blob: 7b99917ffadc05e07dd480e54aaec385c378298c [file] [log] [blame]
Michael Halcrow237fead2006-10-04 02:16:22 -07001/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08006 * Copyright (C) 2004-2007 International Business Machines Corp.
Michael Halcrow237fead2006-10-04 02:16:22 -07007 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 * 02111-1307, USA.
24 */
25
26#include <linux/fs.h>
27#include <linux/mount.h>
28#include <linux/pagemap.h>
29#include <linux/random.h>
30#include <linux/compiler.h>
31#include <linux/key.h>
32#include <linux/namei.h>
33#include <linux/crypto.h>
34#include <linux/file.h>
35#include <linux/scatterlist.h>
Harvey Harrison29335c62008-07-23 21:30:06 -070036#include <asm/unaligned.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070037#include "ecryptfs_kernel.h"
38
39static int
40ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
41 struct page *dst_page, int dst_offset,
42 struct page *src_page, int src_offset, int size,
43 unsigned char *iv);
44static int
45ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
46 struct page *dst_page, int dst_offset,
47 struct page *src_page, int src_offset, int size,
48 unsigned char *iv);
49
50/**
51 * ecryptfs_to_hex
52 * @dst: Buffer to take hex character representation of contents of
53 * src; must be at least of size (src_size * 2)
54 * @src: Buffer to be converted to a hex string respresentation
55 * @src_size: number of bytes to convert
56 */
57void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
58{
59 int x;
60
61 for (x = 0; x < src_size; x++)
62 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
63}
64
65/**
66 * ecryptfs_from_hex
67 * @dst: Buffer to take the bytes from src hex; must be at least of
68 * size (src_size / 2)
69 * @src: Buffer to be converted from a hex string respresentation to raw value
70 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
71 */
72void ecryptfs_from_hex(char *dst, char *src, int dst_size)
73{
74 int x;
75 char tmp[3] = { 0, };
76
77 for (x = 0; x < dst_size; x++) {
78 tmp[0] = src[x * 2];
79 tmp[1] = src[x * 2 + 1];
80 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
81 }
82}
83
84/**
85 * ecryptfs_calculate_md5 - calculates the md5 of @src
86 * @dst: Pointer to 16 bytes of allocated memory
87 * @crypt_stat: Pointer to crypt_stat struct for the current inode
88 * @src: Data to be md5'd
89 * @len: Length of @src
90 *
91 * Uses the allocated crypto context that crypt_stat references to
92 * generate the MD5 sum of the contents of src.
93 */
94static int ecryptfs_calculate_md5(char *dst,
95 struct ecryptfs_crypt_stat *crypt_stat,
96 char *src, int len)
97{
Michael Halcrow237fead2006-10-04 02:16:22 -070098 struct scatterlist sg;
Michael Halcrow565d9722006-10-30 22:07:17 -080099 struct hash_desc desc = {
100 .tfm = crypt_stat->hash_tfm,
101 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
102 };
103 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700104
Michael Halcrow565d9722006-10-30 22:07:17 -0800105 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700106 sg_init_one(&sg, (u8 *)src, len);
Michael Halcrow565d9722006-10-30 22:07:17 -0800107 if (!desc.tfm) {
108 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
109 CRYPTO_ALG_ASYNC);
110 if (IS_ERR(desc.tfm)) {
111 rc = PTR_ERR(desc.tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700112 ecryptfs_printk(KERN_ERR, "Error attempting to "
Michael Halcrow565d9722006-10-30 22:07:17 -0800113 "allocate crypto context; rc = [%d]\n",
114 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700115 goto out;
116 }
Michael Halcrow565d9722006-10-30 22:07:17 -0800117 crypt_stat->hash_tfm = desc.tfm;
Michael Halcrow237fead2006-10-04 02:16:22 -0700118 }
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800119 rc = crypto_hash_init(&desc);
120 if (rc) {
121 printk(KERN_ERR
122 "%s: Error initializing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700123 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800124 goto out;
125 }
126 rc = crypto_hash_update(&desc, &sg, len);
127 if (rc) {
128 printk(KERN_ERR
129 "%s: Error updating crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700130 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800131 goto out;
132 }
133 rc = crypto_hash_final(&desc, dst);
134 if (rc) {
135 printk(KERN_ERR
136 "%s: Error finalizing crypto hash; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700137 __func__, rc);
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800138 goto out;
139 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700140out:
Michael Halcrow8a29f2b2007-11-05 14:51:04 -0800141 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700142 return rc;
143}
144
Michael Halcrowcd9d67d2007-10-16 01:28:04 -0700145static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
146 char *cipher_name,
147 char *chaining_modifier)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800148{
149 int cipher_name_len = strlen(cipher_name);
150 int chaining_modifier_len = strlen(chaining_modifier);
151 int algified_name_len;
152 int rc;
153
154 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
155 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
Michael Halcrow7bd473f2006-11-02 22:06:56 -0800156 if (!(*algified_name)) {
Michael Halcrow8bba0662006-10-30 22:07:18 -0800157 rc = -ENOMEM;
158 goto out;
159 }
160 snprintf((*algified_name), algified_name_len, "%s(%s)",
161 chaining_modifier, cipher_name);
162 rc = 0;
163out:
164 return rc;
165}
166
Michael Halcrow237fead2006-10-04 02:16:22 -0700167/**
168 * ecryptfs_derive_iv
169 * @iv: destination for the derived iv vale
170 * @crypt_stat: Pointer to crypt_stat struct for the current inode
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700171 * @offset: Offset of the extent whose IV we are to derive
Michael Halcrow237fead2006-10-04 02:16:22 -0700172 *
173 * Generate the initialization vector from the given root IV and page
174 * offset.
175 *
176 * Returns zero on success; non-zero on error.
177 */
178static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700179 loff_t offset)
Michael Halcrow237fead2006-10-04 02:16:22 -0700180{
181 int rc = 0;
182 char dst[MD5_DIGEST_SIZE];
183 char src[ECRYPTFS_MAX_IV_BYTES + 16];
184
185 if (unlikely(ecryptfs_verbosity > 0)) {
186 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
187 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
188 }
189 /* TODO: It is probably secure to just cast the least
190 * significant bits of the root IV into an unsigned long and
191 * add the offset to that rather than go through all this
192 * hashing business. -Halcrow */
193 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
194 memset((src + crypt_stat->iv_bytes), 0, 16);
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700195 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700196 if (unlikely(ecryptfs_verbosity > 0)) {
197 ecryptfs_printk(KERN_DEBUG, "source:\n");
198 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
199 }
200 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
201 (crypt_stat->iv_bytes + 16));
202 if (rc) {
203 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
204 "MD5 while generating IV for a page\n");
205 goto out;
206 }
207 memcpy(iv, dst, crypt_stat->iv_bytes);
208 if (unlikely(ecryptfs_verbosity > 0)) {
209 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
210 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
211 }
212out:
213 return rc;
214}
215
216/**
217 * ecryptfs_init_crypt_stat
218 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
219 *
220 * Initialize the crypt_stat structure.
221 */
222void
223ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
224{
225 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
Michael Halcrowf4aad162007-10-16 01:27:53 -0700226 INIT_LIST_HEAD(&crypt_stat->keysig_list);
227 mutex_init(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700228 mutex_init(&crypt_stat->cs_mutex);
229 mutex_init(&crypt_stat->cs_tfm_mutex);
Michael Halcrow565d9722006-10-30 22:07:17 -0800230 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800231 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
Michael Halcrow237fead2006-10-04 02:16:22 -0700232}
233
234/**
Michael Halcrowfcd12832007-10-16 01:28:01 -0700235 * ecryptfs_destroy_crypt_stat
Michael Halcrow237fead2006-10-04 02:16:22 -0700236 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
237 *
238 * Releases all memory associated with a crypt_stat struct.
