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Commit | Line | Data |
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1a59d1b8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
5da877ea | 2 | /* |
237fead6 MH |
3 | * eCryptfs: Linux filesystem encryption layer |
4 | * | |
5 | * Copyright (C) 1997-2004 Erez Zadok | |
6 | * Copyright (C) 2001-2004 Stony Brook University | |
dd2a3b7a | 7 | * Copyright (C) 2004-2007 International Business Machines Corp. |
237fead6 MH |
8 | * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> |
9 | * Michael C. Thompson <mcthomps@us.ibm.com> | |
237fead6 MH |
10 | */ |
11 | ||
3095e8e3 HX |
12 | #include <crypto/hash.h> |
13 | #include <crypto/skcipher.h> | |
237fead6 MH |
14 | #include <linux/fs.h> |
15 | #include <linux/mount.h> | |
16 | #include <linux/pagemap.h> | |
17 | #include <linux/random.h> | |
18 | #include <linux/compiler.h> | |
19 | #include <linux/key.h> | |
20 | #include <linux/namei.h> | |
237fead6 MH |
21 | #include <linux/file.h> |
22 | #include <linux/scatterlist.h> | |
5a0e3ad6 | 23 | #include <linux/slab.h> |
29335c6a | 24 | #include <asm/unaligned.h> |
02f9876e | 25 | #include <linux/kernel.h> |
d43388de | 26 | #include <linux/xattr.h> |
237fead6 MH |
27 | #include "ecryptfs_kernel.h" |
28 | ||
00a69940 TH |
29 | #define DECRYPT 0 |
30 | #define ENCRYPT 1 | |
237fead6 | 31 | |
237fead6 MH |
32 | /** |
33 | * ecryptfs_from_hex | |
34 | * @dst: Buffer to take the bytes from src hex; must be at least of | |
35 | * size (src_size / 2) | |
5f9f2c2a | 36 | * @src: Buffer to be converted from a hex string representation to raw value |
237fead6 MH |
37 | * @dst_size: size of dst buffer, or number of hex characters pairs to convert |
38 | */ | |
39 | void ecryptfs_from_hex(char *dst, char *src, int dst_size) | |
40 | { | |
41 | int x; | |
42 | char tmp[3] = { 0, }; | |
43 | ||
44 | for (x = 0; x < dst_size; x++) { | |
45 | tmp[0] = src[x * 2]; | |
46 | tmp[1] = src[x * 2 + 1]; | |
47 | dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16); | |
48 | } | |
49 | } | |
50 | ||
51 | /** | |
52 | * ecryptfs_calculate_md5 - calculates the md5 of @src | |
53 | * @dst: Pointer to 16 bytes of allocated memory | |
54 | * @crypt_stat: Pointer to crypt_stat struct for the current inode | |
55 | * @src: Data to be md5'd | |
56 | * @len: Length of @src | |
57 | * | |
58 | * Uses the allocated crypto context that crypt_stat references to | |
59 | * generate the MD5 sum of the contents of src. | |
60 | */ | |
61 | static int ecryptfs_calculate_md5(char *dst, | |
62 | struct ecryptfs_crypt_stat *crypt_stat, | |
63 | char *src, int len) | |
64 | { | |
19798113 | 65 | int rc = crypto_shash_tfm_digest(crypt_stat->hash_tfm, src, len, dst); |
237fead6 | 66 | |
8a29f2b0 MH |
67 | if (rc) { |
68 | printk(KERN_ERR | |
3095e8e3 | 69 | "%s: Error computing crypto hash; rc = [%d]\n", |
18d1dbf1 | 70 | __func__, rc); |
8a29f2b0 MH |
71 | goto out; |
72 | } | |
237fead6 MH |
73 | out: |
74 | return rc; | |
75 | } | |
76 | ||
cd9d67df MH |
77 | static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name, |
78 | char *cipher_name, | |
79 | char *chaining_modifier) | |
8bba066f MH |
80 | { |
81 | int cipher_name_len = strlen(cipher_name); | |
82 | int chaining_modifier_len = strlen(chaining_modifier); | |
83 | int algified_name_len; | |
