blob: f6caeb1d110621e7c24c1ab0b714f5774e333a93 [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) {
949 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
950 if (rc) {
951 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
952 mutex_unlock(
953 &mount_crypt_stat->global_auth_tok_list_mutex);
954 goto out;
955 }
956 }
957 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
958out:
959 return rc;
960}
961
Michael Halcrow17398952007-02-12 00:53:45 -0800962/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700963 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700964 * @crypt_stat: The inode's cryptographic context
965 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700966 *
967 * Default values in the event that policy does not override them.
968 */
969static void ecryptfs_set_default_crypt_stat_vals(
970 struct ecryptfs_crypt_stat *crypt_stat,
971 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
972{
Michael Halcrow17398952007-02-12 00:53:45 -0800973 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
974 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700975 ecryptfs_set_default_sizes(crypt_stat);
976 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
977 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800978 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -0700979 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
980 crypt_stat->mount_crypt_stat = mount_crypt_stat;
981}
982
983/**
984 * ecryptfs_new_file_context
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700985 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -0700986 *
987 * If the crypto context for the file has not yet been established,
988 * this is where we do that. Establishing a new crypto context
989 * involves the following decisions:
990 * - What cipher to use?
991 * - What set of authentication tokens to use?
992 * Here we just worry about getting enough information into the
993 * authentication tokens so that we know that they are available.
994 * We associate the available authentication tokens with the new file
995 * via the set of signatures in the crypt_stat struct. Later, when
996 * the headers are actually written out, we may again defer to
997 * userspace to perform the encryption of the session key; for the
998 * foreseeable future, this will be the case with public key packets.
999 *
1000 * Returns zero on success; non-zero otherwise
1001 */
Michael Halcrow237fead2006-10-04 02:16:22 -07001002int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
1003{
Michael Halcrow237fead2006-10-04 02:16:22 -07001004 struct ecryptfs_crypt_stat *crypt_stat =
1005 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1006 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1007 &ecryptfs_superblock_to_private(
1008 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1009 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001010 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001011
1012 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -07001013 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001014 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1015 mount_crypt_stat);
1016 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1017 mount_crypt_stat);
1018 if (rc) {
1019 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1020 "to the inode key sigs; rc = [%d]\n", rc);
1021 goto out;
1022 }
1023 cipher_name_len =
1024 strlen(mount_crypt_stat->global_default_cipher_name);
1025 memcpy(crypt_stat->cipher,
1026 mount_crypt_stat->global_default_cipher_name,
1027 cipher_name_len);
1028 crypt_stat->cipher[cipher_name_len] = '\0';
1029 crypt_stat->key_size =
1030 mount_crypt_stat->global_default_cipher_key_size;
1031 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001032 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1033 if (rc)
1034 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1035 "context for cipher [%s]: rc = [%d]\n",
1036 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001037out:
Michael Halcrow237fead2006-10-04 02:16:22 -07001038 return rc;
1039}
1040
1041/**
1042 * contains_ecryptfs_marker - check for the ecryptfs marker
1043 * @data: The data block in which to check
1044 *
1045 * Returns one if marker found; zero if not found
1046 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001047static int contains_ecryptfs_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -07001048{
1049 u32 m_1, m_2;
1050
Harvey Harrison29335c62008-07-23 21:30:06 -07001051 m_1 = get_unaligned_be32(data);
1052 m_2 = get_unaligned_be32(data + 4);
Michael Halcrow237fead2006-10-04 02:16:22 -07001053 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1054 return 1;
1055 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1056 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1057 MAGIC_ECRYPTFS_MARKER);
1058 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1059 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1060 return 0;
1061}
1062
1063struct ecryptfs_flag_map_elem {
1064 u32 file_flag;
1065 u32 local_flag;
1066};
1067
1068/* Add support for additional flags by adding elements here. */
1069static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1070 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001071 {0x00000002, ECRYPTFS_ENCRYPTED},
Michael Halcrowaddd65ad2009-01-06 14:42:00 -08001072 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1073 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
Michael Halcrow237fead2006-10-04 02:16:22 -07001074};
1075
1076/**
1077 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001078 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001079 * @page_virt: Source data to be parsed
1080 * @bytes_read: Updated with the number of bytes read
1081 *
1082 * Returns zero on success; non-zero if the flag set is invalid
1083 */
1084static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1085 char *page_virt, int *bytes_read)
1086{
1087 int rc = 0;
1088 int i;
1089 u32 flags;
1090
Harvey Harrison29335c62008-07-23 21:30:06 -07001091 flags = get_unaligned_be32(page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001092 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1093 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1094 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001095 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -07001096 } else
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 /* Version is in top 8 bits of the 32-bit flag vector */
1099 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1100 (*bytes_read) = 4;
1101 return rc;
1102}
1103
1104/**
1105 * write_ecryptfs_marker
1106 * @page_virt: The pointer to in a page to begin writing the marker
1107 * @written: Number of bytes written
1108 *
1109 * Marker = 0x3c81b7f5
1110 */
1111static void write_ecryptfs_marker(char *page_virt, size_t *written)
1112{
1113 u32 m_1, m_2;
1114
