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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 | |
6 | * Copyright (C) 2004-2006 International Business Machines Corp. | |
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 | ||
8bba066f MH |
126 | int ecryptfs_crypto_api_algify_cipher_name(char **algified_name, |
127 | char *cipher_name, | |
128 | char *chaining_modifier) | |
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 | |
152 | * @offset: Offset of the page whose's iv we are to derive | |
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, | |
160 | pgoff_t offset) | |
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); | |
176 | snprintf((src + crypt_stat->iv_bytes), 16, "%ld", offset); | |
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)); | |
207 | mutex_init(&crypt_stat->cs_mutex); | |
208 | mutex_init(&crypt_stat->cs_tfm_mutex); | |
565d9724 | 209 | mutex_init(&crypt_stat->cs_hash_tfm_mutex); |
237fead6 MH |
210 | ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_STRUCT_INITIALIZED); |
211 | } | |
212 | ||
213 | /** | |
214 | * ecryptfs_destruct_crypt_stat | |
215 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. | |
216 | * | |
217 | * Releases all memory associated with a crypt_stat struct. | |
218 | */ | |
219 | void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) | |
220 | { | |
221 | if (crypt_stat->tfm) | |
8bba066f | 222 | crypto_free_blkcipher(crypt_stat->tfm); |
565d9724 MH |
223 | if (crypt_stat->hash_tfm) |
224 | crypto_free_hash(crypt_stat->hash_tfm); | |
237fead6 MH |
225 | memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
226 | } | |
227 | ||
228 | void ecryptfs_destruct_mount_crypt_stat( | |
229 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
230 | { | |
231 | if (mount_crypt_stat->global_auth_tok_key) | |
232 | key_put(mount_crypt_stat->global_auth_tok_key); | |
233 | if (mount_crypt_stat->global_key_tfm) | |
8bba066f | 234 | crypto_free_blkcipher(mount_crypt_stat->global_key_tfm); |
237fead6 MH |
235 | memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat)); |
236 | } | |
237 | ||
238 | /** | |
239 | * virt_to_scatterlist | |
240 | * @addr: Virtual address | |
241 | * @size: Size of data; should be an even multiple of the block size | |
242 | * @sg: Pointer to scatterlist array; set to NULL to obtain only | |
243 | * the number of scatterlist structs required in array | |
244 | * @sg_size: Max array size | |
245 | * | |
246 | * Fills in a scatterlist array with page references for a passed | |
247 | * virtual address. | |
248 | * | |
249 | * Returns the number of scatterlist structs in array used | |
250 | */ | |
251 | int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg, | |
252 | int sg_size) | |
253 | { | |
254 | int i = 0; | |
255 | struct page *pg; | |
256 | int offset; | |
257 | int remainder_of_page; | |
258 | ||
259 | while (size > 0 && i < sg_size) { | |
260 | pg = virt_to_page(addr); | |
261 | offset = offset_in_page(addr); | |
262 | if (sg) { | |
263 | sg[i].page = pg; | |
264 | sg[i].offset = offset; | |
265 | } | |
266 | remainder_of_page = PAGE_CACHE_SIZE - offset; | |
267 | if (size >= remainder_of_page) { | |
268 | if (sg) | |
269 | sg[i].length = remainder_of_page; | |
270 | addr += remainder_of_page; | |
271 | size -= remainder_of_page; | |
272 | } else { | |
273 | if (sg) | |
274 | sg[i].length = size; | |
275 | addr += size; | |
276 | size = 0; | |
277 | } | |
278 | i++; | |
279 | } | |
280 | if (size > 0) | |
281 | return -ENOMEM; | |
282 | return i; | |
283 | } | |
284 | ||
285 | /** | |
286 | * encrypt_scatterlist | |
287 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. | |
288 | * @dest_sg: Destination of encrypted data | |
289 | * @src_sg: Data to be encrypted | |
290 | * @size: Length of data to be encrypted | |
291 | * @iv: iv to use during encryption | |
292 | * | |
293 | * Returns the number of bytes encrypted; negative value on error | |
294 | */ | |
295 | static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, | |
296 | struct scatterlist *dest_sg, | |
297 | struct scatterlist *src_sg, int size, | |
298 | unsigned char *iv) | |
299 | { | |
8bba066f MH |
300 | struct blkcipher_desc desc = { |
301 | .tfm = crypt_stat->tfm, | |
302 | .info = iv, | |
303 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP | |
304 | }; | |
237fead6 MH |
305 | int rc = 0; |
306 | ||
307 | BUG_ON(!crypt_stat || !crypt_stat->tfm | |
308 | || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags, | |
309 | ECRYPTFS_STRUCT_INITIALIZED)); | |
310 | if (unlikely(ecryptfs_verbosity > 0)) { | |
311 | ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n", | |
312 | crypt_stat->key_size); | |
313 | ecryptfs_dump_hex(crypt_stat->key, | |
314 | crypt_stat->key_size); | |
315 | } | |
316 | /* Consider doing this once, when the file is opened */ | |
317 | mutex_lock(&crypt_stat->cs_tfm_mutex); | |
8bba066f MH |
318 | rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
319 | crypt_stat->key_size); | |
237fead6 MH |
320 | if (rc) { |
321 | ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n", | |
322 | rc); | |
323 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
324 | rc = -EINVAL; | |
325 | goto out; | |
326 | } | |
327 | ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size); | |
8bba066f | 328 | crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size); |
237fead6 MH |
329 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
330 | out: | |
331 | return rc; | |
332 | } | |
333 | ||
334 | static void | |
335 | ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx, | |
336 | int *byte_offset, | |
337 | struct ecryptfs_crypt_stat *crypt_stat, | |
338 | unsigned long extent_num) | |
339 | { | |
340 | unsigned long lower_extent_num; | |
341 | int extents_occupied_by_headers_at_front; | |
342 | int bytes_occupied_by_headers_at_front; | |
343 | int extent_offset; | |
344 | int extents_per_page; | |
345 | ||
346 | bytes_occupied_by_headers_at_front = | |
347 | ( crypt_stat->header_extent_size | |
348 | * crypt_stat->num_header_extents_at_front ); | |
349 | extents_occupied_by_headers_at_front = | |
350 | ( bytes_occupied_by_headers_at_front | |
351 | / crypt_stat->extent_size ); | |
352 | lower_extent_num = extents_occupied_by_headers_at_front + extent_num; | |
353 | extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; | |
354 | (*lower_page_idx) = lower_extent_num / extents_per_page; | |
355 | extent_offset = lower_extent_num % extents_per_page; | |
356 | (*byte_offset) = extent_offset * crypt_stat->extent_size; | |
357 | ecryptfs_printk(KERN_DEBUG, " * crypt_stat->header_extent_size = " | |
358 | "[%d]\n", crypt_stat->header_extent_size); | |
359 | ecryptfs_printk(KERN_DEBUG, " * crypt_stat->" | |
360 | "num_header_extents_at_front = [%d]\n", | |
361 | crypt_stat->num_header_extents_at_front); | |
362 | ecryptfs_printk(KERN_DEBUG, " * extents_occupied_by_headers_at_" | |
363 | "front = [%d]\n", extents_occupied_by_headers_at_front); | |
364 | ecryptfs_printk(KERN_DEBUG, " * lower_extent_num = [0x%.16x]\n", | |
365 | lower_extent_num); | |