84 | int rc; | |
85 | ||
86 | algified_name_len = (chaining_modifier_len + cipher_name_len + 3); | |
87 | (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL); | |
7bd473fc | 88 | if (!(*algified_name)) { |
8bba066f MH |
89 | rc = -ENOMEM; |
90 | goto out; | |
91 | } | |
92 | snprintf((*algified_name), algified_name_len, "%s(%s)", | |
93 | chaining_modifier, cipher_name); | |
94 | rc = 0; | |
95 | out: | |
96 | return rc; | |
97 | } | |
98 | ||
237fead6 MH |
99 | /** |
100 | * ecryptfs_derive_iv | |
101 | * @iv: destination for the derived iv vale | |
102 | * @crypt_stat: Pointer to crypt_stat struct for the current inode | |
d6a13c17 | 103 | * @offset: Offset of the extent whose IV we are to derive |
237fead6 MH |
104 | * |
105 | * Generate the initialization vector from the given root IV and page | |
106 | * offset. | |
107 | * | |
108 | * Returns zero on success; non-zero on error. | |
109 | */ | |
a34f60f7 MH |
110 | int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat, |
111 | loff_t offset) | |
237fead6 MH |
112 | { |
113 | int rc = 0; | |
114 | char dst[MD5_DIGEST_SIZE]; | |
115 | char src[ECRYPTFS_MAX_IV_BYTES + 16]; | |
116 | ||
117 | if (unlikely(ecryptfs_verbosity > 0)) { | |
118 | ecryptfs_printk(KERN_DEBUG, "root iv:\n"); | |
119 | ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes); | |
120 | } | |
121 | /* TODO: It is probably secure to just cast the least | |
122 | * significant bits of the root IV into an unsigned long and | |
123 | * add the offset to that rather than go through all this | |
124 | * hashing business. -Halcrow */ | |
125 | memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes); | |
126 | memset((src + crypt_stat->iv_bytes), 0, 16); | |
d6a13c17 | 127 | snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset); |
237fead6 MH |
128 | if (unlikely(ecryptfs_verbosity > 0)) { |
129 | ecryptfs_printk(KERN_DEBUG, "source:\n"); | |
130 | ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16)); | |
131 | } | |
132 | rc = ecryptfs_calculate_md5(dst, crypt_stat, src, | |
133 | (crypt_stat->iv_bytes + 16)); | |
134 | if (rc) { | |
135 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " | |
136 | "MD5 while generating IV for a page\n"); | |
137 | goto out; | |
138 | } | |
139 | memcpy(iv, dst, crypt_stat->iv_bytes); | |
140 | if (unlikely(ecryptfs_verbosity > 0)) { | |
141 | ecryptfs_printk(KERN_DEBUG, "derived iv:\n"); | |
142 | ecryptfs_dump_hex(iv, crypt_stat->iv_bytes); | |
143 | } | |
144 | out: | |
145 | return rc; | |
146 | } | |
147 | ||
148 | /** | |
149 | * ecryptfs_init_crypt_stat | |
150 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. | |
151 | * | |
152 | * Initialize the crypt_stat structure. | |
153 | */ | |
e81f3340 | 154 | int ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
237fead6 | 155 | { |
e81f3340 HX |
156 | struct crypto_shash *tfm; |
157 | int rc; | |
158 | ||
159 | tfm = crypto_alloc_shash(ECRYPTFS_DEFAULT_HASH, 0, 0); | |
160 | if (IS_ERR(tfm)) { | |
161 | rc = PTR_ERR(tfm); | |
162 | ecryptfs_printk(KERN_ERR, "Error attempting to " | |
163 | "allocate crypto context; rc = [%d]\n", | |
164 | rc); | |
165 | return rc; | |
166 | } | |
167 | ||
237fead6 | 168 | memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
f4aad16a MH |
169 | INIT_LIST_HEAD(&crypt_stat->keysig_list); |
