Commit | Line | Data |
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237fead6 MH |
1 | /** |
2 | * eCryptfs: Linux filesystem encryption layer | |
3 | * | |
4 | * Copyright (C) 1997-2004 Erez Zadok | |
5 | * Copyright (C) 2001-2004 Stony Brook University | |
dd2a3b7a | 6 | * Copyright (C) 2004-2007 International Business Machines Corp. |
237fead6 MH |
7 | * 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 | ||
38 | static int | |
39 | ecryptfs_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); | |
43 | static int | |
44 | ecryptfs_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 | */ | |
56 | void 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 | */ | |
71 | void 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 | */ | |
93 | static int ecryptfs_calculate_md5(char *dst, | |
94 | struct ecryptfs_crypt_stat *crypt_stat, | |
95 | char *src, int len) | |
96 | { | |
237fead6 | 97 | struct scatterlist sg; |
565d9724 MH |
98 | struct hash_desc desc = { |
99 | .tfm = crypt_stat->hash_tfm, | |
100 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP | |
101 | }; | |
102 | int rc = 0; | |
237fead6 | 103 | |
565d9724 | 104 | mutex_lock(&crypt_stat->cs_hash_tfm_mutex); |
237fead6 | 105 | sg_init_one(&sg, (u8 *)src, len); |
565d9724 MH |
106 | 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); | |
237fead6 | 111 | ecryptfs_printk(KERN_ERR, "Error attempting to " |
565d9724 MH |
112 | "allocate crypto context; rc = [%d]\n", |
113 | rc); | |
237fead6 MH |
114 | goto out; |
115 | } | |
565d9724 | 116 | crypt_stat->hash_tfm = desc.tfm; |
237fead6 | 117 | } |
565d9724 MH |
118 | crypto_hash_init(&desc); |
119 | crypto_hash_update(&desc, &sg, len); | |
120 | crypto_hash_final(&desc, dst); | |
121 | mutex_unlock(&crypt_stat->cs_hash_tfm_mutex); | |
237fead6 MH |
122 | out: |
123 | return rc; | |
124 | } | |
125 | ||
cd9d67df MH |
126 | static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name, |
127 | char *cipher_name, | |
128 | char *chaining_modifier) | |
8bba066f MH |
129 | { |
130 | int cipher_name_len = strlen(cipher_name); | |
131 | int chaining_modifier_len = strlen(chaining_modifier); | |
132 | int algified_name_len; | |
133 | int rc; | |
134 | ||
135 | algified_name_len = (chaining_modifier_len + cipher_name_len + 3); | |
136 | (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL); | |
7bd473fc | 137 | if (!(*algified_name)) { |
8bba066f MH |
138 | rc = -ENOMEM; |
139 | goto out; | |
140 | } | |
141 | snprintf((*algified_name), algified_name_len, "%s(%s)", | |
142 | chaining_modifier, cipher_name); | |
143 | rc = 0; | |
144 | out: | |
145 | return rc; | |
146 | } | |
147 | ||
237fead6 MH |
148 | /** |
149 | * ecryptfs_derive_iv | |
150 | * @iv: destination for the derived iv vale | |
151 | * @crypt_stat: Pointer to crypt_stat struct for the current inode | |
d6a13c17 | 152 | * @offset: Offset of the extent whose IV we are to derive |
237fead6 MH |
153 | * |
154 | * Generate the initialization vector from the given root IV and page | |
155 | * offset. | |
156 | * | |
157 | * Returns zero on success; non-zero on error. | |
158 | */ | |
159 | static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat, | |
d6a13c17 | 160 | loff_t offset) |
237fead6 MH |
161 | { |
162 | int rc = 0; | |
163 | char dst[MD5_DIGEST_SIZE]; | |
164 | char src[ECRYPTFS_MAX_IV_BYTES + 16]; | |
165 | ||
166 | if (unlikely(ecryptfs_verbosity > 0)) { | |
167 | ecryptfs_printk(KERN_DEBUG, "root iv:\n"); | |
168 | ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes); | |
169 | } | |
170 | /* TODO: It is probably secure to just cast the least | |
171 | * significant bits of the root IV into an unsigned long and | |
172 | * add the offset to that rather than go through all this | |
173 | * hashing business. -Halcrow */ | |
174 | memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes); | |
175 | memset((src + crypt_stat->iv_bytes), 0, 16); | |
d6a13c17 | 176 | snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset); |
237fead6 MH |
177 | if (unlikely(ecryptfs_verbosity > 0)) { |
178 | ecryptfs_printk(KERN_DEBUG, "source:\n"); | |
179 | ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16)); | |
180 | } | |
181 | rc = ecryptfs_calculate_md5(dst, crypt_stat, src, | |
182 | (crypt_stat->iv_bytes + 16)); | |
183 | if (rc) { | |
184 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " | |
185 | "MD5 while generating IV for a page\n"); | |
186 | goto out; | |
187 | } | |
188 | memcpy(iv, dst, crypt_stat->iv_bytes); | |
189 | if (unlikely(ecryptfs_verbosity > 0)) { | |
190 | ecryptfs_printk(KERN_DEBUG, "derived iv:\n"); | |
191 | ecryptfs_dump_hex(iv, crypt_stat->iv_bytes); | |
192 | } | |
193 | out: | |
194 | return rc; | |
195 | } | |
196 | ||
197 | /** | |
198 | * ecryptfs_init_crypt_stat | |
199 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. | |
200 | * | |
201 | * Initialize the crypt_stat structure. | |
202 | */ | |
203 | void | |
204 | ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) | |
205 | { | |
206 | memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); | |
f4aad16a MH |
207 | INIT_LIST_HEAD(&crypt_stat->keysig_list); |
208 | mutex_init(&crypt_stat->keysig_list_mutex); | |
237fead6 MH |
209 | mutex_init(&crypt_stat->cs_mutex); |
210 | mutex_init(&crypt_stat->cs_tfm_mutex); | |
565d9724 | 211 | mutex_init(&crypt_stat->cs_hash_tfm_mutex); |
e2bd99ec | 212 | crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED; |
237fead6 MH |
213 | } |
214 | ||
215 | /** | |
fcd12835 | 216 | * ecryptfs_destroy_crypt_stat |
237fead6 MH |
217 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
218 | * | |
219 | * Releases all memory associated with a crypt_stat struct. | |
220 | */ | |
fcd12835 | 221 | void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
237fead6 | 222 | { |
f4aad16a MH |
223 | struct ecryptfs_key_sig *key_sig, *key_sig_tmp; |
224 | ||
237fead6 | 225 | if (crypt_stat->tfm) |
8bba066f | 226 | crypto_free_blkcipher(crypt_stat->tfm); |
565d9724 MH |
227 | if (crypt_stat->hash_tfm) |
228 | crypto_free_hash(crypt_stat->hash_tfm); | |
f4aad16a MH |
229 | mutex_lock(&crypt_stat->keysig_list_mutex); |
230 | list_for_each_entry_safe(key_sig, key_sig_tmp, | |
231 | &crypt_stat->keysig_list, crypt_stat_list) { | |
232 | list_del(&key_sig->crypt_stat_list); | |
233 | kmem_cache_free(ecryptfs_key_sig_cache, key_sig); | |
234 | } | |
235 | mutex_unlock(&crypt_stat->keysig_list_mutex); | |
237fead6 MH |
236 | memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
237 | } | |
238 | ||
fcd12835 | 239 | void ecryptfs_destroy_mount_crypt_stat( |
237fead6 MH |
240 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
241 | { | |
f4aad16a MH |
242 | struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp; |
243 | ||
244 | if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED)) | |
245 | return; | |
246 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
247 | list_for_each_entry_safe(auth_tok, auth_tok_tmp, | |
248 | &mount_crypt_stat->global_auth_tok_list, | |
249 | mount_crypt_stat_list) { | |
250 | list_del(&auth_tok->mount_crypt_stat_list); | |
251 | mount_crypt_stat->num_global_auth_toks--; | |
252 | if (auth_tok->global_auth_tok_key | |
253 | && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID)) | |
254 | key_put(auth_tok->global_auth_tok_key); | |
255 | kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok); | |
256 | } | |
257 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
237fead6 MH |
258 | memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat)); |
259 | } | |
260 | ||
261 | /** | |
262 | * virt_to_scatterlist | |
263 | * @addr: Virtual address | |
264 | * @size: Size of data; should be an even multiple of the block size | |
265 | * @sg: Pointer to scatterlist array; set to NULL to obtain only | |
266 | * the number of scatterlist structs required in array | |
267 | * @sg_size: Max array size | |
268 | * | |
269 | * Fills in a scatterlist array with page references for a passed | |
270 | * virtual address. | |
271 | * | |
272 | * Returns the number of scatterlist structs in array used | |
273 | */ | |
274 | int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg, | |
275 | int sg_size) | |
276 | { | |
277 | int i = 0; | |
278 | struct page *pg; | |
279 | int offset; | |
280 | int remainder_of_page; | |
281 | ||
282 | while (size > 0 && i < sg_size) { | |
283 | pg = virt_to_page(addr); | |
284 | offset = offset_in_page(addr); | |
285 | if (sg) { | |
286 | sg[i].page = pg; | |
287 | sg[i].offset = offset; | |
288 | } | |
289 | remainder_of_page = PAGE_CACHE_SIZE - offset; | |
290 | if (size >= remainder_of_page) { | |
291 | if (sg) | |
292 | sg[i].length = remainder_of_page; | |
293 | addr += remainder_of_page; | |
294 | size -= remainder_of_page; | |
295 | } else { | |
296 | if (sg) | |
297 | sg[i].length = size; | |
298 | addr += size; | |
299 | size = 0; | |
300 | } | |
301 | i++; | |
302 | } | |
303 | if (size > 0) | |
304 | return -ENOMEM; | |
305 | return i; | |
306 | } | |
307 | ||
308 | /** | |
309 | * encrypt_scatterlist | |
310 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. | |
311 | * @dest_sg: Destination of encrypted data | |
312 | * @src_sg: Data to be encrypted | |
313 | * @size: Length of data to be encrypted | |
314 | * @iv: iv to use during encryption | |
315 | * | |
316 | * Returns the number of bytes encrypted; negative value on error | |
317 | */ | |
318 | static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, | |
319 | struct scatterlist *dest_sg, | |
320 | struct scatterlist *src_sg, int size, | |
321 | unsigned char *iv) | |
322 | { | |
8bba066f MH |
323 | struct blkcipher_desc desc = { |
324 | .tfm = crypt_stat->tfm, | |
325 | .info = iv, | |
326 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP | |
327 | }; | |
237fead6 MH |
328 | int rc = 0; |
329 | ||