1115 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1116 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
Harvey Harrison29335c62008-07-23 21:30:06 -07001117 put_unaligned_be32(m_1, page_virt);
1118 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1119 put_unaligned_be32(m_2, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001120 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1121}
1122
1123static void
1124write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1125 size_t *written)
1126{
1127 u32 flags = 0;
1128 int i;
1129
1130 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1131 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001132 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -07001133 flags |= ecryptfs_flag_map[i].file_flag;
1134 /* Version is in top 8 bits of the 32-bit flag vector */
1135 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
Harvey Harrison29335c62008-07-23 21:30:06 -07001136 put_unaligned_be32(flags, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001137 (*written) = 4;
1138}
1139
1140struct ecryptfs_cipher_code_str_map_elem {
1141 char cipher_str[16];
Trevor Highland19e66a62008-02-06 01:38:36 -08001142 u8 cipher_code;
Michael Halcrow237fead2006-10-04 02:16:22 -07001143};
1144
1145/* Add support for additional ciphers by adding elements here. The
1146 * cipher_code is whatever OpenPGP applicatoins use to identify the
1147 * ciphers. List in order of probability. */
1148static struct ecryptfs_cipher_code_str_map_elem
1149ecryptfs_cipher_code_str_map[] = {
1150 {"aes",RFC2440_CIPHER_AES_128 },
1151 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1152 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1153 {"cast5", RFC2440_CIPHER_CAST_5},
1154 {"twofish", RFC2440_CIPHER_TWOFISH},
1155 {"cast6", RFC2440_CIPHER_CAST_6},
1156 {"aes", RFC2440_CIPHER_AES_192},
1157 {"aes", RFC2440_CIPHER_AES_256}
1158};
1159
1160/**
1161 * ecryptfs_code_for_cipher_string
Michael Halcrow9c79f342009-01-06 14:41:57 -08001162 * @cipher_name: The string alias for the cipher
1163 * @key_bytes: Length of key in bytes; used for AES code selection
Michael Halcrow237fead2006-10-04 02:16:22 -07001164 *
1165 * Returns zero on no match, or the cipher code on match
1166 */
Michael Halcrow9c79f342009-01-06 14:41:57 -08001167u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
Michael Halcrow237fead2006-10-04 02:16:22 -07001168{
1169 int i;
Trevor Highland19e66a62008-02-06 01:38:36 -08001170 u8 code = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001171 struct ecryptfs_cipher_code_str_map_elem *map =
1172 ecryptfs_cipher_code_str_map;
1173
Michael Halcrow9c79f342009-01-06 14:41:57 -08001174 if (strcmp(cipher_name, "aes") == 0) {
1175 switch (key_bytes) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001176 case 16:
1177 code = RFC2440_CIPHER_AES_128;
1178 break;
1179 case 24:
1180 code = RFC2440_CIPHER_AES_192;
1181 break;
1182 case 32:
1183 code = RFC2440_CIPHER_AES_256;
1184 }
1185 } else {
1186 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
Michael Halcrow9c79f342009-01-06 14:41:57 -08001187 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001188 code = map[i].cipher_code;
1189 break;
1190 }
1191 }
1192 return code;
1193}
1194
1195/**
1196 * ecryptfs_cipher_code_to_string
1197 * @str: Destination to write out the cipher name
1198 * @cipher_code: The code to convert to cipher name string
1199 *
1200 * Returns zero on success
1201 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001202int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
Michael Halcrow237fead2006-10-04 02:16:22 -07001203{
1204 int rc = 0;
1205 int i;
1206
1207 str[0] = '\0';
1208 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1209 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1210 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1211 if (str[0] == '\0') {
1212 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1213 "[%d]\n", cipher_code);
1214 rc = -EINVAL;
1215 }
1216 return rc;
1217}
1218
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001219int ecryptfs_read_and_validate_header_region(char *data,
1220 struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001221{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001222 struct ecryptfs_crypt_stat *crypt_stat =
1223 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001224 int rc;
1225
Michael Halcrowaddd65ad2009-01-06 14:42:00 -08001226 if (crypt_stat->extent_size == 0)
1227 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001228 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1229 ecryptfs_inode);
1230 if (rc) {
1231 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001232 __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001233 goto out;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001234 }
1235 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001236 rc = -EINVAL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001237 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001238out:
1239 return rc;
1240}
1241
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001242void
1243ecryptfs_write_header_metadata(char *virt,
1244 struct ecryptfs_crypt_stat *crypt_stat,
1245 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001246{
1247 u32 header_extent_size;
1248 u16 num_header_extents_at_front;
1249
Michael Halcrow45eaab72007-10-16 01:28:05 -07001250 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001251 num_header_extents_at_front =
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001252 (u16)(crypt_stat->num_header_bytes_at_front
1253 / crypt_stat->extent_size);
Harvey Harrison29335c62008-07-23 21:30:06 -07001254 put_unaligned_be32(header_extent_size, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001255 virt += 4;
Harvey Harrison29335c62008-07-23 21:30:06 -07001256 put_unaligned_be16(num_header_extents_at_front, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001257 (*written) = 6;
1258}
1259
Michael Halcrow237fead2006-10-04 02:16:22 -07001260struct kmem_cache *ecryptfs_header_cache_1;
1261struct kmem_cache *ecryptfs_header_cache_2;
1262
1263/**
1264 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001265 * @page_virt: The virtual address to write the headers to
Eric Sandeen87b811c2008-10-29 14:01:08 -07001266 * @max: The size of memory allocated at page_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001267 * @size: Set to the number of bytes written by this function
1268 * @crypt_stat: The cryptographic context
1269 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001270 *
1271 * Format version: 1
1272 *
1273 * Header Extent:
1274 * Octets 0-7: Unencrypted file size (big-endian)
1275 * Octets 8-15: eCryptfs special marker
1276 * Octets 16-19: Flags
1277 * Octet 16: File format version number (between 0 and 255)
1278 * Octets 17-18: Reserved
1279 * Octet 19: Bit 1 (lsb): Reserved
1280 * Bit 2: Encrypted?