170 | mutex_init(&crypt_stat->keysig_list_mutex); | |
237fead6 MH |
171 | mutex_init(&crypt_stat->cs_mutex); |
172 | mutex_init(&crypt_stat->cs_tfm_mutex); | |
e81f3340 | 173 | crypt_stat->hash_tfm = tfm; |
e2bd99ec | 174 | crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED; |
e81f3340 HX |
175 | |
176 | return 0; | |
237fead6 MH |
177 | } |
178 | ||
179 | /** | |
fcd12835 | 180 | * ecryptfs_destroy_crypt_stat |
237fead6 MH |
181 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
182 | * | |
183 | * Releases all memory associated with a crypt_stat struct. | |
184 | */ | |
fcd12835 | 185 | void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
237fead6 | 186 | { |
f4aad16a MH |
187 | struct ecryptfs_key_sig *key_sig, *key_sig_tmp; |
188 | ||
3095e8e3 HX |
189 | crypto_free_skcipher(crypt_stat->tfm); |
190 | crypto_free_shash(crypt_stat->hash_tfm); | |
f4aad16a MH |
191 | list_for_each_entry_safe(key_sig, key_sig_tmp, |
192 | &crypt_stat->keysig_list, crypt_stat_list) { | |
193 | list_del(&key_sig->crypt_stat_list); | |
194 | kmem_cache_free(ecryptfs_key_sig_cache, key_sig); | |
195 | } | |
237fead6 MH |
196 | memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
197 | } | |
198 | ||
fcd12835 | 199 | void ecryptfs_destroy_mount_crypt_stat( |
237fead6 MH |
200 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
201 | { | |
f4aad16a MH |
202 | struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp; |
203 | ||
204 | if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED)) | |
205 | return; | |
206 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
207 | list_for_each_entry_safe(auth_tok, auth_tok_tmp, | |
208 | &mount_crypt_stat->global_auth_tok_list, | |
209 | mount_crypt_stat_list) { | |
210 | list_del(&auth_tok->mount_crypt_stat_list); | |
0dad87fc | 211 | if (!(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID)) |
f4aad16a MH |
212 | key_put(auth_tok->global_auth_tok_key); |
213 | kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok); | |
214 | } | |
215 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
237fead6 MH |
216 | memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat)); |
217 | } | |
218 | ||
219 | /** | |
220 | * virt_to_scatterlist | |
221 | * @addr: Virtual address | |
222 | * @size: Size of data; should be an even multiple of the block size | |
223 | * @sg: Pointer to scatterlist array; set to NULL to obtain only | |
224 | * the number of scatterlist structs required in array | |
225 | * @sg_size: Max array size | |
226 | * | |
227 | * Fills in a scatterlist array with page references for a passed | |
228 | * virtual address. | |
229 | * | |
230 | * Returns the number of scatterlist structs in array used | |
231 | */ | |
232 | int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg, | |
233 | int sg_size) | |
234 | { | |
235 | int i = 0; | |
236 | struct page *pg; | |
237 | int offset; | |
238 | int remainder_of_page; | |
239 | ||
68e3f5dd HX |
240 | sg_init_table(sg, sg_size); |
241 | ||
237fead6 MH |
242 | while (size > 0 && i < sg_size) { |
243 | pg = virt_to_page(addr); | |
244 | offset = offset_in_page(addr); | |
a07c48ad | 245 | sg_set_page(&sg[i], pg, 0, offset); |
09cbfeaf | 246 | remainder_of_page = PAGE_SIZE - offset; |
237fead6 | 247 | if (size >= remainder_of_page) { |
