blob: a066e109ad9c05a7cbc0670f92045a3475e9aac1 [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>
36#include "ecryptfs_kernel.h"
37
38static int
39ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
40 struct page *dst_page, int dst_offset,
41 struct page *src_page, int src_offset, int size,
42 unsigned char *iv);
43static int
44ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
45 struct page *dst_page, int dst_offset,
46 struct page *src_page, int src_offset, int size,
47 unsigned char *iv);
48
49/**
50 * ecryptfs_to_hex
51 * @dst: Buffer to take hex character representation of contents of
52 * src; must be at least of size (src_size * 2)
53 * @src: Buffer to be converted to a hex string respresentation
54 * @src_size: number of bytes to convert
55 */
56void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
57{
58 int x;
59
60 for (x = 0; x < src_size; x++)
61 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
62}
63
64/**
65 * ecryptfs_from_hex
66 * @dst: Buffer to take the bytes from src hex; must be at least of
67 * size (src_size / 2)
68 * @src: Buffer to be converted from a hex string respresentation to raw value
69 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
70 */
71void ecryptfs_from_hex(char *dst, char *src, int dst_size)
72{
73 int x;
74 char tmp[3] = { 0, };
75
76 for (x = 0; x < dst_size; x++) {
77 tmp[0] = src[x * 2];
78 tmp[1] = src[x * 2 + 1];
79 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
80 }
81}
82
83/**
84 * ecryptfs_calculate_md5 - calculates the md5 of @src
85 * @dst: Pointer to 16 bytes of allocated memory
86 * @crypt_stat: Pointer to crypt_stat struct for the current inode
87 * @src: Data to be md5'd
88 * @len: Length of @src
89 *
90 * Uses the allocated crypto context that crypt_stat references to
91 * generate the MD5 sum of the contents of src.
92 */
93static int ecryptfs_calculate_md5(char *dst,
94 struct ecryptfs_crypt_stat *crypt_stat,
95 char *src, int len)
96{
Michael Halcrow237fead2006-10-04 02:16:22 -070097 struct scatterlist sg;
Michael Halcrow565d97242006-10-30 22:07:17 -080098 struct hash_desc desc = {
99 .tfm = crypt_stat->hash_tfm,
100 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
101 };
102 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700103
Michael Halcrow565d97242006-10-30 22:07:17 -0800104 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700105 sg_init_one(&sg, (u8 *)src, len);
Michael Halcrow565d97242006-10-30 22:07:17 -0800106 if (!desc.tfm) {
107 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
108 CRYPTO_ALG_ASYNC);
109 if (IS_ERR(desc.tfm)) {
110 rc = PTR_ERR(desc.tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700111 ecryptfs_printk(KERN_ERR, "Error attempting to "
Michael Halcrow565d97242006-10-30 22:07:17 -0800112 "allocate crypto context; rc = [%d]\n",
113 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700114 goto out;
115 }
Michael Halcrow565d97242006-10-30 22:07:17 -0800116 crypt_stat->hash_tfm = desc.tfm;
Michael Halcrow237fead2006-10-04 02:16:22 -0700117 }
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800118 rc = crypto_hash_init(&desc);
119 if (rc) {
120 printk(KERN_ERR
121 "%s: Error initializing crypto hash; rc = [%d]\n",
122 __FUNCTION__, rc);
123 goto out;
124 }
125 rc = crypto_hash_update(&desc, &sg, len);
126 if (rc) {
127 printk(KERN_ERR
128 "%s: Error updating crypto hash; rc = [%d]\n",
129 __FUNCTION__, rc);
130 goto out;
131 }
132 rc = crypto_hash_final(&desc, dst);
133 if (rc) {
134 printk(KERN_ERR
135 "%s: Error finalizing crypto hash; rc = [%d]\n",
136 __FUNCTION__, rc);
137 goto out;
138 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700139out:
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800140 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700141 return rc;
142}
143
Michael Halcrowcd9d67d2007-10-16 01:28:04 -0700144static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
145 char *cipher_name,
146 char *chaining_modifier)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800147{
148 int cipher_name_len = strlen(cipher_name);
149 int chaining_modifier_len = strlen(chaining_modifier);
150 int algified_name_len;
151 int rc;
152
153 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
154 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
Michael Halcrow7bd473f2006-11-02 22:06:56 -0800155 if (!(*algified_name)) {
Michael Halcrow8bba0662006-10-30 22:07:18 -0800156 rc = -ENOMEM;
157 goto out;
158 }
159 snprintf((*algified_name), algified_name_len, "%s(%s)",
160 chaining_modifier, cipher_name);
161 rc = 0;
162out:
163 return rc;
164}
165
Michael Halcrow237fead2006-10-04 02:16:22 -0700166/**
167 * ecryptfs_derive_iv
168 * @iv: destination for the derived iv vale
169 * @crypt_stat: Pointer to crypt_stat struct for the current inode
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700170 * @offset: Offset of the extent whose IV we are to derive
Michael Halcrow237fead2006-10-04 02:16:22 -0700171 *
172 * Generate the initialization vector from the given root IV and page
173 * offset.
174 *
175 * Returns zero on success; non-zero on error.
176 */
177static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700178 loff_t offset)
Michael Halcrow237fead2006-10-04 02:16:22 -0700179{
180 int rc = 0;
181 char dst[MD5_DIGEST_SIZE];
182 char src[ECRYPTFS_MAX_IV_BYTES + 16];
183
184 if (unlikely(ecryptfs_verbosity > 0)) {
185 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
186 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
187 }
188 /* TODO: It is probably secure to just cast the least
189 * significant bits of the root IV into an unsigned long and
190 * add the offset to that rather than go through all this
191 * hashing business. -Halcrow */
192 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
193 memset((src + crypt_stat->iv_bytes), 0, 16);
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700194 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700195 if (unlikely(ecryptfs_verbosity > 0)) {
196 ecryptfs_printk(KERN_DEBUG, "source:\n");
197 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
198 }
199 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
200 (crypt_stat->iv_bytes + 16));
201 if (rc) {
202 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
203 "MD5 while generating IV for a page\n");
204 goto out;
205 }
206 memcpy(iv, dst, crypt_stat->iv_bytes);
207 if (unlikely(ecryptfs_verbosity > 0)) {
208 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
209 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
210 }
211out:
212 return rc;
213}
214
215/**
216 * ecryptfs_init_crypt_stat
217 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
218 *
219 * Initialize the crypt_stat structure.
220 */
221void
222ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
223{
224 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
Michael Halcrowf4aad162007-10-16 01:27:53 -0700225 INIT_LIST_HEAD(&crypt_stat->keysig_list);
226 mutex_init(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700227 mutex_init(&crypt_stat->cs_mutex);
228 mutex_init(&crypt_stat->cs_tfm_mutex);
Michael Halcrow565d97242006-10-30 22:07:17 -0800229 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800230 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
Michael Halcrow237fead2006-10-04 02:16:22 -0700231}
232
233/**
Michael Halcrowfcd12832007-10-16 01:28:01 -0700234 * ecryptfs_destroy_crypt_stat
Michael Halcrow237fead2006-10-04 02:16:22 -0700235 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
236 *
237 * Releases all memory associated with a crypt_stat struct.