239 */
Michael Halcrowfcd12832007-10-16 01:28:01 -0700240void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -0700241{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700242 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
243
Michael Halcrow237fead2006-10-04 02:16:22 -0700244 if (crypt_stat->tfm)
Michael Halcrow8bba0662006-10-30 22:07:18 -0800245 crypto_free_blkcipher(crypt_stat->tfm);
Michael Halcrow565d9722006-10-30 22:07:17 -0800246 if (crypt_stat->hash_tfm)
247 crypto_free_hash(crypt_stat->hash_tfm);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700248 mutex_lock(&crypt_stat->keysig_list_mutex);
249 list_for_each_entry_safe(key_sig, key_sig_tmp,
250 &crypt_stat->keysig_list, crypt_stat_list) {
251 list_del(&key_sig->crypt_stat_list);
252 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
253 }
254 mutex_unlock(&crypt_stat->keysig_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700255 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
256}
257
Michael Halcrowfcd12832007-10-16 01:28:01 -0700258void ecryptfs_destroy_mount_crypt_stat(
Michael Halcrow237fead2006-10-04 02:16:22 -0700259 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
260{
Michael Halcrowf4aad162007-10-16 01:27:53 -0700261 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
262
263 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
264 return;
265 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
266 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
267 &mount_crypt_stat->global_auth_tok_list,
268 mount_crypt_stat_list) {
269 list_del(&auth_tok->mount_crypt_stat_list);
270 mount_crypt_stat->num_global_auth_toks--;
271 if (auth_tok->global_auth_tok_key
272 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
273 key_put(auth_tok->global_auth_tok_key);
274 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
275 }
276 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700277 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
278}
279
280/**
281 * virt_to_scatterlist
282 * @addr: Virtual address
283 * @size: Size of data; should be an even multiple of the block size
284 * @sg: Pointer to scatterlist array; set to NULL to obtain only
285 * the number of scatterlist structs required in array
286 * @sg_size: Max array size
287 *
288 * Fills in a scatterlist array with page references for a passed
289 * virtual address.
290 *
291 * Returns the number of scatterlist structs in array used
292 */
293int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
294 int sg_size)
295{
296 int i = 0;
297 struct page *pg;
298 int offset;
299 int remainder_of_page;
300
Herbert Xu68e3f5d2007-10-27 00:52:07 -0700301 sg_init_table(sg, sg_size);
302
Michael Halcrow237fead2006-10-04 02:16:22 -0700303 while (size > 0 && i < sg_size) {
304 pg = virt_to_page(addr);
305 offset = offset_in_page(addr);
Jens Axboe642f1492007-10-24 11:20:47 +0200306 if (sg)
307 sg_set_page(&sg[i], pg, 0, offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700308 remainder_of_page = PAGE_CACHE_SIZE - offset;
309 if (size >= remainder_of_page) {
310 if (sg)
311 sg[i].length = remainder_of_page;
312 addr += remainder_of_page;
313 size -= remainder_of_page;
314 } else {
315 if (sg)
316 sg[i].length = size;
317 addr += size;
318 size = 0;
319 }
320 i++;
321 }
322 if (size > 0)
323 return -ENOMEM;
324 return i;
325}
326
327/**
328 * encrypt_scatterlist
329 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
330 * @dest_sg: Destination of encrypted data
331 * @src_sg: Data to be encrypted
332 * @size: Length of data to be encrypted
333 * @iv: iv to use during encryption
334 *
335 * Returns the number of bytes encrypted; negative value on error
336 */
337static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
338 struct scatterlist *dest_sg,
339 struct scatterlist *src_sg, int size,
340 unsigned char *iv)
341{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800342 struct blkcipher_desc desc = {
343 .tfm = crypt_stat->tfm,
344 .info = iv,
345 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
346 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700347 int rc = 0;
348
349 BUG_ON(!crypt_stat || !crypt_stat->tfm
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800350 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
Michael Halcrow237fead2006-10-04 02:16:22 -0700351 if (unlikely(ecryptfs_verbosity > 0)) {
352 ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n",
353 crypt_stat->key_size);
354 ecryptfs_dump_hex(crypt_stat->key,
355 crypt_stat->key_size);
356 }
357 /* Consider doing this once, when the file is opened */
358 mutex_lock(&crypt_stat->cs_tfm_mutex);
Trevor Highland8e3a6f12008-02-06 01:38:33 -0800359 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
360 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
361 crypt_stat->key_size);
362 crypt_stat->flags |= ECRYPTFS_KEY_SET;
363 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700364 if (rc) {
365 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
366 rc);
367 mutex_unlock(&crypt_stat->cs_tfm_mutex);
368 rc = -EINVAL;
369 goto out;
370 }
371 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800372 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700373 mutex_unlock(&crypt_stat->cs_tfm_mutex);
374out:
375 return rc;
376}
377
Michael Halcrow237fead2006-10-04 02:16:22 -0700378/**
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700379 * ecryptfs_lower_offset_for_extent
380 *
381 * Convert an eCryptfs page index into a lower byte offset
382 */
Adrian Bunk7896b632008-02-06 01:38:32 -0800383static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
384 struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700385{
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800386 (*offset) = (crypt_stat->num_header_bytes_at_front
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700387 + (crypt_stat->extent_size * extent_num));
388}
389
390/**
391 * ecryptfs_encrypt_extent
392 * @enc_extent_page: Allocated page into which to encrypt the data in
393 * @page
394 * @crypt_stat: crypt_stat containing cryptographic context for the
395 * encryption operation
396 * @page: Page containing plaintext data extent to encrypt
397 * @extent_offset: Page extent offset for use in generating IV
398 *
399 * Encrypts one extent of data.
400 *
401 * Return zero on success; non-zero otherwise
402 */
403static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
404 struct ecryptfs_crypt_stat *crypt_stat,
405 struct page *page,
406 unsigned long extent_offset)
407{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700408 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700409 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
410 int rc;
411
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700412 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700413 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
414 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
415 (extent_base + extent_offset));
416 if (rc) {
417 ecryptfs_printk(KERN_ERR, "Error attempting to "
418 "derive IV for extent [0x%.16x]; "
419 "rc = [%d]\n", (extent_base + extent_offset),
420 rc);
421 goto out;
422 }
423 if (unlikely(ecryptfs_verbosity > 0)) {
424 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
425 "with iv:\n");
426 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
427 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
428 "encryption:\n");
429 ecryptfs_dump_hex((char *)
430 (page_address(page)
431 + (extent_offset * crypt_stat->extent_size)),
432 8);
433 }
434 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
435 page, (extent_offset
436 * crypt_stat->extent_size),
437 crypt_stat->extent_size, extent_iv);
438 if (rc < 0) {
439 printk(KERN_ERR "%s: Error attempting to encrypt page with "
440 "page->index = [%ld], extent_offset = [%ld]; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700441 "rc = [%d]\n", __func__, page->index, extent_offset,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700442 rc);
443 goto out;
444 }
445 rc = 0;
446 if (unlikely(ecryptfs_verbosity > 0)) {
447 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
448 "rc = [%d]\n", (extent_base + extent_offset),
449 rc);
450 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
451 "encryption:\n");
452 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
453 }
454out:
455 return rc;
456}
457
458/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700459 * ecryptfs_encrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700460 * @page: Page mapped from the eCryptfs inode for the file; contains
461 * decrypted content that needs to be encrypted (to a temporary
462 * page; not in place) and written out to the lower file
Michael Halcrow237fead2006-10-04 02:16:22 -0700463 *
464 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
465 * that eCryptfs pages may straddle the lower pages -- for instance,
466 * if the file was created on a machine with an 8K page size
467 * (resulting in an 8K header), and then the file is copied onto a
468 * host with a 32K page size, then when reading page 0 of the eCryptfs
469 * file, 24K of page 0 of the lower file will be read and decrypted,
470 * and then 8K of page 1 of the lower file will be read and decrypted.