1281 * Bits 3-8: Reserved
1282 * Octets 20-23: Header extent size (big-endian)
1283 * Octets 24-25: Number of header extents at front of file
1284 * (big-endian)
1285 * Octet 26: Begin RFC 2440 authentication token packet set
1286 * Data Extent 0:
1287 * Lower data (CBC encrypted)
1288 * Data Extent 1:
1289 * Lower data (CBC encrypted)
1290 * ...
1291 *
1292 * Returns zero on success
1293 */
Eric Sandeen87b811c2008-10-29 14:01:08 -07001294static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1295 size_t *size,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001296 struct ecryptfs_crypt_stat *crypt_stat,
1297 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001298{
1299 int rc;
1300 size_t written;
1301 size_t offset;
1302
1303 offset = ECRYPTFS_FILE_SIZE_BYTES;
1304 write_ecryptfs_marker((page_virt + offset), &written);
1305 offset += written;
1306 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1307 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001308 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1309 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001310 offset += written;
1311 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1312 ecryptfs_dentry, &written,
Eric Sandeen87b811c2008-10-29 14:01:08 -07001313 max - offset);
Michael Halcrow237fead2006-10-04 02:16:22 -07001314 if (rc)
1315 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1316 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001317 if (size) {
1318 offset += written;
1319 *size = offset;
1320 }
1321 return rc;
1322}
1323
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001324static int
1325ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001326 struct dentry *ecryptfs_dentry,
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001327 char *virt)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001328{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001329 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001330
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001331 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
1332 0, crypt_stat->num_header_bytes_at_front);
1333 if (rc)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001334 printk(KERN_ERR "%s: Error attempting to write header "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001335 "information to lower file; rc = [%d]\n", __func__,
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001336 rc);
Michael Halcrow70456602007-02-12 00:53:48 -08001337 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001338}
1339
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001340static int
1341ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1342 struct ecryptfs_crypt_stat *crypt_stat,
1343 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
1352/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001353 * ecryptfs_write_metadata
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001354 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001355 *
1356 * Write the file headers out. This will likely involve a userspace
1357 * callout, in which the session key is encrypted with one or more
1358 * public keys and/or the passphrase necessary to do the encryption is
1359 * retrieved via a prompt. Exactly what happens at this point should
1360 * be policy-dependent.
1361 *
1362 * Returns zero on success; non-zero on error
1363 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001364int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001365{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001366 struct ecryptfs_crypt_stat *crypt_stat =
1367 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001368 char *virt;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001369 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001370 int rc = 0;
1371
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001372 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1373 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001374 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001375 rc = -EINVAL;
1376 goto out;
1377 }
1378 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001379 printk(KERN_WARNING "%s: Encrypted flag not set\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001380 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001381 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001382 goto out;
1383 }
1384 /* Released in this function */
Eric Sandeen87b811c2008-10-29 14:01:08 -07001385 virt = (char *)get_zeroed_page(GFP_KERNEL);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001386 if (!virt) {
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001387 printk(KERN_ERR "%s: Out of memory\n", __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001388 rc = -ENOMEM;
1389 goto out;
1390 }
Eric Sandeen87b811c2008-10-29 14:01:08 -07001391 rc = ecryptfs_write_headers_virt(virt, PAGE_CACHE_SIZE, &size,
1392 crypt_stat, ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001393 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001394 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001395 __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001396 goto out_free;
1397 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001398 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1399 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001400 crypt_stat, virt, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001401 else
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001402 rc = ecryptfs_write_metadata_to_contents(crypt_stat,
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001403 ecryptfs_dentry, virt);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001404 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001405 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001406 "rc = [%d]\n", __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001407 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001408 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001409out_free:
Eric Sandeen87b811c2008-10-29 14:01:08 -07001410 free_page((unsigned long)virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001411out:
1412 return rc;
1413}
1414
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001415#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1416#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001417static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001418 char *virt, int *bytes_read,
1419 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001420{
1421 int rc = 0;
1422 u32 header_extent_size;
1423 u16 num_header_extents_at_front;
1424
Harvey Harrison29335c62008-07-23 21:30:06 -07001425 header_extent_size = get_unaligned_be32(virt);
1426 virt += sizeof(__be32);
1427 num_header_extents_at_front = get_unaligned_be16(virt);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001428 crypt_stat->num_header_bytes_at_front =
1429 (((size_t)num_header_extents_at_front
1430 * (size_t)header_extent_size));
Harvey Harrison29335c62008-07-23 21:30:06 -07001431 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001432 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001433 && (crypt_stat->num_header_bytes_at_front
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001434 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001435 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001436 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1437 crypt_stat->num_header_bytes_at_front);
Michael Halcrow237fead2006-10-04 02:16:22 -07001438 }
1439 return rc;
1440}
1441
1442/**
1443 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001444 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001445 *
1446 * For version 0 file format; this function is only for backwards
1447 * compatibility for files created with the prior versions of
1448 * eCryptfs.