238 */
Michael Halcrowfcd12832007-10-16 01:28:01 -0700239void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -0700240{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700241 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
242
Michael Halcrow237fead2006-10-04 02:16:22 -0700243 if (crypt_stat->tfm)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800244 crypto_free_blkcipher(crypt_stat->tfm);
Michael Halcrow565d97242006-10-30 22:07:17 -0800245 if (crypt_stat->hash_tfm)
246 crypto_free_hash(crypt_stat->hash_tfm);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700247 mutex_lock(&crypt_stat->keysig_list_mutex);
248 list_for_each_entry_safe(key_sig, key_sig_tmp,
249 &crypt_stat->keysig_list, crypt_stat_list) {
250 list_del(&key_sig->crypt_stat_list);
251 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
252 }
253 mutex_unlock(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700254 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
255}
256
Michael Halcrowfcd12832007-10-16 01:28:01 -0700257void ecryptfs_destroy_mount_crypt_stat(
Michael Halcrow237fead2006-10-04 02:16:22 -0700258 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
259{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700260 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
261
262 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
263 return;
264 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
265 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
266 &mount_crypt_stat->global_auth_tok_list,
267 mount_crypt_stat_list) {
268 list_del(&auth_tok->mount_crypt_stat_list);
269 mount_crypt_stat->num_global_auth_toks--;
270 if (auth_tok->global_auth_tok_key
271 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
272 key_put(auth_tok->global_auth_tok_key);
273 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
274 }
275 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700276 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
277}
278
279/**
280 * virt_to_scatterlist
281 * @addr: Virtual address
282 * @size: Size of data; should be an even multiple of the block size
283 * @sg: Pointer to scatterlist array; set to NULL to obtain only
284 * the number of scatterlist structs required in array
285 * @sg_size: Max array size
286 *
287 * Fills in a scatterlist array with page references for a passed
288 * virtual address.
289 *
290 * Returns the number of scatterlist structs in array used
291 */
292int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
293 int sg_size)
294{
295 int i = 0;
296 struct page *pg;
297 int offset;
298 int remainder_of_page;
299
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700300 sg_init_table(sg, sg_size);
301
Michael Halcrow237fead2006-10-04 02:16:22 -0700302 while (size > 0 && i < sg_size) {
303 pg = virt_to_page(addr);
304 offset = offset_in_page(addr);
Jens Axboe642f1492007-10-24 11:20:47 +0200305 if (sg)
306 sg_set_page(&sg[i], pg, 0, offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700307 remainder_of_page = PAGE_CACHE_SIZE - offset;
308 if (size >= remainder_of_page) {
309 if (sg)
310 sg[i].length = remainder_of_page;
311 addr += remainder_of_page;
312 size -= remainder_of_page;
313 } else {
314 if (sg)
315 sg[i].length = size;
316 addr += size;
317 size = 0;
318 }
319 i++;
320 }
321 if (size > 0)
322 return -ENOMEM;
323 return i;
324}
325
326/**
327 * encrypt_scatterlist
328 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
329 * @dest_sg: Destination of encrypted data
330 * @src_sg: Data to be encrypted
331 * @size: Length of data to be encrypted
332 * @iv: iv to use during encryption
333 *
334 * Returns the number of bytes encrypted; negative value on error
335 */
336static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
337 struct scatterlist *dest_sg,
338 struct scatterlist *src_sg, int size,
339 unsigned char *iv)
340{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800341 struct blkcipher_desc desc = {
342 .tfm = crypt_stat->tfm,
343 .info = iv,
344 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
345 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700346 int rc = 0;
347
348 BUG_ON(!crypt_stat || !crypt_stat->tfm
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800349 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
Michael Halcrow237fead2006-10-04 02:16:22 -0700350 if (unlikely(ecryptfs_verbosity > 0)) {
351 ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n",
352 crypt_stat->key_size);
353 ecryptfs_dump_hex(crypt_stat->key,
354 crypt_stat->key_size);
355 }
356 /* Consider doing this once, when the file is opened */
357 mutex_lock(&crypt_stat->cs_tfm_mutex);
Trevor Highland8e3a6f12008-02-06 01:38:33 -0800358 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
359 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
360 crypt_stat->key_size);
361 crypt_stat->flags |= ECRYPTFS_KEY_SET;
362 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700363 if (rc) {
364 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
365 rc);
366 mutex_unlock(&crypt_stat->cs_tfm_mutex);
367 rc = -EINVAL;
368 goto out;
369 }
370 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800371 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700372 mutex_unlock(&crypt_stat->cs_tfm_mutex);
373out:
374 return rc;
375}
376
Michael Halcrow237fead2006-10-04 02:16:22 -0700377/**
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700378 * ecryptfs_lower_offset_for_extent
379 *
380 * Convert an eCryptfs page index into a lower byte offset
381 */
Adrian Bunk7896b632008-02-06 01:38:32 -0800382static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
383 struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700384{
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800385 (*offset) = (crypt_stat->num_header_bytes_at_front
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700386 + (crypt_stat->extent_size * extent_num));
387}
388
389/**
390 * ecryptfs_encrypt_extent
391 * @enc_extent_page: Allocated page into which to encrypt the data in
392 * @page
393 * @crypt_stat: crypt_stat containing cryptographic context for the
394 * encryption operation
395 * @page: Page containing plaintext data extent to encrypt
396 * @extent_offset: Page extent offset for use in generating IV
397 *
398 * Encrypts one extent of data.
399 *
400 * Return zero on success; non-zero otherwise
401 */
402static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
403 struct ecryptfs_crypt_stat *crypt_stat,
404 struct page *page,
405 unsigned long extent_offset)
406{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700407 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700408 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
409 int rc;
410
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700411 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700412 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
413 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
414 (extent_base + extent_offset));
415 if (rc) {
416 ecryptfs_printk(KERN_ERR, "Error attempting to "
417 "derive IV for extent [0x%.16x]; "
418 "rc = [%d]\n", (extent_base + extent_offset),
419 rc);
420 goto out;
421 }
422 if (unlikely(ecryptfs_verbosity > 0)) {
423 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
424 "with iv:\n");
425 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
426 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
427 "encryption:\n");
428 ecryptfs_dump_hex((char *)
429 (page_address(page)
430 + (extent_offset * crypt_stat->extent_size)),
431 8);
432 }
433 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
434 page, (extent_offset
435 * crypt_stat->extent_size),
436 crypt_stat->extent_size, extent_iv);
437 if (rc < 0) {
438 printk(KERN_ERR "%s: Error attempting to encrypt page with "
439 "page->index = [%ld], extent_offset = [%ld]; "
440 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
441 rc);
442 goto out;
443 }
444 rc = 0;
445 if (unlikely(ecryptfs_verbosity > 0)) {
446 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
447 "rc = [%d]\n", (extent_base + extent_offset),
448 rc);
449 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
450 "encryption:\n");
451 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
452 }
453out:
454 return rc;
455}
456
457/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700458 * ecryptfs_encrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700459 * @page: Page mapped from the eCryptfs inode for the file; contains
460 * decrypted content that needs to be encrypted (to a temporary
461 * page; not in place) and written out to the lower file
Michael Halcrow237fead2006-10-04 02:16:22 -0700462 *
463 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
464 * that eCryptfs pages may straddle the lower pages -- for instance,
465 * if the file was created on a machine with an 8K page size
466 * (resulting in an 8K header), and then the file is copied onto a
467 * host with a 32K page size, then when reading page 0 of the eCryptfs
468 * file, 24K of page 0 of the lower file will be read and decrypted,
469 * and then 8K of page 1 of the lower file will be read and decrypted.