366 | ecryptfs_printk(KERN_DEBUG, " * extents_per_page = [%d]\n", | |
367 | extents_per_page); | |
368 | ecryptfs_printk(KERN_DEBUG, " * (*lower_page_idx) = [0x%.16x]\n", | |
369 | (*lower_page_idx)); | |
370 | ecryptfs_printk(KERN_DEBUG, " * extent_offset = [%d]\n", | |
371 | extent_offset); | |
372 | ecryptfs_printk(KERN_DEBUG, " * (*byte_offset) = [%d]\n", | |
373 | (*byte_offset)); | |
374 | } | |
375 | ||
376 | static int ecryptfs_write_out_page(struct ecryptfs_page_crypt_context *ctx, | |
377 | struct page *lower_page, | |
378 | struct inode *lower_inode, | |
379 | int byte_offset_in_page, int bytes_to_write) | |
380 | { | |
381 | int rc = 0; | |
382 | ||
383 | if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) { | |
384 | rc = ecryptfs_commit_lower_page(lower_page, lower_inode, | |
385 | ctx->param.lower_file, | |
386 | byte_offset_in_page, | |
387 | bytes_to_write); | |
388 | if (rc) { | |
389 | ecryptfs_printk(KERN_ERR, "Error calling lower " | |
390 | "commit; rc = [%d]\n", rc); | |
391 | goto out; | |
392 | } | |
393 | } else { | |
394 | rc = ecryptfs_writepage_and_release_lower_page(lower_page, | |
395 | lower_inode, | |
396 | ctx->param.wbc); | |
397 | if (rc) { | |
398 | ecryptfs_printk(KERN_ERR, "Error calling lower " | |
399 | "writepage(); rc = [%d]\n", rc); | |
400 | goto out; | |
401 | } | |
402 | } | |
403 | out: | |
404 | return rc; | |
405 | } | |
406 | ||
407 | static int ecryptfs_read_in_page(struct ecryptfs_page_crypt_context *ctx, | |
408 | struct page **lower_page, | |
409 | struct inode *lower_inode, | |
410 | unsigned long lower_page_idx, | |
411 | int byte_offset_in_page) | |
412 | { | |
413 | int rc = 0; | |
414 | ||
415 | if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) { | |
416 | /* TODO: Limit this to only the data extents that are | |
417 | * needed */ | |
418 | rc = ecryptfs_get_lower_page(lower_page, lower_inode, | |
419 | ctx->param.lower_file, | |
420 | lower_page_idx, | |
421 | byte_offset_in_page, | |
422 | (PAGE_CACHE_SIZE | |
423 | - byte_offset_in_page)); | |
424 | if (rc) { | |
425 | ecryptfs_printk( | |
426 | KERN_ERR, "Error attempting to grab, map, " | |
427 | "and prepare_write lower page with index " | |
428 | "[0x%.16x]; rc = [%d]\n", lower_page_idx, rc); | |
429 | goto out; | |
430 | } | |
431 | } else { | |
432 | rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL, | |
433 | lower_inode, | |
434 | lower_page_idx); | |
435 | if (rc) { | |
436 | ecryptfs_printk( | |
437 | KERN_ERR, "Error attempting to grab and map " | |
438 | "lower page with index [0x%.16x]; rc = [%d]\n", | |
439 | lower_page_idx, rc); | |
440 | goto out; | |
441 | } | |
442 | } | |
443 | out: | |
444 | return rc; | |
445 | } | |
446 | ||
447 | /** | |
448 | * ecryptfs_encrypt_page | |
449 | * @ctx: The context of the page | |
450 | * | |
451 | * Encrypt an eCryptfs page. This is done on a per-extent basis. Note | |
452 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
453 | * if the file was created on a machine with an 8K page size | |
454 | * (resulting in an 8K header), and then the file is copied onto a | |
455 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
456 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
457 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
458 | * | |
459 | * The actual operations performed on each page depends on the | |
460 | * contents of the ecryptfs_page_crypt_context struct. | |
461 | * | |
462 | * Returns zero on success; negative on error | |
463 | */ | |
464 | int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx) | |
465 | { | |
466 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; | |
467 | unsigned long base_extent; | |
468 | unsigned long extent_offset = 0; | |
469 | unsigned long lower_page_idx = 0; | |
470 | unsigned long prior_lower_page_idx = 0; | |
471 | struct page *lower_page; | |
472 | struct inode *lower_inode; | |
473 | struct ecryptfs_inode_info *inode_info; | |
474 | struct ecryptfs_crypt_stat *crypt_stat; | |
475 | int rc = 0; | |
476 | int lower_byte_offset = 0; | |
477 | int orig_byte_offset = 0; | |
478 | int num_extents_per_page; | |
479 | #define ECRYPTFS_PAGE_STATE_UNREAD 0 | |
480 | #define ECRYPTFS_PAGE_STATE_READ 1 | |
481 | #define ECRYPTFS_PAGE_STATE_MODIFIED 2 | |
482 | #define ECRYPTFS_PAGE_STATE_WRITTEN 3 | |
483 | int page_state; | |
484 | ||
485 | lower_inode = ecryptfs_inode_to_lower(ctx->page->mapping->host); | |
486 | inode_info = ecryptfs_inode_to_private(ctx->page->mapping->host); | |
487 | crypt_stat = &inode_info->crypt_stat; | |
488 | if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)) { | |
489 | rc = ecryptfs_copy_page_to_lower(ctx->page, lower_inode, | |
490 | ctx->param.lower_file); | |
491 | if (rc) | |
492 | ecryptfs_printk(KERN_ERR, "Error attempting to copy " | |
493 | "page at index [0x%.16x]\n", | |
494 | ctx->page->index); | |
495 | goto out; | |
496 | } | |
497 | num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; | |
498 | base_extent = (ctx->page->index * num_extents_per_page); | |
499 | page_state = ECRYPTFS_PAGE_STATE_UNREAD; | |
500 | while (extent_offset < num_extents_per_page) { | |
501 | ecryptfs_extent_to_lwr_pg_idx_and_offset( | |
502 | &lower_page_idx, &lower_byte_offset, crypt_stat, | |
503 | (base_extent + extent_offset)); | |
504 | if (prior_lower_page_idx != lower_page_idx | |
505 | && page_state == ECRYPTFS_PAGE_STATE_MODIFIED) { | |
506 | rc = ecryptfs_write_out_page(ctx, lower_page, | |
507 | lower_inode, | |
508 | orig_byte_offset, | |
509 | (PAGE_CACHE_SIZE | |
510 | - orig_byte_offset)); | |
511 | if (rc) { | |
512 | ecryptfs_printk(KERN_ERR, "Error attempting " | |
513 | "to write out page; rc = [%d]" | |
514 | "\n", rc); | |
515 | goto out; | |
516 | } | |
517 | page_state = ECRYPTFS_PAGE_STATE_WRITTEN; | |
518 | } | |
519 | if (page_state == ECRYPTFS_PAGE_STATE_UNREAD | |
520 | || page_state == ECRYPTFS_PAGE_STATE_WRITTEN) { | |
521 | rc = ecryptfs_read_in_page(ctx, &lower_page, | |
522 | lower_inode, lower_page_idx, | |
523 | lower_byte_offset); | |
524 | if (rc) { | |
525 | ecryptfs_printk(KERN_ERR, "Error attempting " | |
526 | "to read in lower page with " | |
527 | "index [0x%.16x]; rc = [%d]\n", | |
528 | lower_page_idx, rc); | |
529 | goto out; | |
530 | } | |
531 | orig_byte_offset = lower_byte_offset; | |
532 | prior_lower_page_idx = lower_page_idx; | |
533 | page_state = ECRYPTFS_PAGE_STATE_READ; | |
534 | } | |
535 | BUG_ON(!(page_state == ECRYPTFS_PAGE_STATE_MODIFIED | |
536 | || page_state == ECRYPTFS_PAGE_STATE_READ)); | |
537 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, | |
538 | (base_extent + extent_offset)); | |
539 | if (rc) { | |
540 | ecryptfs_printk(KERN_ERR, "Error attempting to " | |
541 | "derive IV for extent [0x%.16x]; " | |
542 | "rc = [%d]\n", | |
543 | (base_extent + extent_offset), rc); | |
544 | goto out; | |
545 | } | |
546 | if (unlikely(ecryptfs_verbosity > 0)) { | |
547 | ecryptfs_printk(KERN_DEBUG, "Encrypting extent " | |
548 | "with iv:\n"); | |
549 | ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); | |
550 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " | |
551 | "encryption:\n"); | |