a07c48ad | 248 | sg[i].length = remainder_of_page; |
237fead6 MH |
249 | addr += remainder_of_page; |
250 | size -= remainder_of_page; | |
251 | } else { | |
a07c48ad | 252 | sg[i].length = size; |
237fead6 MH |
253 | addr += size; |
254 | size = 0; | |
255 | } | |
256 | i++; | |
257 | } | |
258 | if (size > 0) | |
259 | return -ENOMEM; | |
260 | return i; | |
261 | } | |
262 | ||
4dfea4f0 TH |
263 | struct extent_crypt_result { |
264 | struct completion completion; | |
265 | int rc; | |
266 | }; | |
267 | ||
268 | static void extent_crypt_complete(struct crypto_async_request *req, int rc) | |
269 | { | |
270 | struct extent_crypt_result *ecr = req->data; | |
271 | ||
272 | if (rc == -EINPROGRESS) | |
273 | return; | |
274 | ||
275 | ecr->rc = rc; | |
276 | complete(&ecr->completion); | |
277 | } | |
278 | ||
237fead6 | 279 | /** |
00a69940 | 280 | * crypt_scatterlist |
237fead6 | 281 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
0df5ed65 | 282 | * @dst_sg: Destination of the data after performing the crypto operation |
00a69940 TH |
283 | * @src_sg: Data to be encrypted or decrypted |
284 | * @size: Length of data | |
285 | * @iv: IV to use | |
286 | * @op: ENCRYPT or DECRYPT to indicate the desired operation | |
237fead6 | 287 | * |
00a69940 | 288 | * Returns the number of bytes encrypted or decrypted; negative value on error |
237fead6 | 289 | */ |
00a69940 | 290 | static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, |
0df5ed65 | 291 | struct scatterlist *dst_sg, |
00a69940 TH |
292 | struct scatterlist *src_sg, int size, |
293 | unsigned char *iv, int op) | |
237fead6 | 294 | { |
3095e8e3 | 295 | struct skcipher_request *req = NULL; |
4dfea4f0 | 296 | struct extent_crypt_result ecr; |
237fead6 MH |
297 | int rc = 0; |
298 | ||
237fead6 | 299 | if (unlikely(ecryptfs_verbosity > 0)) { |
f24b3887 | 300 | ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n", |
237fead6 MH |
301 | crypt_stat->key_size); |
302 | ecryptfs_dump_hex(crypt_stat->key, | |
303 | crypt_stat->key_size); | |
304 | } | |
4dfea4f0 TH |
305 | |
306 | init_completion(&ecr.completion); | |
307 | ||
237fead6 | 308 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
3095e8e3 | 309 | req = skcipher_request_alloc(crypt_stat->tfm, GFP_NOFS); |
4dfea4f0 | 310 | if (!req) { |
237fead6 | 311 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
4dfea4f0 | 312 | rc = -ENOMEM; |
237fead6 MH |
313 | goto out; |
314 | } | |
4dfea4f0 | 315 | |
3095e8e3 | 316 | skcipher_request_set_callback(req, |
4dfea4f0 TH |
317 | CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, |
318 | extent_crypt_complete, &ecr); | |
319 | /* Consider doing this once, when the file is opened */ | |
320 | if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) { | |
3095e8e3 HX |
321 | rc = crypto_skcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
322 | crypt_stat->key_size); | |
4dfea4f0 TH |
323 | if (rc) { |
324 | ecryptfs_printk(KERN_ERR, | |
325 | "Error setting key; rc = [%d]\n", | |
326 | rc); | |
327 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
328 | rc = -EINVAL; | |
329 | goto out; | |
330 | } | |
331 | crypt_stat->flags |= ECRYPTFS_KEY_SET; | |
332 | } | |
237fead6 | 333 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
3095e8e3 HX |
334 | skcipher_request_set_crypt(req, src_sg, dst_sg, size, iv); |