470 *
Michael Halcrow237fead2006-10-04 02:16:22 -0700471 * Returns zero on success; negative on error
472 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700473int ecryptfs_encrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700474{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700475 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700476 struct ecryptfs_crypt_stat *crypt_stat;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700477 char *enc_extent_virt = NULL;
478 struct page *enc_extent_page;
479 loff_t extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700480 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700481
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700482 ecryptfs_inode = page->mapping->host;
483 crypt_stat =
484 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800485 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700486 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
487 0, PAGE_CACHE_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -0700488 if (rc)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700489 printk(KERN_ERR "%s: Error attempting to copy "
490 "page at index [%ld]\n", __FUNCTION__,
491 page->index);
Michael Halcrow237fead2006-10-04 02:16:22 -0700492 goto out;
493 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700494 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
495 if (!enc_extent_virt) {
496 rc = -ENOMEM;
497 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
498 "encrypted extent\n");
499 goto out;
500 }
501 enc_extent_page = virt_to_page(enc_extent_virt);
502 for (extent_offset = 0;
503 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
504 extent_offset++) {
505 loff_t offset;
506
507 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
508 extent_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700509 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700510 printk(KERN_ERR "%s: Error encrypting extent; "
511 "rc = [%d]\n", __FUNCTION__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700512 goto out;
513 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700514 ecryptfs_lower_offset_for_extent(
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700515 &offset, ((((loff_t)page->index)
516 * (PAGE_CACHE_SIZE
517 / crypt_stat->extent_size))
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700518 + extent_offset), crypt_stat);
519 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
520 offset, crypt_stat->extent_size);
521 if (rc) {
522 ecryptfs_printk(KERN_ERR, "Error attempting "
523 "to write lower page; rc = [%d]"
524 "\n", rc);
525 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700526 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700527 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700528out:
529 kfree(enc_extent_virt);
530 return rc;
531}
532
533static int ecryptfs_decrypt_extent(struct page *page,
534 struct ecryptfs_crypt_stat *crypt_stat,
535 struct page *enc_extent_page,
536 unsigned long extent_offset)
537{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700538 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700539 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
540 int rc;
541
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700542 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700543 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
544 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
545 (extent_base + extent_offset));
Michael Halcrow237fead2006-10-04 02:16:22 -0700546 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700547 ecryptfs_printk(KERN_ERR, "Error attempting to "
548 "derive IV for extent [0x%.16x]; "
549 "rc = [%d]\n", (extent_base + extent_offset),
550 rc);
551 goto out;
552 }
553 if (unlikely(ecryptfs_verbosity > 0)) {
554 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
555 "with iv:\n");
556 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
557 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
558 "decryption:\n");
559 ecryptfs_dump_hex((char *)
560 (page_address(enc_extent_page)
561 + (extent_offset * crypt_stat->extent_size)),
562 8);
563 }
564 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
565 (extent_offset
566 * crypt_stat->extent_size),
567 enc_extent_page, 0,
568 crypt_stat->extent_size, extent_iv);
569 if (rc < 0) {
570 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
571 "page->index = [%ld], extent_offset = [%ld]; "
572 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
573 rc);
574 goto out;
575 }
576 rc = 0;
577 if (unlikely(ecryptfs_verbosity > 0)) {
578 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
579 "rc = [%d]\n", (extent_base + extent_offset),
580 rc);
581 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
582 "decryption:\n");
583 ecryptfs_dump_hex((char *)(page_address(page)
584 + (extent_offset
585 * crypt_stat->extent_size)), 8);
Michael Halcrow237fead2006-10-04 02:16:22 -0700586 }
587out:
588 return rc;
589}
590
591/**
592 * ecryptfs_decrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700593 * @page: Page mapped from the eCryptfs inode for the file; data read
594 * and decrypted from the lower file will be written into this
595 * page
Michael Halcrow237fead2006-10-04 02:16:22 -0700596 *
597 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
598 * that eCryptfs pages may straddle the lower pages -- for instance,
599 * if the file was created on a machine with an 8K page size
600 * (resulting in an 8K header), and then the file is copied onto a
601 * host with a 32K page size, then when reading page 0 of the eCryptfs
602 * file, 24K of page 0 of the lower file will be read and decrypted,
603 * and then 8K of page 1 of the lower file will be read and decrypted.
604 *
605 * Returns zero on success; negative on error
606 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700607int ecryptfs_decrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700608{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700609 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700610 struct ecryptfs_crypt_stat *crypt_stat;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700611 char *enc_extent_virt = NULL;
612 struct page *enc_extent_page;
613 unsigned long extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700614 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700615
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700616 ecryptfs_inode = page->mapping->host;
617 crypt_stat =
618 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800619 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700620 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
621 PAGE_CACHE_SIZE,
622 ecryptfs_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700623 if (rc)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700624 printk(KERN_ERR "%s: Error attempting to copy "
625 "page at index [%ld]\n", __FUNCTION__,
626 page->index);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700627 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700628 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700629 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
630 if (!enc_extent_virt) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700631 rc = -ENOMEM;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700632 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
633 "encrypted extent\n");
Michael Halcrow16a72c42007-10-16 01:28:14 -0700634 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700635 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700636 enc_extent_page = virt_to_page(enc_extent_virt);
637 for (extent_offset = 0;
638 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
639 extent_offset++) {
640 loff_t offset;
641
642 ecryptfs_lower_offset_for_extent(
643 &offset, ((page->index * (PAGE_CACHE_SIZE
644 / crypt_stat->extent_size))
645 + extent_offset), crypt_stat);
646 rc = ecryptfs_read_lower(enc_extent_virt, offset,
647 crypt_stat->extent_size,
648 ecryptfs_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700649 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700650 ecryptfs_printk(KERN_ERR, "Error attempting "
651 "to read lower page; rc = [%d]"
652 "\n", rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700653 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700654 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700655 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
656 extent_offset);
657 if (rc) {
658 printk(KERN_ERR "%s: Error encrypting extent; "
659 "rc = [%d]\n", __FUNCTION__, rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700660 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700661 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700662 }
663out:
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700664 kfree(enc_extent_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700665 return rc;
666}
667
668/**
669 * decrypt_scatterlist
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700670 * @crypt_stat: Cryptographic context
