcrow17398952007-02-12 00:53:45 -0800936}
937
Michael Halcrowf4aad162007-10-16 01:27:53 -0700938static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
939 struct ecryptfs_crypt_stat *crypt_stat,
940 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
941{
942 struct ecryptfs_global_auth_tok *global_auth_tok;
943 int rc = 0;
944
945 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
946 list_for_each_entry(global_auth_tok,
947 &mount_crypt_stat->global_auth_tok_list,
948 mount_crypt_stat_list) {
Tyler Hicks84814d62009-03-13 13:51:59 -0700949 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
950 continue;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700951 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
952 if (rc) {
953 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
954 mutex_unlock(
955 &mount_crypt_stat->global_auth_tok_list_mutex);
956 goto out;
957 }
958 }
959 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
960out:
961 return rc;
962}
963
Michael Halcrow17398952007-02-12 00:53:45 -0800964/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700965 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700966 * @crypt_stat: The inode's cryptographic context
967 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700968 *
969 * Default values in the event that policy does not override them.
970 */
971static void ecryptfs_set_default_crypt_stat_vals(
972 struct ecryptfs_crypt_stat *crypt_stat,
973 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
974{
Michael Halcrow17398952007-02-12 00:53:45 -0800975 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
976 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700977 ecryptfs_set_default_sizes(crypt_stat);
978 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
979 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800980 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -0700981 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
982 crypt_stat->mount_crypt_stat = mount_crypt_stat;
983}
984
985/**
986 * ecryptfs_new_file_context
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700987 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -0700988 *
989 * If the crypto context for the file has not yet been established,
990 * this is where we do that. Establishing a new crypto context
991 * involves the following decisions:
992 * - What cipher to use?
993 * - What set of authentication tokens to use?
994 * Here we just worry about getting enough information into the
995 * authentication tokens so that we know that they are available.
996 * We associate the available authentication tokens with the new file
997 * via the set of signatures in the crypt_stat struct. Later, when
998 * the headers are actually written out, we may again defer to
999 * userspace to perform the encryption of the session key; for the
1000 * foreseeable future, this will be the case with public key packets.
1001 *
1002 * Returns zero on success; non-zero otherwise
1003 */
Michael Halcrow237fead2006-10-04 02:16:22 -07001004int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
1005{
Michael Halcrow237fead2006-10-04 02:16:22 -07001006 struct ecryptfs_crypt_stat *crypt_stat =
1007 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1008 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1009 &ecryptfs_superblock_to_private(
1010 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1011 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001012 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001013
1014 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -07001015 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001016 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1017 mount_crypt_stat);
1018 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1019 mount_crypt_stat);
1020 if (rc) {
1021 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1022 "to the inode key sigs; rc = [%d]\n", rc);
1023 goto out;
1024 }
1025 cipher_name_len =
1026 strlen(mount_crypt_stat->global_default_cipher_name);
1027 memcpy(crypt_stat->cipher,
1028 mount_crypt_stat->global_default_cipher_name,
1029 cipher_name_len);
1030 crypt_stat->cipher[cipher_name_len] = '\0';
1031 crypt_stat->key_size =
1032 mount_crypt_stat->global_default_cipher_key_size;
1033 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001034 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1035 if (rc)
1036 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1037 "context for cipher [%s]: rc = [%d]\n",
1038 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001039out:
Michael Halcrow237fead2006-10-04 02:16:22 -07001040 return rc;
1041}
1042
1043/**
1044 * contains_ecryptfs_marker - check for the ecryptfs marker
1045 * @data: The data block in which to check
1046 *
1047 * Returns one if marker found; zero if not found
1048 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001049static int contains_ecryptfs_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -07001050{
1051 u32 m_1, m_2;
1052
Harvey Harrison29335c62008-07-23 21:30:06 -07001053 m_1 = get_unaligned_be32(data);
1054 m_2 = get_unaligned_be32(data + 4);
Michael Halcrow237fead2006-10-04 02:16:22 -07001055 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1056 return 1;
1057 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1058 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1059 MAGIC_ECRYPTFS_MARKER);
1060 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1061 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1062 return 0;
1063}
1064
1065struct ecryptfs_flag_map_elem {
1066 u32 file_flag;
1067 u32 local_flag;
1068};
1069
1070/* Add support for additional flags by adding elements here. */
1071static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1072 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001073 {0x00000002, ECRYPTFS_ENCRYPTED},
Michael Halcrowaddd65ad2009-01-06 14:42:00 -08001074 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1075 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
Michael Halcrow237fead2006-10-04 02:16:22 -07001076};
1077
1078/**
1079 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001080 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001081 * @page_virt: Source data to be parsed
1082 * @bytes_read: Updated with the number of bytes read
1083 *
1084 * Returns zero on success; non-zero if the flag set is invalid
1085 */
1086static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1087 char *page_virt, int *bytes_read)
1088{
1089 int rc = 0;
1090 int i;
1091 u32 flags;
1092
Harvey Harrison29335c62008-07-23 21:30:06 -07001093 flags = get_unaligned_be32(page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001094 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1095 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1096 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001097 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -07001098 } else
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001099 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
Michael Halcrow237fead2006-10-04 02:16:22 -07001100 /* Version is in top 8 bits of the 32-bit flag vector */
1101 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1102 (*bytes_read) = 4;