330 | BUG_ON(!crypt_stat || !crypt_stat->tfm | |
e2bd99ec | 331 | || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)); |
237fead6 MH |
332 | if (unlikely(ecryptfs_verbosity > 0)) { |
333 | ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n", | |
334 | crypt_stat->key_size); | |
335 | ecryptfs_dump_hex(crypt_stat->key, | |
336 | crypt_stat->key_size); | |
337 | } | |
338 | /* Consider doing this once, when the file is opened */ | |
339 | mutex_lock(&crypt_stat->cs_tfm_mutex); | |
8bba066f MH |
340 | rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
341 | crypt_stat->key_size); | |
237fead6 MH |
342 | if (rc) { |
343 | ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n", | |
344 | rc); | |
345 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
346 | rc = -EINVAL; | |
347 | goto out; | |
348 | } | |
349 | ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size); | |
8bba066f | 350 | crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size); |
237fead6 MH |
351 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
352 | out: | |
353 | return rc; | |
354 | } | |
355 | ||
356 | static void | |
357 | ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx, | |
358 | int *byte_offset, | |
359 | struct ecryptfs_crypt_stat *crypt_stat, | |
360 | unsigned long extent_num) | |
361 | { | |
362 | unsigned long lower_extent_num; | |
363 | int extents_occupied_by_headers_at_front; | |
364 | int bytes_occupied_by_headers_at_front; | |
365 | int extent_offset; | |
366 | int extents_per_page; | |
367 | ||
368 | bytes_occupied_by_headers_at_front = | |
45eaab79 MH |
369 | (crypt_stat->extent_size |
370 | * crypt_stat->num_header_extents_at_front); | |
237fead6 MH |
371 | extents_occupied_by_headers_at_front = |
372 | ( bytes_occupied_by_headers_at_front | |
373 | / crypt_stat->extent_size ); | |
374 | lower_extent_num = extents_occupied_by_headers_at_front + extent_num; | |
375 | extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; | |
376 | (*lower_page_idx) = lower_extent_num / extents_per_page; | |
377 | extent_offset = lower_extent_num % extents_per_page; | |
378 | (*byte_offset) = extent_offset * crypt_stat->extent_size; | |
45eaab79 MH |
379 | ecryptfs_printk(KERN_DEBUG, " * crypt_stat->extent_size = " |
380 | "[%d]\n", crypt_stat->extent_size); | |
237fead6 MH |
381 | ecryptfs_printk(KERN_DEBUG, " * crypt_stat->" |
382 | "num_header_extents_at_front = [%d]\n", | |
383 | crypt_stat->num_header_extents_at_front); | |
384 | ecryptfs_printk(KERN_DEBUG, " * extents_occupied_by_headers_at_" | |
385 | "front = [%d]\n", extents_occupied_by_headers_at_front); | |
386 | ecryptfs_printk(KERN_DEBUG, " * lower_extent_num = [0x%.16x]\n", | |
387 | lower_extent_num); | |
388 | ecryptfs_printk(KERN_DEBUG, " * extents_per_page = [%d]\n", | |
389 | extents_per_page); | |
390 | ecryptfs_printk(KERN_DEBUG, " * (*lower_page_idx) = [0x%.16x]\n", | |
391 | (*lower_page_idx)); | |
392 | ecryptfs_printk(KERN_DEBUG, " * extent_offset = [%d]\n", | |
393 | extent_offset); | |
394 | ecryptfs_printk(KERN_DEBUG, " * (*byte_offset) = [%d]\n", | |
395 | (*byte_offset)); | |
396 | } | |
397 | ||
398 | static int ecryptfs_write_out_page(struct ecryptfs_page_crypt_context *ctx, | |
399 | struct page *lower_page, | |
400 | struct inode *lower_inode, | |
401 | int byte_offset_in_page, int bytes_to_write) | |
402 | { | |
403 | int rc = 0; | |
404 | ||
405 | if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) { | |
406 | rc = ecryptfs_commit_lower_page(lower_page, lower_inode, | |
407 | ctx->param.lower_file, | |
408 | byte_offset_in_page, | |
409 | bytes_to_write); | |
410 | if (rc) { | |
411 | ecryptfs_printk(KERN_ERR, "Error calling lower " | |
412 | "commit; rc = [%d]\n", rc); | |
413 | goto out; | |
414 | } | |
415 | } else { | |
416 | rc = ecryptfs_writepage_and_release_lower_page(lower_page, | |
417 | lower_inode, | |
418 | ctx->param.wbc); | |
419 | if (rc) { | |
420 | ecryptfs_printk(KERN_ERR, "Error calling lower " | |
421 | "writepage(); rc = [%d]\n", rc); | |
422 | goto out; | |
423 | } | |
424 | } | |
425 | out: | |
426 | return rc; | |
427 | } | |
428 | ||
429 | static int ecryptfs_read_in_page(struct ecryptfs_page_crypt_context *ctx, | |
430 | struct page **lower_page, | |
431 | struct inode *lower_inode, | |
432 | unsigned long lower_page_idx, | |
433 | int byte_offset_in_page) | |
434 | { | |
435 | int rc = 0; | |
436 | ||
437 | if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) { | |
438 | /* TODO: Limit this to only the data extents that are | |
439 | * needed */ | |
440 | rc = ecryptfs_get_lower_page(lower_page, lower_inode, | |
441 | ctx->param.lower_file, | |
442 | lower_page_idx, | |
443 | byte_offset_in_page, | |
444 | (PAGE_CACHE_SIZE | |
445 | - byte_offset_in_page)); | |
446 | if (rc) { | |
447 | ecryptfs_printk( | |
448 | KERN_ERR, "Error attempting to grab, map, " | |
449 | "and prepare_write lower page with index " | |
450 | "[0x%.16x]; rc = [%d]\n", lower_page_idx, rc); | |
451 | goto out; | |
452 | } | |
453 | } else { | |
9d8b8ce5 MH |
454 | *lower_page = grab_cache_page(lower_inode->i_mapping, |
455 | lower_page_idx); | |
456 | if (!(*lower_page)) { | |
457 | rc = -EINVAL; | |
237fead6 MH |
458 | ecryptfs_printk( |
459 | KERN_ERR, "Error attempting to grab and map " | |
460 | "lower page with index [0x%.16x]; rc = [%d]\n", | |
461 | lower_page_idx, rc); | |
462 | goto out; | |
463 | } | |
464 | } | |
465 | out: | |
466 | return rc; | |
467 | } | |
468 | ||
0216f7f7 MH |
469 | /** |
470 | * ecryptfs_lower_offset_for_extent | |
471 | * | |
472 | * Convert an eCryptfs page index into a lower byte offset | |
473 | */ | |
474 | void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num, | |
475 | struct ecryptfs_crypt_stat *crypt_stat) | |
476 | { | |
477 | (*offset) = ((crypt_stat->extent_size | |
478 | * crypt_stat->num_header_extents_at_front) | |
479 | + (crypt_stat->extent_size * extent_num)); | |
480 | } | |
481 | ||
482 | /** | |
483 | * ecryptfs_encrypt_extent | |
484 | * @enc_extent_page: Allocated page into which to encrypt the data in | |
485 | * @page | |
486 | * @crypt_stat: crypt_stat containing cryptographic context for the | |
487 | * encryption operation | |
488 | * @page: Page containing plaintext data extent to encrypt | |
489 | * @extent_offset: Page extent offset for use in generating IV | |
490 | * | |
491 | * Encrypts one extent of data. | |
492 | * | |
493 | * Return zero on success; non-zero otherwise | |
494 | */ | |
495 | static int ecryptfs_encrypt_extent(struct page *enc_extent_page, | |
496 | struct ecryptfs_crypt_stat *crypt_stat, | |
497 | struct page *page, | |
498 | unsigned long extent_offset) | |
499 | { | |
d6a13c17 | 500 | loff_t extent_base; |
0216f7f7 MH |
501 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
502 | int rc; | |
503 | ||
d6a13c17 | 504 | extent_base = (((loff_t)page->index) |
0216f7f7 MH |
505 | * (PAGE_CACHE_SIZE / crypt_stat->extent_size)); |
506 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, | |
507 | (extent_base + extent_offset)); | |
508 | if (rc) { | |
509 | ecryptfs_printk(KERN_ERR, "Error attempting to " | |
510 | "derive IV for extent [0x%.16x]; " | |
511 | "rc = [%d]\n", (extent_base + extent_offset), | |
512 | rc); | |
513 | goto out; | |
514 | } | |
515 | if (unlikely(ecryptfs_verbosity > 0)) { | |
516 | ecryptfs_printk(KERN_DEBUG, "Encrypting extent " | |
517 | "with iv:\n"); | |
518 | ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); | |
519 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " | |
520 | "encryption:\n"); | |
521 | ecryptfs_dump_hex((char *) | |
522 | (page_address(page) | |
523 | + (extent_offset * crypt_stat->extent_size)), | |
524 | 8); | |
525 | } | |
526 | rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0, | |
527 | page, (extent_offset | |
528 | * crypt_stat->extent_size), | |
529 | crypt_stat->extent_size, extent_iv); | |
530 | if (rc < 0) { | |
531 | printk(KERN_ERR "%s: Error attempting to encrypt page with " | |
532 | "page->index = [%ld], extent_offset = [%ld]; " | |
533 | "rc = [%d]\n", __FUNCTION__, page->index, extent_offset, | |
534 | rc); | |
535 | goto out; | |
536 | } | |
537 | rc = 0; | |
538 | if (unlikely(ecryptfs_verbosity > 0)) { | |
539 | ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; " | |
540 | "rc = [%d]\n", (extent_base + extent_offset), | |
541 | rc); | |
542 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " | |
543 | "encryption:\n"); | |
544 | ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8); | |
545 | } | |
546 | out: | |
547 | return rc; | |
548 | } | |
549 | ||
237fead6 MH |
550 | /** |
551 | * ecryptfs_encrypt_page | |
0216f7f7 MH |
552 | * @page: Page mapped from the eCryptfs inode for the file; contains |
553 | * decrypted content that needs to be encrypted (to a temporary | |
554 | * page; not in place) and written out to the lower file | |
237fead6 MH |
555 | * |
556 | * Encrypt an eCryptfs page. This is done on a per-extent basis. Note | |
557 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
558 | * if the file was created on a machine with an 8K page size | |
559 | * (resulting in an 8K header), and then the file is copied onto a | |
560 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
561 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
562 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
563 | * | |
237fead6 MH |
564 | * Returns zero on success; negative on error |
565 | */ | |
0216f7f7 | 566 | int ecryptfs_encrypt_page(struct page *page) |
237fead6 | 567 | { |
0216f7f7 | 568 | struct inode *ecryptfs_inode; |
237fead6 | 569 | struct ecryptfs_crypt_stat *crypt_stat; |
0216f7f7 MH |
570 | char *enc_extent_virt = NULL; |
571 | struct page *enc_extent_page; | |
572 | loff_t extent_offset; | |
237fead6 | 573 | int rc = 0; |
0216f7f7 MH |
574 | |
575 | ecryptfs_inode = page->mapping->host; | |