671 * @dest_sg: The destination scatterlist to decrypt into
672 * @src_sg: The source scatterlist to decrypt from
673 * @size: The number of bytes to decrypt
674 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700675 *
676 * Returns the number of bytes decrypted; negative value on error
677 */
678static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
679 struct scatterlist *dest_sg,
680 struct scatterlist *src_sg, int size,
681 unsigned char *iv)
682{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800683 struct blkcipher_desc desc = {
684 .tfm = crypt_stat->tfm,
685 .info = iv,
686 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
687 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700688 int rc = 0;
689
690 /* Consider doing this once, when the file is opened */
691 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800692 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
693 crypt_stat->key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700694 if (rc) {
695 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
696 rc);
697 mutex_unlock(&crypt_stat->cs_tfm_mutex);
698 rc = -EINVAL;
699 goto out;
700 }
701 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800702 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700703 mutex_unlock(&crypt_stat->cs_tfm_mutex);
704 if (rc) {
705 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
706 rc);
707 goto out;
708 }
709 rc = size;
710out:
711 return rc;
712}
713
714/**
715 * ecryptfs_encrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700716 * @crypt_stat: The cryptographic context
717 * @dst_page: The page to encrypt into
718 * @dst_offset: The offset in the page to encrypt into
719 * @src_page: The page to encrypt from
720 * @src_offset: The offset in the page to encrypt from
721 * @size: The number of bytes to encrypt
722 * @iv: The initialization vector to use for the encryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700723 *
724 * Returns the number of bytes encrypted
725 */
726static int
727ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
728 struct page *dst_page, int dst_offset,
729 struct page *src_page, int src_offset, int size,
730 unsigned char *iv)
731{
732 struct scatterlist src_sg, dst_sg;
733
Jens Axboe60c74f82007-10-22 19:43:30 +0200734 sg_init_table(&src_sg, 1);
735 sg_init_table(&dst_sg, 1);
736
Jens Axboe642f1492007-10-24 11:20:47 +0200737 sg_set_page(&src_sg, src_page, size, src_offset);
738 sg_set_page(&dst_sg, dst_page, size, dst_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700739 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
740}
741
742/**
743 * ecryptfs_decrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700744 * @crypt_stat: The cryptographic context
745 * @dst_page: The page to decrypt into
746 * @dst_offset: The offset in the page to decrypt into
747 * @src_page: The page to decrypt from
748 * @src_offset: The offset in the page to decrypt from
749 * @size: The number of bytes to decrypt
750 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700751 *
752 * Returns the number of bytes decrypted
753 */
754static int
755ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
756 struct page *dst_page, int dst_offset,
757 struct page *src_page, int src_offset, int size,
758 unsigned char *iv)
759{
760 struct scatterlist src_sg, dst_sg;
761
Jens Axboe60c74f82007-10-22 19:43:30 +0200762 sg_init_table(&src_sg, 1);
Jens Axboe642f1492007-10-24 11:20:47 +0200763 sg_set_page(&src_sg, src_page, size, src_offset);
Jens Axboe60c74f82007-10-22 19:43:30 +0200764
Jens Axboe642f1492007-10-24 11:20:47 +0200765 sg_init_table(&dst_sg, 1);
766 sg_set_page(&dst_sg, dst_page, size, dst_offset);
767
Michael Halcrow237fead2006-10-04 02:16:22 -0700768 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
769}
770
771#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
772
773/**
774 * ecryptfs_init_crypt_ctx
775 * @crypt_stat: Uninitilized crypt stats structure
776 *
777 * Initialize the crypto context.
778 *
779 * TODO: Performance: Keep a cache of initialized cipher contexts;
780 * only init if needed
781 */
782int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
783{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800784 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700785 int rc = -EINVAL;
786
787 if (!crypt_stat->cipher) {
788 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
789 goto out;
790 }
791 ecryptfs_printk(KERN_DEBUG,
792 "Initializing cipher [%s]; strlen = [%d]; "
793 "key_size_bits = [%d]\n",
794 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
795 crypt_stat->key_size << 3);
796 if (crypt_stat->tfm) {
797 rc = 0;
798 goto out;
799 }
800 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800801 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
802 crypt_stat->cipher, "cbc");
803 if (rc)
Eric Sandeenc8161f62007-12-22 14:03:26 -0800804 goto out_unlock;
Michael Halcrow8bba0662006-10-30 22:07:18 -0800805 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
806 CRYPTO_ALG_ASYNC);
807 kfree(full_alg_name);
Akinobu Mitade887772006-11-28 12:29:49 -0800808 if (IS_ERR(crypt_stat->tfm)) {
809 rc = PTR_ERR(crypt_stat->tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700810 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
811 "Error initializing cipher [%s]\n",
812 crypt_stat->cipher);
Eric Sandeenc8161f62007-12-22 14:03:26 -0800813 goto out_unlock;
Michael Halcrow237fead2006-10-04 02:16:22 -0700814 }
Herbert Xuf1ddcaf2007-01-27 10:05:15 +1100815 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow237fead2006-10-04 02:16:22 -0700816 rc = 0;
Eric Sandeenc8161f62007-12-22 14:03:26 -0800817out_unlock:
818 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700819out:
820 return rc;
821}
822
823static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
824{
825 int extent_size_tmp;
826
827 crypt_stat->extent_mask = 0xFFFFFFFF;
828 crypt_stat->extent_shift = 0;
829 if (crypt_stat->extent_size == 0)
830 return;
831 extent_size_tmp = crypt_stat->extent_size;
832 while ((extent_size_tmp & 0x01) == 0) {
833 extent_size_tmp >>= 1;
834 crypt_stat->extent_mask <<= 1;
835 crypt_stat->extent_shift++;
836 }
837}
838
839void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
840{
841 /* Default values; may be overwritten as we are parsing the
842 * packets. */
843 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
844 set_extent_mask_and_shift(crypt_stat);
845 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800846 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800847 crypt_stat->num_header_bytes_at_front = 0;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700848 else {
849 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800850 crypt_stat->num_header_bytes_at_front =
851 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700852 else
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800853 crypt_stat->num_header_bytes_at_front = PAGE_CACHE_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700854 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700855}
856
857/**
858 * ecryptfs_compute_root_iv
859 * @crypt_stats
860 *
861 * On error, sets the root IV to all 0's.
862 */
863int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
864{
865 int rc = 0;
866 char dst[MD5_DIGEST_SIZE];
867
868 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
869 BUG_ON(crypt_stat->iv_bytes <= 0);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800870 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700871 rc = -EINVAL;
872 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
873 "cannot generate root IV\n");
874 goto out;
875 }
876 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
877 crypt_stat->key_size);
878 if (rc) {
879 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
880 "MD5 while generating root IV\n");
881 goto out;
882 }
883 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
884out:
885 if (rc) {
886 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800887 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
Michael Halcrow237fead2006-10-04 02:16:22 -0700888 }
889 return rc;
890}
891
892static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
893{
894 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800895 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
Michael Halcrow237fead2006-10-04 02:16:22 -0700896 ecryptfs_compute_root_iv(crypt_stat);
897 if (unlikely(ecryptfs_verbosity > 0)) {
898 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
899 ecryptfs_dump_hex(crypt_stat->key,
900 crypt_stat->key_size);
901 }
902}
903
904/**
Michael Halcrow17398952007-02-12 00:53:45 -0800905 * ecryptfs_copy_mount_wide_flags_to_inode_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700906 * @crypt_stat: The inode's cryptographic context
907 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow17398952007-02-12 00:53:45 -0800908 *
909 * This function propagates the mount-wide flags to individual inode
910 * flags.