552 | ecryptfs_dump_hex((char *) | |
553 | (page_address(ctx->page) | |
554 | + (extent_offset | |
555 | * crypt_stat->extent_size)), 8); | |
556 | } | |
557 | rc = ecryptfs_encrypt_page_offset( | |
558 | crypt_stat, lower_page, lower_byte_offset, ctx->page, | |
559 | (extent_offset * crypt_stat->extent_size), | |
560 | crypt_stat->extent_size, extent_iv); | |
561 | ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; " | |
562 | "rc = [%d]\n", | |
563 | (base_extent + extent_offset), rc); | |
564 | if (unlikely(ecryptfs_verbosity > 0)) { | |
565 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " | |
566 | "encryption:\n"); | |
567 | ecryptfs_dump_hex((char *)(page_address(lower_page) | |
568 | + lower_byte_offset), 8); | |
569 | } | |
570 | page_state = ECRYPTFS_PAGE_STATE_MODIFIED; | |
571 | extent_offset++; | |
572 | } | |
573 | BUG_ON(orig_byte_offset != 0); | |
574 | rc = ecryptfs_write_out_page(ctx, lower_page, lower_inode, 0, | |
575 | (lower_byte_offset | |
576 | + crypt_stat->extent_size)); | |
577 | if (rc) { | |
578 | ecryptfs_printk(KERN_ERR, "Error attempting to write out " | |
579 | "page; rc = [%d]\n", rc); | |
580 | goto out; | |
581 | } | |
582 | out: | |
583 | return rc; | |
584 | } | |
585 | ||
586 | /** | |
587 | * ecryptfs_decrypt_page | |
588 | * @file: The ecryptfs file | |
589 | * @page: The page in ecryptfs to decrypt | |
590 | * | |
591 | * Decrypt an eCryptfs page. This is done on a per-extent basis. Note | |
592 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
593 | * if the file was created on a machine with an 8K page size | |
594 | * (resulting in an 8K header), and then the file is copied onto a | |
595 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
596 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
597 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
598 | * | |
599 | * Returns zero on success; negative on error | |
600 | */ | |
601 | int ecryptfs_decrypt_page(struct file *file, struct page *page) | |
602 | { | |
603 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; | |
604 | unsigned long base_extent; | |
605 | unsigned long extent_offset = 0; | |
606 | unsigned long lower_page_idx = 0; | |
607 | unsigned long prior_lower_page_idx = 0; | |
608 | struct page *lower_page; | |
609 | char *lower_page_virt = NULL; | |
610 | struct inode *lower_inode; | |
611 | struct ecryptfs_crypt_stat *crypt_stat; | |
612 | int rc = 0; | |
613 | int byte_offset; | |
614 | int num_extents_per_page; | |
615 | int page_state; | |
616 | ||
617 | crypt_stat = &(ecryptfs_inode_to_private( | |
618 | page->mapping->host)->crypt_stat); | |
619 | lower_inode = ecryptfs_inode_to_lower(page->mapping->host); | |
620 | if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)) { | |
621 | rc = ecryptfs_do_readpage(file, page, page->index); | |
622 | if (rc) | |
623 | ecryptfs_printk(KERN_ERR, "Error attempting to copy " | |
624 | "page at index [0x%.16x]\n", | |
625 | page->index); | |
626 | goto out; | |
627 | } | |
628 | num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; | |
629 | base_extent = (page->index * num_extents_per_page); | |
630 | lower_page_virt = kmem_cache_alloc(ecryptfs_lower_page_cache, | |
e94b1766 | 631 | GFP_KERNEL); |
237fead6 MH |
632 | if (!lower_page_virt) { |
633 | rc = -ENOMEM; | |
634 | ecryptfs_printk(KERN_ERR, "Error getting page for encrypted " | |
635 | "lower page(s)\n"); | |
636 | goto out; | |
637 | } | |
638 | lower_page = virt_to_page(lower_page_virt); | |
639 | page_state = ECRYPTFS_PAGE_STATE_UNREAD; | |
640 | while (extent_offset < num_extents_per_page) { | |
641 | ecryptfs_extent_to_lwr_pg_idx_and_offset( | |
642 | &lower_page_idx, &byte_offset, crypt_stat, | |
643 | (base_extent + extent_offset)); | |
644 | if (prior_lower_page_idx != lower_page_idx | |
645 | || page_state == ECRYPTFS_PAGE_STATE_UNREAD) { | |
646 | rc = ecryptfs_do_readpage(file, lower_page, | |
647 | lower_page_idx); | |
648 | if (rc) { | |
649 | ecryptfs_printk(KERN_ERR, "Error reading " | |
650 | "lower encrypted page; rc = " | |
651 | "[%d]\n", rc); | |
652 | goto out; | |
653 | } | |
654 | prior_lower_page_idx = lower_page_idx; | |
655 | page_state = ECRYPTFS_PAGE_STATE_READ; | |
656 | } | |
657 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, | |
658 | (base_extent + extent_offset)); | |
659 | if (rc) { | |
660 | ecryptfs_printk(KERN_ERR, "Error attempting to " | |
661 | "derive IV for extent [0x%.16x]; rc = " | |
662 | "[%d]\n", | |
663 | (base_extent + extent_offset), rc); | |
664 | goto out; | |
665 | } | |
666 | if (unlikely(ecryptfs_verbosity > 0)) { | |
667 | ecryptfs_printk(KERN_DEBUG, "Decrypting extent " | |
668 | "with iv:\n"); | |
669 | ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); | |
670 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " | |
671 | "decryption:\n"); | |
672 | ecryptfs_dump_hex((lower_page_virt + byte_offset), 8); | |
673 | } | |
674 | rc = ecryptfs_decrypt_page_offset(crypt_stat, page, | |
675 | (extent_offset | |
676 | * crypt_stat->extent_size), | |
677 | lower_page, byte_offset, | |
678 | crypt_stat->extent_size, | |
679 | extent_iv); | |
680 | if (rc != crypt_stat->extent_size) { | |
681 | ecryptfs_printk(KERN_ERR, "Error attempting to " | |
682 | "decrypt extent [0x%.16x]\n", | |
683 | (base_extent + extent_offset)); | |
684 | goto out; | |
685 | } | |
686 | rc = 0; | |
687 | if (unlikely(ecryptfs_verbosity > 0)) { | |
688 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " | |
689 | "decryption:\n"); | |
690 | ecryptfs_dump_hex((char *)(page_address(page) | |
691 | + byte_offset), 8); | |
692 | } | |
693 | extent_offset++; | |
694 | } | |
695 | out: | |
696 | if (lower_page_virt) | |
697 | kmem_cache_free(ecryptfs_lower_page_cache, lower_page_virt); | |
698 | return rc; | |
699 | } | |
700 | ||
701 | /** | |
702 | * decrypt_scatterlist | |
703 | * | |
704 | * Returns the number of bytes decrypted; negative value on error | |
705 | */ | |
706 | static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, | |
707 | struct scatterlist *dest_sg, | |
708 | struct scatterlist *src_sg, int size, | |
709 | unsigned char *iv) | |
710 | { | |
8bba066f MH |
711 | struct blkcipher_desc desc = { |
712 | .tfm = crypt_stat->tfm, | |
713 | .info = iv, | |
714 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP | |
715 | }; | |
237fead6 MH |
716 | int rc = 0; |
717 | ||
718 | /* Consider doing this once, when the file is opened */ | |
719 | mutex_lock(&crypt_stat->cs_tfm_mutex); | |
8bba066f MH |
720 | rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
721 | crypt_stat->key_size); | |
237fead6 MH |
722 | if (rc) { |
723 | ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n", | |
724 | rc); | |
725 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
726 | rc = -EINVAL; | |
727 | goto out; | |
728 | } | |
729 | ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size); | |
8bba066f | 730 | rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size); |
237fead6 MH |
731 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
732 | if (rc) { | |
733 | ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n", | |
