blob: 67e8b16f7bcb752215a8ac235a7090e2616e14ef [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 Halcrow565d9722006-10-30 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 Halcrow565d9722006-10-30 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 Halcrow565d9722006-10-30 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 Halcrow565d9722006-10-30 22:07:17 -0800112 "allocate crypto context; rc = [%d]\n",
113 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700114 goto out;
115 }
Michael Halcrow565d9722006-10-30 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 Halcrow565d9722006-10-30 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 Halcrow565d9722006-10-30 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);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800358 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
359 crypt_stat->key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700360 if (rc) {
361 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
362 rc);
363 mutex_unlock(&crypt_stat->cs_tfm_mutex);
364 rc = -EINVAL;
365 goto out;
366 }
367 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800368 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700369 mutex_unlock(&crypt_stat->cs_tfm_mutex);
370out:
371 return rc;
372}
373
Michael Halcrow237fead2006-10-04 02:16:22 -0700374/**
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700375 * ecryptfs_lower_offset_for_extent
376 *
377 * Convert an eCryptfs page index into a lower byte offset
378 */
379void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
380 struct ecryptfs_crypt_stat *crypt_stat)
381{
382 (*offset) = ((crypt_stat->extent_size
383 * crypt_stat->num_header_extents_at_front)
384 + (crypt_stat->extent_size * extent_num));
385}
386
387/**
388 * ecryptfs_encrypt_extent
389 * @enc_extent_page: Allocated page into which to encrypt the data in
390 * @page
391 * @crypt_stat: crypt_stat containing cryptographic context for the
392 * encryption operation
393 * @page: Page containing plaintext data extent to encrypt
394 * @extent_offset: Page extent offset for use in generating IV
395 *
396 * Encrypts one extent of data.
397 *
398 * Return zero on success; non-zero otherwise
399 */
400static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
401 struct ecryptfs_crypt_stat *crypt_stat,
402 struct page *page,
403 unsigned long extent_offset)
404{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700405 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700406 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
407 int rc;
408
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700409 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700410 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
411 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
412 (extent_base + extent_offset));
413 if (rc) {
414 ecryptfs_printk(KERN_ERR, "Error attempting to "
415 "derive IV for extent [0x%.16x]; "
416 "rc = [%d]\n", (extent_base + extent_offset),
417 rc);
418 goto out;
419 }
420 if (unlikely(ecryptfs_verbosity > 0)) {
421 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
422 "with iv:\n");
423 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
424 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
425 "encryption:\n");
426 ecryptfs_dump_hex((char *)
427 (page_address(page)
428 + (extent_offset * crypt_stat->extent_size)),
429 8);
430 }
431 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
432 page, (extent_offset
433 * crypt_stat->extent_size),
434 crypt_stat->extent_size, extent_iv);
435 if (rc < 0) {
436 printk(KERN_ERR "%s: Error attempting to encrypt page with "
437 "page->index = [%ld], extent_offset = [%ld]; "
438 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
439 rc);
440 goto out;
441 }
442 rc = 0;
443 if (unlikely(ecryptfs_verbosity > 0)) {
444 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
445 "rc = [%d]\n", (extent_base + extent_offset),
446 rc);
447 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
448 "encryption:\n");
449 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
450 }
451out:
452 return rc;
453}
454
455/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700456 * ecryptfs_encrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700457 * @page: Page mapped from the eCryptfs inode for the file; contains
458 * decrypted content that needs to be encrypted (to a temporary
459 * page; not in place) and written out to the lower file
Michael Halcrow237fead2006-10-04 02:16:22 -0700460 *
461 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
462 * that eCryptfs pages may straddle the lower pages -- for instance,
463 * if the file was created on a machine with an 8K page size
464 * (resulting in an 8K header), and then the file is copied onto a
465 * host with a 32K page size, then when reading page 0 of the eCryptfs
466 * file, 24K of page 0 of the lower file will be read and decrypted,
467 * and then 8K of page 1 of the lower file will be read and decrypted.