911 */
912static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
913 struct ecryptfs_crypt_stat *crypt_stat,
914 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
915{
916 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
917 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
918 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
919 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
920}
921
Michael Halcrowf4aad162007-10-16 01:27:53 -0700922static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
923 struct ecryptfs_crypt_stat *crypt_stat,
924 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
925{
926 struct ecryptfs_global_auth_tok *global_auth_tok;
927 int rc = 0;
928
929 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
930 list_for_each_entry(global_auth_tok,
931 &mount_crypt_stat->global_auth_tok_list,
932 mount_crypt_stat_list) {
933 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
934 if (rc) {
935 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
936 mutex_unlock(
937 &mount_crypt_stat->global_auth_tok_list_mutex);
938 goto out;
939 }
940 }
941 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
942out:
943 return rc;
944}
945
Michael Halcrow17398952007-02-12 00:53:45 -0800946/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700947 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700948 * @crypt_stat: The inode's cryptographic context
949 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700950 *
951 * Default values in the event that policy does not override them.
952 */
953static void ecryptfs_set_default_crypt_stat_vals(
954 struct ecryptfs_crypt_stat *crypt_stat,
955 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
956{
Michael Halcrow17398952007-02-12 00:53:45 -0800957 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
958 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700959 ecryptfs_set_default_sizes(crypt_stat);
960 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
961 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800962 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -0700963 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
964 crypt_stat->mount_crypt_stat = mount_crypt_stat;
965}
966
967/**
968 * ecryptfs_new_file_context
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700969 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -0700970 *
971 * If the crypto context for the file has not yet been established,
972 * this is where we do that. Establishing a new crypto context
973 * involves the following decisions:
974 * - What cipher to use?
975 * - What set of authentication tokens to use?
976 * Here we just worry about getting enough information into the
977 * authentication tokens so that we know that they are available.
978 * We associate the available authentication tokens with the new file
979 * via the set of signatures in the crypt_stat struct. Later, when
980 * the headers are actually written out, we may again defer to
981 * userspace to perform the encryption of the session key; for the
982 * foreseeable future, this will be the case with public key packets.
983 *
984 * Returns zero on success; non-zero otherwise
985 */
Michael Halcrow237fead2006-10-04 02:16:22 -0700986int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
987{
Michael Halcrow237fead2006-10-04 02:16:22 -0700988 struct ecryptfs_crypt_stat *crypt_stat =
989 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
990 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
991 &ecryptfs_superblock_to_private(
992 ecryptfs_dentry->d_sb)->mount_crypt_stat;
993 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700994 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700995
996 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -0700997 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700998 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
999 mount_crypt_stat);
1000 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1001 mount_crypt_stat);
1002 if (rc) {
1003 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1004 "to the inode key sigs; rc = [%d]\n", rc);
1005 goto out;
1006 }
1007 cipher_name_len =
1008 strlen(mount_crypt_stat->global_default_cipher_name);
1009 memcpy(crypt_stat->cipher,
1010 mount_crypt_stat->global_default_cipher_name,
1011 cipher_name_len);
1012 crypt_stat->cipher[cipher_name_len] = '\0';
1013 crypt_stat->key_size =
1014 mount_crypt_stat->global_default_cipher_key_size;
1015 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001016 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1017 if (rc)
1018 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1019 "context for cipher [%s]: rc = [%d]\n",
1020 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001021out:
Michael Halcrow237fead2006-10-04 02:16:22 -07001022 return rc;
1023}
1024
1025/**
1026 * contains_ecryptfs_marker - check for the ecryptfs marker
1027 * @data: The data block in which to check
1028 *
1029 * Returns one if marker found; zero if not found
1030 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001031static int contains_ecryptfs_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -07001032{
1033 u32 m_1, m_2;
1034
1035 memcpy(&m_1, data, 4);
1036 m_1 = be32_to_cpu(m_1);
1037 memcpy(&m_2, (data + 4), 4);
1038 m_2 = be32_to_cpu(m_2);
1039 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1040 return 1;
1041 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1042 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1043 MAGIC_ECRYPTFS_MARKER);
1044 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1045 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1046 return 0;
1047}
1048
1049struct ecryptfs_flag_map_elem {
1050 u32 file_flag;
1051 u32 local_flag;
1052};
1053
1054/* Add support for additional flags by adding elements here. */
1055static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1056 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001057 {0x00000002, ECRYPTFS_ENCRYPTED},
1058 {0x00000004, ECRYPTFS_METADATA_IN_XATTR}
Michael Halcrow237fead2006-10-04 02:16:22 -07001059};
1060
1061/**
1062 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001063 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001064 * @page_virt: Source data to be parsed
1065 * @bytes_read: Updated with the number of bytes read
1066 *
1067 * Returns zero on success; non-zero if the flag set is invalid
1068 */
1069static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1070 char *page_virt, int *bytes_read)
1071{
1072 int rc = 0;
1073 int i;
1074 u32 flags;
1075
1076 memcpy(&flags, page_virt, 4);
1077 flags = be32_to_cpu(flags);
1078 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1079 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1080 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001081 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -07001082 } else
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001083 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
Michael Halcrow237fead2006-10-04 02:16:22 -07001084 /* Version is in top 8 bits of the 32-bit flag vector */
1085 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1086 (*bytes_read) = 4;
1087 return rc;
1088}
1089
1090/**
1091 * write_ecryptfs_marker
1092 * @page_virt: The pointer to in a page to begin writing the marker
1093 * @written: Number of bytes written
1094 *
1095 * Marker = 0x3c81b7f5
1096 */
1097static void write_ecryptfs_marker(char *page_virt, size_t *written)
1098{
1099 u32 m_1, m_2;
1100
1101 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1102 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1103 m_1 = cpu_to_be32(m_1);
1104 memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1105 m_2 = cpu_to_be32(m_2);
1106 memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2,
1107 (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1108 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1109}
1110
1111static void
1112write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1113 size_t *written)
1114{
1115 u32 flags = 0;
1116 int i;
1117
1118 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1119 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001120 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -07001121 flags |= ecryptfs_flag_map[i].file_flag;
1122 /* Version is in top 8 bits of the 32-bit flag vector */
1123 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1124 flags = cpu_to_be32(flags);
1125 memcpy(page_virt, &flags, 4);
1126 (*written) = 4;
1127}
1128
1129struct ecryptfs_cipher_code_str_map_elem {
1130 char cipher_str[16];
Trevor Highland19e66a62008-02-06 01:38:36 -08001131 u8 cipher_code;
Michael Halcrow237fead2006-10-04 02:16:22 -07001132};
1133
1134/* Add support for additional ciphers by adding elements here. The
1135 * cipher_code is whatever OpenPGP applicatoins use to identify the
1136 * ciphers. List in order of probability. */
1137static struct ecryptfs_cipher_code_str_map_elem
1138ecryptfs_cipher_code_str_map[] = {
1139 {"aes",RFC2440_CIPHER_AES_128 },
1140 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1141 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1142 {"cast5", RFC2440_CIPHER_CAST_5},
1143 {"twofish", RFC2440_CIPHER_TWOFISH},
1144 {"cast6", RFC2440_CIPHER_CAST_6},
1145 {"aes", RFC2440_CIPHER_AES_192},
1146 {"aes", RFC2440_CIPHER_AES_256}
1147};
1148
1149/**
1150 * ecryptfs_code_for_cipher_string
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001151 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001152 *
1153 * Returns zero on no match, or the cipher code on match
1154 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001155u8 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -07001156{
1157 int i;
Trevor Highland19e66a62008-02-06 01:38:36 -08001158 u8 code = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001159 struct ecryptfs_cipher_code_str_map_elem *map =
1160 ecryptfs_cipher_code_str_map;
1161
1162 if (strcmp(crypt_stat->cipher, "aes") == 0) {
1163 switch (crypt_stat->key_size) {
1164 case 16:
1165 code = RFC2440_CIPHER_AES_128;
1166 break;
1167 case 24:
1168 code = RFC2440_CIPHER_AES_192;
1169 break;
1170 case 32:
1171 code = RFC2440_CIPHER_AES_256;
1172 }
1173 } else {
1174 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1175 if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){
1176 code = map[i].cipher_code;
1177 break;
1178 }
1179 }
1180 return code;
1181}
1182
1183/**
1184 * ecryptfs_cipher_code_to_string
1185 * @str: Destination to write out the cipher name
1186 * @cipher_code: The code to convert to cipher name string
1187 *
1188 * Returns zero on success
1189 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001190int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
Michael Halcrow237fead2006-10-04 02:16:22 -07001191{
1192 int rc = 0;
1193 int i;
1194
1195 str[0] = '\0';