1449 */
1450static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1451{
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001452 crypt_stat->num_header_bytes_at_front =
1453 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001454}
1455
1456/**
1457 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001458 * @page_virt: The virtual address into which to read the headers
1459 * @crypt_stat: The cryptographic context
1460 * @ecryptfs_dentry: The eCryptfs dentry
1461 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001462 *
1463 * Read/parse the header data. The header format is detailed in the
1464 * comment block for the ecryptfs_write_headers_virt() function.
1465 *
1466 * Returns zero on success
1467 */
1468static int ecryptfs_read_headers_virt(char *page_virt,
1469 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001470 struct dentry *ecryptfs_dentry,
1471 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001472{
1473 int rc = 0;
1474 int offset;
1475 int bytes_read;
1476
1477 ecryptfs_set_default_sizes(crypt_stat);
1478 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1479 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1480 offset = ECRYPTFS_FILE_SIZE_BYTES;
1481 rc = contains_ecryptfs_marker(page_virt + offset);
1482 if (rc == 0) {
1483 rc = -EINVAL;
1484 goto out;
1485 }
1486 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1487 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1488 &bytes_read);
1489 if (rc) {
1490 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1491 goto out;
1492 }
1493 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1494 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1495 "file version [%d] is supported by this "
1496 "version of eCryptfs\n",
1497 crypt_stat->file_version,
1498 ECRYPTFS_SUPPORTED_FILE_VERSION);
1499 rc = -EINVAL;
1500 goto out;
1501 }
1502 offset += bytes_read;
1503 if (crypt_stat->file_version >= 1) {
1504 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001505 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001506 if (rc) {
1507 ecryptfs_printk(KERN_WARNING, "Error reading header "
1508 "metadata; rc = [%d]\n", rc);
1509 }
1510 offset += bytes_read;
1511 } else
1512 set_default_header_data(crypt_stat);
1513 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1514 ecryptfs_dentry);
1515out:
1516 return rc;
1517}
1518
1519/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001520 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001521 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001522 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001523 *
1524 * Attempts to read the crypto metadata from the extended attribute
1525 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001526 *
1527 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001528 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001529int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001530{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001531 struct dentry *lower_dentry =
1532 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001533 ssize_t size;
1534 int rc = 0;
1535
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001536 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1537 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001538 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001539 if (unlikely(ecryptfs_verbosity > 0))
1540 printk(KERN_INFO "Error attempting to read the [%s] "
1541 "xattr from the lower file; return value = "
1542 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001543 rc = -EINVAL;
1544 goto out;
1545 }
1546out:
1547 return rc;
1548}
1549
1550int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1551 struct dentry *ecryptfs_dentry)
1552{
1553 int rc;
1554
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001555 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001556 if (rc)
1557 goto out;
1558 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1559 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1560 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1561 rc = -EINVAL;
1562 }
1563out:
1564 return rc;
1565}
1566
1567/**
1568 * ecryptfs_read_metadata
1569 *
1570 * Common entry point for reading file metadata. From here, we could
1571 * retrieve the header information from the header region of the file,
1572 * the xattr region of the file, or some other repostory that is
1573 * stored separately from the file itself. The current implementation
1574 * supports retrieving the metadata information from the file contents
1575 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001576 *
1577 * Returns zero if valid headers found and parsed; non-zero otherwise
1578 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001579int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001580{
1581 int rc = 0;
1582 char *page_virt = NULL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001583 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -07001584 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001585 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001586 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1587 &ecryptfs_superblock_to_private(
1588 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001589
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001590 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1591 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001592 /* Read the first page from the underlying file */
Christoph Lameterf7267c02006-12-06 20:33:15 -08001593 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001594 if (!page_virt) {
1595 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001596 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001597 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001598 goto out;
1599 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001600 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1601 ecryptfs_inode);
1602 if (!rc)
1603 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1604 ecryptfs_dentry,
1605 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001606 if (rc) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001607 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001608 if (rc) {
1609 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1610 "file header region or xattr region\n");
1611 rc = -EINVAL;
1612 goto out;
1613 }
1614 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1615 ecryptfs_dentry,
1616 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1617 if (rc) {
1618 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1619 "file xattr region either\n");
1620 rc = -EINVAL;
1621 }
1622 if (crypt_stat->mount_crypt_stat->flags
1623 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1624 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1625 } else {
1626 printk(KERN_WARNING "Attempt to access file with "
1627 "crypto metadata only in the extended attribute "
1628 "region, but eCryptfs was mounted without "
1629 "xattr support enabled. eCryptfs will not treat "
1630 "this like an encrypted file.\n");
1631 rc = -EINVAL;
1632 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001633 }
1634out:
1635 if (page_virt) {
1636 memset(page_virt, 0, PAGE_CACHE_SIZE);
1637 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1638 }
1639 return rc;
1640}
1641
1642/**
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001643 * ecryptfs_encrypt_filename - encrypt filename
1644 *
1645 * CBC-encrypts the filename. We do not want to encrypt the same
1646 * filename with the same key and IV, which may happen with hard
1647 * links, so we prepend random bits to each filename.