1103 return rc;
1104}
1105
1106/**
1107 * write_ecryptfs_marker
1108 * @page_virt: The pointer to in a page to begin writing the marker
1109 * @written: Number of bytes written
1110 *
1111 * Marker = 0x3c81b7f5
1112 */
1113static void write_ecryptfs_marker(char *page_virt, size_t *written)
1114{
1115 u32 m_1, m_2;
1116
1117 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1118 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
Harvey Harrison29335c62008-07-23 21:30:06 -07001119 put_unaligned_be32(m_1, page_virt);
1120 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1121 put_unaligned_be32(m_2, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001122 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1123}
1124
1125static void
1126write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1127 size_t *written)
1128{
1129 u32 flags = 0;
1130 int i;
1131
1132 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1133 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001134 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -07001135 flags |= ecryptfs_flag_map[i].file_flag;
1136 /* Version is in top 8 bits of the 32-bit flag vector */
1137 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
Harvey Harrison29335c62008-07-23 21:30:06 -07001138 put_unaligned_be32(flags, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001139 (*written) = 4;
1140}
1141
1142struct ecryptfs_cipher_code_str_map_elem {
1143 char cipher_str[16];
Trevor Highland19e66a62008-02-06 01:38:36 -08001144 u8 cipher_code;
Michael Halcrow237fead2006-10-04 02:16:22 -07001145};
1146
1147/* Add support for additional ciphers by adding elements here. The
1148 * cipher_code is whatever OpenPGP applicatoins use to identify the
1149 * ciphers. List in order of probability. */
1150static struct ecryptfs_cipher_code_str_map_elem
1151ecryptfs_cipher_code_str_map[] = {
1152 {"aes",RFC2440_CIPHER_AES_128 },
1153 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1154 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1155 {"cast5", RFC2440_CIPHER_CAST_5},
1156 {"twofish", RFC2440_CIPHER_TWOFISH},
1157 {"cast6", RFC2440_CIPHER_CAST_6},
1158 {"aes", RFC2440_CIPHER_AES_192},
1159 {"aes", RFC2440_CIPHER_AES_256}
1160};
1161
1162/**
1163 * ecryptfs_code_for_cipher_string
Michael Halcrow9c79f342009-01-06 14:41:57 -08001164 * @cipher_name: The string alias for the cipher
1165 * @key_bytes: Length of key in bytes; used for AES code selection
Michael Halcrow237fead2006-10-04 02:16:22 -07001166 *
1167 * Returns zero on no match, or the cipher code on match
1168 */
Michael Halcrow9c79f342009-01-06 14:41:57 -08001169u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
Michael Halcrow237fead2006-10-04 02:16:22 -07001170{
1171 int i;
Trevor Highland19e66a62008-02-06 01:38:36 -08001172 u8 code = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001173 struct ecryptfs_cipher_code_str_map_elem *map =
1174 ecryptfs_cipher_code_str_map;
1175
Michael Halcrow9c79f342009-01-06 14:41:57 -08001176 if (strcmp(cipher_name, "aes") == 0) {
1177 switch (key_bytes) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001178 case 16:
1179 code = RFC2440_CIPHER_AES_128;
1180 break;
1181 case 24:
1182 code = RFC2440_CIPHER_AES_192;
1183 break;
1184 case 32:
1185 code = RFC2440_CIPHER_AES_256;
1186 }
1187 } else {
1188 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
Michael Halcrow9c79f342009-01-06 14:41:57 -08001189 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001190 code = map[i].cipher_code;
1191 break;
1192 }
1193 }
1194 return code;
1195}
1196
1197/**
1198 * ecryptfs_cipher_code_to_string
1199 * @str: Destination to write out the cipher name
1200 * @cipher_code: The code to convert to cipher name string
1201 *
1202 * Returns zero on success
1203 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001204int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
Michael Halcrow237fead2006-10-04 02:16:22 -07001205{
1206 int rc = 0;
1207 int i;
1208
1209 str[0] = '\0';
1210 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1211 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1212 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1213 if (str[0] == '\0') {
1214 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1215 "[%d]\n", cipher_code);
1216 rc = -EINVAL;
1217 }
1218 return rc;
1219}
1220
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001221int ecryptfs_read_and_validate_header_region(char *data,
1222 struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001223{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001224 struct ecryptfs_crypt_stat *crypt_stat =
1225 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001226 int rc;
1227
Michael Halcrowaddd65ad2009-01-06 14:42:00 -08001228 if (crypt_stat->extent_size == 0)
1229 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001230 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1231 ecryptfs_inode);
1232 if (rc) {
1233 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001234 __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001235 goto out;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001236 }
1237 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001238 rc = -EINVAL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001239 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001240out:
1241 return rc;
1242}
1243
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001244void
1245ecryptfs_write_header_metadata(char *virt,
1246 struct ecryptfs_crypt_stat *crypt_stat,
1247 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001248{
1249 u32 header_extent_size;
1250 u16 num_header_extents_at_front;
1251
Michael Halcrow45eaab72007-10-16 01:28:05 -07001252 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001253 num_header_extents_at_front =
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001254 (u16)(crypt_stat->num_header_bytes_at_front
1255 / crypt_stat->extent_size);
Harvey Harrison29335c62008-07-23 21:30:06 -07001256 put_unaligned_be32(header_extent_size, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001257 virt += 4;
Harvey Harrison29335c62008-07-23 21:30:06 -07001258 put_unaligned_be16(num_header_extents_at_front, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001259 (*written) = 6;
1260}
1261
Michael Halcrow237fead2006-10-04 02:16:22 -07001262struct kmem_cache *ecryptfs_header_cache_1;
1263struct kmem_cache *ecryptfs_header_cache_2;
1264
1265/**
1266 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001267 * @page_virt: The virtual address to write the headers to
Eric Sandeen87b811c2008-10-29 14:01:08 -07001268 * @max: The size of memory allocated at page_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001269 * @size: Set to the number of bytes written by this function
1270 * @crypt_stat: The cryptographic context
1271 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001272 *
1273 * Format version: 1
1274 *
1275 * Header Extent:
1276 * Octets 0-7: Unencrypted file size (big-endian)
1277 * Octets 8-15: eCryptfs special marker
1278 * Octets 16-19: Flags
1279 * Octet 16: File format version number (between 0 and 255)
1280 * Octets 17-18: Reserved
1281 * Octet 19: Bit 1 (lsb): Reserved
1282 * Bit 2: Encrypted?