471 *
Michael Halcrow237fead2006-10-04 02:16:22 -0700472 * Returns zero on success; negative on error
473 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700474int ecryptfs_encrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700475{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700476 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700477 struct ecryptfs_crypt_stat *crypt_stat;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700478 char *enc_extent_virt = NULL;
479 struct page *enc_extent_page;
480 loff_t extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700481 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700482
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700483 ecryptfs_inode = page->mapping->host;
484 crypt_stat =
485 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800486 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700487 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
488 0, PAGE_CACHE_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -0700489 if (rc)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700490 printk(KERN_ERR "%s: Error attempting to copy "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700491 "page at index [%ld]\n", __func__,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700492 page->index);
Michael Halcrow237fead2006-10-04 02:16:22 -0700493 goto out;
494 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700495 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
496 if (!enc_extent_virt) {
497 rc = -ENOMEM;
498 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
499 "encrypted extent\n");
500 goto out;
501 }
502 enc_extent_page = virt_to_page(enc_extent_virt);
503 for (extent_offset = 0;
504 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
505 extent_offset++) {
506 loff_t offset;
507
508 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
509 extent_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700510 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700511 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700512 "rc = [%d]\n", __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700513 goto out;
514 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700515 ecryptfs_lower_offset_for_extent(
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700516 &offset, ((((loff_t)page->index)
517 * (PAGE_CACHE_SIZE
518 / crypt_stat->extent_size))
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700519 + extent_offset), crypt_stat);
520 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
521 offset, crypt_stat->extent_size);
522 if (rc) {
523 ecryptfs_printk(KERN_ERR, "Error attempting "
524 "to write lower page; rc = [%d]"
525 "\n", rc);
526 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700527 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700528 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700529out:
530 kfree(enc_extent_virt);
531 return rc;
532}
533
534static int ecryptfs_decrypt_extent(struct page *page,
535 struct ecryptfs_crypt_stat *crypt_stat,
536 struct page *enc_extent_page,
537 unsigned long extent_offset)
538{
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700539 loff_t extent_base;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700540 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
541 int rc;
542
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700543 extent_base = (((loff_t)page->index)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700544 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
545 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
546 (extent_base + extent_offset));
Michael Halcrow237fead2006-10-04 02:16:22 -0700547 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700548 ecryptfs_printk(KERN_ERR, "Error attempting to "
549 "derive IV for extent [0x%.16x]; "
550 "rc = [%d]\n", (extent_base + extent_offset),
551 rc);
552 goto out;
553 }
554 if (unlikely(ecryptfs_verbosity > 0)) {
555 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
556 "with iv:\n");
557 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
558 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
559 "decryption:\n");
560 ecryptfs_dump_hex((char *)
561 (page_address(enc_extent_page)
562 + (extent_offset * crypt_stat->extent_size)),
563 8);
564 }
565 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
566 (extent_offset
567 * crypt_stat->extent_size),
568 enc_extent_page, 0,
569 crypt_stat->extent_size, extent_iv);
570 if (rc < 0) {
571 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
572 "page->index = [%ld], extent_offset = [%ld]; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700573 "rc = [%d]\n", __func__, page->index, extent_offset,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700574 rc);
575 goto out;
576 }
577 rc = 0;
578 if (unlikely(ecryptfs_verbosity > 0)) {
579 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
580 "rc = [%d]\n", (extent_base + extent_offset),
581 rc);
582 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
583 "decryption:\n");
584 ecryptfs_dump_hex((char *)(page_address(page)
585 + (extent_offset
586 * crypt_stat->extent_size)), 8);
Michael Halcrow237fead2006-10-04 02:16:22 -0700587 }
588out:
589 return rc;
590}
591
592/**
593 * ecryptfs_decrypt_page
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700594 * @page: Page mapped from the eCryptfs inode for the file; data read
595 * and decrypted from the lower file will be written into this
596 * page
Michael Halcrow237fead2006-10-04 02:16:22 -0700597 *
598 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
599 * that eCryptfs pages may straddle the lower pages -- for instance,
600 * if the file was created on a machine with an 8K page size
601 * (resulting in an 8K header), and then the file is copied onto a
602 * host with a 32K page size, then when reading page 0 of the eCryptfs
603 * file, 24K of page 0 of the lower file will be read and decrypted,
604 * and then 8K of page 1 of the lower file will be read and decrypted.
605 *
606 * Returns zero on success; negative on error
607 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700608int ecryptfs_decrypt_page(struct page *page)
Michael Halcrow237fead2006-10-04 02:16:22 -0700609{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700610 struct inode *ecryptfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700611 struct ecryptfs_crypt_stat *crypt_stat;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700612 char *enc_extent_virt = NULL;
613 struct page *enc_extent_page;
614 unsigned long extent_offset;
Michael Halcrow237fead2006-10-04 02:16:22 -0700615 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700616
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700617 ecryptfs_inode = page->mapping->host;
618 crypt_stat =
619 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800620 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700621 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
622 PAGE_CACHE_SIZE,
623 ecryptfs_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700624 if (rc)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700625 printk(KERN_ERR "%s: Error attempting to copy "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700626 "page at index [%ld]\n", __func__,
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700627 page->index);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700628 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700629 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700630 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
631 if (!enc_extent_virt) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700632 rc = -ENOMEM;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700633 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
634 "encrypted extent\n");
Michael Halcrow16a72c42007-10-16 01:28:14 -0700635 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700636 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700637 enc_extent_page = virt_to_page(enc_extent_virt);
638 for (extent_offset = 0;
639 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
640 extent_offset++) {
641 loff_t offset;
642
643 ecryptfs_lower_offset_for_extent(
644 &offset, ((page->index * (PAGE_CACHE_SIZE
645 / crypt_stat->extent_size))
646 + extent_offset), crypt_stat);
647 rc = ecryptfs_read_lower(enc_extent_virt, offset,
648 crypt_stat->extent_size,
649 ecryptfs_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700650 if (rc) {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700651 ecryptfs_printk(KERN_ERR, "Error attempting "
652 "to read lower page; rc = [%d]"
653 "\n", rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700654 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700655 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700656 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
657 extent_offset);
658 if (rc) {
659 printk(KERN_ERR "%s: Error encrypting extent; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700660 "rc = [%d]\n", __func__, rc);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700661 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700662 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700663 }
664out:
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700665 kfree(enc_extent_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -0700666 return rc;
667}
668
669/**
670 * decrypt_scatterlist
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700671 * @crypt_stat: Cryptographic context
672 * @dest_sg: The destination scatterlist to decrypt into
673 * @src_sg: The source scatterlist to decrypt from
674 * @size: The number of bytes to decrypt
675 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700676 *
677 * Returns the number of bytes decrypted; negative value on error
678 */
679static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
680 struct scatterlist *dest_sg,
681 struct scatterlist *src_sg, int size,
682 unsigned char *iv)
683{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800684 struct blkcipher_desc desc = {
685 .tfm = crypt_stat->tfm,
686 .info = iv,
687 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
688 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700689 int rc = 0;
690
691 /* Consider doing this once, when the file is opened */
692 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800693 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
694 crypt_stat->key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700695 if (rc) {
696 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
697 rc);
698 mutex_unlock(&crypt_stat->cs_tfm_mutex);
699 rc = -EINVAL;
700 goto out;
701 }
702 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800703 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
Michael Halcrow237fead2006-10-04 02:16:22 -0700704 mutex_unlock(&crypt_stat->cs_tfm_mutex);
705 if (rc) {
706 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
707 rc);
708 goto out;
709 }
710 rc = size;
711out:
712 return rc;
713}
714
715/**
716 * ecryptfs_encrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700717 * @crypt_stat: The cryptographic context
718 * @dst_page: The page to encrypt into
719 * @dst_offset: The offset in the page to encrypt into
720 * @src_page: The page to encrypt from
721 * @src_offset: The offset in the page to encrypt from
722 * @size: The number of bytes to encrypt
723 * @iv: The initialization vector to use for the encryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700724 *
725 * Returns the number of bytes encrypted
726 */
727static int
728ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
729 struct page *dst_page, int dst_offset,
730 struct page *src_page, int src_offset, int size,
731 unsigned char *iv)
732{
733 struct scatterlist src_sg, dst_sg;
734
Jens Axboe60c74f82007-10-22 19:43:30 +0200735 sg_init_table(&src_sg, 1);
736 sg_init_table(&dst_sg, 1);
737
Jens Axboe642f1492007-10-24 11:20:47 +0200738 sg_set_page(&src_sg, src_page, size, src_offset);
739 sg_set_page(&dst_sg, dst_page, size, dst_offset);
Michael Halcrow237fead2006-10-04 02:16:22 -0700740 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
741}
742
743/**
744 * ecryptfs_decrypt_page_offset
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700745 * @crypt_stat: The cryptographic context
746 * @dst_page: The page to decrypt into
747 * @dst_offset: The offset in the page to decrypt into
748 * @src_page: The page to decrypt from
749 * @src_offset: The offset in the page to decrypt from
750 * @size: The number of bytes to decrypt
751 * @iv: The initialization vector to use for the decryption
Michael Halcrow237fead2006-10-04 02:16:22 -0700752 *
753 * Returns the number of bytes decrypted
754 */
755static int
756ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
757 struct page *dst_page, int dst_offset,
758 struct page *src_page, int src_offset, int size,
759 unsigned char *iv)
760{
761 struct scatterlist src_sg, dst_sg;
762
Jens Axboe60c74f82007-10-22 19:43:30 +0200763 sg_init_table(&src_sg, 1);
Jens Axboe642f1492007-10-24 11:20:47 +0200764 sg_set_page(&src_sg, src_page, size, src_offset);
Jens Axboe60c74f82007-10-22 19:43:30 +0200765
Jens Axboe642f1492007-10-24 11:20:47 +0200766 sg_init_table(&dst_sg, 1);
767 sg_set_page(&dst_sg, dst_page, size, dst_offset);
768
Michael Halcrow237fead2006-10-04 02:16:22 -0700769 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
770}
771
772#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
773
774/**
775 * ecryptfs_init_crypt_ctx
776 * @crypt_stat: Uninitilized crypt stats structure
777 *
778 * Initialize the crypto context.