1648 *
1649 * Returns zero on success; non-zero otherwise
1650 */
1651static int
1652ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1653 struct ecryptfs_crypt_stat *crypt_stat,
1654 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1655{
1656 int rc = 0;
1657
1658 filename->encrypted_filename = NULL;
1659 filename->encrypted_filename_size = 0;
1660 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1661 || (mount_crypt_stat && (mount_crypt_stat->flags
1662 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1663 size_t packet_size;
1664 size_t remaining_bytes;
1665
1666 rc = ecryptfs_write_tag_70_packet(
1667 NULL, NULL,
1668 &filename->encrypted_filename_size,
1669 mount_crypt_stat, NULL,
1670 filename->filename_size);
1671 if (rc) {
1672 printk(KERN_ERR "%s: Error attempting to get packet "
1673 "size for tag 72; rc = [%d]\n", __func__,
1674 rc);
1675 filename->encrypted_filename_size = 0;
1676 goto out;
1677 }
1678 filename->encrypted_filename =
1679 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1680 if (!filename->encrypted_filename) {
1681 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08001682 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001683 filename->encrypted_filename_size);
1684 rc = -ENOMEM;
1685 goto out;
1686 }
1687 remaining_bytes = filename->encrypted_filename_size;
1688 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1689 &remaining_bytes,
1690 &packet_size,
1691 mount_crypt_stat,
1692 filename->filename,
1693 filename->filename_size);
1694 if (rc) {
1695 printk(KERN_ERR "%s: Error attempting to generate "
1696 "tag 70 packet; rc = [%d]\n", __func__,
1697 rc);
1698 kfree(filename->encrypted_filename);
1699 filename->encrypted_filename = NULL;
1700 filename->encrypted_filename_size = 0;
1701 goto out;
1702 }
1703 filename->encrypted_filename_size = packet_size;
1704 } else {
1705 printk(KERN_ERR "%s: No support for requested filename "
1706 "encryption method in this release\n", __func__);
1707 rc = -ENOTSUPP;
1708 goto out;
1709 }
1710out:
1711 return rc;
1712}
1713
1714static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1715 const char *name, size_t name_size)
1716{
1717 int rc = 0;
1718
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001719 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001720 if (!(*copied_name)) {
1721 rc = -ENOMEM;
1722 goto out;
1723 }
1724 memcpy((void *)(*copied_name), (void *)name, name_size);
1725 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1726 * in printing out the
1727 * string in debug
1728 * messages */
Tyler Hicksfd9fc842009-02-06 18:06:51 -06001729 (*copied_name_size) = name_size;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001730out:
1731 return rc;
1732}
1733
1734/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001735 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001736 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001737 * @cipher_name: Name of the cipher
1738 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001739 *
1740 * Returns zero on success. Any crypto_tfm structs allocated here
1741 * should be released by other functions, such as on a superblock put
1742 * event, regardless of whether this function succeeds for fails.