734 | rc); | |
735 | goto out; | |
736 | } | |
737 | rc = size; | |
738 | out: | |
739 | return rc; | |
740 | } | |
741 | ||
742 | /** | |
743 | * ecryptfs_encrypt_page_offset | |
744 | * | |
745 | * Returns the number of bytes encrypted | |
746 | */ | |
747 | static int | |
748 | ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, | |
749 | struct page *dst_page, int dst_offset, | |
750 | struct page *src_page, int src_offset, int size, | |
751 | unsigned char *iv) | |
752 | { | |
753 | struct scatterlist src_sg, dst_sg; | |
754 | ||
755 | src_sg.page = src_page; | |
756 | src_sg.offset = src_offset; | |
757 | src_sg.length = size; | |
758 | dst_sg.page = dst_page; | |
759 | dst_sg.offset = dst_offset; | |
760 | dst_sg.length = size; | |
761 | return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv); | |
762 | } | |
763 | ||
764 | /** | |
765 | * ecryptfs_decrypt_page_offset | |
766 | * | |
767 | * Returns the number of bytes decrypted | |
768 | */ | |
769 | static int | |
770 | ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, | |
771 | struct page *dst_page, int dst_offset, | |
772 | struct page *src_page, int src_offset, int size, | |
773 | unsigned char *iv) | |
774 | { | |
775 | struct scatterlist src_sg, dst_sg; | |
776 | ||
777 | src_sg.page = src_page; | |
778 | src_sg.offset = src_offset; | |
779 | src_sg.length = size; | |
780 | dst_sg.page = dst_page; | |
781 | dst_sg.offset = dst_offset; | |
782 | dst_sg.length = size; | |
783 | return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv); | |
784 | } | |
785 | ||
786 | #define ECRYPTFS_MAX_SCATTERLIST_LEN 4 | |
787 | ||
788 | /** | |
789 | * ecryptfs_init_crypt_ctx | |
790 | * @crypt_stat: Uninitilized crypt stats structure | |
791 | * | |
792 | * Initialize the crypto context. | |
793 | * | |
794 | * TODO: Performance: Keep a cache of initialized cipher contexts; | |
795 | * only init if needed | |
796 | */ | |
797 | int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat) | |
798 | { | |
8bba066f | 799 | char *full_alg_name; |
237fead6 MH |
800 | int rc = -EINVAL; |
801 | ||
802 | if (!crypt_stat->cipher) { | |
803 | ecryptfs_printk(KERN_ERR, "No cipher specified\n"); | |
804 | goto out; | |
805 | } | |
806 | ecryptfs_printk(KERN_DEBUG, | |
807 | "Initializing cipher [%s]; strlen = [%d]; " | |
808 | "key_size_bits = [%d]\n", | |
809 | crypt_stat->cipher, (int)strlen(crypt_stat->cipher), | |
810 | crypt_stat->key_size << 3); | |
811 | if (crypt_stat->tfm) { | |
812 | rc = 0; | |
813 | goto out; | |
814 | } | |
815 | mutex_lock(&crypt_stat->cs_tfm_mutex); | |
8bba066f MH |
816 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, |
817 | crypt_stat->cipher, "cbc"); | |
818 | if (rc) | |
819 | goto out; | |
820 | crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0, | |
821 | CRYPTO_ALG_ASYNC); | |
822 | kfree(full_alg_name); | |
de88777e AM |
823 | if (IS_ERR(crypt_stat->tfm)) { |
824 | rc = PTR_ERR(crypt_stat->tfm); | |
237fead6 MH |
825 | ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): " |
826 | "Error initializing cipher [%s]\n", | |
827 | crypt_stat->cipher); | |
8bba066f | 828 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
237fead6 MH |
829 | goto out; |
830 | } | |
f1ddcaf3 | 831 | crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY); |
8bba066f | 832 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
237fead6 MH |
833 | rc = 0; |
834 | out: | |
835 | return rc; | |
836 | } | |
837 | ||
838 | static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat) | |
839 | { | |
840 | int extent_size_tmp; | |
841 | ||
842 | crypt_stat->extent_mask = 0xFFFFFFFF; | |
843 | crypt_stat->extent_shift = 0; | |
844 | if (crypt_stat->extent_size == 0) | |
845 | return; | |
846 | extent_size_tmp = crypt_stat->extent_size; | |
847 | while ((extent_size_tmp & 0x01) == 0) { | |
848 | extent_size_tmp >>= 1; | |
849 | crypt_stat->extent_mask <<= 1; | |
850 | crypt_stat->extent_shift++; | |
851 | } | |
852 | } | |
853 | ||
854 | void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) | |
855 | { | |
856 | /* Default values; may be overwritten as we are parsing the | |
857 | * packets. */ | |
858 | crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; | |
859 | set_extent_mask_and_shift(crypt_stat); | |
860 | crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES; | |
861 | if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) { | |
862 | crypt_stat->header_extent_size = | |
863 | ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; | |
864 | } else | |
865 | crypt_stat->header_extent_size = PAGE_CACHE_SIZE; | |
866 | crypt_stat->num_header_extents_at_front = 1; | |
867 | } | |
868 | ||
869 | /** | |
870 | * ecryptfs_compute_root_iv | |
871 | * @crypt_stats | |
872 | * | |
873 | * On error, sets the root IV to all 0's. | |
874 | */ | |
875 | int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat) | |
876 | { | |
877 | int rc = 0; | |
878 | char dst[MD5_DIGEST_SIZE]; | |
879 | ||
880 | BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE); | |
881 | BUG_ON(crypt_stat->iv_bytes <= 0); | |
882 | if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID)) { | |
883 | rc = -EINVAL; | |
884 | ecryptfs_printk(KERN_WARNING, "Session key not valid; " | |
885 | "cannot generate root IV\n"); | |
886 | goto out; | |
887 | } | |
888 | rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key, | |
889 | crypt_stat->key_size); | |
890 | if (rc) { | |
891 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " | |
892 | "MD5 while generating root IV\n"); | |
893 | goto out; | |
894 | } | |
895 | memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes); | |
896 | out: | |
897 | if (rc) { | |
898 | memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes); | |
899 | ECRYPTFS_SET_FLAG(crypt_stat->flags, | |
900 | ECRYPTFS_SECURITY_WARNING); | |
901 | } | |
902 | return rc; | |
903 | } | |
904 | ||
905 | static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat) | |
906 | { | |
907 | get_random_bytes(crypt_stat->key, crypt_stat->key_size); | |
908 | ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID); | |
909 | ecryptfs_compute_root_iv(crypt_stat); | |
910 | if (unlikely(ecryptfs_verbosity > 0)) { | |
911 | ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n"); | |
912 | ecryptfs_dump_hex(crypt_stat->key, | |
913 | crypt_stat->key_size); | |
914 | } | |
915 | } | |
916 | ||
17398957 MH |
917 | /** |
918 | * ecryptfs_copy_mount_wide_flags_to_inode_flags | |
919 | * | |
920 | * This function propagates the mount-wide flags to individual inode | |
921 | * flags. | |
922 | */ | |
923 | static void ecryptfs_copy_mount_wide_flags_to_inode_flags( | |
924 | struct ecryptfs_crypt_stat *crypt_stat, | |
925 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
926 | { | |
927 | if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) | |
928 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
929 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) | |
930 | crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED; | |
931 | } | |
932 | ||
237fead6 MH |
933 | /** |