468 *
Michael Halcrow237fead2006-10-04 02:16:22 -0700469 * Returns zero on success; negative on error
470 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700471int ecryptfs_encrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700472{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700473 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700474 struct ecryptfs_crypt_stat *crypt_stat;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700475 char *enc_extent_virt = NULL;
476 struct page *enc_extent_page;
477 loff_t extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700478 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700479
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700480 ecryptfs_inode = page->mapping->host;
481 crypt_stat =
482 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800483 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700484 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
485 0, PAGE_CACHE_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -0700486 if (rc)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700487 printk(KERN_ERR "%s: Error attempting to copy "
488 "page at index [%ld]\n", __FUNCTION__,
489 page->index);
Michael Halcrow237fead2006-10-04 02:16:22 -0700490 goto out;
491 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700492 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
493 if (!enc_extent_virt) {
494 rc = -ENOMEM;
495 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
496 "encrypted extent\n");
497 goto out;
498 }
499 enc_extent_page = virt_to_page(enc_extent_virt);
500 for (extent_offset = 0;
501 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
502 extent_offset++) {
503 loff_t offset;
504
505 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
506 extent_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700507 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700508 printk(KERN_ERR "%s: Error encrypting extent; "
509 "rc = [%d]\n", __FUNCTION__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700510 goto out;
511 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700512 ecryptfs_lower_offset_for_extent(
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700513 &offset, ((((loff_t)page->index)
514 * (PAGE_CACHE_SIZE
515 / crypt_stat->extent_size))
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700516 + extent_offset), crypt_stat);
517 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
518 offset, crypt_stat->extent_size);
519 if (rc) {
520 ecryptfs_printk(KERN_ERR, "Error attempting "
521 "to write lower page; rc = [%d]"
522 "\n", rc);
523 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700524 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700525 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700526out:
527 kfree(enc_extent_virt);
528 return rc;
529}
530
531static int ecryptfs_decrypt_extent(struct page *page,
532 struct ecryptfs_crypt_stat *crypt_stat,
533 struct page *enc_extent_page,
534 unsigned long extent_offset)
535{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700536 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700537 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
538 int rc;
539
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700540 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700541 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
542 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
543 (extent_base + extent_offset));
Michael Halcrow237fead2006-10-04 02:16:22 -0700544 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700545 ecryptfs_printk(KERN_ERR, "Error attempting to "
546 "derive IV for extent [0x%.16x]; "
547 "rc = [%d]\n", (extent_base + extent_offset),
548 rc);
549 goto out;
550 }
551 if (unlikely(ecryptfs_verbosity > 0)) {
552 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
553 "with iv:\n");
554 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
555 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
556 "decryption:\n");
557 ecryptfs_dump_hex((char *)
558 (page_address(enc_extent_page)
559 + (extent_offset * crypt_stat->extent_size)),
560 8);
561 }
562 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
563 (extent_offset
564 * crypt_stat->extent_size),
565 enc_extent_page, 0,
566 crypt_stat->extent_size, extent_iv);
567 if (rc < 0) {
568 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
569 "page->index = [%ld], extent_offset = [%ld]; "
570 "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
571 rc);
572 goto out;
573 }
574 rc = 0;
575 if (unlikely(ecryptfs_verbosity > 0)) {
576 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
577 "rc = [%d]\n", (extent_base + extent_offset),
578 rc);
579 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
580 "decryption:\n");
581 ecryptfs_dump_hex((char *)(page_address(page)
582 + (extent_offset
583 * crypt_stat->extent_size)), 8);
Michael Halcrow237fead2006-10-04 02:16:22 -0700584 }
585out:
586 return rc;
587}
588
589/**
590 * ecryptfs_decrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700591 * @page: Page mapped from the eCryptfs inode for the file; data read
592 * and decrypted from the lower file will be written into this
593 * page
Michael Halcrow237fead2006-10-04 02:16:22 -0700594 *
595 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
596 * that eCryptfs pages may straddle the lower pages -- for instance,
597 * if the file was created on a machine with an 8K page size
598 * (resulting in an 8K header), and then the file is copied onto a
599 * host with a 32K page size, then when reading page 0 of the eCryptfs
600 * file, 24K of page 0 of the lower file will be read and decrypted,
601 * and then 8K of page 1 of the lower file will be read and decrypted.