1283 * Bits 3-8: Reserved
1284 * Octets 20-23: Header extent size (big-endian)
1285 * Octets 24-25: Number of header extents at front of file
1286 * (big-endian)
1287 * Octet 26: Begin RFC 2440 authentication token packet set
1288 * Data Extent 0:
1289 * Lower data (CBC encrypted)
1290 * Data Extent 1:
1291 * Lower data (CBC encrypted)
1292 * ...
1293 *
1294 * Returns zero on success
1295 */
Eric Sandeen87b811c2008-10-29 14:01:08 -07001296static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1297 size_t *size,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001298 struct ecryptfs_crypt_stat *crypt_stat,
1299 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001300{
1301 int rc;
1302 size_t written;
1303 size_t offset;
1304
1305 offset = ECRYPTFS_FILE_SIZE_BYTES;
1306 write_ecryptfs_marker((page_virt + offset), &written);
1307 offset += written;
1308 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1309 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001310 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1311 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001312 offset += written;
1313 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1314 ecryptfs_dentry, &written,
Eric Sandeen87b811c2008-10-29 14:01:08 -07001315 max - offset);
Michael Halcrow237fead2006-10-04 02:16:22 -07001316 if (rc)
1317 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1318 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001319 if (size) {
1320 offset += written;
1321 *size = offset;
1322 }
1323 return rc;
1324}
1325
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001326static int
Tyler Hicks8faece52009-03-20 01:25:09 -05001327ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
1328 char *virt, size_t virt_len)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001329{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001330 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001331
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001332 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
Tyler Hicks8faece52009-03-20 01:25:09 -05001333 0, virt_len);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001334 if (rc)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001335 printk(KERN_ERR "%s: Error attempting to write header "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001336 "information to lower file; rc = [%d]\n", __func__,
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001337 rc);
Michael Halcrow70456602007-02-12 00:53:48 -08001338 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001339}
1340
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001341static int
1342ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001343 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001344{
1345 int rc;
1346
1347 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1348 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001349 return rc;
1350}
1351
Tyler Hicks8faece52009-03-20 01:25:09 -05001352static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1353 unsigned int order)
1354{
1355 struct page *page;
1356
1357 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1358 if (page)
1359 return (unsigned long) page_address(page);
1360 return 0;
1361}
1362
Michael Halcrow237fead2006-10-04 02:16:22 -07001363/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001364 * ecryptfs_write_metadata
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001365 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001366 *
1367 * Write the file headers out. This will likely involve a userspace
1368 * callout, in which the session key is encrypted with one or more
1369 * public keys and/or the passphrase necessary to do the encryption is
1370 * retrieved via a prompt. Exactly what happens at this point should
1371 * be policy-dependent.