934 | * ecryptfs_set_default_crypt_stat_vals | |
935 | * @crypt_stat | |
936 | * | |
937 | * Default values in the event that policy does not override them. | |
938 | */ | |
939 | static void ecryptfs_set_default_crypt_stat_vals( | |
940 | struct ecryptfs_crypt_stat *crypt_stat, | |
941 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
942 | { | |
17398957 MH |
943 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
944 | mount_crypt_stat); | |
237fead6 MH |
945 | ecryptfs_set_default_sizes(crypt_stat); |
946 | strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER); | |
947 | crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES; | |
948 | ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID); | |
949 | crypt_stat->file_version = ECRYPTFS_FILE_VERSION; | |
950 | crypt_stat->mount_crypt_stat = mount_crypt_stat; | |
951 | } | |
952 | ||
953 | /** | |
954 | * ecryptfs_new_file_context | |
955 | * @ecryptfs_dentry | |
956 | * | |
957 | * If the crypto context for the file has not yet been established, | |
958 | * this is where we do that. Establishing a new crypto context | |
959 | * involves the following decisions: | |
960 | * - What cipher to use? | |
961 | * - What set of authentication tokens to use? | |
962 | * Here we just worry about getting enough information into the | |
963 | * authentication tokens so that we know that they are available. | |
964 | * We associate the available authentication tokens with the new file | |
965 | * via the set of signatures in the crypt_stat struct. Later, when | |
966 | * the headers are actually written out, we may again defer to | |
967 | * userspace to perform the encryption of the session key; for the | |
968 | * foreseeable future, this will be the case with public key packets. | |
969 | * | |
970 | * Returns zero on success; non-zero otherwise | |
971 | */ | |
972 | /* Associate an authentication token(s) with the file */ | |
973 | int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry) | |
974 | { | |
975 | int rc = 0; | |
976 | struct ecryptfs_crypt_stat *crypt_stat = | |
977 | &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; | |
978 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = | |
979 | &ecryptfs_superblock_to_private( | |
980 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
981 | int cipher_name_len; | |
982 | ||
983 | ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat); | |
984 | /* See if there are mount crypt options */ | |
985 | if (mount_crypt_stat->global_auth_tok) { | |
986 | ecryptfs_printk(KERN_DEBUG, "Initializing context for new " | |
987 | "file using mount_crypt_stat\n"); | |
988 | ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED); | |
989 | ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID); | |
17398957 MH |
990 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
991 | mount_crypt_stat); | |
237fead6 MH |
992 | memcpy(crypt_stat->keysigs[crypt_stat->num_keysigs++], |
993 | mount_crypt_stat->global_auth_tok_sig, | |
994 | ECRYPTFS_SIG_SIZE_HEX); | |
995 | cipher_name_len = | |
996 | strlen(mount_crypt_stat->global_default_cipher_name); | |
997 | memcpy(crypt_stat->cipher, | |
998 | mount_crypt_stat->global_default_cipher_name, | |
999 | cipher_name_len); | |
1000 | crypt_stat->cipher[cipher_name_len] = '\0'; | |
1001 | crypt_stat->key_size = | |
1002 | mount_crypt_stat->global_default_cipher_key_size; | |
1003 | ecryptfs_generate_new_key(crypt_stat); | |
1004 | } else | |
1005 | /* We should not encounter this scenario since we | |
1006 | * should detect lack of global_auth_tok at mount time | |
1007 | * TODO: Applies to 0.1 release only; remove in future | |
1008 | * release */ | |
1009 | BUG(); | |
1010 | rc = ecryptfs_init_crypt_ctx(crypt_stat); | |
1011 | if (rc) | |
1012 | ecryptfs_printk(KERN_ERR, "Error initializing cryptographic " | |
1013 | "context for cipher [%s]: rc = [%d]\n", | |
1014 | crypt_stat->cipher, rc); | |
1015 | return rc; | |
1016 | } | |
1017 | ||
1018 | /** | |
1019 | * contains_ecryptfs_marker - check for the ecryptfs marker | |
1020 | * @data: The data block in which to check | |
1021 | * | |
1022 | * Returns one if marker found; zero if not found | |
1023 | */ | |
1024 | int contains_ecryptfs_marker(char *data) | |
1025 | { | |
1026 | u32 m_1, m_2; | |
1027 | ||
1028 | memcpy(&m_1, data, 4); | |
1029 | m_1 = be32_to_cpu(m_1); | |
1030 | memcpy(&m_2, (data + 4), 4); | |
1031 | m_2 = be32_to_cpu(m_2); | |
1032 | if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2) | |
1033 | return 1; | |
1034 | ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; " | |
1035 | "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2, | |
1036 | MAGIC_ECRYPTFS_MARKER); | |
1037 | ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = " | |
1038 | "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER)); | |
1039 | return 0; | |
1040 | } | |
1041 | ||
1042 | struct ecryptfs_flag_map_elem { | |
1043 | u32 file_flag; | |
1044 | u32 local_flag; | |
1045 | }; | |
1046 | ||
1047 | /* Add support for additional flags by adding elements here. */ | |
1048 | static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = { | |
1049 | {0x00000001, ECRYPTFS_ENABLE_HMAC}, | |
1050 | {0x00000002, ECRYPTFS_ENCRYPTED} | |
1051 | }; | |
1052 | ||
1053 | /** | |
1054 | * ecryptfs_process_flags | |
1055 | * @crypt_stat | |
1056 | * @page_virt: Source data to be parsed | |
1057 | * @bytes_read: Updated with the number of bytes read | |
1058 | * | |
1059 | * Returns zero on success; non-zero if the flag set is invalid | |
1060 | */ | |
1061 | static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat, | |
1062 | char *page_virt, int *bytes_read) | |
1063 | { | |
1064 | int rc = 0; | |
1065 | int i; | |
1066 | u32 flags; | |
1067 | ||
1068 | memcpy(&flags, page_virt, 4); | |
1069 | flags = be32_to_cpu(flags); | |
1070 | for (i = 0; i < ((sizeof(ecryptfs_flag_map) | |
1071 | / sizeof(struct ecryptfs_flag_map_elem))); i++) | |
1072 | if (flags & ecryptfs_flag_map[i].file_flag) { | |
1073 | ECRYPTFS_SET_FLAG(crypt_stat->flags, | |
1074 | ecryptfs_flag_map[i].local_flag); | |
1075 | } else | |
1076 | ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, | |
1077 | ecryptfs_flag_map[i].local_flag); | |
1078 | /* Version is in top 8 bits of the 32-bit flag vector */ | |
1079 | crypt_stat->file_version = ((flags >> 24) & 0xFF); | |
1080 | (*bytes_read) = 4; | |
1081 | return rc; | |
1082 | } | |
1083 | ||
1084 | /** | |
1085 | * write_ecryptfs_marker | |
1086 | * @page_virt: The pointer to in a page to begin writing the marker | |
1087 | * @written: Number of bytes written | |
1088 | * | |
1089 | * Marker = 0x3c81b7f5 | |
1090 | */ | |
1091 | static void write_ecryptfs_marker(char *page_virt, size_t *written) | |
1092 | { | |
1093 | u32 m_1, m_2; | |
1094 | ||
1095 | get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); | |
1096 | m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER); | |
1097 | m_1 = cpu_to_be32(m_1); | |
1098 | memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); | |
1099 | m_2 = cpu_to_be32(m_2); | |
1100 | memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2, | |