1196 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1197 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1198 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1199 if (str[0] == '\0') {
1200 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1201 "[%d]\n", cipher_code);
1202 rc = -EINVAL;
1203 }
1204 return rc;
1205}
1206
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001207int ecryptfs_read_and_validate_header_region(char *data,
1208 struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001209{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001210 struct ecryptfs_crypt_stat *crypt_stat =
1211 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001212 int rc;
1213
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001214 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1215 ecryptfs_inode);
1216 if (rc) {
1217 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
1218 __FUNCTION__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001219 goto out;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001220 }
1221 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001222 rc = -EINVAL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001223 ecryptfs_printk(KERN_DEBUG, "Valid marker not found\n");
1224 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001225out:
1226 return rc;
1227}
1228
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001229void
1230ecryptfs_write_header_metadata(char *virt,
1231 struct ecryptfs_crypt_stat *crypt_stat,
1232 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001233{
1234 u32 header_extent_size;
1235 u16 num_header_extents_at_front;
1236
Michael Halcrow45eaab72007-10-16 01:28:05 -07001237 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001238 num_header_extents_at_front =
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001239 (u16)(crypt_stat->num_header_bytes_at_front
1240 / crypt_stat->extent_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001241 header_extent_size = cpu_to_be32(header_extent_size);
1242 memcpy(virt, &header_extent_size, 4);
1243 virt += 4;
1244 num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front);
1245 memcpy(virt, &num_header_extents_at_front, 2);
1246 (*written) = 6;
1247}
1248
1249struct kmem_cache *ecryptfs_header_cache_0;
1250struct kmem_cache *ecryptfs_header_cache_1;
1251struct kmem_cache *ecryptfs_header_cache_2;
1252
1253/**
1254 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001255 * @page_virt: The virtual address to write the headers to
1256 * @size: Set to the number of bytes written by this function
1257 * @crypt_stat: The cryptographic context
1258 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001259 *
1260 * Format version: 1
1261 *
1262 * Header Extent:
1263 * Octets 0-7: Unencrypted file size (big-endian)
1264 * Octets 8-15: eCryptfs special marker
1265 * Octets 16-19: Flags
1266 * Octet 16: File format version number (between 0 and 255)
1267 * Octets 17-18: Reserved
1268 * Octet 19: Bit 1 (lsb): Reserved
1269 * Bit 2: Encrypted?
1270 * Bits 3-8: Reserved
1271 * Octets 20-23: Header extent size (big-endian)
1272 * Octets 24-25: Number of header extents at front of file
1273 * (big-endian)
1274 * Octet 26: Begin RFC 2440 authentication token packet set
1275 * Data Extent 0:
1276 * Lower data (CBC encrypted)
1277 * Data Extent 1:
1278 * Lower data (CBC encrypted)
1279 * ...
1280 *
1281 * Returns zero on success
1282 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001283static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
1284 struct ecryptfs_crypt_stat *crypt_stat,
1285 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001286{
1287 int rc;
1288 size_t written;
1289 size_t offset;
1290
1291 offset = ECRYPTFS_FILE_SIZE_BYTES;
1292 write_ecryptfs_marker((page_virt + offset), &written);
1293 offset += written;
1294 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1295 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001296 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1297 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001298 offset += written;
1299 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1300 ecryptfs_dentry, &written,
1301 PAGE_CACHE_SIZE - offset);
1302 if (rc)
1303 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1304 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001305 if (size) {
1306 offset += written;
1307 *size = offset;
1308 }
1309 return rc;
1310}
1311
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001312static int
1313ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001314 struct dentry *ecryptfs_dentry,
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001315 char *virt)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001316{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001317 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001318
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001319 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
1320 0, crypt_stat->num_header_bytes_at_front);
1321 if (rc)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001322 printk(KERN_ERR "%s: Error attempting to write header "
1323 "information to lower file; rc = [%d]\n", __FUNCTION__,
1324 rc);
Michael Halcrow70456602007-02-12 00:53:48 -08001325 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001326}
1327
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001328static int
1329ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1330 struct ecryptfs_crypt_stat *crypt_stat,
1331 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001332{
1333 int rc;
1334
1335 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1336 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001337 return rc;
1338}
1339
1340/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001341 * ecryptfs_write_metadata
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001342 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001343 *
1344 * Write the file headers out. This will likely involve a userspace
1345 * callout, in which the session key is encrypted with one or more
1346 * public keys and/or the passphrase necessary to do the encryption is
1347 * retrieved via a prompt. Exactly what happens at this point should
1348 * be policy-dependent.
1349 *
1350 * Returns zero on success; non-zero on error
1351 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001352int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001353{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001354 struct ecryptfs_crypt_stat *crypt_stat =
1355 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001356 char *virt;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001357 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001358 int rc = 0;
1359
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001360 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1361 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001362 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001363 rc = -EINVAL;
1364 goto out;
1365 }
1366 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001367 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1368 __FUNCTION__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001369 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001370 goto out;
1371 }
1372 /* Released in this function */
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001373 virt = kzalloc(crypt_stat->num_header_bytes_at_front, GFP_KERNEL);
1374 if (!virt) {
1375 printk(KERN_ERR "%s: Out of memory\n", __FUNCTION__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001376 rc = -ENOMEM;
1377 goto out;
1378 }
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001379 rc = ecryptfs_write_headers_virt(virt, &size, crypt_stat,
1380 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001381 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001382 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1383 __FUNCTION__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001384 goto out_free;
1385 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001386 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1387 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001388 crypt_stat, virt, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001389 else
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001390 rc = ecryptfs_write_metadata_to_contents(crypt_stat,
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001391 ecryptfs_dentry, virt);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001392 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001393 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1394 "rc = [%d]\n", __FUNCTION__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001395 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001396 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001397out_free:
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001398 memset(virt, 0, crypt_stat->num_header_bytes_at_front);
1399 kfree(virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001400out:
1401 return rc;
1402}
1403
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001404#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1405#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001406static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001407 char *virt, int *bytes_read,
1408 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001409{
1410 int rc = 0;
1411 u32 header_extent_size;
1412 u16 num_header_extents_at_front;
1413
Michael Halcrowecbdc932007-10-16 01:28:14 -07001414 memcpy(&header_extent_size, virt, sizeof(u32));
Michael Halcrow237fead2006-10-04 02:16:22 -07001415 header_extent_size = be32_to_cpu(header_extent_size);
Michael Halcrowecbdc932007-10-16 01:28:14 -07001416 virt += sizeof(u32);
1417 memcpy(&num_header_extents_at_front, virt, sizeof(u16));
Michael Halcrow237fead2006-10-04 02:16:22 -07001418 num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001419 crypt_stat->num_header_bytes_at_front =
1420 (((size_t)num_header_extents_at_front
1421 * (size_t)header_extent_size));
Michael Halcrow45eaab72007-10-16 01:28:05 -07001422 (*bytes_read) = (sizeof(u32) + sizeof(u16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001423 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001424 && (crypt_stat->num_header_bytes_at_front
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001425 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001426 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001427 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1428 crypt_stat->num_header_bytes_at_front);
Michael Halcrow237fead2006-10-04 02:16:22 -07001429 }
1430 return rc;
1431}
1432
1433/**
1434 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001435 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001436 *
1437 * For version 0 file format; this function is only for backwards
1438 * compatibility for files created with the prior versions of
1439 * eCryptfs.