1372 *
1373 * Returns zero on success; non-zero on error
1374 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001375int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001376{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001377 struct ecryptfs_crypt_stat *crypt_stat =
1378 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
Tyler Hicks8faece52009-03-20 01:25:09 -05001379 unsigned int order;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001380 char *virt;
Tyler Hicks8faece52009-03-20 01:25:09 -05001381 size_t virt_len;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001382 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001383 int rc = 0;
1384
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001385 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1386 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001387 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001388 rc = -EINVAL;
1389 goto out;
1390 }
1391 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001392 printk(KERN_WARNING "%s: Encrypted flag not set\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001393 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001394 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001395 goto out;
1396 }
Tyler Hicks8faece52009-03-20 01:25:09 -05001397 virt_len = crypt_stat->num_header_bytes_at_front;
1398 order = get_order(virt_len);
Michael Halcrow237fead2006-10-04 02:16:22 -07001399 /* Released in this function */
Tyler Hicks8faece52009-03-20 01:25:09 -05001400 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001401 if (!virt) {
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001402 printk(KERN_ERR "%s: Out of memory\n", __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001403 rc = -ENOMEM;
1404 goto out;
1405 }
Tyler Hicks8faece52009-03-20 01:25:09 -05001406 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1407 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001408 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001409 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001410 __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001411 goto out_free;
1412 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001413 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Tyler Hicks8faece52009-03-20 01:25:09 -05001414 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1415 size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001416 else
Tyler Hicks8faece52009-03-20 01:25:09 -05001417 rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
1418 virt_len);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001419 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001420 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001421 "rc = [%d]\n", __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001422 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001423 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001424out_free:
Tyler Hicks8faece52009-03-20 01:25:09 -05001425 free_pages((unsigned long)virt, order);
Michael Halcrow237fead2006-10-04 02:16:22 -07001426out:
1427 return rc;
1428}
1429
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001430#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1431#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001432static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001433 char *virt, int *bytes_read,
1434 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001435{
1436 int rc = 0;
1437 u32 header_extent_size;
1438 u16 num_header_extents_at_front;
1439
Harvey Harrison29335c62008-07-23 21:30:06 -07001440 header_extent_size = get_unaligned_be32(virt);
1441 virt += sizeof(__be32);
1442 num_header_extents_at_front = get_unaligned_be16(virt);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001443 crypt_stat->num_header_bytes_at_front =
1444 (((size_t)num_header_extents_at_front
1445 * (size_t)header_extent_size));
Harvey Harrison29335c62008-07-23 21:30:06 -07001446 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001447 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001448 && (crypt_stat->num_header_bytes_at_front
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001449 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001450 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001451 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1452 crypt_stat->num_header_bytes_at_front);
Michael Halcrow237fead2006-10-04 02:16:22 -07001453 }
1454 return rc;
1455}
1456
1457/**
1458 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001459 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001460 *
1461 * For version 0 file format; this function is only for backwards
1462 * compatibility for files created with the prior versions of
1463 * eCryptfs.
1464 */
1465static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1466{
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001467 crypt_stat->num_header_bytes_at_front =
1468 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001469}
1470
1471/**
1472 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001473 * @page_virt: The virtual address into which to read the headers
1474 * @crypt_stat: The cryptographic context
1475 * @ecryptfs_dentry: The eCryptfs dentry
1476 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001477 *
1478 * Read/parse the header data. The header format is detailed in the
1479 * comment block for the ecryptfs_write_headers_virt() function.
1480 *
1481 * Returns zero on success
1482 */
1483static int ecryptfs_read_headers_virt(char *page_virt,
1484 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001485 struct dentry *ecryptfs_dentry,
1486 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001487{
1488 int rc = 0;
1489 int offset;
1490 int bytes_read;
1491
1492 ecryptfs_set_default_sizes(crypt_stat);
1493 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1494 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1495 offset = ECRYPTFS_FILE_SIZE_BYTES;
1496 rc = contains_ecryptfs_marker(page_virt + offset);
1497 if (rc == 0) {
1498 rc = -EINVAL;
1499 goto out;
1500 }
1501 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1502 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1503 &bytes_read);
1504 if (rc) {
1505 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1506 goto out;
1507 }
1508 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1509 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1510 "file version [%d] is supported by this "
1511 "version of eCryptfs\n",
1512 crypt_stat->file_version,
1513 ECRYPTFS_SUPPORTED_FILE_VERSION);
1514 rc = -EINVAL;
1515 goto out;
1516 }
1517 offset += bytes_read;
1518 if (crypt_stat->file_version >= 1) {
1519 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001520 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001521 if (rc) {
1522 ecryptfs_printk(KERN_WARNING, "Error reading header "
1523 "metadata; rc = [%d]\n", rc);
1524 }
1525 offset += bytes_read;
1526 } else
1527 set_default_header_data(crypt_stat);
1528 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1529 ecryptfs_dentry);
1530out:
1531 return rc;
1532}
1533
1534/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001535 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001536 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001537 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001538 *
1539 * Attempts to read the crypto metadata from the extended attribute
1540 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001541 *
1542 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001543 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001544int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001545{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001546 struct dentry *lower_dentry =
1547 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001548 ssize_t size;