1101 | (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); | |
1102 | (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; | |
1103 | } | |
1104 | ||
1105 | static void | |
1106 | write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat, | |
1107 | size_t *written) | |
1108 | { | |
1109 | u32 flags = 0; | |
1110 | int i; | |
1111 | ||
1112 | for (i = 0; i < ((sizeof(ecryptfs_flag_map) | |
1113 | / sizeof(struct ecryptfs_flag_map_elem))); i++) | |
1114 | if (ECRYPTFS_CHECK_FLAG(crypt_stat->flags, | |
1115 | ecryptfs_flag_map[i].local_flag)) | |
1116 | flags |= ecryptfs_flag_map[i].file_flag; | |
1117 | /* Version is in top 8 bits of the 32-bit flag vector */ | |
1118 | flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000); | |
1119 | flags = cpu_to_be32(flags); | |
1120 | memcpy(page_virt, &flags, 4); | |
1121 | (*written) = 4; | |
1122 | } | |
1123 | ||
1124 | struct ecryptfs_cipher_code_str_map_elem { | |
1125 | char cipher_str[16]; | |
1126 | u16 cipher_code; | |
1127 | }; | |
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. */ | |
1132 | static struct ecryptfs_cipher_code_str_map_elem | |
1133 | ecryptfs_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 | |
1146 | * @str: The string representing the cipher name | |
1147 | * | |
1148 | * Returns zero on no match, or the cipher code on match | |
1149 | */ | |
1150 | u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat) | |
1151 | { | |
1152 | int i; | |
1153 | u16 code = 0; | |
1154 | 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 | */ | |
1185 | int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code) | |
1186 | { | |
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 | ||
1202 | /** | |
1203 | * ecryptfs_read_header_region | |
1204 | * @data | |
1205 | * @dentry | |
1206 | * @nd | |
1207 | * | |
1208 | * Returns zero on success; non-zero otherwise | |
1209 | */ | |
1210 | int ecryptfs_read_header_region(char *data, struct dentry *dentry, | |
1211 | struct vfsmount *mnt) | |
1212 | { | |
7ff1d74f | 1213 | struct file *lower_file; |
237fead6 MH |
1214 | mm_segment_t oldfs; |
1215 | int rc; | |
1216 | ||
7ff1d74f MH |
1217 | if ((rc = ecryptfs_open_lower_file(&lower_file, dentry, mnt, |
1218 | O_RDONLY))) { | |
1219 | printk(KERN_ERR | |
1220 | "Error opening lower_file to read header region\n"); | |
237fead6 MH |
1221 | goto out; |
1222 | } | |
7ff1d74f | 1223 | lower_file->f_pos = 0; |
237fead6 MH |
1224 | oldfs = get_fs(); |
1225 | set_fs(get_ds()); | |
1226 | /* For releases 0.1 and 0.2, all of the header information | |
1227 | * fits in the first data extent-sized region. */ | |
7ff1d74f MH |
1228 | rc = lower_file->f_op->read(lower_file, (char __user *)data, |
1229 | ECRYPTFS_DEFAULT_EXTENT_SIZE, &lower_file->f_pos); | |
237fead6 | 1230 | set_fs(oldfs); |
7ff1d74f MH |
1231 | if ((rc = ecryptfs_close_lower_file(lower_file))) { |
1232 | printk(KERN_ERR "Error closing lower_file\n"); | |
1233 | goto out; | |
1234 | } | |
237fead6 MH |
1235 | rc = 0; |
1236 | out: | |
1237 | return rc; | |
1238 | } | |
1239 | ||
1240 | static void | |
1241 | write_header_metadata(char *virt, struct ecryptfs_crypt_stat *crypt_stat, | |
1242 | size_t *written) | |
1243 | { | |
1244 | u32 header_extent_size; | |
1245 | u16 num_header_extents_at_front; | |
1246 | ||
1247 | header_extent_size = (u32)crypt_stat->header_extent_size; | |
1248 | num_header_extents_at_front = | |
1249 | (u16)crypt_stat->num_header_extents_at_front; | |
1250 | header_extent_size = cpu_to_be32(header_extent_size); | |
1251 | memcpy(virt, &header_extent_size, 4); | |
1252 | virt += 4; | |
1253 | num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front); | |
1254 | memcpy(virt, &num_header_extents_at_front, 2); | |
1255 | (*written) = 6; | |
1256 | } | |
1257 | ||
1258 | struct kmem_cache *ecryptfs_header_cache_0; | |
1259 | struct kmem_cache *ecryptfs_header_cache_1; | |
1260 | struct kmem_cache *ecryptfs_header_cache_2; | |
1261 | ||
1262 | /** | |
1263 | * ecryptfs_write_headers_virt | |
1264 | * @page_virt | |
1265 | * @crypt_stat | |
1266 | * @ecryptfs_dentry | |
1267 | * | |
1268 | * Format version: 1 | |
1269 | * | |
1270 | * Header Extent: | |
1271 | * Octets 0-7: Unencrypted file size (big-endian) | |
1272 | * Octets 8-15: eCryptfs special marker | |
1273 | * Octets 16-19: Flags | |
1274 | * Octet 16: File format version number (between 0 and 255) | |
1275 | * Octets 17-18: Reserved | |
1276 | * Octet 19: Bit 1 (lsb): Reserved | |
1277 | * Bit 2: Encrypted? | |
1278 | * Bits 3-8: Reserved | |
1279 | * Octets 20-23: Header extent size (big-endian) | |
1280 | * Octets 24-25: Number of header extents at front of file | |
1281 | * (big-endian) | |
1282 | * Octet 26: Begin RFC 2440 authentication token packet set | |
1283 | * Data Extent 0: | |
1284 | * Lower data (CBC encrypted) | |
1285 | * Data Extent 1: | |
1286 | * Lower data (CBC encrypted) | |
1287 | * ... | |
1288 | * | |
1289 | * Returns zero on success | |
1290 | */ | |
1291 | int ecryptfs_write_headers_virt(char *page_virt, | |
1292 | struct ecryptfs_crypt_stat *crypt_stat, | |
1293 | struct dentry *ecryptfs_dentry) | |
1294 | { | |
1295 | int rc; | |
1296 | size_t written; | |
1297 | size_t offset; | |
1298 | ||
1299 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
1300 | write_ecryptfs_marker((page_virt + offset), &written); | |
1301 | offset += written; | |
1302 | write_ecryptfs_flags((page_virt + offset), crypt_stat, &written); | |
1303 | offset += written; | |
1304 | write_header_metadata((page_virt + offset), crypt_stat, &written); | |
1305 | offset += written; | |
1306 | rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat, | |
1307 | ecryptfs_dentry, &written, | |
1308 | PAGE_CACHE_SIZE - offset); | |
1309 | if (rc) | |
1310 | ecryptfs_printk(KERN_WARNING, "Error generating key packet " | |
1311 | "set; rc = [%d]\n", rc); | |
1312 | return rc; | |
1313 | } | |
1314 | ||
1315 | /** | |
1316 | * ecryptfs_write_headers | |
1317 | * @lower_file: The lower file struct, which was returned from dentry_open | |
1318 | * | |
1319 | * Write the file headers out. This will likely involve a userspace | |
1320 | * callout, in which the session key is encrypted with one or more | |
1321 | * public keys and/or the passphrase necessary to do the encryption is | |
1322 | * retrieved via a prompt. Exactly what happens at this point should | |
1323 | * be policy-dependent. | |
1324 | * | |
1325 | * Returns zero on success; non-zero on error | |
1326 | */ | |
1327 | int ecryptfs_write_headers(struct dentry *ecryptfs_dentry, | |
1328 | struct file *lower_file) | |
1329 | { | |
1330 | mm_segment_t oldfs; | |
1331 | struct ecryptfs_crypt_stat *crypt_stat; | |
1332 | char *page_virt; | |
1333 | int current_header_page; | |
1334 | int header_pages; | |
1335 | int rc = 0; | |
1336 | ||
1337 | crypt_stat = &ecryptfs_inode_to_private( | |
1338 | ecryptfs_dentry->d_inode)->crypt_stat; | |
1339 | if (likely(ECRYPTFS_CHECK_FLAG(crypt_stat->flags, | |
1340 | ECRYPTFS_ENCRYPTED))) { | |
1341 | if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, | |
1342 | ECRYPTFS_KEY_VALID)) { | |