335 | rc = op == ENCRYPT ? crypto_skcipher_encrypt(req) : | |
336 | crypto_skcipher_decrypt(req); | |
4dfea4f0 TH |
337 | if (rc == -EINPROGRESS || rc == -EBUSY) { |
338 | struct extent_crypt_result *ecr = req->base.data; | |
339 | ||
340 | wait_for_completion(&ecr->completion); | |
341 | rc = ecr->rc; | |
16735d02 | 342 | reinit_completion(&ecr->completion); |
4dfea4f0 | 343 | } |
237fead6 | 344 | out: |
3095e8e3 | 345 | skcipher_request_free(req); |
237fead6 MH |
346 | return rc; |
347 | } | |
348 | ||
5da877ea | 349 | /* |
24d15266 | 350 | * lower_offset_for_page |
0216f7f7 MH |
351 | * |
352 | * Convert an eCryptfs page index into a lower byte offset | |
353 | */ | |
24d15266 TH |
354 | static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat, |
355 | struct page *page) | |
0216f7f7 | 356 | { |
24d15266 | 357 | return ecryptfs_lower_header_size(crypt_stat) + |
09cbfeaf | 358 | ((loff_t)page->index << PAGE_SHIFT); |
0216f7f7 MH |
359 | } |
360 | ||
361 | /** | |
d78de618 | 362 | * crypt_extent |
0216f7f7 MH |
363 | * @crypt_stat: crypt_stat containing cryptographic context for the |
364 | * encryption operation | |
0df5ed65 | 365 | * @dst_page: The page to write the result into |
d78de618 | 366 | * @src_page: The page to read from |
0216f7f7 | 367 | * @extent_offset: Page extent offset for use in generating IV |
d78de618 | 368 | * @op: ENCRYPT or DECRYPT to indicate the desired operation |
0216f7f7 | 369 | * |
d78de618 | 370 | * Encrypts or decrypts one extent of data. |
0216f7f7 MH |
371 | * |
372 | * Return zero on success; non-zero otherwise | |
373 | */ | |
0df5ed65 TH |
374 | static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat, |
375 | struct page *dst_page, | |
d78de618 TH |
376 | struct page *src_page, |
377 | unsigned long extent_offset, int op) | |
0216f7f7 | 378 | { |
d78de618 | 379 | pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index; |
d6a13c17 | 380 | loff_t extent_base; |
0216f7f7 | 381 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
406c93df TH |
382 | struct scatterlist src_sg, dst_sg; |
383 | size_t extent_size = crypt_stat->extent_size; | |
0216f7f7 MH |
384 | int rc; |
385 | ||
09cbfeaf | 386 | extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size)); |
0216f7f7 MH |
387 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, |
388 | (extent_base + extent_offset)); | |
389 | if (rc) { | |
888d57bb JP |
390 | ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for " |
391 | "extent [0x%.16llx]; rc = [%d]\n", | |
392 | (unsigned long long)(extent_base + extent_offset), rc); | |
0216f7f7 MH |
393 | goto out; |
394 | } | |
406c93df TH |
395 | |
396 | sg_init_table(&src_sg, 1); | |
397 | sg_init_table(&dst_sg, 1); | |
398 | ||
399 | sg_set_page(&src_sg, src_page, extent_size, | |
400 | extent_offset * extent_size); | |
401 | sg_set_page(&dst_sg, dst_page, extent_size, | |
402 | extent_offset * extent_size); | |
403 | ||
404 | rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size, | |
405 | extent_iv, op); | |
0216f7f7 | 406 | if (rc < 0) { |
d78de618 TH |
407 | printk(KERN_ERR "%s: Error attempting to crypt page with " |
408 | "page_index = [%ld], extent_offset = [%ld]; " | |
409 | "rc = [%d]\n", __func__, page_index, extent_offset, rc); | |
0216f7f7 MH |
410 | goto out; |