779 *
780 * TODO: Performance: Keep a cache of initialized cipher contexts;
781 * only init if needed
782 */
783int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
784{
Michael Halcrow8bba0662006-10-30 22:07:18 -0800785 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -0700786 int rc = -EINVAL;
787
788 if (!crypt_stat->cipher) {
789 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
790 goto out;
791 }
792 ecryptfs_printk(KERN_DEBUG,
793 "Initializing cipher [%s]; strlen = [%d]; "
794 "key_size_bits = [%d]\n",
795 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
796 crypt_stat->key_size << 3);
797 if (crypt_stat->tfm) {
798 rc = 0;
799 goto out;
800 }
801 mutex_lock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow8bba0662006-10-30 22:07:18 -0800802 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
803 crypt_stat->cipher, "cbc");
804 if (rc)
Eric Sandeenc8161f62007-12-22 14:03:26 -0800805 goto out_unlock;
Michael Halcrow8bba0662006-10-30 22:07:18 -0800806 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
807 CRYPTO_ALG_ASYNC);
808 kfree(full_alg_name);
Akinobu Mitade887772006-11-28 12:29:49 -0800809 if (IS_ERR(crypt_stat->tfm)) {
810 rc = PTR_ERR(crypt_stat->tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -0700811 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
812 "Error initializing cipher [%s]\n",
813 crypt_stat->cipher);
Eric Sandeenc8161f62007-12-22 14:03:26 -0800814 goto out_unlock;
Michael Halcrow237fead2006-10-04 02:16:22 -0700815 }
Herbert Xuf1ddcaf2007-01-27 10:05:15 +1100816 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
Michael Halcrow237fead2006-10-04 02:16:22 -0700817 rc = 0;
Eric Sandeenc8161f62007-12-22 14:03:26 -0800818out_unlock:
819 mutex_unlock(&crypt_stat->cs_tfm_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700820out:
821 return rc;
822}
823
824static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
825{
826 int extent_size_tmp;
827
828 crypt_stat->extent_mask = 0xFFFFFFFF;
829 crypt_stat->extent_shift = 0;
830 if (crypt_stat->extent_size == 0)
831 return;
832 extent_size_tmp = crypt_stat->extent_size;
833 while ((extent_size_tmp & 0x01) == 0) {
834 extent_size_tmp >>= 1;
835 crypt_stat->extent_mask <<= 1;
836 crypt_stat->extent_shift++;
837 }
838}
839
840void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
841{
842 /* Default values; may be overwritten as we are parsing the
843 * packets. */
844 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
845 set_extent_mask_and_shift(crypt_stat);
846 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800847 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800848 crypt_stat->num_header_bytes_at_front = 0;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700849 else {
850 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800851 crypt_stat->num_header_bytes_at_front =
852 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700853 else
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800854 crypt_stat->num_header_bytes_at_front = PAGE_CACHE_SIZE;
Michael Halcrow45eaab72007-10-16 01:28:05 -0700855 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700856}
857
858/**
859 * ecryptfs_compute_root_iv
860 * @crypt_stats
861 *
862 * On error, sets the root IV to all 0's.
863 */
864int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
865{
866 int rc = 0;
867 char dst[MD5_DIGEST_SIZE];
868
869 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
870 BUG_ON(crypt_stat->iv_bytes <= 0);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800871 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700872 rc = -EINVAL;
873 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
874 "cannot generate root IV\n");
875 goto out;
876 }
877 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
878 crypt_stat->key_size);
879 if (rc) {
880 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
881 "MD5 while generating root IV\n");
882 goto out;
883 }
884 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
885out:
886 if (rc) {
887 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800888 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
Michael Halcrow237fead2006-10-04 02:16:22 -0700889 }
890 return rc;
891}
892
893static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
894{
895 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800896 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
Michael Halcrow237fead2006-10-04 02:16:22 -0700897 ecryptfs_compute_root_iv(crypt_stat);
898 if (unlikely(ecryptfs_verbosity > 0)) {
899 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
900 ecryptfs_dump_hex(crypt_stat->key,
901 crypt_stat->key_size);
902 }
903}
904
905/**
Michael Halcrow17398952007-02-12 00:53:45 -0800906 * ecryptfs_copy_mount_wide_flags_to_inode_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700907 * @crypt_stat: The inode's cryptographic context
908 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow17398952007-02-12 00:53:45 -0800909 *
910 * This function propagates the mount-wide flags to individual inode
911 * flags.
912 */
913static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
914 struct ecryptfs_crypt_stat *crypt_stat,
915 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
916{
917 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
918 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
919 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
920 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
921}
922
Michael Halcrowf4aad162007-10-16 01:27:53 -0700923static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
924 struct ecryptfs_crypt_stat *crypt_stat,
925 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
926{
927 struct ecryptfs_global_auth_tok *global_auth_tok;
928 int rc = 0;
929
930 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
931 list_for_each_entry(global_auth_tok,
932 &mount_crypt_stat->global_auth_tok_list,
933 mount_crypt_stat_list) {
934 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
935 if (rc) {
936 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
937 mutex_unlock(
938 &mount_crypt_stat->global_auth_tok_list_mutex);
939 goto out;
940 }
941 }
942 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
943out:
944 return rc;
945}
946
Michael Halcrow17398952007-02-12 00:53:45 -0800947/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700948 * ecryptfs_set_default_crypt_stat_vals
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700949 * @crypt_stat: The inode's cryptographic context
950 * @mount_crypt_stat: The mount point's cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -0700951 *
952 * Default values in the event that policy does not override them.
953 */
954static void ecryptfs_set_default_crypt_stat_vals(
955 struct ecryptfs_crypt_stat *crypt_stat,
956 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
957{
Michael Halcrow17398952007-02-12 00:53:45 -0800958 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
959 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700960 ecryptfs_set_default_sizes(crypt_stat);
961 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
962 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800963 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
Michael Halcrow237fead2006-10-04 02:16:22 -0700964 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
965 crypt_stat->mount_crypt_stat = mount_crypt_stat;
966}
967
968/**
969 * ecryptfs_new_file_context
Michael Halcrow22e78fa2007-10-16 01:28:02 -0700970 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -0700971 *
972 * If the crypto context for the file has not yet been established,
973 * this is where we do that. Establishing a new crypto context
974 * involves the following decisions:
975 * - What cipher to use?
976 * - What set of authentication tokens to use?
977 * Here we just worry about getting enough information into the
978 * authentication tokens so that we know that they are available.
979 * We associate the available authentication tokens with the new file
980 * via the set of signatures in the crypt_stat struct. Later, when
981 * the headers are actually written out, we may again defer to
982 * userspace to perform the encryption of the session key; for the
983 * foreseeable future, this will be the case with public key packets.