576 | crypt_stat = | |
577 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
e2bd99ec | 578 | if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
0216f7f7 MH |
579 | rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page, |
580 | 0, PAGE_CACHE_SIZE); | |
237fead6 | 581 | if (rc) |
0216f7f7 MH |
582 | printk(KERN_ERR "%s: Error attempting to copy " |
583 | "page at index [%ld]\n", __FUNCTION__, | |
584 | page->index); | |
237fead6 MH |
585 | goto out; |
586 | } | |
0216f7f7 MH |
587 | enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER); |
588 | if (!enc_extent_virt) { | |
589 | rc = -ENOMEM; | |
590 | ecryptfs_printk(KERN_ERR, "Error allocating memory for " | |
591 | "encrypted extent\n"); | |
592 | goto out; | |
593 | } | |
594 | enc_extent_page = virt_to_page(enc_extent_virt); | |
595 | for (extent_offset = 0; | |
596 | extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size); | |
597 | extent_offset++) { | |
598 | loff_t offset; | |
599 | ||
600 | rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page, | |
601 | extent_offset); | |
237fead6 | 602 | if (rc) { |
0216f7f7 MH |
603 | printk(KERN_ERR "%s: Error encrypting extent; " |
604 | "rc = [%d]\n", __FUNCTION__, rc); | |
237fead6 MH |
605 | goto out; |
606 | } | |
0216f7f7 | 607 | ecryptfs_lower_offset_for_extent( |
d6a13c17 MH |
608 | &offset, ((((loff_t)page->index) |
609 | * (PAGE_CACHE_SIZE | |
610 | / crypt_stat->extent_size)) | |
0216f7f7 MH |
611 | + extent_offset), crypt_stat); |
612 | rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, | |
613 | offset, crypt_stat->extent_size); | |
614 | if (rc) { | |
615 | ecryptfs_printk(KERN_ERR, "Error attempting " | |
616 | "to write lower page; rc = [%d]" | |
617 | "\n", rc); | |
618 | goto out; | |
237fead6 | 619 | } |
237fead6 MH |
620 | extent_offset++; |
621 | } | |
0216f7f7 MH |
622 | out: |
623 | kfree(enc_extent_virt); | |
624 | return rc; | |
625 | } | |
626 | ||
627 | static int ecryptfs_decrypt_extent(struct page *page, | |
628 | struct ecryptfs_crypt_stat *crypt_stat, | |
629 | struct page *enc_extent_page, | |
630 | unsigned long extent_offset) | |
631 | { | |
d6a13c17 | 632 | loff_t extent_base; |
0216f7f7 MH |
633 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
634 | int rc; | |
635 | ||
d6a13c17 | 636 | extent_base = (((loff_t)page->index) |
0216f7f7 MH |
637 | * (PAGE_CACHE_SIZE / crypt_stat->extent_size)); |
638 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, | |
639 | (extent_base + extent_offset)); | |
237fead6 | 640 | if (rc) { |
0216f7f7 MH |
641 | ecryptfs_printk(KERN_ERR, "Error attempting to " |
642 | "derive IV for extent [0x%.16x]; " | |
643 | "rc = [%d]\n", (extent_base + extent_offset), | |
644 | rc); | |
645 | goto out; | |
646 | } | |
647 | if (unlikely(ecryptfs_verbosity > 0)) { | |
648 | ecryptfs_printk(KERN_DEBUG, "Decrypting extent " | |
649 | "with iv:\n"); | |
650 | ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); | |
651 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " | |
652 | "decryption:\n"); | |
653 | ecryptfs_dump_hex((char *) | |
654 | (page_address(enc_extent_page) | |
655 | + (extent_offset * crypt_stat->extent_size)), | |
656 | 8); | |
657 | } | |
658 | rc = ecryptfs_decrypt_page_offset(crypt_stat, page, | |
659 | (extent_offset | |
660 | * crypt_stat->extent_size), | |
661 | enc_extent_page, 0, | |
662 | crypt_stat->extent_size, extent_iv); | |
663 | if (rc < 0) { | |
664 | printk(KERN_ERR "%s: Error attempting to decrypt to page with " | |
665 | "page->index = [%ld], extent_offset = [%ld]; " | |
666 | "rc = [%d]\n", __FUNCTION__, page->index, extent_offset, | |
667 | rc); | |
668 | goto out; | |
669 | } | |
670 | rc = 0; | |
671 | if (unlikely(ecryptfs_verbosity > 0)) { | |
672 | ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; " | |
673 | "rc = [%d]\n", (extent_base + extent_offset), | |
674 | rc); | |
675 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " | |
676 | "decryption:\n"); | |
677 | ecryptfs_dump_hex((char *)(page_address(page) | |
678 | + (extent_offset | |
679 | * crypt_stat->extent_size)), 8); | |
237fead6 MH |
680 | } |
681 | out: | |
682 | return rc; | |
683 | } | |
684 | ||
685 | /** | |
686 | * ecryptfs_decrypt_page | |
0216f7f7 MH |
687 | * @page: Page mapped from the eCryptfs inode for the file; data read |
688 | * and decrypted from the lower file will be written into this | |
689 | * page | |
237fead6 MH |
690 | * |
691 | * Decrypt an eCryptfs page. This is done on a per-extent basis. Note | |
692 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
693 | * if the file was created on a machine with an 8K page size | |
694 | * (resulting in an 8K header), and then the file is copied onto a | |
695 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
696 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
697 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
698 | * | |
699 | * Returns zero on success; negative on error | |
700 | */ | |
0216f7f7 | 701 | int ecryptfs_decrypt_page(struct page *page) |
237fead6 | 702 | { |
0216f7f7 | 703 | struct inode *ecryptfs_inode; |
237fead6 | 704 | struct ecryptfs_crypt_stat *crypt_stat; |
0216f7f7 MH |
705 | char *enc_extent_virt = NULL; |
706 | struct page *enc_extent_page; | |
707 | unsigned long extent_offset; | |
237fead6 | 708 | int rc = 0; |
237fead6 | 709 | |
0216f7f7 MH |
710 | ecryptfs_inode = page->mapping->host; |
711 | crypt_stat = | |
712 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
e2bd99ec | 713 | if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
0216f7f7 MH |
714 | rc = ecryptfs_read_lower_page_segment(page, page->index, 0, |
715 | PAGE_CACHE_SIZE, | |
716 | ecryptfs_inode); | |
237fead6 | 717 | if (rc) |
0216f7f7 MH |
718 | printk(KERN_ERR "%s: Error attempting to copy " |
719 | "page at index [%ld]\n", __FUNCTION__, | |
720 | page->index); | |
721 | goto out_clear_uptodate; | |
237fead6 | 722 | } |
0216f7f7 MH |
723 | enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER); |
724 | if (!enc_extent_virt) { | |
237fead6 | 725 | rc = -ENOMEM; |
0216f7f7 MH |
726 | ecryptfs_printk(KERN_ERR, "Error allocating memory for " |
727 | "encrypted extent\n"); | |
728 | goto out_clear_uptodate; | |
237fead6 | 729 | } |
0216f7f7 MH |
730 | enc_extent_page = virt_to_page(enc_extent_virt); |
731 | for (extent_offset = 0; | |
732 | extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size); | |
733 | extent_offset++) { | |
734 | loff_t offset; | |
735 | ||
736 | ecryptfs_lower_offset_for_extent( | |
737 | &offset, ((page->index * (PAGE_CACHE_SIZE | |
738 | / crypt_stat->extent_size)) | |
739 | + extent_offset), crypt_stat); | |
740 | rc = ecryptfs_read_lower(enc_extent_virt, offset, | |
741 | crypt_stat->extent_size, | |
742 | ecryptfs_inode); | |
237fead6 | 743 | if (rc) { |
0216f7f7 MH |
744 | ecryptfs_printk(KERN_ERR, "Error attempting " |
745 | "to read lower page; rc = [%d]" | |
746 | "\n", rc); | |
747 | goto out_clear_uptodate; | |
237fead6 | 748 | } |
0216f7f7 MH |
749 | rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page, |
750 | extent_offset); | |
751 | if (rc) { | |
752 | printk(KERN_ERR "%s: Error encrypting extent; " | |
753 | "rc = [%d]\n", __FUNCTION__, rc); | |
754 | goto out_clear_uptodate; | |
237fead6 MH |
755 | } |
756 | extent_offset++; | |
757 | } | |
0216f7f7 MH |
758 | SetPageUptodate(page); |
759 | goto out; | |
760 | out_clear_uptodate: | |
761 | ClearPageUptodate(page); | |
237fead6 | 762 | out: |
0216f7f7 | 763 | kfree(enc_extent_virt); |
237fead6 MH |
764 | return rc; |
765 | } | |
766 | ||
767 | /** | |
768 | * decrypt_scatterlist | |
22e78faf MH |
769 | * @crypt_stat: Cryptographic context |
770 | * @dest_sg: The destination scatterlist to decrypt into | |
771 | * @src_sg: The source scatterlist to decrypt from | |
772 | * @size: The number of bytes to decrypt | |
773 | * @iv: The initialization vector to use for the decryption | |
237fead6 MH |
774 | * |
775 | * Returns the number of bytes decrypted; negative value on error | |
776 | */ | |
777 | static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, | |
778 | struct scatterlist *dest_sg, | |
779 | struct scatterlist *src_sg, int size, | |
780 | unsigned char *iv) | |
781 | { | |
8bba066f MH |
782 | struct blkcipher_desc desc = { |
783 | .tfm = crypt_stat->tfm, | |
784 | .info = iv, | |
785 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP | |
786 | }; | |
237fead6 MH |
787 | int rc = 0; |
788 | ||
789 | /* Consider doing this once, when the file is opened */ | |
790 | mutex_lock(&crypt_stat->cs_tfm_mutex); | |
8bba066f MH |
791 | rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
792 | crypt_stat->key_size); | |
237fead6 MH |
793 | if (rc) { |
794 | ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n", | |
795 | rc); | |
796 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
797 | rc = -EINVAL; | |
798 | goto out; | |
799 | } | |
800 | ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size); | |
8bba066f | 801 | rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size); |
237fead6 MH |
802 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
803 | if (rc) { | |
804 | ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n", | |
805 | rc); | |
806 | goto out; | |
807 | } | |
808 | rc = size; | |
809 | out: | |
810 | return rc; | |
811 | } | |
812 | ||
813 | /** | |
814 | * ecryptfs_encrypt_page_offset | |
22e78faf MH |
815 | * @crypt_stat: The cryptographic context |
816 | * @dst_page: The page to encrypt into | |
817 | * @dst_offset: The offset in the page to encrypt into | |
818 | * @src_page: The page to encrypt from | |
819 | * @src_offset: The offset in the page to encrypt from | |
820 | * @size: The number of bytes to encrypt | |
821 | * @iv: The initialization vector to use for the encryption | |
237fead6 MH |
822 | * |
823 | * Returns the number of bytes encrypted | |