411 | } | |
412 | rc = 0; | |
0216f7f7 MH |
413 | out: |
414 | return rc; | |
415 | } | |
416 | ||
237fead6 MH |
417 | /** |
418 | * ecryptfs_encrypt_page | |
0216f7f7 MH |
419 | * @page: Page mapped from the eCryptfs inode for the file; contains |
420 | * decrypted content that needs to be encrypted (to a temporary | |
421 | * page; not in place) and written out to the lower file | |
237fead6 MH |
422 | * |
423 | * Encrypt an eCryptfs page. This is done on a per-extent basis. Note | |
424 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
425 | * if the file was created on a machine with an 8K page size | |
426 | * (resulting in an 8K header), and then the file is copied onto a | |
427 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
428 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
429 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
430 | * | |
237fead6 MH |
431 | * Returns zero on success; negative on error |
432 | */ | |
0216f7f7 | 433 | int ecryptfs_encrypt_page(struct page *page) |
237fead6 | 434 | { |
0216f7f7 | 435 | struct inode *ecryptfs_inode; |
237fead6 | 436 | struct ecryptfs_crypt_stat *crypt_stat; |
7fcba054 ES |
437 | char *enc_extent_virt; |
438 | struct page *enc_extent_page = NULL; | |
0216f7f7 | 439 | loff_t extent_offset; |
0f896176 | 440 | loff_t lower_offset; |
237fead6 | 441 | int rc = 0; |
0216f7f7 MH |
442 | |
443 | ecryptfs_inode = page->mapping->host; | |
444 | crypt_stat = | |
445 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
13a791b4 | 446 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
7fcba054 ES |
447 | enc_extent_page = alloc_page(GFP_USER); |
448 | if (!enc_extent_page) { | |
0216f7f7 MH |
449 | rc = -ENOMEM; |
450 | ecryptfs_printk(KERN_ERR, "Error allocating memory for " | |
451 | "encrypted extent\n"); | |
452 | goto out; | |
453 | } | |
0f896176 | 454 | |
0216f7f7 | 455 | for (extent_offset = 0; |
09cbfeaf | 456 | extent_offset < (PAGE_SIZE / crypt_stat->extent_size); |
0216f7f7 | 457 | extent_offset++) { |
0df5ed65 | 458 | rc = crypt_extent(crypt_stat, enc_extent_page, page, |
d78de618 | 459 | extent_offset, ENCRYPT); |
237fead6 | 460 | if (rc) { |
0216f7f7 | 461 | printk(KERN_ERR "%s: Error encrypting extent; " |
18d1dbf1 | 462 | "rc = [%d]\n", __func__, rc); |
237fead6 MH |
463 | goto out; |
464 | } | |
7fcba054 | 465 | } |
0216f7f7 | 466 | |
24d15266 | 467 | lower_offset = lower_offset_for_page(crypt_stat, page); |
0f896176 TH |
468 | enc_extent_virt = kmap(enc_extent_page); |
469 | rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset, | |
09cbfeaf | 470 | PAGE_SIZE); |
0f896176 | 471 | kunmap(enc_extent_page); |
0216f7f7 | 472 | if (rc < 0) { |
0f896176 TH |
473 | ecryptfs_printk(KERN_ERR, |
474 | "Error attempting to write lower page; rc = [%d]\n", | |
475 | rc); | |
0216f7f7 MH |
476 | goto out; |
477 | } | |
478 | rc = 0; | |
237fead6 | 479 | out: |
7fcba054 | 480 | if (enc_extent_page) { |
7fcba054 ES |
481 | __free_page(enc_extent_page); |
482 | } | |
237fead6 MH |
483 | return rc; |
484 | } | |
485 | ||
486 | /** | |
487 | * ecryptfs_decrypt_page | |
0216f7f7 MH |
488 | * @page: Page mapped from the eCryptfs inode for the file; data read |
489 | * and decrypted from the lower file will be written into this | |
490 | * page | |
237fead6 MH |
491 | * |