1743 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001744static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001745ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1746 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001747{
1748 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Michael Halcrow8bba0662006-10-30 22:07:18 -08001749 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -07001750 int rc;
1751
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001752 *key_tfm = NULL;
1753 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001754 rc = -EINVAL;
Michael Halcrowdf261c52009-01-06 14:42:02 -08001755 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001756 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001757 goto out;
1758 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001759 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1760 "ecb");
1761 if (rc)
1762 goto out;
1763 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1764 kfree(full_alg_name);
1765 if (IS_ERR(*key_tfm)) {
1766 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001767 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Michael Halcrow8bba0662006-10-30 22:07:18 -08001768 "[%s]; rc = [%d]\n", cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001769 goto out;
1770 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001771 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1772 if (*key_size == 0) {
1773 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1774
1775 *key_size = alg->max_keysize;
1776 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001777 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001778 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001779 if (rc) {
Michael Halcrowdf261c52009-01-06 14:42:02 -08001780 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001781 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001782 rc = -EINVAL;
1783 goto out;
1784 }
1785out:
1786 return rc;
1787}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001788
1789struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001790static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001791struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001792
1793int ecryptfs_init_crypto(void)
1794{
1795 mutex_init(&key_tfm_list_mutex);
1796 INIT_LIST_HEAD(&key_tfm_list);
1797 return 0;
1798}
1799
Eric Sandeenaf440f52008-02-06 01:38:37 -08001800/**
1801 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1802 *
1803 * Called only at module unload time
1804 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001805int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001806{
1807 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1808
1809 mutex_lock(&key_tfm_list_mutex);
1810 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1811 key_tfm_list) {
1812 list_del(&key_tfm->key_tfm_list);
1813 if (key_tfm->key_tfm)
1814 crypto_free_blkcipher(key_tfm->key_tfm);
1815 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1816 }
1817 mutex_unlock(&key_tfm_list_mutex);
1818 return 0;
1819}
1820
1821int
1822ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1823 size_t key_size)
1824{
1825 struct ecryptfs_key_tfm *tmp_tfm;
1826 int rc = 0;
1827
Eric Sandeenaf440f52008-02-06 01:38:37 -08001828 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1829
Michael Halcrowf4aad162007-10-16 01:27:53 -07001830 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1831 if (key_tfm != NULL)
1832 (*key_tfm) = tmp_tfm;
1833 if (!tmp_tfm) {
1834 rc = -ENOMEM;
1835 printk(KERN_ERR "Error attempting to allocate from "
1836 "ecryptfs_key_tfm_cache\n");
1837 goto out;
1838 }
1839 mutex_init(&tmp_tfm->key_tfm_mutex);
1840 strncpy(tmp_tfm->cipher_name, cipher_name,
1841 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001842 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001843 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001844 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1845 tmp_tfm->cipher_name,
1846 &tmp_tfm->key_size);
1847 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001848 printk(KERN_ERR "Error attempting to initialize key TFM "
1849 "cipher with name = [%s]; rc = [%d]\n",
1850 tmp_tfm->cipher_name, rc);
1851 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1852 if (key_tfm != NULL)
1853 (*key_tfm) = NULL;
1854 goto out;
1855 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001856 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001857out:
1858 return rc;
1859}
1860
Eric Sandeenaf440f52008-02-06 01:38:37 -08001861/**
1862 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1863 * @cipher_name: the name of the cipher to search for
1864 * @key_tfm: set to corresponding tfm if found
1865 *
1866 * Searches for cached key_tfm matching @cipher_name
1867 * Must be called with &key_tfm_list_mutex held
1868 * Returns 1 if found, with @key_tfm set
1869 * Returns 0 if not found, with @key_tfm set to NULL
1870 */
1871int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1872{
1873 struct ecryptfs_key_tfm *tmp_key_tfm;
1874
1875 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1876
1877 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1878 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1879 if (key_tfm)
1880 (*key_tfm) = tmp_key_tfm;
1881 return 1;
1882 }
1883 }
1884 if (key_tfm)
1885 (*key_tfm) = NULL;
1886 return 0;
1887}
1888
1889/**
1890 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1891 *
1892 * @tfm: set to cached tfm found, or new tfm created
1893 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1894 * @cipher_name: the name of the cipher to search for and/or add
1895 *
1896 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1897 * Searches for cached item first, and creates new if not found.
1898 * Returns 0 on success, non-zero if adding new cipher failed
1899 */
Michael Halcrowf4aad162007-10-16 01:27:53 -07001900int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1901 struct mutex **tfm_mutex,
1902 char *cipher_name)
1903{
1904 struct ecryptfs_key_tfm *key_tfm;
1905 int rc = 0;
1906
1907 (*tfm) = NULL;
1908 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001909
Michael Halcrowf4aad162007-10-16 01:27:53 -07001910 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001911 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1912 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1913 if (rc) {