1549 int rc = 0;
1550
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001551 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1552 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001553 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001554 if (unlikely(ecryptfs_verbosity > 0))
1555 printk(KERN_INFO "Error attempting to read the [%s] "
1556 "xattr from the lower file; return value = "
1557 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001558 rc = -EINVAL;
1559 goto out;
1560 }
1561out:
1562 return rc;
1563}
1564
1565int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1566 struct dentry *ecryptfs_dentry)
1567{
1568 int rc;
1569
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001570 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001571 if (rc)
1572 goto out;
1573 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1574 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1575 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1576 rc = -EINVAL;
1577 }
1578out:
1579 return rc;
1580}
1581
1582/**
1583 * ecryptfs_read_metadata
1584 *
1585 * Common entry point for reading file metadata. From here, we could
1586 * retrieve the header information from the header region of the file,
1587 * the xattr region of the file, or some other repostory that is
1588 * stored separately from the file itself. The current implementation
1589 * supports retrieving the metadata information from the file contents
1590 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001591 *
1592 * Returns zero if valid headers found and parsed; non-zero otherwise
1593 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001594int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001595{
1596 int rc = 0;
1597 char *page_virt = NULL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001598 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -07001599 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001600 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001601 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1602 &ecryptfs_superblock_to_private(
1603 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001604
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001605 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1606 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001607 /* Read the first page from the underlying file */
Christoph Lameterf7267c02006-12-06 20:33:15 -08001608 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001609 if (!page_virt) {
1610 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001611 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001612 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001613 goto out;
1614 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001615 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1616 ecryptfs_inode);
1617 if (!rc)
1618 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1619 ecryptfs_dentry,
1620 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001621 if (rc) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001622 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001623 if (rc) {
1624 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1625 "file header region or xattr region\n");
1626 rc = -EINVAL;
1627 goto out;
1628 }
1629 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1630 ecryptfs_dentry,
1631 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1632 if (rc) {
1633 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1634 "file xattr region either\n");
1635 rc = -EINVAL;
1636 }
1637 if (crypt_stat->mount_crypt_stat->flags
1638 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1639 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1640 } else {
1641 printk(KERN_WARNING "Attempt to access file with "
1642 "crypto metadata only in the extended attribute "
1643 "region, but eCryptfs was mounted without "
1644 "xattr support enabled. eCryptfs will not treat "
1645 "this like an encrypted file.\n");
1646 rc = -EINVAL;
1647 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001648 }
1649out:
1650 if (page_virt) {
1651 memset(page_virt, 0, PAGE_CACHE_SIZE);
1652 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1653 }
1654 return rc;
1655}
1656
1657/**
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001658 * ecryptfs_encrypt_filename - encrypt filename
1659 *
1660 * CBC-encrypts the filename. We do not want to encrypt the same
1661 * filename with the same key and IV, which may happen with hard
1662 * links, so we prepend random bits to each filename.
1663 *
1664 * Returns zero on success; non-zero otherwise
1665 */
1666static int
1667ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1668 struct ecryptfs_crypt_stat *crypt_stat,
1669 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1670{
1671 int rc = 0;
1672
1673 filename->encrypted_filename = NULL;
1674 filename->encrypted_filename_size = 0;
1675 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1676 || (mount_crypt_stat && (mount_crypt_stat->flags
1677 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1678 size_t packet_size;
1679 size_t remaining_bytes;
1680
1681 rc = ecryptfs_write_tag_70_packet(
1682 NULL, NULL,
1683 &filename->encrypted_filename_size,
1684 mount_crypt_stat, NULL,
1685 filename->filename_size);
1686 if (rc) {
1687 printk(KERN_ERR "%s: Error attempting to get packet "
1688 "size for tag 72; rc = [%d]\n", __func__,
1689 rc);
1690 filename->encrypted_filename_size = 0;
1691 goto out;
1692 }
1693 filename->encrypted_filename =
1694 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1695 if (!filename->encrypted_filename) {
1696 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08001697 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001698 filename->encrypted_filename_size);
1699 rc = -ENOMEM;
1700 goto out;
1701 }
1702 remaining_bytes = filename->encrypted_filename_size;
1703 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1704 &remaining_bytes,
1705 &packet_size,
1706 mount_crypt_stat,
1707 filename->filename,
1708 filename->filename_size);
1709 if (rc) {
1710 printk(KERN_ERR "%s: Error attempting to generate "
1711 "tag 70 packet; rc = [%d]\n", __func__,
1712 rc);
1713 kfree(filename->encrypted_filename);
1714 filename->encrypted_filename = NULL;
1715 filename->encrypted_filename_size = 0;
1716 goto out;
1717 }
1718 filename->encrypted_filename_size = packet_size;
1719 } else {
1720 printk(KERN_ERR "%s: No support for requested filename "
1721 "encryption method in this release\n", __func__);
1722 rc = -ENOTSUPP;
1723 goto out;
1724 }
1725out:
1726 return rc;
1727}
1728
1729static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1730 const char *name, size_t name_size)
1731{
1732 int rc = 0;
1733
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001734 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001735 if (!(*copied_name)) {
1736 rc = -ENOMEM;
1737 goto out;
1738 }
1739 memcpy((void *)(*copied_name), (void *)name, name_size);
1740 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1741 * in printing out the
1742 * string in debug
1743 * messages */
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001744 (*copied_name_size) = name_size;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001745out:
1746 return rc;
1747}
1748
1749/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001750 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001751 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001752 * @cipher_name: Name of the cipher
1753 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001754 *
1755 * Returns zero on success. Any crypto_tfm structs allocated here
1756 * should be released by other functions, such as on a superblock put
1757 * event, regardless of whether this function succeeds for fails.