984 *
985 * Returns zero on success; non-zero otherwise
986 */
Michael Halcrow237fead2006-10-04 02:16:22 -0700987int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
988{
Michael Halcrow237fead2006-10-04 02:16:22 -0700989 struct ecryptfs_crypt_stat *crypt_stat =
990 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
991 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
992 &ecryptfs_superblock_to_private(
993 ecryptfs_dentry->d_sb)->mount_crypt_stat;
994 int cipher_name_len;
Michael Halcrowf4aad162007-10-16 01:27:53 -0700995 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700996
997 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
Michael Halcrowaf655dc2007-10-16 01:28:00 -0700998 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
Michael Halcrowf4aad162007-10-16 01:27:53 -0700999 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1000 mount_crypt_stat);
1001 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1002 mount_crypt_stat);
1003 if (rc) {
1004 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1005 "to the inode key sigs; rc = [%d]\n", rc);
1006 goto out;
1007 }
1008 cipher_name_len =
1009 strlen(mount_crypt_stat->global_default_cipher_name);
1010 memcpy(crypt_stat->cipher,
1011 mount_crypt_stat->global_default_cipher_name,
1012 cipher_name_len);
1013 crypt_stat->cipher[cipher_name_len] = '\0';
1014 crypt_stat->key_size =
1015 mount_crypt_stat->global_default_cipher_key_size;
1016 ecryptfs_generate_new_key(crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001017 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1018 if (rc)
1019 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1020 "context for cipher [%s]: rc = [%d]\n",
1021 crypt_stat->cipher, rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001022out:
Michael Halcrow237fead2006-10-04 02:16:22 -07001023 return rc;
1024}
1025
1026/**
1027 * contains_ecryptfs_marker - check for the ecryptfs marker
1028 * @data: The data block in which to check
1029 *
1030 * Returns one if marker found; zero if not found
1031 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001032static int contains_ecryptfs_marker(char *data)
Michael Halcrow237fead2006-10-04 02:16:22 -07001033{
1034 u32 m_1, m_2;
1035
Harvey Harrison29335c62008-07-23 21:30:06 -07001036 m_1 = get_unaligned_be32(data);
1037 m_2 = get_unaligned_be32(data + 4);
Michael Halcrow237fead2006-10-04 02:16:22 -07001038 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1039 return 1;
1040 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1041 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1042 MAGIC_ECRYPTFS_MARKER);
1043 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1044 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1045 return 0;
1046}
1047
1048struct ecryptfs_flag_map_elem {
1049 u32 file_flag;
1050 u32 local_flag;
1051};
1052
1053/* Add support for additional flags by adding elements here. */
1054static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1055 {0x00000001, ECRYPTFS_ENABLE_HMAC},
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001056 {0x00000002, ECRYPTFS_ENCRYPTED},
1057 {0x00000004, ECRYPTFS_METADATA_IN_XATTR}
Michael Halcrow237fead2006-10-04 02:16:22 -07001058};
1059
1060/**
1061 * ecryptfs_process_flags
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001062 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001063 * @page_virt: Source data to be parsed
1064 * @bytes_read: Updated with the number of bytes read
1065 *
1066 * Returns zero on success; non-zero if the flag set is invalid
1067 */
1068static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1069 char *page_virt, int *bytes_read)
1070{
1071 int rc = 0;
1072 int i;
1073 u32 flags;
1074
Harvey Harrison29335c62008-07-23 21:30:06 -07001075 flags = get_unaligned_be32(page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001076 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1077 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1078 if (flags & ecryptfs_flag_map[i].file_flag) {
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001079 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
Michael Halcrow237fead2006-10-04 02:16:22 -07001080 } else
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 /* Version is in top 8 bits of the 32-bit flag vector */
1083 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1084 (*bytes_read) = 4;
1085 return rc;
1086}
1087
1088/**
1089 * write_ecryptfs_marker
1090 * @page_virt: The pointer to in a page to begin writing the marker
1091 * @written: Number of bytes written
1092 *
1093 * Marker = 0x3c81b7f5
1094 */
1095static void write_ecryptfs_marker(char *page_virt, size_t *written)
1096{
1097 u32 m_1, m_2;
1098
1099 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1100 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
Harvey Harrison29335c62008-07-23 21:30:06 -07001101 put_unaligned_be32(m_1, page_virt);
1102 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1103 put_unaligned_be32(m_2, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001104 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1105}
1106
1107static void
1108write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat,
1109 size_t *written)
1110{
1111 u32 flags = 0;
1112 int i;
1113
1114 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1115 / sizeof(struct ecryptfs_flag_map_elem))); i++)
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001116 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
Michael Halcrow237fead2006-10-04 02:16:22 -07001117 flags |= ecryptfs_flag_map[i].file_flag;
1118 /* Version is in top 8 bits of the 32-bit flag vector */
1119 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
Harvey Harrison29335c62008-07-23 21:30:06 -07001120 put_unaligned_be32(flags, page_virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001121 (*written) = 4;
1122}
1123
1124struct ecryptfs_cipher_code_str_map_elem {
1125 char cipher_str[16];
Trevor Highland19e66a62008-02-06 01:38:36 -08001126 u8 cipher_code;
Michael Halcrow237fead2006-10-04 02:16:22 -07001127};
1128
1129/* Add support for additional ciphers by adding elements here. The
1130 * cipher_code is whatever OpenPGP applicatoins use to identify the
1131 * ciphers. List in order of probability. */
1132static struct ecryptfs_cipher_code_str_map_elem
1133ecryptfs_cipher_code_str_map[] = {
1134 {"aes",RFC2440_CIPHER_AES_128 },
1135 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1136 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1137 {"cast5", RFC2440_CIPHER_CAST_5},
1138 {"twofish", RFC2440_CIPHER_TWOFISH},
1139 {"cast6", RFC2440_CIPHER_CAST_6},
1140 {"aes", RFC2440_CIPHER_AES_192},
1141 {"aes", RFC2440_CIPHER_AES_256}
1142};
1143
1144/**
1145 * ecryptfs_code_for_cipher_string
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001146 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001147 *
1148 * Returns zero on no match, or the cipher code on match
1149 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001150u8 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat)
Michael Halcrow237fead2006-10-04 02:16:22 -07001151{
1152 int i;
Trevor Highland19e66a62008-02-06 01:38:36 -08001153 u8 code = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001154 struct ecryptfs_cipher_code_str_map_elem *map =
1155 ecryptfs_cipher_code_str_map;
1156
1157 if (strcmp(crypt_stat->cipher, "aes") == 0) {
1158 switch (crypt_stat->key_size) {
1159 case 16:
1160 code = RFC2440_CIPHER_AES_128;
1161 break;
1162 case 24:
1163 code = RFC2440_CIPHER_AES_192;
1164 break;
1165 case 32:
1166 code = RFC2440_CIPHER_AES_256;
1167 }
1168 } else {
1169 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1170 if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){
1171 code = map[i].cipher_code;
1172 break;
1173 }
1174 }
1175 return code;
1176}
1177
1178/**
1179 * ecryptfs_cipher_code_to_string
1180 * @str: Destination to write out the cipher name
1181 * @cipher_code: The code to convert to cipher name string
1182 *
1183 * Returns zero on success
1184 */
Trevor Highland19e66a62008-02-06 01:38:36 -08001185int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
Michael Halcrow237fead2006-10-04 02:16:22 -07001186{
1187 int rc = 0;
1188 int i;
1189
1190 str[0] = '\0';
1191 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1192 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1193 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1194 if (str[0] == '\0') {
1195 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1196 "[%d]\n", cipher_code);
1197 rc = -EINVAL;
1198 }
1199 return rc;
1200}
1201
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001202int ecryptfs_read_and_validate_header_region(char *data,
1203 struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001204{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001205 struct ecryptfs_crypt_stat *crypt_stat =
1206 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001207 int rc;
1208
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001209 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1210 ecryptfs_inode);
1211 if (rc) {
1212 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001213 __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001214 goto out;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001215 }
1216 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001217 rc = -EINVAL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001218 ecryptfs_printk(KERN_DEBUG, "Valid marker not found\n");
1219 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001220out:
1221 return rc;
1222}
1223
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001224void
1225ecryptfs_write_header_metadata(char *virt,
1226 struct ecryptfs_crypt_stat *crypt_stat,
1227 size_t *written)
Michael Halcrow237fead2006-10-04 02:16:22 -07001228{
1229 u32 header_extent_size;
1230 u16 num_header_extents_at_front;
1231
Michael Halcrow45eaab72007-10-16 01:28:05 -07001232 header_extent_size = (u32)crypt_stat->extent_size;
Michael Halcrow237fead2006-10-04 02:16:22 -07001233 num_header_extents_at_front =
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001234 (u16)(crypt_stat->num_header_bytes_at_front
1235 / crypt_stat->extent_size);
Harvey Harrison29335c62008-07-23 21:30:06 -07001236 put_unaligned_be32(header_extent_size, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001237 virt += 4;
Harvey Harrison29335c62008-07-23 21:30:06 -07001238 put_unaligned_be16(num_header_extents_at_front, virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001239 (*written) = 6;
1240}
1241
Michael Halcrow237fead2006-10-04 02:16:22 -07001242struct kmem_cache *ecryptfs_header_cache_1;
1243struct kmem_cache *ecryptfs_header_cache_2;
1244
1245/**
1246 * ecryptfs_write_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001247 * @page_virt: The virtual address to write the headers to
1248 * @size: Set to the number of bytes written by this function
1249 * @crypt_stat: The cryptographic context
1250 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001251 *
1252 * Format version: 1
1253 *
1254 * Header Extent:
1255 * Octets 0-7: Unencrypted file size (big-endian)
1256 * Octets 8-15: eCryptfs special marker
1257 * Octets 16-19: Flags
1258 * Octet 16: File format version number (between 0 and 255)
1259 * Octets 17-18: Reserved
1260 * Octet 19: Bit 1 (lsb): Reserved
1261 * Bit 2: Encrypted?