602 *
603 * Returns zero on success; negative on error
604 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700605int ecryptfs_decrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700606{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700607 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700608 struct ecryptfs_crypt_stat *crypt_stat;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700609 char *enc_extent_virt = NULL;
610 struct page *enc_extent_page;
611 unsigned long extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700612 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700613
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700614 ecryptfs_inode = page->mapping->host;
615 crypt_stat =
616 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800617 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700618 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
619 PAGE_CACHE_SIZE,
620 ecryptfs_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700621 if (rc)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700622 printk(KERN_ERR "%s: Error attempting to copy "
623 "page at index [%ld]\n", __FUNCTION__,
624 page->index);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700625 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700626 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700627 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
628 if (!enc_extent_virt) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700629 rc = -ENOMEM;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700630 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
631 "encrypted extent\n");
Michael Halcrow16a72c42007-10-16 01:28:14 -0700632 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700633 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700634 enc_extent_page = virt_to_page(enc_extent_virt);
635 for (extent_offset = 0;
636 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
637 extent_offset++) {
638 loff_t offset;
639
640 ecryptfs_lower_offset_for_extent(
641 &offset, ((page->index * (PAGE_CACHE_SIZE
642 / crypt_stat->extent_size))
643 + extent_offset), crypt_stat);
644 rc = ecryptfs_read_lower(enc_extent_virt, offset,
645 crypt_stat->extent_size,
646 ecryptfs_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700647 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700648 ecryptfs_printk(KERN_ERR, "Error attempting "
649 "to read lower page; rc = [%d]"
650 "\n", rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700651 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700652 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700653 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
654 extent_offset);
655 if (rc) {
656 printk(KERN_ERR "%s: Error encrypting extent; "
657 "rc = [%d]\n", __FUNCTION__, rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700658 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700659 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700660 }
661out:
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700662 kfree(enc_extent_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700663 return rc;
664}
665
666/**
667 * decrypt_scatterlist
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700668 * @crypt_stat: Cryptographic context
669 * @dest_sg: The destination scatterlist to decrypt into
670 * @src_sg: The source scatterlist to decrypt from
671 * @size: The number of bytes to decrypt
672 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700673 *
674 * Returns the number of bytes decrypted; negative value on error
675 */
676static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
677 struct scatterlist *dest_sg,
678 struct scatterlist *src_sg, int size,
679 unsigned char *iv)
680{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800681 struct blkcipher_desc desc = {
682 .tfm = crypt_stat->tfm,
683 .info = iv,
684 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
685 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700686 int rc = 0;
687
688 /* Consider doing this once, when the file is opened */
689 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800690 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
691 crypt_stat->key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700692 if (rc) {
693 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
694 rc);
695 mutex_unlock(&crypt_stat->cs_tfm_mutex);
696 rc = -EINVAL;
697 goto out;
698 }
699 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800700 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700701 mutex_unlock(&crypt_stat->cs_tfm_mutex);
702 if (rc) {
703 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
704 rc);
705 goto out;
706 }
707 rc = size;
708out:
709 return rc;
710}
711
712/**
713 * ecryptfs_encrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700714 * @crypt_stat: The cryptographic context
715 * @dst_page: The page to encrypt into
716 * @dst_offset: The offset in the page to encrypt into
717 * @src_page: The page to encrypt from
718 * @src_offset: The offset in the page to encrypt from
719 * @size: The number of bytes to encrypt
720 * @iv: The initialization vector to use for the encryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700721 *
722 * Returns the number of bytes encrypted
723 */
724static int
725ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
726 struct page *dst_page, int dst_offset,
727 struct page *src_page, int src_offset, int size,
728 unsigned char *iv)
729{
730 struct scatterlist src_sg, dst_sg;
731
Jens Axboe60c74f82007-10-22 19:43:30 +0200732 sg_init_table(&src_sg, 1);
733 sg_init_table(&dst_sg, 1);
734
Jens Axboe642f1492007-10-24 11:20:47 +0200735 sg_set_page(&src_sg, src_page, size, src_offset);
736 sg_set_page(&dst_sg, dst_page, size, dst_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700737 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
738}
739
740/**
741 * ecryptfs_decrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700742 * @crypt_stat: The cryptographic context
743 * @dst_page: The page to decrypt into
744 * @dst_offset: The offset in the page to decrypt into
745 * @src_page: The page to decrypt from
746 * @src_offset: The offset in the page to decrypt from
747 * @size: The number of bytes to decrypt
748 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700749 *
750 * Returns the number of bytes decrypted
751 */
752static int
753ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
754 struct page *dst_page, int dst_offset,
755 struct page *src_page, int src_offset, int size,
756 unsigned char *iv)
757{
758 struct scatterlist src_sg, dst_sg;
759
Jens Axboe60c74f82007-10-22 19:43:30 +0200760 sg_init_table(&src_sg, 1);
Jens Axboe642f1492007-10-24 11:20:47 +0200761 sg_set_page(&src_sg, src_page, size, src_offset);
Jens Axboe60c74f82007-10-22 19:43:30 +0200762
Jens Axboe642f1492007-10-24 11:20:47 +0200763 sg_init_table(&dst_sg, 1);
764 sg_set_page(&dst_sg, dst_page, size, dst_offset);
765
Michael Halcrow237fead2006-10-04 02:16:22 -0700766 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
767}
768
769#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
770
771/**
772 * ecryptfs_init_crypt_ctx
773 * @crypt_stat: Uninitilized crypt stats structure
774 *
775 * Initialize the crypto context.