1914 printk(KERN_ERR "Error adding new key_tfm to list; "
1915 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001916 goto out;
1917 }
1918 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001919 (*tfm) = key_tfm->key_tfm;
1920 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1921out:
Cyrill Gorcunov71fd5172008-05-23 13:04:20 -07001922 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001923 return rc;
1924}
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001925
1926/* 64 characters forming a 6-bit target field */
1927static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1928 "EFGHIJKLMNOPQRST"
1929 "UVWXYZabcdefghij"
1930 "klmnopqrstuvwxyz");
1931
1932/* We could either offset on every reverse map or just pad some 0x00's
1933 * at the front here */
Michael Halcrow71c11c32009-01-06 14:42:05 -08001934static const unsigned char filename_rev_map[] = {
Michael Halcrow51ca58d2009-01-06 14:41:59 -08001935 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1936 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1937 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1938 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1939 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1940 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1941 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1942 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1943 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1944 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1945 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1946 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1947 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1948 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1949 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1950 0x3D, 0x3E, 0x3F
1951};
1952
1953/**
1954 * ecryptfs_encode_for_filename
1955 * @dst: Destination location for encoded filename
1956 * @dst_size: Size of the encoded filename in bytes
1957 * @src: Source location for the filename to encode
1958 * @src_size: Size of the source in bytes
1959 */
1960void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1961 unsigned char *src, size_t src_size)
1962{
1963 size_t num_blocks;
1964 size_t block_num = 0;
1965 size_t dst_offset = 0;
1966 unsigned char last_block[3];
1967
1968 if (src_size == 0) {
1969 (*dst_size) = 0;
1970 goto out;
1971 }
1972 num_blocks = (src_size / 3);
1973 if ((src_size % 3) == 0) {
1974 memcpy(last_block, (&src[src_size - 3]), 3);
1975 } else {
1976 num_blocks++;
1977 last_block[2] = 0x00;
1978 switch (src_size % 3) {
1979 case 1:
1980 last_block[0] = src[src_size - 1];
1981 last_block[1] = 0x00;
1982 break;
1983 case 2:
1984 last_block[0] = src[src_size - 2];
1985 last_block[1] = src[src_size - 1];
1986 }
1987 }
1988 (*dst_size) = (num_blocks * 4);
1989 if (!dst)
1990 goto out;
1991 while (block_num < num_blocks) {
1992 unsigned char *src_block;
1993 unsigned char dst_block[4];
1994
1995 if (block_num == (num_blocks - 1))
1996 src_block = last_block;
1997 else
1998 src_block = &src[block_num * 3];
1999 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2000 dst_block[1] = (((src_block[0] << 4) & 0x30)
2001 | ((src_block[1] >> 4) & 0x0F));
2002 dst_block[2] = (((src_block[1] << 2) & 0x3C)
2003 | ((src_block[2] >> 6) & 0x03));
2004 dst_block[3] = (src_block[2] & 0x3F);
2005 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2006 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2007 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2008 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2009 block_num++;
2010 }
2011out:
2012 return;
2013}
2014
Michael Halcrow71c11c32009-01-06 14:42:05 -08002015/**
2016 * ecryptfs_decode_from_filename
2017 * @dst: If NULL, this function only sets @dst_size and returns. If
2018 * non-NULL, this function decodes the encoded octets in @src
2019 * into the memory that @dst points to.
2020 * @dst_size: Set to the size of the decoded string.
2021 * @src: The encoded set of octets to decode.
2022 * @src_size: The size of the encoded set of octets to decode.
2023 */
2024static void
2025ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2026 const unsigned char *src, size_t src_size)
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002027{
2028 u8 current_bit_offset = 0;
2029 size_t src_byte_offset = 0;
2030 size_t dst_byte_offset = 0;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002031
2032 if (dst == NULL) {
Michael Halcrow71c11c32009-01-06 14:42:05 -08002033 /* Not exact; conservatively long. Every block of 4
2034 * encoded characters decodes into a block of 3
2035 * decoded characters. This segment of code provides
2036 * the caller with the maximum amount of allocated
2037 * space that @dst will need to point to in a
2038 * subsequent call. */
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002039 (*dst_size) = (((src_size + 1) * 3) / 4);
2040 goto out;
2041 }
2042 while (src_byte_offset < src_size) {
2043 unsigned char src_byte =
2044 filename_rev_map[(int)src[src_byte_offset]];
2045
2046 switch (current_bit_offset) {
2047 case 0:
2048 dst[dst_byte_offset] = (src_byte << 2);
2049 current_bit_offset = 6;
2050 break;
2051 case 6:
2052 dst[dst_byte_offset++] |= (src_byte >> 4);
2053 dst[dst_byte_offset] = ((src_byte & 0xF)
2054 << 4);
2055 current_bit_offset = 4;
2056 break;
2057 case 4:
2058 dst[dst_byte_offset++] |= (src_byte >> 2);
2059 dst[dst_byte_offset] = (src_byte << 6);
2060 current_bit_offset = 2;
2061 break;
2062 case 2:
2063 dst[dst_byte_offset++] |= (src_byte);
2064 dst[dst_byte_offset] = 0;
2065 current_bit_offset = 0;
2066 break;
2067 }
2068 src_byte_offset++;
2069 }
2070 (*dst_size) = dst_byte_offset;
2071out:
Michael Halcrow71c11c32009-01-06 14:42:05 -08002072 return;
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002073}
2074
2075/**
2076 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2077 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2078 * @name: The plaintext name
2079 * @length: The length of the plaintext
2080 * @encoded_name: The encypted name
2081 *
2082 * Encrypts and encodes a filename into something that constitutes a
2083 * valid filename for a filesystem, with printable characters.
2084 *
2085 * We assume that we have a properly initialized crypto context,
2086 * pointed to by crypt_stat->tfm.