1262 * Bits 3-8: Reserved
1263 * Octets 20-23: Header extent size (big-endian)
1264 * Octets 24-25: Number of header extents at front of file
1265 * (big-endian)
1266 * Octet 26: Begin RFC 2440 authentication token packet set
1267 * Data Extent 0:
1268 * Lower data (CBC encrypted)
1269 * Data Extent 1:
1270 * Lower data (CBC encrypted)
1271 * ...
1272 *
1273 * Returns zero on success
1274 */
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001275static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
1276 struct ecryptfs_crypt_stat *crypt_stat,
1277 struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001278{
1279 int rc;
1280 size_t written;
1281 size_t offset;
1282
1283 offset = ECRYPTFS_FILE_SIZE_BYTES;
1284 write_ecryptfs_marker((page_virt + offset), &written);
1285 offset += written;
1286 write_ecryptfs_flags((page_virt + offset), crypt_stat, &written);
1287 offset += written;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001288 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1289 &written);
Michael Halcrow237fead2006-10-04 02:16:22 -07001290 offset += written;
1291 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1292 ecryptfs_dentry, &written,
1293 PAGE_CACHE_SIZE - offset);
1294 if (rc)
1295 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1296 "set; rc = [%d]\n", rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001297 if (size) {
1298 offset += written;
1299 *size = offset;
1300 }
1301 return rc;
1302}
1303
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001304static int
1305ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001306 struct dentry *ecryptfs_dentry,
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001307 char *virt)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001308{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001309 int rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001310
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001311 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
1312 0, crypt_stat->num_header_bytes_at_front);
1313 if (rc)
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001314 printk(KERN_ERR "%s: Error attempting to write header "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001315 "information to lower file; rc = [%d]\n", __func__,
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001316 rc);
Michael Halcrow70456602007-02-12 00:53:48 -08001317 return rc;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001318}
1319
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001320static int
1321ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1322 struct ecryptfs_crypt_stat *crypt_stat,
1323 char *page_virt, size_t size)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001324{
1325 int rc;
1326
1327 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1328 size, 0);
Michael Halcrow237fead2006-10-04 02:16:22 -07001329 return rc;
1330}
1331
1332/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001333 * ecryptfs_write_metadata
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001334 * @ecryptfs_dentry: The eCryptfs dentry
Michael Halcrow237fead2006-10-04 02:16:22 -07001335 *
1336 * Write the file headers out. This will likely involve a userspace
1337 * callout, in which the session key is encrypted with one or more
1338 * public keys and/or the passphrase necessary to do the encryption is
1339 * retrieved via a prompt. Exactly what happens at this point should
1340 * be policy-dependent.
1341 *
1342 * Returns zero on success; non-zero on error
1343 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001344int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001345{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001346 struct ecryptfs_crypt_stat *crypt_stat =
1347 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001348 char *virt;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001349 size_t size = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -07001350 int rc = 0;
1351
Michael Halcrowe2bd99e2007-02-12 00:53:49 -08001352 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1353 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001354 printk(KERN_ERR "Key is invalid; bailing out\n");
Michael Halcrow237fead2006-10-04 02:16:22 -07001355 rc = -EINVAL;
1356 goto out;
1357 }
1358 } else {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001359 printk(KERN_WARNING "%s: Encrypted flag not set\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001360 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001361 rc = -EINVAL;
Michael Halcrow237fead2006-10-04 02:16:22 -07001362 goto out;
1363 }
1364 /* Released in this function */
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001365 virt = kzalloc(crypt_stat->num_header_bytes_at_front, GFP_KERNEL);
1366 if (!virt) {
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001367 printk(KERN_ERR "%s: Out of memory\n", __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001368 rc = -ENOMEM;
1369 goto out;
1370 }
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001371 rc = ecryptfs_write_headers_virt(virt, &size, crypt_stat,
1372 ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -07001373 if (unlikely(rc)) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001374 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001375 __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001376 goto out_free;
1377 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001378 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1379 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001380 crypt_stat, virt, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001381 else
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001382 rc = ecryptfs_write_metadata_to_contents(crypt_stat,
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001383 ecryptfs_dentry, virt);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001384 if (rc) {
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001385 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001386 "rc = [%d]\n", __func__, rc);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001387 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -07001388 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001389out_free:
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001390 memset(virt, 0, crypt_stat->num_header_bytes_at_front);
1391 kfree(virt);
Michael Halcrow237fead2006-10-04 02:16:22 -07001392out:
1393 return rc;
1394}
1395
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001396#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1397#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
Michael Halcrow237fead2006-10-04 02:16:22 -07001398static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001399 char *virt, int *bytes_read,
1400 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001401{
1402 int rc = 0;
1403 u32 header_extent_size;
1404 u16 num_header_extents_at_front;
1405
Harvey Harrison29335c62008-07-23 21:30:06 -07001406 header_extent_size = get_unaligned_be32(virt);
1407 virt += sizeof(__be32);
1408 num_header_extents_at_front = get_unaligned_be16(virt);
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001409 crypt_stat->num_header_bytes_at_front =
1410 (((size_t)num_header_extents_at_front
1411 * (size_t)header_extent_size));
Harvey Harrison29335c62008-07-23 21:30:06 -07001412 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001413 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001414 && (crypt_stat->num_header_bytes_at_front
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001415 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001416 rc = -EINVAL;
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001417 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1418 crypt_stat->num_header_bytes_at_front);
Michael Halcrow237fead2006-10-04 02:16:22 -07001419 }
1420 return rc;
1421}
1422
1423/**
1424 * set_default_header_data
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001425 * @crypt_stat: The cryptographic context
Michael Halcrow237fead2006-10-04 02:16:22 -07001426 *
1427 * For version 0 file format; this function is only for backwards
1428 * compatibility for files created with the prior versions of
1429 * eCryptfs.
1430 */
1431static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1432{
Michael Halcrowcc11bef2008-02-06 01:38:32 -08001433 crypt_stat->num_header_bytes_at_front =
1434 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrow237fead2006-10-04 02:16:22 -07001435}
1436
1437/**
1438 * ecryptfs_read_headers_virt
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001439 * @page_virt: The virtual address into which to read the headers
1440 * @crypt_stat: The cryptographic context
1441 * @ecryptfs_dentry: The eCryptfs dentry
1442 * @validate_header_size: Whether to validate the header size while reading
Michael Halcrow237fead2006-10-04 02:16:22 -07001443 *
1444 * Read/parse the header data. The header format is detailed in the
1445 * comment block for the ecryptfs_write_headers_virt() function.