824 | */ | |
825 | static int | |
826 | ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, | |
827 | struct page *dst_page, int dst_offset, | |
828 | struct page *src_page, int src_offset, int size, | |
829 | unsigned char *iv) | |
830 | { | |
831 | struct scatterlist src_sg, dst_sg; | |
832 | ||
833 | src_sg.page = src_page; | |
834 | src_sg.offset = src_offset; | |
835 | src_sg.length = size; | |
836 | dst_sg.page = dst_page; | |
837 | dst_sg.offset = dst_offset; | |
838 | dst_sg.length = size; | |
839 | return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv); | |
840 | } | |
841 | ||
842 | /** | |
843 | * ecryptfs_decrypt_page_offset | |
22e78faf MH |
844 | * @crypt_stat: The cryptographic context |
845 | * @dst_page: The page to decrypt into | |
846 | * @dst_offset: The offset in the page to decrypt into | |
847 | * @src_page: The page to decrypt from | |
848 | * @src_offset: The offset in the page to decrypt from | |
849 | * @size: The number of bytes to decrypt | |
850 | * @iv: The initialization vector to use for the decryption | |
237fead6 MH |
851 | * |
852 | * Returns the number of bytes decrypted | |
853 | */ | |
854 | static int | |
855 | ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, | |
856 | struct page *dst_page, int dst_offset, | |
857 | struct page *src_page, int src_offset, int size, | |
858 | unsigned char *iv) | |
859 | { | |
860 | struct scatterlist src_sg, dst_sg; | |
861 | ||
862 | src_sg.page = src_page; | |
863 | src_sg.offset = src_offset; | |
864 | src_sg.length = size; | |
865 | dst_sg.page = dst_page; | |
866 | dst_sg.offset = dst_offset; | |
867 | dst_sg.length = size; | |
868 | return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv); | |
869 | } | |
870 | ||
871 | #define ECRYPTFS_MAX_SCATTERLIST_LEN 4 | |
872 | ||
873 | /** | |
874 | * ecryptfs_init_crypt_ctx | |
875 | * @crypt_stat: Uninitilized crypt stats structure | |
876 | * | |
877 | * Initialize the crypto context. | |
878 | * | |
879 | * TODO: Performance: Keep a cache of initialized cipher contexts; | |
880 | * only init if needed | |
881 | */ | |
882 | int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat) | |
883 | { | |
8bba066f | 884 | char *full_alg_name; |
237fead6 MH |
885 | int rc = -EINVAL; |
886 | ||
887 | if (!crypt_stat->cipher) { | |
888 | ecryptfs_printk(KERN_ERR, "No cipher specified\n"); | |
889 | goto out; | |
890 | } | |
891 | ecryptfs_printk(KERN_DEBUG, | |
892 | "Initializing cipher [%s]; strlen = [%d]; " | |
893 | "key_size_bits = [%d]\n", | |
894 | crypt_stat->cipher, (int)strlen(crypt_stat->cipher), | |
895 | crypt_stat->key_size << 3); | |
896 | if (crypt_stat->tfm) { | |
897 | rc = 0; | |
898 | goto out; | |
899 | } | |
900 | mutex_lock(&crypt_stat->cs_tfm_mutex); | |
8bba066f MH |
901 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, |
902 | crypt_stat->cipher, "cbc"); | |
903 | if (rc) | |
904 | goto out; | |
905 | crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0, | |
906 | CRYPTO_ALG_ASYNC); | |
907 | kfree(full_alg_name); | |
de88777e AM |
908 | if (IS_ERR(crypt_stat->tfm)) { |
909 | rc = PTR_ERR(crypt_stat->tfm); | |
237fead6 MH |
910 | ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): " |
911 | "Error initializing cipher [%s]\n", | |
912 | crypt_stat->cipher); | |
8bba066f | 913 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
237fead6 MH |
914 | goto out; |
915 | } | |
f1ddcaf3 | 916 | crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY); |
8bba066f | 917 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
237fead6 MH |
918 | rc = 0; |
919 | out: | |
920 | return rc; | |
921 | } | |
922 | ||
923 | static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat) | |
924 | { | |
925 | int extent_size_tmp; | |
926 | ||
927 | crypt_stat->extent_mask = 0xFFFFFFFF; | |
928 | crypt_stat->extent_shift = 0; | |
929 | if (crypt_stat->extent_size == 0) | |
930 | return; | |
931 | extent_size_tmp = crypt_stat->extent_size; | |
932 | while ((extent_size_tmp & 0x01) == 0) { | |
933 | extent_size_tmp >>= 1; | |
934 | crypt_stat->extent_mask <<= 1; | |
935 | crypt_stat->extent_shift++; | |
936 | } | |
937 | } | |
938 | ||
939 | void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) | |
940 | { | |
941 | /* Default values; may be overwritten as we are parsing the | |
942 | * packets. */ | |
943 | crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; | |
944 | set_extent_mask_and_shift(crypt_stat); | |
945 | crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES; | |
dd2a3b7a MH |
946 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
947 | crypt_stat->num_header_extents_at_front = 0; | |
45eaab79 MH |
948 | else { |
949 | if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) | |
950 | crypt_stat->num_header_extents_at_front = | |
951 | (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE | |
952 | / crypt_stat->extent_size); | |
953 | else | |
954 | crypt_stat->num_header_extents_at_front = | |
955 | (PAGE_CACHE_SIZE / crypt_stat->extent_size); | |
956 | } | |
237fead6 MH |
957 | } |
958 | ||
959 | /** | |
960 | * ecryptfs_compute_root_iv | |
961 | * @crypt_stats | |
962 | * | |
963 | * On error, sets the root IV to all 0's. | |
964 | */ | |
965 | int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat) | |
966 | { | |
967 | int rc = 0; | |
968 | char dst[MD5_DIGEST_SIZE]; | |
969 | ||
970 | BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE); | |
971 | BUG_ON(crypt_stat->iv_bytes <= 0); | |
e2bd99ec | 972 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { |
237fead6 MH |
973 | rc = -EINVAL; |
974 | ecryptfs_printk(KERN_WARNING, "Session key not valid; " | |
975 | "cannot generate root IV\n"); | |
976 | goto out; | |
977 | } | |
978 | rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key, | |
979 | crypt_stat->key_size); | |
980 | if (rc) { | |
981 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " | |
982 | "MD5 while generating root IV\n"); | |
983 | goto out; | |
984 | } | |
985 | memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes); | |
986 | out: | |
987 | if (rc) { | |
988 | memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes); | |
e2bd99ec | 989 | crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING; |
237fead6 MH |
990 | } |
991 | return rc; | |
992 | } | |
993 | ||
994 | static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat) | |
995 | { | |
996 | get_random_bytes(crypt_stat->key, crypt_stat->key_size); | |
e2bd99ec | 997 | crypt_stat->flags |= ECRYPTFS_KEY_VALID; |
237fead6 MH |
998 | ecryptfs_compute_root_iv(crypt_stat); |
999 | if (unlikely(ecryptfs_verbosity > 0)) { | |
1000 | ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n"); | |
1001 | ecryptfs_dump_hex(crypt_stat->key, | |
1002 | crypt_stat->key_size); | |
1003 | } | |
1004 | } | |
1005 | ||
17398957 MH |
1006 | /** |
1007 | * ecryptfs_copy_mount_wide_flags_to_inode_flags | |
22e78faf MH |
1008 | * @crypt_stat: The inode's cryptographic context |
1009 | * @mount_crypt_stat: The mount point's cryptographic context | |
17398957 MH |
1010 | * |
1011 | * This function propagates the mount-wide flags to individual inode | |
1012 | * flags. | |
1013 | */ | |
1014 | static void ecryptfs_copy_mount_wide_flags_to_inode_flags( | |
1015 | struct ecryptfs_crypt_stat *crypt_stat, | |
1016 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
1017 | { | |
1018 | if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) | |
1019 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
1020 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) | |
1021 | crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED; | |
1022 | } | |
1023 | ||
f4aad16a MH |
1024 | static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs( |
1025 | struct ecryptfs_crypt_stat *crypt_stat, | |
1026 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
1027 | { | |
1028 | struct ecryptfs_global_auth_tok *global_auth_tok; | |
1029 | int rc = 0; | |
1030 | ||
1031 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
1032 | list_for_each_entry(global_auth_tok, | |
1033 | &mount_crypt_stat->global_auth_tok_list, | |
1034 | mount_crypt_stat_list) { | |
1035 | rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig); | |
1036 | if (rc) { | |
1037 | printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc); | |
1038 | mutex_unlock( | |
1039 | &mount_crypt_stat->global_auth_tok_list_mutex); | |
1040 | goto out; | |
1041 | } | |
1042 | } | |
1043 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
1044 | out: | |
1045 | return rc; | |
1046 | } | |
1047 | ||
237fead6 MH |
1048 | /** |
1049 | * ecryptfs_set_default_crypt_stat_vals | |
22e78faf MH |
1050 | * @crypt_stat: The inode's cryptographic context |
1051 | * @mount_crypt_stat: The mount point's cryptographic context | |
237fead6 MH |
1052 | * |
1053 | * Default values in the event that policy does not override them. | |
1054 | */ | |
1055 | static void ecryptfs_set_default_crypt_stat_vals( | |
1056 | struct ecryptfs_crypt_stat *crypt_stat, | |
1057 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
1058 | { | |
17398957 MH |
1059 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
1060 | mount_crypt_stat); | |
237fead6 MH |
1061 | ecryptfs_set_default_sizes(crypt_stat); |
1062 | strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER); | |
1063 | crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES; | |
e2bd99ec | 1064 | crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID); |
237fead6 MH |
1065 | crypt_stat->file_version = ECRYPTFS_FILE_VERSION; |
1066 | crypt_stat->mount_crypt_stat = mount_crypt_stat; | |
1067 | } | |
1068 | ||
1069 | /** | |
1070 | * ecryptfs_new_file_context | |
22e78faf | 1071 | * @ecryptfs_dentry: The eCryptfs dentry |
237fead6 MH |
1072 | * |
1073 | * If the crypto context for the file has not yet been established, | |