776 *
777 * TODO: Performance: Keep a cache of initialized cipher contexts;
778 * only init if needed
779 */
780int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
781{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800782 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700783 int rc = -EINVAL;
784
785 if (!crypt_stat->cipher) {
786 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
787 goto out;
788 }
789 ecryptfs_printk(KERN_DEBUG,
790 "Initializing cipher [%s]; strlen = [%d]; "
791 "key_size_bits = [%d]\n",
792 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
793 crypt_stat->key_size << 3);
794 if (crypt_stat->tfm) {
795 rc = 0;
796 goto out;
797 }
798 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800799 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
800 crypt_stat->cipher, "cbc");
801 if (rc)
802 goto out;
803 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
804 CRYPTO_ALG_ASYNC);
805 kfree(full_alg_name);
Akinobu Mitade887772006-11-28 12:29:49 -0800806 if (IS_ERR(crypt_stat->tfm)) {
807 rc = PTR_ERR(crypt_stat->tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700808 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
809 "Error initializing cipher [%s]\n",
810 crypt_stat->cipher);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800811 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700812 goto out;
813 }
Herbert Xuf1ddcaf2007-01-27 10:05:15 +1100814 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800815 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700816 rc = 0;
817out:
818 return rc;
819}
820
821static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
822{
823 int extent_size_tmp;
824
825 crypt_stat->extent_mask = 0xFFFFFFFF;
826 crypt_stat->extent_shift = 0;
827 if (crypt_stat->extent_size == 0)
828 return;
829 extent_size_tmp = crypt_stat->extent_size;
830 while ((extent_size_tmp & 0x01) == 0) {
831 extent_size_tmp >>= 1;
832 crypt_stat->extent_mask <<= 1;
833 crypt_stat->extent_shift++;
834 }
835}
836
837void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
838{
839 /* Default values; may be overwritten as we are parsing the
840 * packets. */
841 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
842 set_extent_mask_and_shift(crypt_stat);
843 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800844 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
845 crypt_stat->num_header_extents_at_front = 0;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700846 else {
847 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
848 crypt_stat->num_header_extents_at_front =
849 (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
850 / crypt_stat->extent_size);
851 else
852 crypt_stat->num_header_extents_at_front =
853 (PAGE_CACHE_SIZE / crypt_stat->extent_size);
854 }
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];
1131 u16 cipher_code;
1132};
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 */
1155u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat)
1156{
1157 int i;
1158 u16 code = 0;
1159 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 */
1190int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
1191{
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 =
1239 (u16)crypt_stat->num_header_extents_at_front;
1240 header_extent_size = cpu_to_be32(header_extent_size);
1241 memcpy(virt, &header_extent_size, 4);
1242 virt += 4;
1243 num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front);
1244 memcpy(virt, &num_header_extents_at_front, 2);
1245 (*written) = 6;
1246}
1247
1248struct kmem_cache *ecryptfs_header_cache_0;
1249struct kmem_cache *ecryptfs_header_cache_1;
1250struct kmem_cache *ecryptfs_header_cache_2;
1251
1252/**
1253 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001254 * @page_virt: The virtual address to write the headers to
1255 * @size: Set to the number of bytes written by this function
1256 * @crypt_stat: The cryptographic context
1257 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001258 *
1259 * Format version: 1
1260 *
1261 * Header Extent:
1262 * Octets 0-7: Unencrypted file size (big-endian)
1263 * Octets 8-15: eCryptfs special marker
1264 * Octets 16-19: Flags
1265 * Octet 16: File format version number (between 0 and 255)
1266 * Octets 17-18: Reserved
1267 * Octet 19: Bit 1 (lsb): Reserved
1268 * Bit 2: Encrypted?
1269 * Bits 3-8: Reserved
1270 * Octets 20-23: Header extent size (big-endian)
1271 * Octets 24-25: Number of header extents at front of file
1272 * (big-endian)
1273 * Octet 26: Begin RFC 2440 authentication token packet set
1274 * Data Extent 0:
1275 * Lower data (CBC encrypted)
1276 * Data Extent 1:
1277 * Lower data (CBC encrypted)
1278 * ...