1758 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001759static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001760ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1761 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001762{
1763 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Michael Halcrow8bba0662006-10-30 22:07:18 -08001764 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -07001765 int rc;
1766
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001767 *key_tfm = NULL;
1768 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001769 rc = -EINVAL;
Michael Halcrowdf261c52009-01-06 14:42:02 -08001770 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001771 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001772 goto out;
1773 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001774 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1775 "ecb");
1776 if (rc)
1777 goto out;
1778 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1779 kfree(full_alg_name);
1780 if (IS_ERR(*key_tfm)) {
1781 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001782 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Michael Halcrow8bba0662006-10-30 22:07:18 -08001783 "[%s]; rc = [%d]\n", cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001784 goto out;
1785 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001786 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1787 if (*key_size == 0) {
1788 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1789
1790 *key_size = alg->max_keysize;
1791 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001792 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001793 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001794 if (rc) {
Michael Halcrowdf261c52009-01-06 14:42:02 -08001795 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001796 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001797 rc = -EINVAL;
1798 goto out;
1799 }
1800out:
1801 return rc;
1802}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001803
1804struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001805static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001806struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001807
1808int ecryptfs_init_crypto(void)
1809{
1810 mutex_init(&key_tfm_list_mutex);
1811 INIT_LIST_HEAD(&key_tfm_list);
1812 return 0;
1813}
1814
Eric Sandeenaf440f52008-02-06 01:38:37 -08001815/**
1816 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1817 *
1818 * Called only at module unload time
1819 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001820int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001821{
1822 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1823
1824 mutex_lock(&key_tfm_list_mutex);
1825 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1826 key_tfm_list) {
1827 list_del(&key_tfm->key_tfm_list);
1828 if (key_tfm->key_tfm)
1829 crypto_free_blkcipher(key_tfm->key_tfm);
1830 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1831 }
1832 mutex_unlock(&key_tfm_list_mutex);
1833 return 0;
1834}
1835
1836int
1837ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1838 size_t key_size)
1839{
1840 struct ecryptfs_key_tfm *tmp_tfm;
1841 int rc = 0;
1842
Eric Sandeenaf440f52008-02-06 01:38:37 -08001843 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1844
Michael Halcrowf4aad162007-10-16 01:27:53 -07001845 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1846 if (key_tfm != NULL)
1847 (*key_tfm) = tmp_tfm;
1848 if (!tmp_tfm) {
1849 rc = -ENOMEM;
1850 printk(KERN_ERR "Error attempting to allocate from "
1851 "ecryptfs_key_tfm_cache\n");
1852 goto out;
1853 }
1854 mutex_init(&tmp_tfm->key_tfm_mutex);
1855 strncpy(tmp_tfm->cipher_name, cipher_name,
1856 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001857 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001858 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001859 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1860 tmp_tfm->cipher_name,
1861 &tmp_tfm->key_size);
1862 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001863 printk(KERN_ERR "Error attempting to initialize key TFM "
1864 "cipher with name = [%s]; rc = [%d]\n",
1865 tmp_tfm->cipher_name, rc);
1866 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1867 if (key_tfm != NULL)
1868 (*key_tfm) = NULL;
1869 goto out;
1870 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001871 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001872out:
1873 return rc;
1874}
1875
Eric Sandeenaf440f52008-02-06 01:38:37 -08001876/**
1877 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1878 * @cipher_name: the name of the cipher to search for
1879 * @key_tfm: set to corresponding tfm if found
1880 *
1881 * Searches for cached key_tfm matching @cipher_name
1882 * Must be called with &key_tfm_list_mutex held
1883 * Returns 1 if found, with @key_tfm set
1884 * Returns 0 if not found, with @key_tfm set to NULL
1885 */
1886int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1887{
1888 struct ecryptfs_key_tfm *tmp_key_tfm;
1889
1890 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1891
1892 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1893 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1894 if (key_tfm)
1895 (*key_tfm) = tmp_key_tfm;
1896 return 1;
1897 }
1898 }
1899 if (key_tfm)
1900 (*key_tfm) = NULL;
1901 return 0;
1902}
1903
1904/**
1905 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1906 *
1907 * @tfm: set to cached tfm found, or new tfm created
1908 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1909 * @cipher_name: the name of the cipher to search for and/or add
1910 *
1911 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1912 * Searches for cached item first, and creates new if not found.