1446 *
1447 * Returns zero on success
1448 */
1449static int ecryptfs_read_headers_virt(char *page_virt,
1450 struct ecryptfs_crypt_stat *crypt_stat,
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001451 struct dentry *ecryptfs_dentry,
1452 int validate_header_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001453{
1454 int rc = 0;
1455 int offset;
1456 int bytes_read;
1457
1458 ecryptfs_set_default_sizes(crypt_stat);
1459 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1460 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1461 offset = ECRYPTFS_FILE_SIZE_BYTES;
1462 rc = contains_ecryptfs_marker(page_virt + offset);
1463 if (rc == 0) {
1464 rc = -EINVAL;
1465 goto out;
1466 }
1467 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1468 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1469 &bytes_read);
1470 if (rc) {
1471 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1472 goto out;
1473 }
1474 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1475 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1476 "file version [%d] is supported by this "
1477 "version of eCryptfs\n",
1478 crypt_stat->file_version,
1479 ECRYPTFS_SUPPORTED_FILE_VERSION);
1480 rc = -EINVAL;
1481 goto out;
1482 }
1483 offset += bytes_read;
1484 if (crypt_stat->file_version >= 1) {
1485 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001486 &bytes_read, validate_header_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001487 if (rc) {
1488 ecryptfs_printk(KERN_WARNING, "Error reading header "
1489 "metadata; rc = [%d]\n", rc);
1490 }
1491 offset += bytes_read;
1492 } else
1493 set_default_header_data(crypt_stat);
1494 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1495 ecryptfs_dentry);
1496out:
1497 return rc;
1498}
1499
1500/**
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001501 * ecryptfs_read_xattr_region
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001502 * @page_virt: The vitual address into which to read the xattr data
Michael Halcrow2ed92552007-10-16 01:28:10 -07001503 * @ecryptfs_inode: The eCryptfs inode
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001504 *
1505 * Attempts to read the crypto metadata from the extended attribute
1506 * region of the lower file.
Michael Halcrow22e78fa2007-10-16 01:28:02 -07001507 *
1508 * Returns zero on success; non-zero on error
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001509 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001510int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001511{
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001512 struct dentry *lower_dentry =
1513 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001514 ssize_t size;
1515 int rc = 0;
1516
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001517 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1518 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001519 if (size < 0) {
Michael Halcrow25bd8172008-02-06 01:38:35 -08001520 if (unlikely(ecryptfs_verbosity > 0))
1521 printk(KERN_INFO "Error attempting to read the [%s] "
1522 "xattr from the lower file; return value = "
1523 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001524 rc = -EINVAL;
1525 goto out;
1526 }
1527out:
1528 return rc;
1529}
1530
1531int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1532 struct dentry *ecryptfs_dentry)
1533{
1534 int rc;
1535
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001536 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001537 if (rc)
1538 goto out;
1539 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1540 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1541 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1542 rc = -EINVAL;
1543 }
1544out:
1545 return rc;
1546}
1547
1548/**
1549 * ecryptfs_read_metadata
1550 *
1551 * Common entry point for reading file metadata. From here, we could
1552 * retrieve the header information from the header region of the file,
1553 * the xattr region of the file, or some other repostory that is
1554 * stored separately from the file itself. The current implementation
1555 * supports retrieving the metadata information from the file contents
1556 * and from the xattr region.
Michael Halcrow237fead2006-10-04 02:16:22 -07001557 *
1558 * Returns zero if valid headers found and parsed; non-zero otherwise
1559 */
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001560int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
Michael Halcrow237fead2006-10-04 02:16:22 -07001561{
1562 int rc = 0;
1563 char *page_virt = NULL;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001564 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -07001565 struct ecryptfs_crypt_stat *crypt_stat =
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001566 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001567 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1568 &ecryptfs_superblock_to_private(
1569 ecryptfs_dentry->d_sb)->mount_crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -07001570
Michael Halcrowe77a56d2007-02-12 00:53:47 -08001571 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1572 mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -07001573 /* Read the first page from the underlying file */
Christoph Lameterf7267c02006-12-06 20:33:15 -08001574 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
Michael Halcrow237fead2006-10-04 02:16:22 -07001575 if (!page_virt) {
1576 rc = -ENOMEM;
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001577 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -07001578 __func__);
Michael Halcrow237fead2006-10-04 02:16:22 -07001579 goto out;
1580 }
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001581 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1582 ecryptfs_inode);
1583 if (!rc)
1584 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1585 ecryptfs_dentry,
1586 ECRYPTFS_VALIDATE_HEADER_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -07001587 if (rc) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -07001588 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08001589 if (rc) {
1590 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1591 "file header region or xattr region\n");
1592 rc = -EINVAL;
1593 goto out;
1594 }
1595 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1596 ecryptfs_dentry,
1597 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1598 if (rc) {
1599 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1600 "file xattr region either\n");
1601 rc = -EINVAL;
1602 }
1603 if (crypt_stat->mount_crypt_stat->flags
1604 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1605 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1606 } else {
1607 printk(KERN_WARNING "Attempt to access file with "
1608 "crypto metadata only in the extended attribute "
1609 "region, but eCryptfs was mounted without "
1610 "xattr support enabled. eCryptfs will not treat "
1611 "this like an encrypted file.\n");
1612 rc = -EINVAL;
1613 }
Michael Halcrow237fead2006-10-04 02:16:22 -07001614 }
1615out:
1616 if (page_virt) {
1617 memset(page_virt, 0, PAGE_CACHE_SIZE);
1618 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1619 }
1620 return rc;
1621}
1622
1623/**
1624 * ecryptfs_encode_filename - converts a plaintext file name to cipher text
1625 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
1626 * @name: The plaintext name
1627 * @length: The length of the plaintext
1628 * @encoded_name: The encypted name
1629 *
1630 * Encrypts and encodes a filename into something that constitutes a
1631 * valid filename for a filesystem, with printable characters.
1632 *
1633 * We assume that we have a properly initialized crypto context,
1634 * pointed to by crypt_stat->tfm.
1635 *
1636 * TODO: Implement filename decoding and decryption here, in place of
1637 * memcpy. We are keeping the framework around for now to (1)
1638 * facilitate testing of the components needed to implement filename
1639 * encryption and (2) to provide a code base from which other
1640 * developers in the community can easily implement this feature.
1641 *
1642 * Returns the length of encoded filename; negative if error
1643 */
1644int
1645ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1646 const char *name, int length, char **encoded_name)
1647{
1648 int error = 0;
1649
1650 (*encoded_name) = kmalloc(length + 2, GFP_KERNEL);
1651 if (!(*encoded_name)) {
1652 error = -ENOMEM;
1653 goto out;
1654 }
1655 /* TODO: Filename encryption is a scheduled feature for a
1656 * future version of eCryptfs. This function is here only for
1657 * the purpose of providing a framework for other developers
1658 * to easily implement filename encryption. Hint: Replace this
1659 * memcpy() with a call to encrypt and encode the
1660 * filename, the set the length accordingly. */
1661 memcpy((void *)(*encoded_name), (void *)name, length);
1662 (*encoded_name)[length] = '\0';
1663 error = length + 1;
1664out:
1665 return error;
1666}
1667
1668/**
1669 * ecryptfs_decode_filename - converts the cipher text name to plaintext
1670 * @crypt_stat: The crypt_stat struct associated with the file
1671 * @name: The filename in cipher text
1672 * @length: The length of the cipher text name
1673 * @decrypted_name: The plaintext name
1674 *
1675 * Decodes and decrypts the filename.
1676 *
1677 * We assume that we have a properly initialized crypto context,
1678 * pointed to by crypt_stat->tfm.
1679 *
1680 * TODO: Implement filename decoding and decryption here, in place of
1681 * memcpy. We are keeping the framework around for now to (1)
1682 * facilitate testing of the components needed to implement filename
1683 * encryption and (2) to provide a code base from which other
1684 * developers in the community can easily implement this feature.
1685 *
1686 * Returns the length of decoded filename; negative if error
1687 */
1688int
1689ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat,
1690 const char *name, int length, char **decrypted_name)
1691{
1692 int error = 0;
1693
1694 (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL);
1695 if (!(*decrypted_name)) {
1696 error = -ENOMEM;
1697 goto out;
1698 }
1699 /* TODO: Filename encryption is a scheduled feature for a
1700 * future version of eCryptfs. This function is here only for
1701 * the purpose of providing a framework for other developers
1702 * to easily implement filename encryption. Hint: Replace this
1703 * memcpy() with a call to decode and decrypt the
1704 * filename, the set the length accordingly. */
1705 memcpy((void *)(*decrypted_name), (void *)name, length);
1706 (*decrypted_name)[length + 1] = '\0'; /* Only for convenience
1707 * in printing out the
1708 * string in debug
1709 * messages */
1710 error = length;
1711out:
1712 return error;
1713}
1714
1715/**
Michael Halcrowf4aad162007-10-16 01:27:53 -07001716 * ecryptfs_process_key_cipher - Perform key cipher initialization.