1440 */
1441static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1442{
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001443 crypt_stat->num_header_bytes_at_front =
1444 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001445}
1446
1447/**
1448 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001449 * @page_virt: The virtual address into which to read the headers
1450 * @crypt_stat: The cryptographic context
1451 * @ecryptfs_dentry: The eCryptfs dentry
1452 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001453 *
1454 * Read/parse the header data. The header format is detailed in the
1455 * comment block for the ecryptfs_write_headers_virt() function.
1456 *
1457 * Returns zero on success
1458 */
1459static int ecryptfs_read_headers_virt(char *page_virt,
1460 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001461 struct dentry *ecryptfs_dentry,
1462 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001463{
1464 int rc = 0;
1465 int offset;
1466 int bytes_read;
1467
1468 ecryptfs_set_default_sizes(crypt_stat);
1469 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1470 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1471 offset = ECRYPTFS_FILE_SIZE_BYTES;
1472 rc = contains_ecryptfs_marker(page_virt + offset);
1473 if (rc == 0) {
1474 rc = -EINVAL;
1475 goto out;
1476 }
1477 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1478 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1479 &bytes_read);
1480 if (rc) {
1481 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1482 goto out;
1483 }
1484 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1485 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1486 "file version [%d] is supported by this "
1487 "version of eCryptfs\n",
1488 crypt_stat->file_version,
1489 ECRYPTFS_SUPPORTED_FILE_VERSION);
1490 rc = -EINVAL;
1491 goto out;
1492 }
1493 offset += bytes_read;
1494 if (crypt_stat->file_version >= 1) {
1495 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001496 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001497 if (rc) {
1498 ecryptfs_printk(KERN_WARNING, "Error reading header "
1499 "metadata; rc = [%d]\n", rc);
1500 }
1501 offset += bytes_read;
1502 } else
1503 set_default_header_data(crypt_stat);
1504 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1505 ecryptfs_dentry);
1506out:
1507 return rc;
1508}
1509
1510/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001511 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001512 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001513 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001514 *
1515 * Attempts to read the crypto metadata from the extended attribute
1516 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001517 *
1518 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001519 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001520int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001521{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001522 struct dentry *lower_dentry =
1523 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001524 ssize_t size;
1525 int rc = 0;
1526
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001527 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1528 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001529 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001530 if (unlikely(ecryptfs_verbosity > 0))
1531 printk(KERN_INFO "Error attempting to read the [%s] "
1532 "xattr from the lower file; return value = "
1533 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001534 rc = -EINVAL;
1535 goto out;
1536 }
1537out:
1538 return rc;
1539}
1540
1541int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1542 struct dentry *ecryptfs_dentry)
1543{
1544 int rc;
1545
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001546 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001547 if (rc)
1548 goto out;
1549 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1550 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1551 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1552 rc = -EINVAL;
1553 }
1554out:
1555 return rc;
1556}
1557
1558/**
1559 * ecryptfs_read_metadata
1560 *
1561 * Common entry point for reading file metadata. From here, we could
1562 * retrieve the header information from the header region of the file,
1563 * the xattr region of the file, or some other repostory that is
1564 * stored separately from the file itself. The current implementation
1565 * supports retrieving the metadata information from the file contents
1566 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001567 *
1568 * Returns zero if valid headers found and parsed; non-zero otherwise
1569 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001570int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001571{
1572 int rc = 0;
1573 char *page_virt = NULL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001574 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -07001575 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001576 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001577 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1578 &ecryptfs_superblock_to_private(
1579 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001580
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001581 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1582 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001583 /* Read the first page from the underlying file */
Christoph Lameterf7267c02006-12-06 20:33:15 -08001584 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001585 if (!page_virt) {
1586 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001587 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1588 __FUNCTION__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001589 goto out;
1590 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001591 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1592 ecryptfs_inode);
1593 if (!rc)
1594 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1595 ecryptfs_dentry,
1596 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001597 if (rc) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001598 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001599 if (rc) {
1600 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1601 "file header region or xattr region\n");
1602 rc = -EINVAL;
1603 goto out;
1604 }
1605 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1606 ecryptfs_dentry,
1607 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1608 if (rc) {
1609 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1610 "file xattr region either\n");
1611 rc = -EINVAL;
1612 }
1613 if (crypt_stat->mount_crypt_stat->flags
1614 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1615 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1616 } else {
1617 printk(KERN_WARNING "Attempt to access file with "
1618 "crypto metadata only in the extended attribute "
1619 "region, but eCryptfs was mounted without "
1620 "xattr support enabled. eCryptfs will not treat "
1621 "this like an encrypted file.\n");
1622 rc = -EINVAL;
1623 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001624 }
1625out:
1626 if (page_virt) {
1627 memset(page_virt, 0, PAGE_CACHE_SIZE);
1628 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1629 }
1630 return rc;
1631}
1632
1633/**
1634 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1635 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1636 * @name: The plaintext name
1637 * @length: The length of the plaintext
1638 * @encoded_name: The encypted name
1639 *
1640 * Encrypts and encodes a filename into something that constitutes a
1641 * valid filename for a filesystem, with printable characters.
1642 *
1643 * We assume that we have a properly initialized crypto context,
1644 * pointed to by crypt_stat->tfm.
1645 *
1646 * TODO: Implement filename decoding and decryption here, in place of
1647 * memcpy. We are keeping the framework around for now to (1)
1648 * facilitate testing of the components needed to implement filename
1649 * encryption and (2) to provide a code base from which other
1650 * developers in the community can easily implement this feature.