1279 *
1280 * Returns zero on success
1281 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001282static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
1283 struct ecryptfs_crypt_stat *crypt_stat,
1284 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001285{
1286 int rc;
1287 size_t written;
1288 size_t offset;
1289
1290 offset = ECRYPTFS_FILE_SIZE_BYTES;
1291 write_ecryptfs_marker((page_virt + offset), &written);
1292 offset += written;
1293 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1294 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001295 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1296 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001297 offset += written;
1298 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1299 ecryptfs_dentry, &written,
1300 PAGE_CACHE_SIZE - offset);
1301 if (rc)
1302 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1303 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001304 if (size) {
1305 offset += written;
1306 *size = offset;
1307 }
1308 return rc;
1309}
1310
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001311static int
1312ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001313 struct dentry *ecryptfs_dentry,
1314 char *page_virt)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001315{
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001316 int current_header_page;
1317 int header_pages;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001318 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001319
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001320 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, page_virt,
1321 0, PAGE_CACHE_SIZE);
1322 if (rc) {
1323 printk(KERN_ERR "%s: Error attempting to write header "
1324 "information to lower file; rc = [%d]\n", __FUNCTION__,
1325 rc);
Michael Halcrow70456602007-02-12 00:53:48 -08001326 goto out;
1327 }
Michael Halcrow45eaab72007-10-16 01:28:05 -07001328 header_pages = ((crypt_stat->extent_size
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001329 * crypt_stat->num_header_extents_at_front)
1330 / PAGE_CACHE_SIZE);
1331 memset(page_virt, 0, PAGE_CACHE_SIZE);
1332 current_header_page = 1;
1333 while (current_header_page < header_pages) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001334 loff_t offset;
1335
Michael Halcrowd6a13c12007-10-16 01:28:12 -07001336 offset = (((loff_t)current_header_page) << PAGE_CACHE_SHIFT);
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001337 if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode,
1338 page_virt, offset,
1339 PAGE_CACHE_SIZE))) {
1340 printk(KERN_ERR "%s: Error attempting to write header "
1341 "information to lower file; rc = [%d]\n",
1342 __FUNCTION__, rc);
Michael Halcrow70456602007-02-12 00:53:48 -08001343 goto out;
1344 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001345 current_header_page++;
1346 }
Michael Halcrow70456602007-02-12 00:53:48 -08001347out:
1348 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001349}
1350
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001351static int
1352ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1353 struct ecryptfs_crypt_stat *crypt_stat,
1354 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001355{
1356 int rc;
1357
1358 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1359 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001360 return rc;
1361}
1362
1363/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001364 * ecryptfs_write_metadata
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001365 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001366 *
1367 * Write the file headers out. This will likely involve a userspace
1368 * callout, in which the session key is encrypted with one or more
1369 * public keys and/or the passphrase necessary to do the encryption is
1370 * retrieved via a prompt. Exactly what happens at this point should
1371 * be policy-dependent.
1372 *
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001373 * TODO: Support header information spanning multiple pages
1374 *
Michael Halcrow237fead2006-10-04 02:16:22 -07001375 * Returns zero on success; non-zero on error
1376 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001377int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001378{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001379 struct ecryptfs_crypt_stat *crypt_stat =
1380 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001381 char *page_virt;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001382 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001383 int rc = 0;
1384
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001385 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1386 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001387 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001388 rc = -EINVAL;
1389 goto out;
1390 }
1391 } else {
1392 rc = -EINVAL;
1393 ecryptfs_printk(KERN_WARNING,
1394 "Called with crypt_stat->encrypted == 0\n");
1395 goto out;
1396 }
1397 /* Released in this function */
Robert P. J. Dayc3762222007-02-10 01:45:03 -08001398 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001399 if (!page_virt) {
1400 ecryptfs_printk(KERN_ERR, "Out of memory\n");
1401 rc = -ENOMEM;
1402 goto out;
1403 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001404 rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat,
1405 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001406 if (unlikely(rc)) {
1407 ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n");
1408 memset(page_virt, 0, PAGE_CACHE_SIZE);
1409 goto out_free;
1410 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001411 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1412 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
1413 crypt_stat, page_virt,
1414 size);
1415 else
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001416 rc = ecryptfs_write_metadata_to_contents(crypt_stat,
1417 ecryptfs_dentry,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001418 page_virt);
1419 if (rc) {
1420 printk(KERN_ERR "Error writing metadata out to lower file; "
1421 "rc = [%d]\n", rc);
1422 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001423 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001424out_free:
1425 kmem_cache_free(ecryptfs_header_cache_0, page_virt);
1426out:
1427 return rc;
1428}
1429
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001430#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1431#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001432static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001433 char *virt, int *bytes_read,
1434 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001435{
1436 int rc = 0;
1437 u32 header_extent_size;
1438 u16 num_header_extents_at_front;
1439
Michael Halcrowecbdc932007-10-16 01:28:14 -07001440 memcpy(&header_extent_size, virt, sizeof(u32));
Michael Halcrow237fead2006-10-04 02:16:22 -07001441 header_extent_size = be32_to_cpu(header_extent_size);
Michael Halcrowecbdc932007-10-16 01:28:14 -07001442 virt += sizeof(u32);
1443 memcpy(&num_header_extents_at_front, virt, sizeof(u16));
Michael Halcrow237fead2006-10-04 02:16:22 -07001444 num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
Michael Halcrow237fead2006-10-04 02:16:22 -07001445 crypt_stat->num_header_extents_at_front =
1446 (int)num_header_extents_at_front;
Michael Halcrow45eaab72007-10-16 01:28:05 -07001447 (*bytes_read) = (sizeof(u32) + sizeof(u16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001448 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Michael Halcrow45eaab72007-10-16 01:28:05 -07001449 && ((crypt_stat->extent_size
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001450 * crypt_stat->num_header_extents_at_front)
1451 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001452 rc = -EINVAL;
Michael Halcrow45eaab72007-10-16 01:28:05 -07001453 printk(KERN_WARNING "Invalid number of header extents: [%zd]\n",
1454 crypt_stat->num_header_extents_at_front);
Michael Halcrow237fead2006-10-04 02:16:22 -07001455 }
1456 return rc;
1457}
1458
1459/**
1460 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001461 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001462 *
1463 * For version 0 file format; this function is only for backwards
1464 * compatibility for files created with the prior versions of
1465 * eCryptfs.