1913 * Returns 0 on success, non-zero if adding new cipher failed
1914 */
Michael Halcrowf4aad162007-10-16 01:27:53 -07001915int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1916 struct mutex **tfm_mutex,
1917 char *cipher_name)
1918{
1919 struct ecryptfs_key_tfm *key_tfm;
1920 int rc = 0;
1921
1922 (*tfm) = NULL;
1923 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001924
Michael Halcrowf4aad162007-10-16 01:27:53 -07001925 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001926 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1927 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1928 if (rc) {
1929 printk(KERN_ERR "Error adding new key_tfm to list; "
1930 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001931 goto out;
1932 }
1933 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001934 (*tfm) = key_tfm->key_tfm;
1935 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1936out:
Cyrill Gorcunov71fd5172008-05-23 13:04:20 -07001937 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001938 return rc;
1939}
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001940
1941/* 64 characters forming a 6-bit target field */
1942static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1943 "EFGHIJKLMNOPQRST"
1944 "UVWXYZabcdefghij"
1945 "klmnopqrstuvwxyz");
1946
1947/* We could either offset on every reverse map or just pad some 0x00's
1948 * at the front here */
Michael Halcrow71c11c32009-01-06 14:42:05 -08001949static const unsigned char filename_rev_map[] = {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001950 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1951 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1952 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1953 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1954 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1955 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1956 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1957 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1958 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1959 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1960 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1961 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1962 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1963 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1964 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1965 0x3D, 0x3E, 0x3F
1966};
1967
1968/**
1969 * ecryptfs_encode_for_filename
1970 * @dst: Destination location for encoded filename
1971 * @dst_size: Size of the encoded filename in bytes
1972 * @src: Source location for the filename to encode
1973 * @src_size: Size of the source in bytes
1974 */
1975void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1976 unsigned char *src, size_t src_size)
1977{
1978 size_t num_blocks;
1979 size_t block_num = 0;
1980 size_t dst_offset = 0;
1981 unsigned char last_block[3];
1982
1983 if (src_size == 0) {
1984 (*dst_size) = 0;
1985 goto out;
1986 }
1987 num_blocks = (src_size / 3);
1988 if ((src_size % 3) == 0) {
1989 memcpy(last_block, (&src[src_size - 3]), 3);
1990 } else {
1991 num_blocks++;
1992 last_block[2] = 0x00;
1993 switch (src_size % 3) {
1994 case 1:
1995 last_block[0] = src[src_size - 1];
1996 last_block[1] = 0x00;
1997 break;
1998 case 2:
1999 last_block[0] = src[src_size - 2];
2000 last_block[1] = src[src_size - 1];
2001 }
2002 }
2003 (*dst_size) = (num_blocks * 4);
2004 if (!dst)
2005 goto out;
2006 while (block_num < num_blocks) {
2007 unsigned char *src_block;
2008 unsigned char dst_block[4];
2009
2010 if (block_num == (num_blocks - 1))
2011 src_block = last_block;
2012 else
2013 src_block = &src[block_num * 3];
2014 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2015 dst_block[1] = (((src_block[0] << 4) & 0x30)
2016 | ((src_block[1] >> 4) & 0x0F));
2017 dst_block[2] = (((src_block[1] << 2) & 0x3C)
2018 | ((src_block[2] >> 6) & 0x03));
2019 dst_block[3] = (src_block[2] & 0x3F);
2020 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2021 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2022 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2023 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2024 block_num++;
2025 }
2026out:
2027 return;
2028}
2029
Michael Halcrow71c11c32009-01-06 14:42:05 -08002030/**
2031 * ecryptfs_decode_from_filename
2032 * @dst: If NULL, this function only sets @dst_size and returns. If
2033 * non-NULL, this function decodes the encoded octets in @src
2034 * into the memory that @dst points to.
2035 * @dst_size: Set to the size of the decoded string.
2036 * @src: The encoded set of octets to decode.
2037 * @src_size: The size of the encoded set of octets to decode.
2038 */
2039static void
2040ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2041 const unsigned char *src, size_t src_size)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002042{
2043 u8 current_bit_offset = 0;
2044 size_t src_byte_offset = 0;
2045 size_t dst_byte_offset = 0;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002046
2047 if (dst == NULL) {
Michael Halcrow71c11c32009-01-06 14:42:05 -08002048 /* Not exact; conservatively long. Every block of 4
2049 * encoded characters decodes into a block of 3
2050 * decoded characters. This segment of code provides
2051 * the caller with the maximum amount of allocated
2052 * space that @dst will need to point to in a
2053 * subsequent call. */
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002054 (*dst_size) = (((src_size + 1) * 3) / 4);
2055 goto out;
2056 }
2057 while (src_byte_offset < src_size) {
2058 unsigned char src_byte =
2059 filename_rev_map[(int)src[src_byte_offset]];
2060
2061 switch (current_bit_offset) {
2062 case 0:
2063 dst[dst_byte_offset] = (src_byte << 2);
2064 current_bit_offset = 6;
2065 break;
2066 case 6:
2067 dst[dst_byte_offset++] |= (src_byte >> 4);
2068 dst[dst_byte_offset] = ((src_byte & 0xF)
2069 << 4);
2070 current_bit_offset = 4;
2071 break;
2072 case 4:
2073 dst[dst_byte_offset++] |= (src_byte >> 2);
2074 dst[dst_byte_offset] = (src_byte << 6);
2075 current_bit_offset = 2;
2076 break;
2077 case 2:
2078 dst[dst_byte_offset++] |= (src_byte);
2079 dst[dst_byte_offset] = 0;
2080 current_bit_offset = 0;
2081 break;
2082 }
2083 src_byte_offset++;
2084 }
2085 (*dst_size) = dst_byte_offset;
2086out:
Michael Halcrow71c11c32009-01-06 14:42:05 -08002087 return;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002088}
2089
2090/**
2091 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2092 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2093 * @name: The plaintext name
2094 * @length: The length of the plaintext
2095 * @encoded_name: The encypted name
2096 *
2097 * Encrypts and encodes a filename into something that constitutes a
2098 * valid filename for a filesystem, with printable characters.
2099 *
2100 * We assume that we have a properly initialized crypto context,
2101 * pointed to by crypt_stat->tfm.