1074 | * this is where we do that. Establishing a new crypto context | |
1075 | * involves the following decisions: | |
1076 | * - What cipher to use? | |
1077 | * - What set of authentication tokens to use? | |
1078 | * Here we just worry about getting enough information into the | |
1079 | * authentication tokens so that we know that they are available. | |
1080 | * We associate the available authentication tokens with the new file | |
1081 | * via the set of signatures in the crypt_stat struct. Later, when | |
1082 | * the headers are actually written out, we may again defer to | |
1083 | * userspace to perform the encryption of the session key; for the | |
1084 | * foreseeable future, this will be the case with public key packets. | |
1085 | * | |
1086 | * Returns zero on success; non-zero otherwise | |
1087 | */ | |
237fead6 MH |
1088 | int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry) |
1089 | { | |
237fead6 MH |
1090 | struct ecryptfs_crypt_stat *crypt_stat = |
1091 | &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; | |
1092 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = | |
1093 | &ecryptfs_superblock_to_private( | |
1094 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
1095 | int cipher_name_len; | |
f4aad16a | 1096 | int rc = 0; |
237fead6 MH |
1097 | |
1098 | ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat); | |
af655dc6 | 1099 | crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID); |
f4aad16a MH |
1100 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
1101 | mount_crypt_stat); | |
1102 | rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat, | |
1103 | mount_crypt_stat); | |
1104 | if (rc) { | |
1105 | printk(KERN_ERR "Error attempting to copy mount-wide key sigs " | |
1106 | "to the inode key sigs; rc = [%d]\n", rc); | |
1107 | goto out; | |
1108 | } | |
1109 | cipher_name_len = | |
1110 | strlen(mount_crypt_stat->global_default_cipher_name); | |
1111 | memcpy(crypt_stat->cipher, | |
1112 | mount_crypt_stat->global_default_cipher_name, | |
1113 | cipher_name_len); | |
1114 | crypt_stat->cipher[cipher_name_len] = '\0'; | |
1115 | crypt_stat->key_size = | |
1116 | mount_crypt_stat->global_default_cipher_key_size; | |
1117 | ecryptfs_generate_new_key(crypt_stat); | |
237fead6 MH |
1118 | rc = ecryptfs_init_crypt_ctx(crypt_stat); |
1119 | if (rc) | |
1120 | ecryptfs_printk(KERN_ERR, "Error initializing cryptographic " | |
1121 | "context for cipher [%s]: rc = [%d]\n", | |
1122 | crypt_stat->cipher, rc); | |
f4aad16a | 1123 | out: |
237fead6 MH |
1124 | return rc; |
1125 | } | |
1126 | ||
1127 | /** | |
1128 | * contains_ecryptfs_marker - check for the ecryptfs marker | |
1129 | * @data: The data block in which to check | |
1130 | * | |
1131 | * Returns one if marker found; zero if not found | |
1132 | */ | |
dd2a3b7a | 1133 | static int contains_ecryptfs_marker(char *data) |
237fead6 MH |
1134 | { |
1135 | u32 m_1, m_2; | |
1136 | ||
1137 | memcpy(&m_1, data, 4); | |
1138 | m_1 = be32_to_cpu(m_1); | |
1139 | memcpy(&m_2, (data + 4), 4); | |
1140 | m_2 = be32_to_cpu(m_2); | |
1141 | if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2) | |
1142 | return 1; | |
1143 | ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; " | |
1144 | "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2, | |
1145 | MAGIC_ECRYPTFS_MARKER); | |
1146 | ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = " | |
1147 | "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER)); | |
1148 | return 0; | |
1149 | } | |
1150 | ||
1151 | struct ecryptfs_flag_map_elem { | |
1152 | u32 file_flag; | |
1153 | u32 local_flag; | |
1154 | }; | |
1155 | ||
1156 | /* Add support for additional flags by adding elements here. */ | |
1157 | static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = { | |
1158 | {0x00000001, ECRYPTFS_ENABLE_HMAC}, | |
dd2a3b7a MH |
1159 | {0x00000002, ECRYPTFS_ENCRYPTED}, |
1160 | {0x00000004, ECRYPTFS_METADATA_IN_XATTR} | |
237fead6 MH |
1161 | }; |
1162 | ||
1163 | /** | |
1164 | * ecryptfs_process_flags | |
22e78faf | 1165 | * @crypt_stat: The cryptographic context |
237fead6 MH |
1166 | * @page_virt: Source data to be parsed |
1167 | * @bytes_read: Updated with the number of bytes read | |
1168 | * | |
1169 | * Returns zero on success; non-zero if the flag set is invalid | |
1170 | */ | |
1171 | static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat, | |
1172 | char *page_virt, int *bytes_read) | |
1173 | { | |
1174 | int rc = 0; | |
1175 | int i; | |
1176 | u32 flags; | |
1177 | ||
1178 | memcpy(&flags, page_virt, 4); | |
1179 | flags = be32_to_cpu(flags); | |
1180 | for (i = 0; i < ((sizeof(ecryptfs_flag_map) | |
1181 | / sizeof(struct ecryptfs_flag_map_elem))); i++) | |
1182 | if (flags & ecryptfs_flag_map[i].file_flag) { | |
e2bd99ec | 1183 | crypt_stat->flags |= ecryptfs_flag_map[i].local_flag; |
237fead6 | 1184 | } else |
e2bd99ec | 1185 | crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag); |
237fead6 MH |
1186 | /* Version is in top 8 bits of the 32-bit flag vector */ |
1187 | crypt_stat->file_version = ((flags >> 24) & 0xFF); | |
1188 | (*bytes_read) = 4; | |
1189 | return rc; | |
1190 | } | |
1191 | ||
1192 | /** | |
1193 | * write_ecryptfs_marker | |
1194 | * @page_virt: The pointer to in a page to begin writing the marker | |
1195 | * @written: Number of bytes written | |
1196 | * | |
1197 | * Marker = 0x3c81b7f5 | |
1198 | */ | |
1199 | static void write_ecryptfs_marker(char *page_virt, size_t *written) | |
1200 | { | |
1201 | u32 m_1, m_2; | |
1202 | ||
1203 | get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); | |
1204 | m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER); | |
1205 | m_1 = cpu_to_be32(m_1); | |
1206 | memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); | |
1207 | m_2 = cpu_to_be32(m_2); | |
1208 | memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2, | |
1209 | (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); | |
1210 | (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; | |
1211 | } | |
1212 | ||
1213 | static void | |
1214 | write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat, | |
1215 | size_t *written) | |
1216 | { | |
1217 | u32 flags = 0; | |
1218 | int i; | |
1219 | ||
1220 | for (i = 0; i < ((sizeof(ecryptfs_flag_map) | |
1221 | / sizeof(struct ecryptfs_flag_map_elem))); i++) | |
e2bd99ec | 1222 | if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag) |
237fead6 MH |
1223 | flags |= ecryptfs_flag_map[i].file_flag; |
1224 | /* Version is in top 8 bits of the 32-bit flag vector */ | |
1225 | flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000); | |
1226 | flags = cpu_to_be32(flags); | |
1227 | memcpy(page_virt, &flags, 4); | |
1228 | (*written) = 4; | |
1229 | } | |
1230 | ||
1231 | struct ecryptfs_cipher_code_str_map_elem { | |
1232 | char cipher_str[16]; | |
1233 | u16 cipher_code; | |
1234 | }; | |
1235 | ||
1236 | /* Add support for additional ciphers by adding elements here. The | |
1237 | * cipher_code is whatever OpenPGP applicatoins use to identify the | |
1238 | * ciphers. List in order of probability. */ | |
1239 | static struct ecryptfs_cipher_code_str_map_elem | |
1240 | ecryptfs_cipher_code_str_map[] = { | |
1241 | {"aes",RFC2440_CIPHER_AES_128 }, | |
1242 | {"blowfish", RFC2440_CIPHER_BLOWFISH}, | |
1243 | {"des3_ede", RFC2440_CIPHER_DES3_EDE}, | |
1244 | {"cast5", RFC2440_CIPHER_CAST_5}, | |
1245 | {"twofish", RFC2440_CIPHER_TWOFISH}, | |
1246 | {"cast6", RFC2440_CIPHER_CAST_6}, | |
1247 | {"aes", RFC2440_CIPHER_AES_192}, | |
1248 | {"aes", RFC2440_CIPHER_AES_256} | |
1249 | }; | |
1250 | ||
1251 | /** | |
1252 | * ecryptfs_code_for_cipher_string | |
22e78faf | 1253 | * @crypt_stat: The cryptographic context |
237fead6 MH |
1254 | * |
1255 | * Returns zero on no match, or the cipher code on match | |
1256 | */ | |
1257 | u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat) | |
1258 | { | |
1259 | int i; | |
1260 | u16 code = 0; | |
1261 | struct ecryptfs_cipher_code_str_map_elem *map = | |
1262 | ecryptfs_cipher_code_str_map; | |
1263 | ||
1264 | if (strcmp(crypt_stat->cipher, "aes") == 0) { | |
1265 | switch (crypt_stat->key_size) { | |
1266 | case 16: | |
1267 | code = RFC2440_CIPHER_AES_128; | |
1268 | break; | |
1269 | case 24: | |
1270 | code = RFC2440_CIPHER_AES_192; | |
1271 | break; | |
1272 | case 32: | |
1273 | code = RFC2440_CIPHER_AES_256; | |
1274 | } | |
1275 | } else { | |
1276 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) | |
1277 | if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){ | |
1278 | code = map[i].cipher_code; | |
1279 | break; | |
1280 | } | |
1281 | } | |
1282 | return code; | |
1283 | } | |
1284 | ||
1285 | /** | |
1286 | * ecryptfs_cipher_code_to_string | |
1287 | * @str: Destination to write out the cipher name | |
1288 | * @cipher_code: The code to convert to cipher name string | |
1289 | * | |
1290 | * Returns zero on success | |
1291 | */ | |
1292 | int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code) | |
1293 | { | |
1294 | int rc = 0; | |
1295 | int i; | |
1296 | ||
1297 | str[0] = '\0'; | |
1298 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) | |
1299 | if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code) | |
1300 | strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str); | |
1301 | if (str[0] == '\0') { | |
1302 | ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: " | |
1303 | "[%d]\n", cipher_code); | |
1304 | rc = -EINVAL; | |
1305 | } | |
1306 | return rc; | |
1307 | } | |
1308 | ||
1309 | /** | |
1310 | * ecryptfs_read_header_region | |
22e78faf MH |
1311 | * @data: The virtual address to write header region data into |
1312 | * @dentry: The lower dentry | |
1313 | * @mnt: The lower VFS mount | |
237fead6 MH |
1314 | * |
1315 | * Returns zero on success; non-zero otherwise | |
1316 | */ | |
dd2a3b7a MH |