1343 | ecryptfs_printk(KERN_DEBUG, "Key is " | |
1344 | "invalid; bailing out\n"); | |
1345 | rc = -EINVAL; | |
1346 | goto out; | |
1347 | } | |
1348 | } else { | |
1349 | rc = -EINVAL; | |
1350 | ecryptfs_printk(KERN_WARNING, | |
1351 | "Called with crypt_stat->encrypted == 0\n"); | |
1352 | goto out; | |
1353 | } | |
1354 | /* Released in this function */ | |
c3762229 | 1355 | page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER); |
237fead6 MH |
1356 | if (!page_virt) { |
1357 | ecryptfs_printk(KERN_ERR, "Out of memory\n"); | |
1358 | rc = -ENOMEM; | |
1359 | goto out; | |
1360 | } | |
c3762229 | 1361 | |
237fead6 MH |
1362 | rc = ecryptfs_write_headers_virt(page_virt, crypt_stat, |
1363 | ecryptfs_dentry); | |
1364 | if (unlikely(rc)) { | |
1365 | ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n"); | |
1366 | memset(page_virt, 0, PAGE_CACHE_SIZE); | |
1367 | goto out_free; | |
1368 | } | |
1369 | ecryptfs_printk(KERN_DEBUG, | |
1370 | "Writing key packet set to underlying file\n"); | |
1371 | lower_file->f_pos = 0; | |
1372 | oldfs = get_fs(); | |
1373 | set_fs(get_ds()); | |
1374 | ecryptfs_printk(KERN_DEBUG, "Calling lower_file->f_op->" | |
1375 | "write() w/ header page; lower_file->f_pos = " | |
1376 | "[0x%.16x]\n", lower_file->f_pos); | |
1377 | lower_file->f_op->write(lower_file, (char __user *)page_virt, | |
1378 | PAGE_CACHE_SIZE, &lower_file->f_pos); | |
1379 | header_pages = ((crypt_stat->header_extent_size | |
1380 | * crypt_stat->num_header_extents_at_front) | |
1381 | / PAGE_CACHE_SIZE); | |
1382 | memset(page_virt, 0, PAGE_CACHE_SIZE); | |
1383 | current_header_page = 1; | |
1384 | while (current_header_page < header_pages) { | |
1385 | ecryptfs_printk(KERN_DEBUG, "Calling lower_file->f_op->" | |
1386 | "write() w/ zero'd page; lower_file->f_pos = " | |
1387 | "[0x%.16x]\n", lower_file->f_pos); | |
1388 | lower_file->f_op->write(lower_file, (char __user *)page_virt, | |
1389 | PAGE_CACHE_SIZE, &lower_file->f_pos); | |
1390 | current_header_page++; | |
1391 | } | |
1392 | set_fs(oldfs); | |
1393 | ecryptfs_printk(KERN_DEBUG, | |
1394 | "Done writing key packet set to underlying file.\n"); | |
1395 | out_free: | |
1396 | kmem_cache_free(ecryptfs_header_cache_0, page_virt); | |
1397 | out: | |
1398 | return rc; | |
1399 | } | |
1400 | ||
1401 | static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat, | |
1402 | char *virt, int *bytes_read) | |
1403 | { | |
1404 | int rc = 0; | |
1405 | u32 header_extent_size; | |
1406 | u16 num_header_extents_at_front; | |
1407 | ||
1408 | memcpy(&header_extent_size, virt, 4); | |
1409 | header_extent_size = be32_to_cpu(header_extent_size); | |
1410 | virt += 4; | |
1411 | memcpy(&num_header_extents_at_front, virt, 2); | |
1412 | num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front); | |
1413 | crypt_stat->header_extent_size = (int)header_extent_size; | |
1414 | crypt_stat->num_header_extents_at_front = | |
1415 | (int)num_header_extents_at_front; | |
1416 | (*bytes_read) = 6; | |
1417 | if ((crypt_stat->header_extent_size | |
1418 | * crypt_stat->num_header_extents_at_front) | |
1419 | < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) { | |
1420 | rc = -EINVAL; | |
1421 | ecryptfs_printk(KERN_WARNING, "Invalid header extent size: " | |
1422 | "[%d]\n", crypt_stat->header_extent_size); | |
1423 | } | |
1424 | return rc; | |
1425 | } | |
1426 | ||
1427 | /** | |
1428 | * set_default_header_data | |
1429 | * | |
1430 | * For version 0 file format; this function is only for backwards | |
1431 | * compatibility for files created with the prior versions of | |
1432 | * eCryptfs. | |
1433 | */ | |
1434 | static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) | |
1435 | { | |
1436 | crypt_stat->header_extent_size = 4096; | |
1437 | crypt_stat->num_header_extents_at_front = 1; | |
1438 | } | |
1439 | ||
1440 | /** | |
1441 | * ecryptfs_read_headers_virt | |
1442 | * | |
1443 | * Read/parse the header data. The header format is detailed in the | |
1444 | * comment block for the ecryptfs_write_headers_virt() function. | |
1445 | * | |
1446 | * Returns zero on success | |
1447 | */ | |
1448 | static int ecryptfs_read_headers_virt(char *page_virt, | |
1449 | struct ecryptfs_crypt_stat *crypt_stat, | |
1450 | struct dentry *ecryptfs_dentry) | |
1451 | { | |
1452 | int rc = 0; | |
1453 | int offset; | |
1454 | int bytes_read; | |
1455 | ||
1456 | ecryptfs_set_default_sizes(crypt_stat); | |
1457 | crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private( | |
1458 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
1459 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
1460 | rc = contains_ecryptfs_marker(page_virt + offset); | |
1461 | if (rc == 0) { | |
1462 | rc = -EINVAL; | |
1463 | goto out; | |
1464 | } | |
1465 | offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; | |
1466 | rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset), | |
1467 | &bytes_read); | |
1468 | if (rc) { | |
1469 | ecryptfs_printk(KERN_WARNING, "Error processing flags\n"); | |
1470 | goto out; | |
1471 | } | |
1472 | if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) { | |
1473 | ecryptfs_printk(KERN_WARNING, "File version is [%d]; only " | |
1474 | "file version [%d] is supported by this " | |
1475 | "version of eCryptfs\n", | |
1476 | crypt_stat->file_version, | |
1477 | ECRYPTFS_SUPPORTED_FILE_VERSION); | |
1478 | rc = -EINVAL; | |
1479 | goto out; | |
1480 | } | |
1481 | offset += bytes_read; | |
1482 | if (crypt_stat->file_version >= 1) { | |
1483 | rc = parse_header_metadata(crypt_stat, (page_virt + offset), | |
1484 | &bytes_read); | |
1485 | if (rc) { | |
1486 | ecryptfs_printk(KERN_WARNING, "Error reading header " | |
1487 | "metadata; rc = [%d]\n", rc); | |
1488 | } | |
1489 | offset += bytes_read; | |
1490 | } else | |
1491 | set_default_header_data(crypt_stat); | |
1492 | rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), | |
1493 | ecryptfs_dentry); | |
1494 | out: | |
1495 | return rc; | |
1496 | } | |
1497 | ||
1498 | /** | |
1499 | * ecryptfs_read_headers | |
1500 | * | |
1501 | * Returns zero if valid headers found and parsed; non-zero otherwise | |
1502 | */ | |
1503 | int ecryptfs_read_headers(struct dentry *ecryptfs_dentry, | |
1504 | struct file *lower_file) | |
1505 | { | |
1506 | int rc = 0; | |
1507 | char *page_virt = NULL; | |
1508 | mm_segment_t oldfs; | |
1509 | ssize_t bytes_read; | |
1510 | struct ecryptfs_crypt_stat *crypt_stat = | |
1511 | &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; | |
1512 | ||
1513 | /* Read the first page from the underlying file */ | |
f7267c0c | 1514 | page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER); |
237fead6 MH |
1515 | if (!page_virt) { |
1516 | rc = -ENOMEM; | |
1517 | ecryptfs_printk(KERN_ERR, "Unable to allocate page_virt\n"); | |
1518 | goto out; | |
1519 | } | |
1520 | lower_file->f_pos = 0; | |
1521 | oldfs = get_fs(); | |
1522 | set_fs(get_ds()); | |
1523 | bytes_read = lower_file->f_op->read(lower_file, | |
1524 | (char __user *)page_virt, | |
1525 | ECRYPTFS_DEFAULT_EXTENT_SIZE, | |
1526 | &lower_file->f_pos); | |