1466 */
1467static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1468{
Michael Halcrow45eaab72007-10-16 01:28:05 -07001469 crypt_stat->num_header_extents_at_front = 2;
Michael Halcrow237fead2006-10-04 02:16:22 -07001470}
1471
1472/**
1473 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001474 * @page_virt: The virtual address into which to read the headers
1475 * @crypt_stat: The cryptographic context
1476 * @ecryptfs_dentry: The eCryptfs dentry
1477 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001478 *
1479 * Read/parse the header data. The header format is detailed in the
1480 * comment block for the ecryptfs_write_headers_virt() function.
1481 *
1482 * Returns zero on success
1483 */
1484static int ecryptfs_read_headers_virt(char *page_virt,
1485 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001486 struct dentry *ecryptfs_dentry,
1487 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001488{
1489 int rc = 0;
1490 int offset;
1491 int bytes_read;
1492
1493 ecryptfs_set_default_sizes(crypt_stat);
1494 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1495 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1496 offset = ECRYPTFS_FILE_SIZE_BYTES;
1497 rc = contains_ecryptfs_marker(page_virt + offset);
1498 if (rc == 0) {
1499 rc = -EINVAL;
1500 goto out;
1501 }
1502 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1503 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1504 &bytes_read);
1505 if (rc) {
1506 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1507 goto out;
1508 }
1509 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1510 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1511 "file version [%d] is supported by this "
1512 "version of eCryptfs\n",
1513 crypt_stat->file_version,
1514 ECRYPTFS_SUPPORTED_FILE_VERSION);
1515 rc = -EINVAL;
1516 goto out;
1517 }
1518 offset += bytes_read;
1519 if (crypt_stat->file_version >= 1) {
1520 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001521 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001522 if (rc) {
1523 ecryptfs_printk(KERN_WARNING, "Error reading header "
1524 "metadata; rc = [%d]\n", rc);
1525 }
1526 offset += bytes_read;
1527 } else
1528 set_default_header_data(crypt_stat);
1529 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1530 ecryptfs_dentry);
1531out:
1532 return rc;
1533}
1534
1535/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001536 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001537 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001538 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001539 *
1540 * Attempts to read the crypto metadata from the extended attribute
1541 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001542 *
1543 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001544 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001545int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001546{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001547 struct dentry *lower_dentry =
1548 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001549 ssize_t size;
1550 int rc = 0;
1551
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001552 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1553 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001554 if (size < 0) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001555 printk(KERN_ERR "Error attempting to read the [%s] "
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001556 "xattr from the lower file; return value = [%zd]\n",
1557 ECRYPTFS_XATTR_NAME, size);
1558 rc = -EINVAL;
1559 goto out;
1560 }
1561out:
1562 return rc;
1563}
1564
1565int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1566 struct dentry *ecryptfs_dentry)
1567{
1568 int rc;
1569
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001570 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001571 if (rc)
1572 goto out;
1573 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1574 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1575 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1576 rc = -EINVAL;
1577 }
1578out:
1579 return rc;
1580}
1581
1582/**
1583 * ecryptfs_read_metadata
1584 *
1585 * Common entry point for reading file metadata. From here, we could
1586 * retrieve the header information from the header region of the file,
1587 * the xattr region of the file, or some other repostory that is
1588 * stored separately from the file itself. The current implementation
1589 * supports retrieving the metadata information from the file contents
1590 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001591 *
1592 * Returns zero if valid headers found and parsed; non-zero otherwise
1593 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001594int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001595{
1596 int rc = 0;