Michael Halcrow237fead2006-10-04 02:16:22 -07001717 * @key_tfm: Crypto context for key material, set by this function
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001718 * @cipher_name: Name of the cipher
1719 * @key_size: Size of the key in bytes
Michael Halcrow237fead2006-10-04 02:16:22 -07001720 *
1721 * Returns zero on success. Any crypto_tfm structs allocated here
1722 * should be released by other functions, such as on a superblock put
1723 * event, regardless of whether this function succeeds for fails.
1724 */
Michael Halcrowcd9d67d2007-10-16 01:28:04 -07001725static int
Michael Halcrowf4aad162007-10-16 01:27:53 -07001726ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1727 char *cipher_name, size_t *key_size)
Michael Halcrow237fead2006-10-04 02:16:22 -07001728{
1729 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
Michael Halcrow8bba0662006-10-30 22:07:18 -08001730 char *full_alg_name;
Michael Halcrow237fead2006-10-04 02:16:22 -07001731 int rc;
1732
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001733 *key_tfm = NULL;
1734 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
Michael Halcrow237fead2006-10-04 02:16:22 -07001735 rc = -EINVAL;
1736 printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001737 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
Michael Halcrow237fead2006-10-04 02:16:22 -07001738 goto out;
1739 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001740 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1741 "ecb");
1742 if (rc)
1743 goto out;
1744 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1745 kfree(full_alg_name);
1746 if (IS_ERR(*key_tfm)) {
1747 rc = PTR_ERR(*key_tfm);
Michael Halcrow237fead2006-10-04 02:16:22 -07001748 printk(KERN_ERR "Unable to allocate crypto cipher with name "
Michael Halcrow8bba0662006-10-30 22:07:18 -08001749 "[%s]; rc = [%d]\n", cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001750 goto out;
1751 }
Michael Halcrow8bba0662006-10-30 22:07:18 -08001752 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1753 if (*key_size == 0) {
1754 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1755
1756 *key_size = alg->max_keysize;
1757 }
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001758 get_random_bytes(dummy_key, *key_size);
Michael Halcrow8bba0662006-10-30 22:07:18 -08001759 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
Michael Halcrow237fead2006-10-04 02:16:22 -07001760 if (rc) {
1761 printk(KERN_ERR "Error attempting to set key of size [%Zd] for "
Michael Halcrowe5d9cbd2006-10-30 22:07:16 -08001762 "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -07001763 rc = -EINVAL;
1764 goto out;
1765 }
1766out:
1767 return rc;
1768}
Michael Halcrowf4aad162007-10-16 01:27:53 -07001769
1770struct kmem_cache *ecryptfs_key_tfm_cache;
Adrian Bunk7896b632008-02-06 01:38:32 -08001771static struct list_head key_tfm_list;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001772struct mutex key_tfm_list_mutex;
Michael Halcrowf4aad162007-10-16 01:27:53 -07001773
1774int ecryptfs_init_crypto(void)
1775{
1776 mutex_init(&key_tfm_list_mutex);
1777 INIT_LIST_HEAD(&key_tfm_list);
1778 return 0;
1779}
1780
Eric Sandeenaf440f52008-02-06 01:38:37 -08001781/**
1782 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1783 *
1784 * Called only at module unload time
1785 */
Michael Halcrowfcd12832007-10-16 01:28:01 -07001786int ecryptfs_destroy_crypto(void)
Michael Halcrowf4aad162007-10-16 01:27:53 -07001787{
1788 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1789
1790 mutex_lock(&key_tfm_list_mutex);
1791 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1792 key_tfm_list) {
1793 list_del(&key_tfm->key_tfm_list);
1794 if (key_tfm->key_tfm)
1795 crypto_free_blkcipher(key_tfm->key_tfm);
1796 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1797 }
1798 mutex_unlock(&key_tfm_list_mutex);
1799 return 0;
1800}
1801
1802int
1803ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1804 size_t key_size)
1805{
1806 struct ecryptfs_key_tfm *tmp_tfm;
1807 int rc = 0;
1808
Eric Sandeenaf440f52008-02-06 01:38:37 -08001809 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1810
Michael Halcrowf4aad162007-10-16 01:27:53 -07001811 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1812 if (key_tfm != NULL)
1813 (*key_tfm) = tmp_tfm;
1814 if (!tmp_tfm) {
1815 rc = -ENOMEM;
1816 printk(KERN_ERR "Error attempting to allocate from "
1817 "ecryptfs_key_tfm_cache\n");
1818 goto out;
1819 }
1820 mutex_init(&tmp_tfm->key_tfm_mutex);
1821 strncpy(tmp_tfm->cipher_name, cipher_name,
1822 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
Eric Sandeenb8862902007-12-22 14:03:24 -08001823 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
Michael Halcrowf4aad162007-10-16 01:27:53 -07001824 tmp_tfm->key_size = key_size;
Michael Halcrow5dda6992007-10-16 01:28:06 -07001825 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1826 tmp_tfm->cipher_name,
1827 &tmp_tfm->key_size);
1828 if (rc) {
Michael Halcrowf4aad162007-10-16 01:27:53 -07001829 printk(KERN_ERR "Error attempting to initialize key TFM "
1830 "cipher with name = [%s]; rc = [%d]\n",
1831 tmp_tfm->cipher_name, rc);
1832 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1833 if (key_tfm != NULL)
1834 (*key_tfm) = NULL;
1835 goto out;
1836 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001837 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001838out:
1839 return rc;
1840}
1841
Eric Sandeenaf440f52008-02-06 01:38:37 -08001842/**
1843 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1844 * @cipher_name: the name of the cipher to search for
1845 * @key_tfm: set to corresponding tfm if found
1846 *
1847 * Searches for cached key_tfm matching @cipher_name
1848 * Must be called with &key_tfm_list_mutex held
1849 * Returns 1 if found, with @key_tfm set
1850 * Returns 0 if not found, with @key_tfm set to NULL
1851 */
1852int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1853{
1854 struct ecryptfs_key_tfm *tmp_key_tfm;
1855
1856 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1857
1858 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1859 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1860 if (key_tfm)
1861 (*key_tfm) = tmp_key_tfm;
1862 return 1;
1863 }
1864 }
1865 if (key_tfm)
1866 (*key_tfm) = NULL;
1867 return 0;
1868}
1869
1870/**
1871 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1872 *
1873 * @tfm: set to cached tfm found, or new tfm created
1874 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1875 * @cipher_name: the name of the cipher to search for and/or add
1876 *
1877 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1878 * Searches for cached item first, and creates new if not found.
1879 * Returns 0 on success, non-zero if adding new cipher failed
1880 */
Michael Halcrowf4aad162007-10-16 01:27:53 -07001881int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1882 struct mutex **tfm_mutex,
1883 char *cipher_name)
1884{
1885 struct ecryptfs_key_tfm *key_tfm;
1886 int rc = 0;
1887
1888 (*tfm) = NULL;
1889 (*tfm_mutex) = NULL;
Eric Sandeenaf440f52008-02-06 01:38:37 -08001890
Michael Halcrowf4aad162007-10-16 01:27:53 -07001891 mutex_lock(&key_tfm_list_mutex);
Eric Sandeenaf440f52008-02-06 01:38:37 -08001892 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1893 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1894 if (rc) {
1895 printk(KERN_ERR "Error adding new key_tfm to list; "
1896 "rc = [%d]\n", rc);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001897 goto out;
1898 }
1899 }
Michael Halcrowf4aad162007-10-16 01:27:53 -07001900 (*tfm) = key_tfm->key_tfm;
1901 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1902out:
Cyrill Gorcunov71fd5172008-05-23 13:04:20 -07001903 mutex_unlock(&key_tfm_list_mutex);
Michael Halcrowf4aad162007-10-16 01:27:53 -07001904 return rc;
1905}