1527 | set_fs(oldfs); | |
1528 | if (bytes_read != ECRYPTFS_DEFAULT_EXTENT_SIZE) { | |
1529 | rc = -EINVAL; | |
1530 | goto out; | |
1531 | } | |
1532 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, | |
1533 | ecryptfs_dentry); | |
1534 | if (rc) { | |
1535 | ecryptfs_printk(KERN_DEBUG, "Valid eCryptfs headers not " | |
1536 | "found\n"); | |
1537 | rc = -EINVAL; | |
1538 | } | |
1539 | out: | |
1540 | if (page_virt) { | |
1541 | memset(page_virt, 0, PAGE_CACHE_SIZE); | |
1542 | kmem_cache_free(ecryptfs_header_cache_1, page_virt); | |
1543 | } | |
1544 | return rc; | |
1545 | } | |
1546 | ||
1547 | /** | |
1548 | * ecryptfs_encode_filename - converts a plaintext file name to cipher text | |
1549 | * @crypt_stat: The crypt_stat struct associated with the file anem to encode | |
1550 | * @name: The plaintext name | |
1551 | * @length: The length of the plaintext | |
1552 | * @encoded_name: The encypted name | |
1553 | * | |
1554 | * Encrypts and encodes a filename into something that constitutes a | |
1555 | * valid filename for a filesystem, with printable characters. | |
1556 | * | |
1557 | * We assume that we have a properly initialized crypto context, | |
1558 | * pointed to by crypt_stat->tfm. | |
1559 | * | |
1560 | * TODO: Implement filename decoding and decryption here, in place of | |
1561 | * memcpy. We are keeping the framework around for now to (1) | |
1562 | * facilitate testing of the components needed to implement filename | |
1563 | * encryption and (2) to provide a code base from which other | |
1564 | * developers in the community can easily implement this feature. | |
1565 | * | |
1566 | * Returns the length of encoded filename; negative if error | |
1567 | */ | |
1568 | int | |
1569 | ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat, | |
1570 | const char *name, int length, char **encoded_name) | |
1571 | { | |
1572 | int error = 0; | |
1573 | ||
1574 | (*encoded_name) = kmalloc(length + 2, GFP_KERNEL); | |
1575 | if (!(*encoded_name)) { | |
1576 | error = -ENOMEM; | |
1577 | goto out; | |
1578 | } | |
1579 | /* TODO: Filename encryption is a scheduled feature for a | |
1580 | * future version of eCryptfs. This function is here only for | |
1581 | * the purpose of providing a framework for other developers | |
1582 | * to easily implement filename encryption. Hint: Replace this | |
1583 | * memcpy() with a call to encrypt and encode the | |
1584 | * filename, the set the length accordingly. */ | |
1585 | memcpy((void *)(*encoded_name), (void *)name, length); | |
1586 | (*encoded_name)[length] = '\0'; | |
1587 | error = length + 1; | |
1588 | out: | |
1589 | return error; | |
1590 | } | |
1591 | ||
1592 | /** | |
1593 | * ecryptfs_decode_filename - converts the cipher text name to plaintext | |
1594 | * @crypt_stat: The crypt_stat struct associated with the file | |
1595 | * @name: The filename in cipher text | |
1596 | * @length: The length of the cipher text name | |
1597 | * @decrypted_name: The plaintext name | |
1598 | * | |
1599 | * Decodes and decrypts the filename. | |
1600 | * | |
1601 | * We assume that we have a properly initialized crypto context, | |
1602 | * pointed to by crypt_stat->tfm. | |
1603 | * | |
1604 | * TODO: Implement filename decoding and decryption here, in place of | |
1605 | * memcpy. We are keeping the framework around for now to (1) | |
1606 | * facilitate testing of the components needed to implement filename | |
1607 | * encryption and (2) to provide a code base from which other | |
1608 | * developers in the community can easily implement this feature. | |
1609 | * | |
1610 | * Returns the length of decoded filename; negative if error | |
1611 | */ | |
1612 | int | |
1613 | ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat, | |
1614 | const char *name, int length, char **decrypted_name) | |
1615 | { | |
1616 | int error = 0; | |
1617 | ||
1618 | (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL); | |
1619 | if (!(*decrypted_name)) { | |
1620 | error = -ENOMEM; | |
1621 | goto out; | |
1622 | } | |
1623 | /* TODO: Filename encryption is a scheduled feature for a | |
1624 | * future version of eCryptfs. This function is here only for | |
1625 | * the purpose of providing a framework for other developers | |
1626 | * to easily implement filename encryption. Hint: Replace this | |
1627 | * memcpy() with a call to decode and decrypt the | |
1628 | * filename, the set the length accordingly. */ | |
1629 | memcpy((void *)(*decrypted_name), (void *)name, length); | |
1630 | (*decrypted_name)[length + 1] = '\0'; /* Only for convenience | |
1631 | * in printing out the | |
1632 | * string in debug | |
1633 | * messages */ | |
1634 | error = length; | |
1635 | out: | |
1636 | return error; | |
1637 | } | |
1638 | ||
1639 | /** | |
1640 | * ecryptfs_process_cipher - Perform cipher initialization. | |
237fead6 | 1641 | * @key_tfm: Crypto context for key material, set by this function |
e5d9cbde MH |
1642 | * @cipher_name: Name of the cipher |
1643 | * @key_size: Size of the key in bytes | |
237fead6 MH |
1644 | * |
1645 | * Returns zero on success. Any crypto_tfm structs allocated here | |
1646 | * should be released by other functions, such as on a superblock put | |
1647 | * event, regardless of whether this function succeeds for fails. | |
1648 | */ | |
1649 | int | |
8bba066f | 1650 | ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name, |
e5d9cbde | 1651 | size_t *key_size) |
237fead6 MH |
1652 | { |
1653 | char dummy_key[ECRYPTFS_MAX_KEY_BYTES]; | |
8bba066f | 1654 | char *full_alg_name; |
237fead6 MH |
1655 | int rc; |
1656 | ||
e5d9cbde MH |
1657 | *key_tfm = NULL; |
1658 | if (*key_size > ECRYPTFS_MAX_KEY_BYTES) { | |
237fead6 MH |
1659 | rc = -EINVAL; |
1660 | printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum " | |
e5d9cbde | 1661 | "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES); |
237fead6 MH |
1662 | goto out; |
1663 | } | |
8bba066f MH |
1664 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name, |
1665 | "ecb"); | |
1666 | if (rc) | |
1667 | goto out; | |
1668 | *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC); | |
1669 | kfree(full_alg_name); | |
1670 | if (IS_ERR(*key_tfm)) { | |
1671 | rc = PTR_ERR(*key_tfm); | |
237fead6 | 1672 | printk(KERN_ERR "Unable to allocate crypto cipher with name " |
8bba066f | 1673 | "[%s]; rc = [%d]\n", cipher_name, rc); |
237fead6 MH |
1674 | goto out; |
1675 | } | |
8bba066f MH |
1676 | crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY); |
1677 | if (*key_size == 0) { | |
1678 | struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm); | |
1679 | ||
1680 | *key_size = alg->max_keysize; | |
1681 | } | |
e5d9cbde | 1682 | get_random_bytes(dummy_key, *key_size); |
8bba066f | 1683 | rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size); |
237fead6 MH |
1684 | if (rc) { |
1685 | printk(KERN_ERR "Error attempting to set key of size [%Zd] for " | |
e5d9cbde | 1686 | "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc); |
237fead6 MH |
1687 | rc = -EINVAL; |
1688 | goto out; | |
1689 | } | |
1690 | out: | |
1691 | return rc; | |
1692 | } |