1317 | static int ecryptfs_read_header_region(char *data, struct dentry *dentry, |
1318 | struct vfsmount *mnt) | |
237fead6 | 1319 | { |
7ff1d74f | 1320 | struct file *lower_file; |
237fead6 MH |
1321 | mm_segment_t oldfs; |
1322 | int rc; | |
1323 | ||
5dda6992 MH |
1324 | rc = ecryptfs_open_lower_file(&lower_file, dentry, mnt, O_RDONLY); |
1325 | if (rc) { | |
7ff1d74f MH |
1326 | printk(KERN_ERR |
1327 | "Error opening lower_file to read header region\n"); | |
237fead6 MH |
1328 | goto out; |
1329 | } | |
7ff1d74f | 1330 | lower_file->f_pos = 0; |
237fead6 MH |
1331 | oldfs = get_fs(); |
1332 | set_fs(get_ds()); | |
7ff1d74f MH |
1333 | rc = lower_file->f_op->read(lower_file, (char __user *)data, |
1334 | ECRYPTFS_DEFAULT_EXTENT_SIZE, &lower_file->f_pos); | |
237fead6 | 1335 | set_fs(oldfs); |
5dda6992 MH |
1336 | rc = ecryptfs_close_lower_file(lower_file); |
1337 | if (rc) { | |
7ff1d74f MH |
1338 | printk(KERN_ERR "Error closing lower_file\n"); |
1339 | goto out; | |
1340 | } | |
237fead6 MH |
1341 | rc = 0; |
1342 | out: | |
1343 | return rc; | |
1344 | } | |
1345 | ||
d7cdc5fe MH |
1346 | int ecryptfs_read_and_validate_header_region(char *data, |
1347 | struct inode *ecryptfs_inode) | |
dd2a3b7a | 1348 | { |
d7cdc5fe MH |
1349 | struct ecryptfs_crypt_stat *crypt_stat = |
1350 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
dd2a3b7a MH |
1351 | int rc; |
1352 | ||
d7cdc5fe MH |
1353 | rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size, |
1354 | ecryptfs_inode); | |
1355 | if (rc) { | |
1356 | printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n", | |
1357 | __FUNCTION__, rc); | |
dd2a3b7a | 1358 | goto out; |
d7cdc5fe MH |
1359 | } |
1360 | if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) { | |
dd2a3b7a | 1361 | rc = -EINVAL; |
d7cdc5fe MH |
1362 | ecryptfs_printk(KERN_DEBUG, "Valid marker not found\n"); |
1363 | } | |
dd2a3b7a MH |
1364 | out: |
1365 | return rc; | |
1366 | } | |
1367 | ||
e77a56dd MH |
1368 | void |
1369 | ecryptfs_write_header_metadata(char *virt, | |
1370 | struct ecryptfs_crypt_stat *crypt_stat, | |
1371 | size_t *written) | |
237fead6 MH |
1372 | { |
1373 | u32 header_extent_size; | |
1374 | u16 num_header_extents_at_front; | |
1375 | ||
45eaab79 | 1376 | header_extent_size = (u32)crypt_stat->extent_size; |
237fead6 MH |
1377 | num_header_extents_at_front = |
1378 | (u16)crypt_stat->num_header_extents_at_front; | |
1379 | header_extent_size = cpu_to_be32(header_extent_size); | |
1380 | memcpy(virt, &header_extent_size, 4); | |
1381 | virt += 4; | |
1382 | num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front); | |
1383 | memcpy(virt, &num_header_extents_at_front, 2); | |
1384 | (*written) = 6; | |
1385 | } | |
1386 | ||
1387 | struct kmem_cache *ecryptfs_header_cache_0; | |
1388 | struct kmem_cache *ecryptfs_header_cache_1; | |
1389 | struct kmem_cache *ecryptfs_header_cache_2; | |
1390 | ||
1391 | /** | |
1392 | * ecryptfs_write_headers_virt | |
22e78faf MH |
1393 | * @page_virt: The virtual address to write the headers to |
1394 | * @size: Set to the number of bytes written by this function | |
1395 | * @crypt_stat: The cryptographic context | |
1396 | * @ecryptfs_dentry: The eCryptfs dentry | |
237fead6 MH |
1397 | * |
1398 | * Format version: 1 | |
1399 | * | |
1400 | * Header Extent: | |
1401 | * Octets 0-7: Unencrypted file size (big-endian) | |
1402 | * Octets 8-15: eCryptfs special marker | |
1403 | * Octets 16-19: Flags | |
1404 | * Octet 16: File format version number (between 0 and 255) | |
1405 | * Octets 17-18: Reserved | |
1406 | * Octet 19: Bit 1 (lsb): Reserved | |
1407 | * Bit 2: Encrypted? | |
1408 | * Bits 3-8: Reserved | |
1409 | * Octets 20-23: Header extent size (big-endian) | |
1410 | * Octets 24-25: Number of header extents at front of file | |
1411 | * (big-endian) | |
1412 | * Octet 26: Begin RFC 2440 authentication token packet set | |
1413 | * Data Extent 0: | |
1414 | * Lower data (CBC encrypted) | |
1415 | * Data Extent 1: | |
1416 | * Lower data (CBC encrypted) | |
1417 | * ... | |
1418 | * | |
1419 | * Returns zero on success | |
1420 | */ | |
dd2a3b7a MH |
1421 | static int ecryptfs_write_headers_virt(char *page_virt, size_t *size, |
1422 | struct ecryptfs_crypt_stat *crypt_stat, | |
1423 | struct dentry *ecryptfs_dentry) | |
237fead6 MH |
1424 | { |
1425 | int rc; | |
1426 | size_t written; | |
1427 | size_t offset; | |
1428 | ||
1429 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
1430 | write_ecryptfs_marker((page_virt + offset), &written); | |
1431 | offset += written; | |
1432 | write_ecryptfs_flags((page_virt + offset), crypt_stat, &written); | |
1433 | offset += written; | |
e77a56dd MH |
1434 | ecryptfs_write_header_metadata((page_virt + offset), crypt_stat, |
1435 | &written); | |
237fead6 MH |
1436 | offset += written; |
1437 | rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat, | |
1438 | ecryptfs_dentry, &written, | |
1439 | PAGE_CACHE_SIZE - offset); | |
1440 | if (rc) | |
1441 | ecryptfs_printk(KERN_WARNING, "Error generating key packet " | |
1442 | "set; rc = [%d]\n", rc); | |
dd2a3b7a MH |
1443 | if (size) { |
1444 | offset += written; | |
1445 | *size = offset; | |
1446 | } | |
1447 | return rc; | |
1448 | } | |
1449 | ||
22e78faf MH |
1450 | static int |
1451 | ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat, | |
d7cdc5fe MH |
1452 | struct dentry *ecryptfs_dentry, |
1453 | char *page_virt) | |
dd2a3b7a | 1454 | { |
dd2a3b7a MH |
1455 | int current_header_page; |
1456 | int header_pages; | |
d7cdc5fe | 1457 | int rc; |
dd2a3b7a | 1458 | |
d7cdc5fe MH |
1459 | rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, page_virt, |
1460 | 0, PAGE_CACHE_SIZE); | |
1461 | if (rc) { | |
1462 | printk(KERN_ERR "%s: Error attempting to write header " | |
1463 | "information to lower file; rc = [%d]\n", __FUNCTION__, | |
1464 | rc); | |
70456600 MH |
1465 | goto out; |
1466 | } | |
45eaab79 | 1467 | header_pages = ((crypt_stat->extent_size |
dd2a3b7a MH |
1468 | * crypt_stat->num_header_extents_at_front) |
1469 | / PAGE_CACHE_SIZE); | |
1470 | memset(page_virt, 0, PAGE_CACHE_SIZE); | |
1471 | current_header_page = 1; | |
1472 | while (current_header_page < header_pages) { | |
d7cdc5fe MH |
1473 | loff_t offset; |
1474 | ||
d6a13c17 | 1475 | offset = (((loff_t)current_header_page) << PAGE_CACHE_SHIFT); |
d7cdc5fe MH |
1476 | if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, |
1477 | page_virt, offset, | |
1478 | PAGE_CACHE_SIZE))) { | |
1479 | printk(KERN_ERR "%s: Error attempting to write header " | |
1480 | "information to lower file; rc = [%d]\n", | |
1481 | __FUNCTION__, rc); | |
70456600 MH |
1482 | goto out; |
1483 | } | |
dd2a3b7a MH |
1484 | current_header_page++; |
1485 | } | |
70456600 MH |
1486 | out: |
1487 | return rc; | |
dd2a3b7a MH |
1488 | } |
1489 | ||
22e78faf MH |
1490 | static int |
1491 | ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry, | |
1492 | struct ecryptfs_crypt_stat *crypt_stat, | |
1493 | char *page_virt, size_t size) | |
dd2a3b7a MH |
1494 | { |
1495 | int rc; | |
1496 | ||
1497 | rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt, | |
1498 | size, 0); | |
237fead6 MH |
1499 | return rc; |
1500 | } | |
1501 | ||
1502 | /** | |
dd2a3b7a | 1503 | * ecryptfs_write_metadata |
22e78faf | 1504 | * @ecryptfs_dentry: The eCryptfs dentry |
237fead6 MH |
1505 | * |
1506 | * Write the file headers out. This will likely involve a userspace | |
1507 | * callout, in which the session key is encrypted with one or more | |
1508 | * public keys and/or the passphrase necessary to do the encryption is | |
1509 | * retrieved via a prompt. Exactly what happens at this point should | |
1510 | * be policy-dependent. | |
1511 | * | |
d7cdc5fe MH |
1512 | * TODO: Support header information spanning multiple pages |
1513 | * | |
237fead6 MH |
1514 | * Returns zero on success; non-zero on error |
1515 | */ | |
d7cdc5fe | 1516 | int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry) |
237fead6 | 1517 | { |
d7cdc5fe MH |
1518 | struct ecryptfs_crypt_stat *crypt_stat = |
1519 | &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; | |
237fead6 | 1520 | char *page_virt; |
d7cdc5fe | 1521 | size_t size = 0; |
237fead6 MH |
1522 | int rc = 0; |
1523 | ||
e2bd99ec MH |
1524 | if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
1525 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { | |
d7cdc5fe | 1526 | printk(KERN_ERR "Key is invalid; bailing out\n"); |
237fead6 MH |
1527 | rc = -EINVAL; |
1528 | goto out; | |
1529 | } | |
1530 | } else { | |
1531 | rc = -EINVAL; | |
1532 | ecryptfs_printk(KERN_WARNING, | |
1533 | "Called with crypt_stat->encrypted == 0\n"); | |
1534 | goto out; | |
1535 | } | |
1536 | /* Released in this function */ | |
c3762229 | 1537 | page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER); |
237fead6 MH |
1538 | if (!page_virt) { |
1539 | ecryptfs_printk(KERN_ERR, "Out of memory\n"); | |
1540 | rc = -ENOMEM; | |
1541 | goto out; | |
1542 | } | |
dd2a3b7a MH |
1543 | rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat, |
1544 | ecryptfs_dentry); | |
237fead6 MH |
1545 | if (unlikely(rc)) { |
1546 | ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n"); | |
1547 | memset(page_virt, 0, PAGE_CACHE_SIZE); | |
1548 | goto out_free; | |
1549 | } | |
dd2a3b7a MH |
1550 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
1551 | rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, | |
1552 | crypt_stat, page_virt, | |
1553 | size); | |
1554 | else | |
d7cdc5fe MH |
1555 | rc = ecryptfs_write_metadata_to_contents(crypt_stat, |
1556 | ecryptfs_dentry, | |
dd2a3b7a MH |
1557 | page_virt); |
1558 | if (rc) { | |
1559 | printk(KERN_ERR "Error writing metadata out to lower file; " | |
1560 | "rc = [%d]\n", rc); | |
1561 | goto out_free; | |
237fead6 | 1562 | } |
237fead6 MH |
1563 | out_free: |