1597 char *page_virt = NULL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001598 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -07001599 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001600 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001601 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1602 &ecryptfs_superblock_to_private(
1603 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001604
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001605 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1606 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001607 /* Read the first page from the underlying file */
Christoph Lameterf7267c02006-12-06 20:33:15 -08001608 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001609 if (!page_virt) {
1610 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001611 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1612 __FUNCTION__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001613 goto out;
1614 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001615 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1616 ecryptfs_inode);
1617 if (!rc)
1618 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1619 ecryptfs_dentry,
1620 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001621 if (rc) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001622 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001623 if (rc) {
1624 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1625 "file header region or xattr region\n");
1626 rc = -EINVAL;
1627 goto out;
1628 }
1629 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1630 ecryptfs_dentry,
1631 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1632 if (rc) {
1633 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1634 "file xattr region either\n");
1635 rc = -EINVAL;
1636 }
1637 if (crypt_stat->mount_crypt_stat->flags
1638 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1639 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1640 } else {
1641 printk(KERN_WARNING "Attempt to access file with "
1642 "crypto metadata only in the extended attribute "
1643 "region, but eCryptfs was mounted without "
1644 "xattr support enabled. eCryptfs will not treat "
1645 "this like an encrypted file.\n");
1646 rc = -EINVAL;
1647 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001648 }
1649out:
1650 if (page_virt) {
1651 memset(page_virt, 0, PAGE_CACHE_SIZE);
1652 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1653 }
1654 return rc;
1655}
1656
1657/**
1658 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1659 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1660 * @name: The plaintext name
1661 * @length: The length of the plaintext
1662 * @encoded_name: The encypted name
1663 *
1664 * Encrypts and encodes a filename into something that constitutes a
1665 * valid filename for a filesystem, with printable characters.
1666 *
1667 * We assume that we have a properly initialized crypto context,
1668 * pointed to by crypt_stat->tfm.
1669 *
1670 * TODO: Implement filename decoding and decryption here, in place of
1671 * memcpy. We are keeping the framework around for now to (1)
1672 * facilitate testing of the components needed to implement filename
1673 * encryption and (2) to provide a code base from which other
1674 * developers in the community can easily implement this feature.
1675 *
1676 * Returns the length of encoded filename; negative if error
1677 */
1678int
1679ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1680 const char *name, int length, char **encoded_name)
1681{
1682 int error = 0;
1683
1684 (*encoded_name) = kmalloc(length + 2, GFP_KERNEL);
1685 if (!(*encoded_name)) {
1686 error = -ENOMEM;
1687 goto out;
1688 }
1689 /* TODO: Filename encryption is a scheduled feature for a
1690 * future version of eCryptfs. This function is here only for
1691 * the purpose of providing a framework for other developers
1692 * to easily implement filename encryption. Hint: Replace this
1693 * memcpy() with a call to encrypt and encode the
1694 * filename, the set the length accordingly. */
1695 memcpy((void *)(*encoded_name), (void *)name, length);
1696 (*encoded_name)[length] = '\0';
1697 error = length + 1;
1698out:
1699 return error;
1700}
1701
1702/**
1703 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1704 * @crypt_stat: The crypt_stat struct associated with the file
1705 * @name: The filename in cipher text
1706 * @length: The length of the cipher text name
1707 * @decrypted_name: The plaintext name
1708 *
1709 * Decodes and decrypts the filename.
1710 *
1711 * We assume that we have a properly initialized crypto context,
1712 * pointed to by crypt_stat->tfm.
1713 *
1714 * TODO: Implement filename decoding and decryption here, in place of
1715 * memcpy. We are keeping the framework around for now to (1)
1716 * facilitate testing of the components needed to implement filename
1717 * encryption and (2) to provide a code base from which other
1718 * developers in the community can easily implement this feature.