2102 *
2103 * Returns zero on success; non-zero on otherwise
2104 */
2105int ecryptfs_encrypt_and_encode_filename(
2106 char **encoded_name,
2107 size_t *encoded_name_size,
2108 struct ecryptfs_crypt_stat *crypt_stat,
2109 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2110 const char *name, size_t name_size)
2111{
2112 size_t encoded_name_no_prefix_size;
2113 int rc = 0;
2114
2115 (*encoded_name) = NULL;
2116 (*encoded_name_size) = 0;
2117 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2118 || (mount_crypt_stat && (mount_crypt_stat->flags
2119 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2120 struct ecryptfs_filename *filename;
2121
2122 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2123 if (!filename) {
2124 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002125 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002126 sizeof(*filename));
2127 rc = -ENOMEM;
2128 goto out;
2129 }
2130 filename->filename = (char *)name;
2131 filename->filename_size = name_size;
2132 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2133 mount_crypt_stat);
2134 if (rc) {
2135 printk(KERN_ERR "%s: Error attempting to encrypt "
2136 "filename; rc = [%d]\n", __func__, rc);
2137 kfree(filename);
2138 goto out;
2139 }
2140 ecryptfs_encode_for_filename(
2141 NULL, &encoded_name_no_prefix_size,
2142 filename->encrypted_filename,
2143 filename->encrypted_filename_size);
2144 if ((crypt_stat && (crypt_stat->flags
2145 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2146 || (mount_crypt_stat
2147 && (mount_crypt_stat->flags
2148 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2149 (*encoded_name_size) =
2150 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2151 + encoded_name_no_prefix_size);
2152 else
2153 (*encoded_name_size) =
2154 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2155 + encoded_name_no_prefix_size);
2156 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2157 if (!(*encoded_name)) {
2158 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002159 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002160 (*encoded_name_size));
2161 rc = -ENOMEM;
2162 kfree(filename->encrypted_filename);
2163 kfree(filename);
2164 goto out;
2165 }
2166 if ((crypt_stat && (crypt_stat->flags
2167 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2168 || (mount_crypt_stat
2169 && (mount_crypt_stat->flags
2170 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2171 memcpy((*encoded_name),
2172 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2173 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2174 ecryptfs_encode_for_filename(
2175 ((*encoded_name)
2176 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2177 &encoded_name_no_prefix_size,
2178 filename->encrypted_filename,
2179 filename->encrypted_filename_size);
2180 (*encoded_name_size) =
2181 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2182 + encoded_name_no_prefix_size);
2183 (*encoded_name)[(*encoded_name_size)] = '\0';
2184 (*encoded_name_size)++;
2185 } else {
2186 rc = -ENOTSUPP;
2187 }
2188 if (rc) {
2189 printk(KERN_ERR "%s: Error attempting to encode "
2190 "encrypted filename; rc = [%d]\n", __func__,
2191 rc);
2192 kfree((*encoded_name));
2193 (*encoded_name) = NULL;
2194 (*encoded_name_size) = 0;
2195 }
2196 kfree(filename->encrypted_filename);
2197 kfree(filename);
2198 } else {
2199 rc = ecryptfs_copy_filename(encoded_name,
2200 encoded_name_size,
2201 name, name_size);
2202 }
2203out:
2204 return rc;
2205}
2206
2207/**
2208 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2209 * @plaintext_name: The plaintext name
2210 * @plaintext_name_size: The plaintext name size
2211 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2212 * @name: The filename in cipher text
2213 * @name_size: The cipher text name size
2214 *
2215 * Decrypts and decodes the filename.
2216 *
2217 * Returns zero on error; non-zero otherwise
2218 */
2219int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2220 size_t *plaintext_name_size,
2221 struct dentry *ecryptfs_dir_dentry,
2222 const char *name, size_t name_size)
2223{
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002224 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2225 &ecryptfs_superblock_to_private(
2226 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002227 char *decoded_name;
2228 size_t decoded_name_size;
2229 size_t packet_size;
2230 int rc = 0;
2231
Tyler Hicks2aac0cf2009-03-20 02:23:57 -05002232 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2233 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2234 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002235 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2236 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002237 const char *orig_name = name;
2238 size_t orig_name_size = name_size;
2239
2240 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2241 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
Michael Halcrow71c11c32009-01-06 14:42:05 -08002242 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2243 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002244 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2245 if (!decoded_name) {
2246 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08002247 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002248 decoded_name_size);
2249 rc = -ENOMEM;
2250 goto out;
2251 }
Michael Halcrow71c11c32009-01-06 14:42:05 -08002252 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2253 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002254 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2255 plaintext_name_size,
2256 &packet_size,
2257 mount_crypt_stat,
2258 decoded_name,
2259 decoded_name_size);
2260 if (rc) {
2261 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2262 "from filename; copying through filename "
2263 "as-is\n", __func__);
2264 rc = ecryptfs_copy_filename(plaintext_name,
2265 plaintext_name_size,
2266 orig_name, orig_name_size);
2267 goto out_free;
2268 }
2269 } else {
2270 rc = ecryptfs_copy_filename(plaintext_name,
2271 plaintext_name_size,
2272 name, name_size);
2273 goto out;
2274 }
2275out_free:
2276 kfree(decoded_name);
2277out:
2278 return rc;
2279}