1564 | kmem_cache_free(ecryptfs_header_cache_0, page_virt); | |
1565 | out: | |
1566 | return rc; | |
1567 | } | |
1568 | ||
dd2a3b7a MH |
1569 | #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0 |
1570 | #define ECRYPTFS_VALIDATE_HEADER_SIZE 1 | |
237fead6 | 1571 | static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat, |
dd2a3b7a MH |
1572 | char *virt, int *bytes_read, |
1573 | int validate_header_size) | |
237fead6 MH |
1574 | { |
1575 | int rc = 0; | |
1576 | u32 header_extent_size; | |
1577 | u16 num_header_extents_at_front; | |
1578 | ||
1579 | memcpy(&header_extent_size, virt, 4); | |
1580 | header_extent_size = be32_to_cpu(header_extent_size); | |
1581 | virt += 4; | |
1582 | memcpy(&num_header_extents_at_front, virt, 2); | |
1583 | num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front); | |
237fead6 MH |
1584 | crypt_stat->num_header_extents_at_front = |
1585 | (int)num_header_extents_at_front; | |
45eaab79 | 1586 | (*bytes_read) = (sizeof(u32) + sizeof(u16)); |
dd2a3b7a | 1587 | if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE) |
45eaab79 | 1588 | && ((crypt_stat->extent_size |
dd2a3b7a MH |
1589 | * crypt_stat->num_header_extents_at_front) |
1590 | < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) { | |
237fead6 | 1591 | rc = -EINVAL; |
45eaab79 MH |
1592 | printk(KERN_WARNING "Invalid number of header extents: [%zd]\n", |
1593 | crypt_stat->num_header_extents_at_front); | |
237fead6 MH |
1594 | } |
1595 | return rc; | |
1596 | } | |
1597 | ||
1598 | /** | |
1599 | * set_default_header_data | |
22e78faf | 1600 | * @crypt_stat: The cryptographic context |
237fead6 MH |
1601 | * |
1602 | * For version 0 file format; this function is only for backwards | |
1603 | * compatibility for files created with the prior versions of | |
1604 | * eCryptfs. | |
1605 | */ | |
1606 | static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) | |
1607 | { | |
45eaab79 | 1608 | crypt_stat->num_header_extents_at_front = 2; |
237fead6 MH |
1609 | } |
1610 | ||
1611 | /** | |
1612 | * ecryptfs_read_headers_virt | |
22e78faf MH |
1613 | * @page_virt: The virtual address into which to read the headers |
1614 | * @crypt_stat: The cryptographic context | |
1615 | * @ecryptfs_dentry: The eCryptfs dentry | |
1616 | * @validate_header_size: Whether to validate the header size while reading | |
237fead6 MH |
1617 | * |
1618 | * Read/parse the header data. The header format is detailed in the | |
1619 | * comment block for the ecryptfs_write_headers_virt() function. | |
1620 | * | |
1621 | * Returns zero on success | |
1622 | */ | |
1623 | static int ecryptfs_read_headers_virt(char *page_virt, | |
1624 | struct ecryptfs_crypt_stat *crypt_stat, | |
dd2a3b7a MH |
1625 | struct dentry *ecryptfs_dentry, |
1626 | int validate_header_size) | |
237fead6 MH |
1627 | { |
1628 | int rc = 0; | |
1629 | int offset; | |
1630 | int bytes_read; | |
1631 | ||
1632 | ecryptfs_set_default_sizes(crypt_stat); | |
1633 | crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private( | |
1634 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
1635 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
1636 | rc = contains_ecryptfs_marker(page_virt + offset); | |
1637 | if (rc == 0) { | |
1638 | rc = -EINVAL; | |
1639 | goto out; | |
1640 | } | |
1641 | offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; | |
1642 | rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset), | |
1643 | &bytes_read); | |
1644 | if (rc) { | |
1645 | ecryptfs_printk(KERN_WARNING, "Error processing flags\n"); | |
1646 | goto out; | |
1647 | } | |
1648 | if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) { | |
1649 | ecryptfs_printk(KERN_WARNING, "File version is [%d]; only " | |
1650 | "file version [%d] is supported by this " | |
1651 | "version of eCryptfs\n", | |
1652 | crypt_stat->file_version, | |
1653 | ECRYPTFS_SUPPORTED_FILE_VERSION); | |
1654 | rc = -EINVAL; | |
1655 | goto out; | |
1656 | } | |
1657 | offset += bytes_read; | |
1658 | if (crypt_stat->file_version >= 1) { | |
1659 | rc = parse_header_metadata(crypt_stat, (page_virt + offset), | |
dd2a3b7a | 1660 | &bytes_read, validate_header_size); |
237fead6 MH |
1661 | if (rc) { |
1662 | ecryptfs_printk(KERN_WARNING, "Error reading header " | |
1663 | "metadata; rc = [%d]\n", rc); | |
1664 | } | |
1665 | offset += bytes_read; | |
1666 | } else | |
1667 | set_default_header_data(crypt_stat); | |
1668 | rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), | |
1669 | ecryptfs_dentry); | |
1670 | out: | |
1671 | return rc; | |
1672 | } | |
1673 | ||
1674 | /** | |
dd2a3b7a | 1675 | * ecryptfs_read_xattr_region |
22e78faf | 1676 | * @page_virt: The vitual address into which to read the xattr data |
2ed92554 | 1677 | * @ecryptfs_inode: The eCryptfs inode |
dd2a3b7a MH |
1678 | * |
1679 | * Attempts to read the crypto metadata from the extended attribute | |
1680 | * region of the lower file. | |
22e78faf MH |
1681 | * |
1682 | * Returns zero on success; non-zero on error | |
dd2a3b7a | 1683 | */ |
d7cdc5fe | 1684 | int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode) |
dd2a3b7a | 1685 | { |
d7cdc5fe MH |
1686 | struct dentry *lower_dentry = |
1687 | ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry; | |
dd2a3b7a MH |
1688 | ssize_t size; |
1689 | int rc = 0; | |
1690 | ||
d7cdc5fe MH |
1691 | size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME, |
1692 | page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE); | |
dd2a3b7a | 1693 | if (size < 0) { |
d7cdc5fe | 1694 | printk(KERN_ERR "Error attempting to read the [%s] " |
dd2a3b7a MH |
1695 | "xattr from the lower file; return value = [%zd]\n", |
1696 | ECRYPTFS_XATTR_NAME, size); | |
1697 | rc = -EINVAL; | |
1698 | goto out; | |
1699 | } | |
1700 | out: | |
1701 | return rc; | |
1702 | } | |
1703 | ||
1704 | int ecryptfs_read_and_validate_xattr_region(char *page_virt, | |
1705 | struct dentry *ecryptfs_dentry) | |
1706 | { | |
1707 | int rc; | |
1708 | ||
d7cdc5fe | 1709 | rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode); |
dd2a3b7a MH |
1710 | if (rc) |
1711 | goto out; | |
1712 | if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) { | |
1713 | printk(KERN_WARNING "Valid data found in [%s] xattr, but " | |
1714 | "the marker is invalid\n", ECRYPTFS_XATTR_NAME); | |
1715 | rc = -EINVAL; | |
1716 | } | |
1717 | out: | |
1718 | return rc; | |
1719 | } | |
1720 | ||
1721 | /** | |
1722 | * ecryptfs_read_metadata | |
1723 | * | |
1724 | * Common entry point for reading file metadata. From here, we could | |
1725 | * retrieve the header information from the header region of the file, | |
1726 | * the xattr region of the file, or some other repostory that is | |
1727 | * stored separately from the file itself. The current implementation | |
1728 | * supports retrieving the metadata information from the file contents | |
1729 | * and from the xattr region. | |
237fead6 MH |
1730 | * |
1731 | * Returns zero if valid headers found and parsed; non-zero otherwise | |
1732 | */ | |
d7cdc5fe | 1733 | int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) |
237fead6 MH |
1734 | { |
1735 | int rc = 0; | |
1736 | char *page_virt = NULL; | |
d7cdc5fe | 1737 | struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode; |
237fead6 | 1738 | struct ecryptfs_crypt_stat *crypt_stat = |
d7cdc5fe | 1739 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
e77a56dd MH |
1740 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
1741 | &ecryptfs_superblock_to_private( | |
1742 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
237fead6 | 1743 | |
e77a56dd MH |
1744 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
1745 | mount_crypt_stat); | |
237fead6 | 1746 | /* Read the first page from the underlying file */ |
f7267c0c | 1747 | page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER); |
237fead6 MH |
1748 | if (!page_virt) { |
1749 | rc = -ENOMEM; | |
d7cdc5fe MH |
1750 | printk(KERN_ERR "%s: Unable to allocate page_virt\n", |
1751 | __FUNCTION__); | |
237fead6 MH |
1752 | goto out; |
1753 | } | |
d7cdc5fe MH |
1754 | rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size, |
1755 | ecryptfs_inode); | |
1756 | if (!rc) | |
1757 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, | |
1758 | ecryptfs_dentry, | |
1759 | ECRYPTFS_VALIDATE_HEADER_SIZE); | |
237fead6 | 1760 | if (rc) { |
d7cdc5fe | 1761 | rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode); |
dd2a3b7a MH |
1762 | if (rc) { |
1763 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " | |
1764 | "file header region or xattr region\n"); | |
1765 | rc = -EINVAL; | |
1766 | goto out; | |
1767 | } | |
1768 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, | |
1769 | ecryptfs_dentry, | |
1770 | ECRYPTFS_DONT_VALIDATE_HEADER_SIZE); | |
1771 | if (rc) { | |
1772 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " | |
1773 | "file xattr region either\n"); | |
1774 | rc = -EINVAL; | |
1775 | } | |
1776 | if (crypt_stat->mount_crypt_stat->flags | |
1777 | & ECRYPTFS_XATTR_METADATA_ENABLED) { | |
1778 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
1779 | } else { | |
1780 | printk(KERN_WARNING "Attempt to access file with " | |
1781 | "crypto metadata only in the extended attribute " | |
1782 | "region, but eCryptfs was mounted without " | |
1783 | "xattr support enabled. eCryptfs will not treat " | |
1784 | "this like an encrypted file.\n"); | |
1785 | rc = -EINVAL; | |
1786 | } | |
237fead6 MH |
1787 | } |
1788 | out: | |
1789 | if (page_virt) { | |
1790 | memset(page_virt, 0, PAGE_CACHE_SIZE); | |
1791 | kmem_cache_free(ecryptfs_header_cache_1, page_virt); | |
1792 | } | |
1793 | return rc; | |
1794 | } | |
1795 | ||
1796 | /** | |
1797 | * ecryptfs_encode_filename - converts a plaintext file name to cipher text | |
1798 | * @crypt_stat: The crypt_stat struct associated with the file anem to encode | |