2087 *
2088 * Returns zero on success; non-zero on otherwise
2089 */
2090int ecryptfs_encrypt_and_encode_filename(
2091 char **encoded_name,
2092 size_t *encoded_name_size,
2093 struct ecryptfs_crypt_stat *crypt_stat,
2094 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2095 const char *name, size_t name_size)
2096{
2097 size_t encoded_name_no_prefix_size;
2098 int rc = 0;
2099
2100 (*encoded_name) = NULL;
2101 (*encoded_name_size) = 0;
2102 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2103 || (mount_crypt_stat && (mount_crypt_stat->flags
2104 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2105 struct ecryptfs_filename *filename;
2106
2107 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2108 if (!filename) {
2109 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002110 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002111 sizeof(*filename));
2112 rc = -ENOMEM;
2113 goto out;
2114 }
2115 filename->filename = (char *)name;
2116 filename->filename_size = name_size;
2117 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2118 mount_crypt_stat);
2119 if (rc) {
2120 printk(KERN_ERR "%s: Error attempting to encrypt "
2121 "filename; rc = [%d]\n", __func__, rc);
2122 kfree(filename);
2123 goto out;
2124 }
2125 ecryptfs_encode_for_filename(
2126 NULL, &encoded_name_no_prefix_size,
2127 filename->encrypted_filename,
2128 filename->encrypted_filename_size);
2129 if ((crypt_stat && (crypt_stat->flags
2130 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2131 || (mount_crypt_stat
2132 && (mount_crypt_stat->flags
2133 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2134 (*encoded_name_size) =
2135 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2136 + encoded_name_no_prefix_size);
2137 else
2138 (*encoded_name_size) =
2139 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2140 + encoded_name_no_prefix_size);
2141 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2142 if (!(*encoded_name)) {
2143 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowa8f12862009-01-06 14:42:03 -08002144 "to kzalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002145 (*encoded_name_size));
2146 rc = -ENOMEM;
2147 kfree(filename->encrypted_filename);
2148 kfree(filename);
2149 goto out;
2150 }
2151 if ((crypt_stat && (crypt_stat->flags
2152 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2153 || (mount_crypt_stat
2154 && (mount_crypt_stat->flags
2155 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2156 memcpy((*encoded_name),
2157 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2158 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2159 ecryptfs_encode_for_filename(
2160 ((*encoded_name)
2161 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2162 &encoded_name_no_prefix_size,
2163 filename->encrypted_filename,
2164 filename->encrypted_filename_size);
2165 (*encoded_name_size) =
2166 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2167 + encoded_name_no_prefix_size);
2168 (*encoded_name)[(*encoded_name_size)] = '\0';
2169 (*encoded_name_size)++;
2170 } else {
2171 rc = -ENOTSUPP;
2172 }
2173 if (rc) {
2174 printk(KERN_ERR "%s: Error attempting to encode "
2175 "encrypted filename; rc = [%d]\n", __func__,
2176 rc);
2177 kfree((*encoded_name));
2178 (*encoded_name) = NULL;
2179 (*encoded_name_size) = 0;
2180 }
2181 kfree(filename->encrypted_filename);
2182 kfree(filename);
2183 } else {
2184 rc = ecryptfs_copy_filename(encoded_name,
2185 encoded_name_size,
2186 name, name_size);
2187 }
2188out:
2189 return rc;
2190}
2191
2192/**
2193 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2194 * @plaintext_name: The plaintext name
2195 * @plaintext_name_size: The plaintext name size
2196 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2197 * @name: The filename in cipher text
2198 * @name_size: The cipher text name size
2199 *
2200 * Decrypts and decodes the filename.
2201 *
2202 * Returns zero on error; non-zero otherwise
2203 */
2204int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2205 size_t *plaintext_name_size,
2206 struct dentry *ecryptfs_dir_dentry,
2207 const char *name, size_t name_size)
2208{
2209 char *decoded_name;
2210 size_t decoded_name_size;
2211 size_t packet_size;
2212 int rc = 0;
2213
2214 if ((name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
2215 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2216 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
2217 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2218 &ecryptfs_superblock_to_private(
2219 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
2220 const char *orig_name = name;
2221 size_t orig_name_size = name_size;
2222
2223 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2224 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
Michael Halcrow71c11c32009-01-06 14:42:05 -08002225 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2226 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002227 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2228 if (!decoded_name) {
2229 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowdf261c52009-01-06 14:42:02 -08002230 "to kmalloc [%zd] bytes\n", __func__,
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002231 decoded_name_size);
2232 rc = -ENOMEM;
2233 goto out;
2234 }
Michael Halcrow71c11c32009-01-06 14:42:05 -08002235 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2236 name, name_size);
Michael Halcrow51ca58d2009-01-06 14:41:59 -08002237 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2238 plaintext_name_size,
2239 &packet_size,
2240 mount_crypt_stat,
2241 decoded_name,
2242 decoded_name_size);
2243 if (rc) {
2244 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2245 "from filename; copying through filename "
2246 "as-is\n", __func__);
2247 rc = ecryptfs_copy_filename(plaintext_name,
2248 plaintext_name_size,
2249 orig_name, orig_name_size);
2250 goto out_free;
2251 }
2252 } else {
2253 rc = ecryptfs_copy_filename(plaintext_name,
2254 plaintext_name_size,
2255 name, name_size);
2256 goto out;
2257 }
2258out_free:
2259 kfree(decoded_name);
2260out:
2261 return rc;
2262}