1719 *
1720 * Returns the length of decoded filename; negative if error
1721 */
1722int
1723ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1724 const char *name, int length, char **decrypted_name)
1725{
1726 int error = 0;
1727
1728 (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL);
1729 if (!(*decrypted_name)) {
1730 error = -ENOMEM;
1731 goto out;
1732 }
1733 /* TODO: Filename encryption is a scheduled feature for a
1734 * future version of eCryptfs. This function is here only for
1735 * the purpose of providing a framework for other developers
1736 * to easily implement filename encryption. Hint: Replace this
1737 * memcpy() with a call to decode and decrypt the
1738 * filename, the set the length accordingly. */
1739 memcpy((void *)(*decrypted_name), (void *)name, length);
1740 (*decrypted_name)[length + 1] = '\0'; /* Only for convenience
1741 * in printing out the
1742 * string in debug
1743 * messages */
1744 error = length;
1745out:
1746 return error;
1747}
1748
1749/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001750 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001751 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001752 * @cipher_name: Name of the cipher
1753 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001754 *
1755 * Returns zero on success. Any crypto_tfm structs allocated here
1756 * should be released by other functions, such as on a superblock put
1757 * event, regardless of whether this function succeeds for fails.
1758 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001759static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001760ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1761 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001762{
1763 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Michael Halcrow8bba0662006-10-30 22:07:18 -08001764 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -07001765 int rc;
1766
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001767 *key_tfm = NULL;
1768 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001769 rc = -EINVAL;
1770 printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001771 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001772 goto out;
1773 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001774 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1775 "ecb");
1776 if (rc)
1777 goto out;
1778 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1779 kfree(full_alg_name);
1780 if (IS_ERR(*key_tfm)) {
1781 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001782 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Michael Halcrow8bba0662006-10-30 22:07:18 -08001783 "[%s]; rc = [%d]\n", cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001784 goto out;
1785 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001786 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1787 if (*key_size == 0) {
1788 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1789
1790 *key_size = alg->max_keysize;
1791 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001792 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001793 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001794 if (rc) {
1795 printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001796 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001797 rc = -EINVAL;
1798 goto out;
1799 }
1800out:
1801 return rc;
1802}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001803
1804struct kmem_cache *ecryptfs_key_tfm_cache;
1805struct list_head key_tfm_list;
1806struct mutex key_tfm_list_mutex;
1807
1808int ecryptfs_init_crypto(void)
1809{
1810 mutex_init(&key_tfm_list_mutex);
1811 INIT_LIST_HEAD(&key_tfm_list);
1812 return 0;
1813}
1814
Michael Halcrowfcd12832007-10-16 01:28:01 -07001815int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001816{
1817 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1818
1819 mutex_lock(&key_tfm_list_mutex);
1820 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1821 key_tfm_list) {
1822 list_del(&key_tfm->key_tfm_list);
1823 if (key_tfm->key_tfm)
1824 crypto_free_blkcipher(key_tfm->key_tfm);
1825 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1826 }
1827 mutex_unlock(&key_tfm_list_mutex);
1828 return 0;
1829}
1830
1831int
1832ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1833 size_t key_size)
1834{
1835 struct ecryptfs_key_tfm *tmp_tfm;
1836 int rc = 0;
1837
1838 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1839 if (key_tfm != NULL)
1840 (*key_tfm) = tmp_tfm;
1841 if (!tmp_tfm) {
1842 rc = -ENOMEM;
1843 printk(KERN_ERR "Error attempting to allocate from "
1844 "ecryptfs_key_tfm_cache\n");
1845 goto out;
1846 }
1847 mutex_init(&tmp_tfm->key_tfm_mutex);
1848 strncpy(tmp_tfm->cipher_name, cipher_name,
1849 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001850 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001851 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001852 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1853 tmp_tfm->cipher_name,
1854 &tmp_tfm->key_size);
1855 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001856 printk(KERN_ERR "Error attempting to initialize key TFM "
1857 "cipher with name = [%s]; rc = [%d]\n",
1858 tmp_tfm->cipher_name, rc);
1859 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1860 if (key_tfm != NULL)
1861 (*key_tfm) = NULL;
1862 goto out;
1863 }
1864 mutex_lock(&key_tfm_list_mutex);
1865 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1866 mutex_unlock(&key_tfm_list_mutex);
1867out:
1868 return rc;
1869}
1870
1871int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1872 struct mutex **tfm_mutex,
1873 char *cipher_name)
1874{
1875 struct ecryptfs_key_tfm *key_tfm;
1876 int rc = 0;
1877
1878 (*tfm) = NULL;
1879 (*tfm_mutex) = NULL;
1880 mutex_lock(&key_tfm_list_mutex);
1881 list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) {
1882 if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
1883 (*tfm) = key_tfm->key_tfm;
1884 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1885 mutex_unlock(&key_tfm_list_mutex);
1886 goto out;
1887 }
1888 }
1889 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrow5dda6992007-10-16 01:28:06 -07001890 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1891 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001892 printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
1893 rc);
1894 goto out;
1895 }
1896 (*tfm) = key_tfm->key_tfm;
1897 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1898out:
1899 return rc;
1900}