1799 | * @name: The plaintext name | |
1800 | * @length: The length of the plaintext | |
1801 | * @encoded_name: The encypted name | |
1802 | * | |
1803 | * Encrypts and encodes a filename into something that constitutes a | |
1804 | * valid filename for a filesystem, with printable characters. | |
1805 | * | |
1806 | * We assume that we have a properly initialized crypto context, | |
1807 | * pointed to by crypt_stat->tfm. | |
1808 | * | |
1809 | * TODO: Implement filename decoding and decryption here, in place of | |
1810 | * memcpy. We are keeping the framework around for now to (1) | |
1811 | * facilitate testing of the components needed to implement filename | |
1812 | * encryption and (2) to provide a code base from which other | |
1813 | * developers in the community can easily implement this feature. | |
1814 | * | |
1815 | * Returns the length of encoded filename; negative if error | |
1816 | */ | |
1817 | int | |
1818 | ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat, | |
1819 | const char *name, int length, char **encoded_name) | |
1820 | { | |
1821 | int error = 0; | |
1822 | ||
1823 | (*encoded_name) = kmalloc(length + 2, GFP_KERNEL); | |
1824 | if (!(*encoded_name)) { | |
1825 | error = -ENOMEM; | |
1826 | goto out; | |
1827 | } | |
1828 | /* TODO: Filename encryption is a scheduled feature for a | |
1829 | * future version of eCryptfs. This function is here only for | |
1830 | * the purpose of providing a framework for other developers | |
1831 | * to easily implement filename encryption. Hint: Replace this | |
1832 | * memcpy() with a call to encrypt and encode the | |
1833 | * filename, the set the length accordingly. */ | |
1834 | memcpy((void *)(*encoded_name), (void *)name, length); | |
1835 | (*encoded_name)[length] = '\0'; | |
1836 | error = length + 1; | |
1837 | out: | |
1838 | return error; | |
1839 | } | |
1840 | ||
1841 | /** | |
1842 | * ecryptfs_decode_filename - converts the cipher text name to plaintext | |
1843 | * @crypt_stat: The crypt_stat struct associated with the file | |
1844 | * @name: The filename in cipher text | |
1845 | * @length: The length of the cipher text name | |
1846 | * @decrypted_name: The plaintext name | |
1847 | * | |
1848 | * Decodes and decrypts the filename. | |
1849 | * | |
1850 | * We assume that we have a properly initialized crypto context, | |
1851 | * pointed to by crypt_stat->tfm. | |
1852 | * | |
1853 | * TODO: Implement filename decoding and decryption here, in place of | |
1854 | * memcpy. We are keeping the framework around for now to (1) | |
1855 | * facilitate testing of the components needed to implement filename | |
1856 | * encryption and (2) to provide a code base from which other | |
1857 | * developers in the community can easily implement this feature. | |
1858 | * | |
1859 | * Returns the length of decoded filename; negative if error | |
1860 | */ | |
1861 | int | |
1862 | ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat, | |
1863 | const char *name, int length, char **decrypted_name) | |
1864 | { | |
1865 | int error = 0; | |
1866 | ||
1867 | (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL); | |
1868 | if (!(*decrypted_name)) { | |
1869 | error = -ENOMEM; | |
1870 | goto out; | |
1871 | } | |
1872 | /* TODO: Filename encryption is a scheduled feature for a | |
1873 | * future version of eCryptfs. This function is here only for | |
1874 | * the purpose of providing a framework for other developers | |
1875 | * to easily implement filename encryption. Hint: Replace this | |
1876 | * memcpy() with a call to decode and decrypt the | |
1877 | * filename, the set the length accordingly. */ | |
1878 | memcpy((void *)(*decrypted_name), (void *)name, length); | |
1879 | (*decrypted_name)[length + 1] = '\0'; /* Only for convenience | |
1880 | * in printing out the | |
1881 | * string in debug | |
1882 | * messages */ | |
1883 | error = length; | |
1884 | out: | |
1885 | return error; | |
1886 | } | |
1887 | ||
1888 | /** | |
f4aad16a | 1889 | * ecryptfs_process_key_cipher - Perform key cipher initialization. |
237fead6 | 1890 | * @key_tfm: Crypto context for key material, set by this function |
e5d9cbde MH |
1891 | * @cipher_name: Name of the cipher |
1892 | * @key_size: Size of the key in bytes | |
237fead6 MH |
1893 | * |
1894 | * Returns zero on success. Any crypto_tfm structs allocated here | |
1895 | * should be released by other functions, such as on a superblock put | |
1896 | * event, regardless of whether this function succeeds for fails. | |
1897 | */ | |
cd9d67df | 1898 | static int |
f4aad16a MH |
1899 | ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm, |
1900 | char *cipher_name, size_t *key_size) | |
237fead6 MH |
1901 | { |
1902 | char dummy_key[ECRYPTFS_MAX_KEY_BYTES]; | |
8bba066f | 1903 | char *full_alg_name; |
237fead6 MH |
1904 | int rc; |
1905 | ||
e5d9cbde MH |
1906 | *key_tfm = NULL; |
1907 | if (*key_size > ECRYPTFS_MAX_KEY_BYTES) { | |
237fead6 MH |
1908 | rc = -EINVAL; |
1909 | printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum " | |
e5d9cbde | 1910 | "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES); |
237fead6 MH |
1911 | goto out; |
1912 | } | |
8bba066f MH |
1913 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name, |
1914 | "ecb"); | |
1915 | if (rc) | |
1916 | goto out; | |
1917 | *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC); | |
1918 | kfree(full_alg_name); | |
1919 | if (IS_ERR(*key_tfm)) { | |
1920 | rc = PTR_ERR(*key_tfm); | |
237fead6 | 1921 | printk(KERN_ERR "Unable to allocate crypto cipher with name " |
8bba066f | 1922 | "[%s]; rc = [%d]\n", cipher_name, rc); |
237fead6 MH |
1923 | goto out; |
1924 | } | |
8bba066f MH |
1925 | crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY); |
1926 | if (*key_size == 0) { | |
1927 | struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm); | |
1928 | ||
1929 | *key_size = alg->max_keysize; | |
1930 | } | |
e5d9cbde | 1931 | get_random_bytes(dummy_key, *key_size); |
8bba066f | 1932 | rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size); |
237fead6 MH |
1933 | if (rc) { |
1934 | printk(KERN_ERR "Error attempting to set key of size [%Zd] for " | |
e5d9cbde | 1935 | "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc); |
237fead6 MH |
1936 | rc = -EINVAL; |
1937 | goto out; | |
1938 | } | |
1939 | out: | |
1940 | return rc; | |
1941 | } | |
f4aad16a MH |
1942 | |
1943 | struct kmem_cache *ecryptfs_key_tfm_cache; | |
1944 | struct list_head key_tfm_list; | |
1945 | struct mutex key_tfm_list_mutex; | |
1946 | ||
1947 | int ecryptfs_init_crypto(void) | |
1948 | { | |
1949 | mutex_init(&key_tfm_list_mutex); | |
1950 | INIT_LIST_HEAD(&key_tfm_list); | |
1951 | return 0; | |
1952 | } | |
1953 | ||
fcd12835 | 1954 | int ecryptfs_destroy_crypto(void) |
f4aad16a MH |
1955 | { |
1956 | struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp; | |
1957 | ||
1958 | mutex_lock(&key_tfm_list_mutex); | |
1959 | list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list, | |
1960 | key_tfm_list) { | |
1961 | list_del(&key_tfm->key_tfm_list); | |
1962 | if (key_tfm->key_tfm) | |
1963 | crypto_free_blkcipher(key_tfm->key_tfm); | |
1964 | kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm); | |
1965 | } | |
1966 | mutex_unlock(&key_tfm_list_mutex); | |
1967 | return 0; | |
1968 | } | |
1969 | ||
1970 | int | |
1971 | ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name, | |
1972 | size_t key_size) | |
1973 | { | |
1974 | struct ecryptfs_key_tfm *tmp_tfm; | |
1975 | int rc = 0; | |
1976 | ||
1977 | tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL); | |
1978 | if (key_tfm != NULL) | |
1979 | (*key_tfm) = tmp_tfm; | |
1980 | if (!tmp_tfm) { | |
1981 | rc = -ENOMEM; | |
1982 | printk(KERN_ERR "Error attempting to allocate from " | |
1983 | "ecryptfs_key_tfm_cache\n"); | |
1984 | goto out; | |
1985 | } | |
1986 | mutex_init(&tmp_tfm->key_tfm_mutex); | |
1987 | strncpy(tmp_tfm->cipher_name, cipher_name, | |
1988 | ECRYPTFS_MAX_CIPHER_NAME_SIZE); | |
1989 | tmp_tfm->key_size = key_size; | |
5dda6992 MH |
1990 | rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm, |
1991 | tmp_tfm->cipher_name, | |
1992 | &tmp_tfm->key_size); | |
1993 | if (rc) { | |
f4aad16a MH |
1994 | printk(KERN_ERR "Error attempting to initialize key TFM " |
1995 | "cipher with name = [%s]; rc = [%d]\n", | |
1996 | tmp_tfm->cipher_name, rc); | |
1997 | kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm); | |
1998 | if (key_tfm != NULL) | |
1999 | (*key_tfm) = NULL; | |
2000 | goto out; | |
2001 | } | |
2002 | mutex_lock(&key_tfm_list_mutex); | |
2003 | list_add(&tmp_tfm->key_tfm_list, &key_tfm_list); | |
2004 | mutex_unlock(&key_tfm_list_mutex); | |
2005 | out: | |
2006 | return rc; | |
2007 | } | |
2008 | ||
2009 | int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm, | |
2010 | struct mutex **tfm_mutex, | |
2011 | char *cipher_name) | |
2012 | { | |
2013 | struct ecryptfs_key_tfm *key_tfm; | |
2014 | int rc = 0; | |
2015 | ||
2016 | (*tfm) = NULL; | |
2017 | (*tfm_mutex) = NULL; | |
2018 | mutex_lock(&key_tfm_list_mutex); | |
2019 | list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) { | |
2020 | if (strcmp(key_tfm->cipher_name, cipher_name) == 0) { | |
2021 | (*tfm) = key_tfm->key_tfm; | |
2022 | (*tfm_mutex) = &key_tfm->key_tfm_mutex; | |
2023 | mutex_unlock(&key_tfm_list_mutex); | |
2024 | goto out; | |
2025 | } | |
2026 | } | |
2027 | mutex_unlock(&key_tfm_list_mutex); | |
5dda6992 MH |
2028 | rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0); |
2029 | if (rc) { | |
f4aad16a MH |
2030 | printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n", |
2031 | rc); | |
2032 | goto out; | |
2033 | } | |
2034 | (*tfm) = key_tfm->key_tfm; | |
2035 | (*tfm_mutex) = &key_tfm->key_tfm_mutex; | |
2036 | out: | |
2037 | return rc; | |
2038 | } |