1651 *
1652 * Returns the length of encoded filename; negative if error
1653 */
1654int
1655ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1656 const char *name, int length, char **encoded_name)
1657{
1658 int error = 0;
1659
1660 (*encoded_name) = kmalloc(length + 2, GFP_KERNEL);
1661 if (!(*encoded_name)) {
1662 error = -ENOMEM;
1663 goto out;
1664 }
1665 /* TODO: Filename encryption is a scheduled feature for a
1666 * future version of eCryptfs. This function is here only for
1667 * the purpose of providing a framework for other developers
1668 * to easily implement filename encryption. Hint: Replace this
1669 * memcpy() with a call to encrypt and encode the
1670 * filename, the set the length accordingly. */
1671 memcpy((void *)(*encoded_name), (void *)name, length);
1672 (*encoded_name)[length] = '\0';
1673 error = length + 1;
1674out:
1675 return error;
1676}
1677
1678/**
1679 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1680 * @crypt_stat: The crypt_stat struct associated with the file
1681 * @name: The filename in cipher text
1682 * @length: The length of the cipher text name
1683 * @decrypted_name: The plaintext name
1684 *
1685 * Decodes and decrypts the filename.
1686 *
1687 * We assume that we have a properly initialized crypto context,
1688 * pointed to by crypt_stat->tfm.
1689 *
1690 * TODO: Implement filename decoding and decryption here, in place of
1691 * memcpy. We are keeping the framework around for now to (1)
1692 * facilitate testing of the components needed to implement filename
1693 * encryption and (2) to provide a code base from which other
1694 * developers in the community can easily implement this feature.
1695 *
1696 * Returns the length of decoded filename; negative if error
1697 */
1698int
1699ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1700 const char *name, int length, char **decrypted_name)
1701{
1702 int error = 0;
1703
1704 (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL);
1705 if (!(*decrypted_name)) {
1706 error = -ENOMEM;
1707 goto out;
1708 }
1709 /* TODO: Filename encryption is a scheduled feature for a
1710 * future version of eCryptfs. This function is here only for
1711 * the purpose of providing a framework for other developers
1712 * to easily implement filename encryption. Hint: Replace this
1713 * memcpy() with a call to decode and decrypt the
1714 * filename, the set the length accordingly. */
1715 memcpy((void *)(*decrypted_name), (void *)name, length);
1716 (*decrypted_name)[length + 1] = '\0'; /* Only for convenience
1717 * in printing out the
1718 * string in debug
1719 * messages */
1720 error = length;
1721out:
1722 return error;
1723}
1724
1725/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001726 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001727 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001728 * @cipher_name: Name of the cipher
1729 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001730 *
1731 * Returns zero on success. Any crypto_tfm structs allocated here
1732 * should be released by other functions, such as on a superblock put
1733 * event, regardless of whether this function succeeds for fails.
1734 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001735static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001736ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1737 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001738{
1739 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Michael Halcrow8bba0662006-10-30 22:07:18 -08001740 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -07001741 int rc;
1742
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001743 *key_tfm = NULL;
1744 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001745 rc = -EINVAL;
1746 printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001747 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001748 goto out;
1749 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001750 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1751 "ecb");
1752 if (rc)
1753 goto out;
1754 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1755 kfree(full_alg_name);
1756 if (IS_ERR(*key_tfm)) {
1757 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001758 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Michael Halcrow8bba0662006-10-30 22:07:18 -08001759 "[%s]; rc = [%d]\n", cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001760 goto out;
1761 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001762 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1763 if (*key_size == 0) {
1764 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1765
1766 *key_size = alg->max_keysize;
1767 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001768 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001769 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001770 if (rc) {
1771 printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001772 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001773 rc = -EINVAL;
1774 goto out;
1775 }
1776out:
1777 return rc;
1778}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001779
1780struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001781static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001782struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001783
1784int ecryptfs_init_crypto(void)
1785{
1786 mutex_init(&key_tfm_list_mutex);
1787 INIT_LIST_HEAD(&key_tfm_list);
1788 return 0;
1789}
1790
Eric Sandeenaf440f52008-02-06 01:38:37 -08001791/**
1792 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1793 *
1794 * Called only at module unload time
1795 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001796int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001797{
1798 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1799
1800 mutex_lock(&key_tfm_list_mutex);
1801 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1802 key_tfm_list) {
1803 list_del(&key_tfm->key_tfm_list);
1804 if (key_tfm->key_tfm)
1805 crypto_free_blkcipher(key_tfm->key_tfm);
1806 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1807 }
1808 mutex_unlock(&key_tfm_list_mutex);
1809 return 0;
1810}
1811
1812int
1813ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1814 size_t key_size)
1815{
1816 struct ecryptfs_key_tfm *tmp_tfm;
1817 int rc = 0;
1818
Eric Sandeenaf440f52008-02-06 01:38:37 -08001819 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1820
Michael Halcrowf4aad162007-10-16 01:27:53 -07001821 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1822 if (key_tfm != NULL)
1823 (*key_tfm) = tmp_tfm;
1824 if (!tmp_tfm) {
1825 rc = -ENOMEM;
1826 printk(KERN_ERR "Error attempting to allocate from "
1827 "ecryptfs_key_tfm_cache\n");
1828 goto out;
1829 }
1830 mutex_init(&tmp_tfm->key_tfm_mutex);
1831 strncpy(tmp_tfm->cipher_name, cipher_name,
1832 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001833 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001834 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001835 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1836 tmp_tfm->cipher_name,
1837 &tmp_tfm->key_size);
1838 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001839 printk(KERN_ERR "Error attempting to initialize key TFM "
1840 "cipher with name = [%s]; rc = [%d]\n",
1841 tmp_tfm->cipher_name, rc);
1842 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1843 if (key_tfm != NULL)
1844 (*key_tfm) = NULL;
1845 goto out;
1846 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001847 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001848out:
1849 return rc;
1850}
1851
Eric Sandeenaf440f52008-02-06 01:38:37 -08001852/**
1853 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1854 * @cipher_name: the name of the cipher to search for
1855 * @key_tfm: set to corresponding tfm if found
1856 *
1857 * Searches for cached key_tfm matching @cipher_name
1858 * Must be called with &key_tfm_list_mutex held
1859 * Returns 1 if found, with @key_tfm set
1860 * Returns 0 if not found, with @key_tfm set to NULL
1861 */
1862int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1863{
1864 struct ecryptfs_key_tfm *tmp_key_tfm;
1865
1866 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1867
1868 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1869 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1870 if (key_tfm)
1871 (*key_tfm) = tmp_key_tfm;
1872 return 1;
1873 }
1874 }
1875 if (key_tfm)
1876 (*key_tfm) = NULL;
1877 return 0;
1878}
1879
1880/**
1881 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1882 *
1883 * @tfm: set to cached tfm found, or new tfm created
1884 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1885 * @cipher_name: the name of the cipher to search for and/or add
1886 *
1887 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1888 * Searches for cached item first, and creates new if not found.
1889 * Returns 0 on success, non-zero if adding new cipher failed
1890 */
Michael Halcrowf4aad162007-10-16 01:27:53 -07001891int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1892 struct mutex **tfm_mutex,
1893 char *cipher_name)
1894{
1895 struct ecryptfs_key_tfm *key_tfm;
1896 int rc = 0;
1897
1898 (*tfm) = NULL;
1899 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001900
Michael Halcrowf4aad162007-10-16 01:27:53 -07001901 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001902 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1903 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1904 if (rc) {
1905 printk(KERN_ERR "Error adding new key_tfm to list; "
1906 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001907 goto out;
1908 }
1909 }
1910 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001911 (*tfm) = key_tfm->key_tfm;
1912 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1913out:
1914 return rc;
1915}