492 | * Decrypt an eCryptfs page. This is done on a per-extent basis. Note | |
493 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
494 | * if the file was created on a machine with an 8K page size | |
495 | * (resulting in an 8K header), and then the file is copied onto a | |
496 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
497 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
498 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
499 | * | |
500 | * Returns zero on success; negative on error | |
501 | */ | |
0216f7f7 | 502 | int ecryptfs_decrypt_page(struct page *page) |
237fead6 | 503 | { |
0216f7f7 | 504 | struct inode *ecryptfs_inode; |
237fead6 | 505 | struct ecryptfs_crypt_stat *crypt_stat; |
9c6043f4 | 506 | char *page_virt; |
0216f7f7 | 507 | unsigned long extent_offset; |
0f896176 | 508 | loff_t lower_offset; |
237fead6 | 509 | int rc = 0; |
237fead6 | 510 | |
0216f7f7 MH |
511 | ecryptfs_inode = page->mapping->host; |
512 | crypt_stat = | |
513 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
13a791b4 | 514 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
0f896176 | 515 | |
24d15266 | 516 | lower_offset = lower_offset_for_page(crypt_stat, page); |
9c6043f4 | 517 | page_virt = kmap(page); |
09cbfeaf | 518 | rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE, |
0f896176 | 519 | ecryptfs_inode); |
9c6043f4 | 520 | kunmap(page); |
0f896176 TH |
521 | if (rc < 0) { |
522 | ecryptfs_printk(KERN_ERR, | |
523 | "Error attempting to read lower page; rc = [%d]\n", | |
524 | rc); | |
16a72c45 | 525 | goto out; |
237fead6 | 526 | } |
0f896176 | 527 | |
0216f7f7 | 528 | for (extent_offset = 0; |
09cbfeaf | 529 | extent_offset < (PAGE_SIZE / crypt_stat->extent_size); |
0216f7f7 | 530 | extent_offset++) { |
0df5ed65 | 531 | rc = crypt_extent(crypt_stat, page, page, |
d78de618 | 532 | extent_offset, DECRYPT); |
0216f7f7 | 533 | if (rc) { |
1abbe110 | 534 | printk(KERN_ERR "%s: Error decrypting extent; " |
18d1dbf1 | 535 | "rc = [%d]\n", __func__, rc); |
16a72c45 | 536 | goto out; |
237fead6 | 537 | } |
237fead6 MH |
538 | } |
539 | out: | |
237fead6 | 540 | return rc; |
237fead6 MH |
541 | } |
542 | ||
543 | #define ECRYPTFS_MAX_SCATTERLIST_LEN 4 | |
544 | ||
545 | /** | |
546 | * ecryptfs_init_crypt_ctx | |
421f91d2 | 547 | * @crypt_stat: Uninitialized crypt stats structure |
237fead6 MH |
548 | * |
549 | * Initialize the crypto context. | |
550 | * | |
551 | * TODO: Performance: Keep a cache of initialized cipher contexts; | |
552 | * only init if needed | |
553 | */ | |
554 | int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat) | |
555 | { | |
8bba066f | 556 | char *full_alg_name; |
237fead6 MH |
557 | int rc = -EINVAL; |
558 | ||
237fead6 MH |
559 | ecryptfs_printk(KERN_DEBUG, |
560 | "Initializing cipher [%s]; strlen = [%d]; " | |
f24b3887 | 561 | "key_size_bits = [%zd]\n", |
237fead6 MH |
562 | crypt_stat->cipher, (int)strlen(crypt_stat->cipher), |
563 | crypt_stat->key_size << 3); | |
cb69f36b | 564 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
237fead6 MH |
565 | if (crypt_stat->tfm) { |
566 | rc = 0; | |
cb69f36b | 567 | goto out_unlock; |
237fead6 | 568 | } |
8bba066f MH |
569 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, |
570 | crypt_stat->cipher, "cbc"); | |
571 | if (rc) | |
c8161f64 | 572 | goto out_unlock; |
3095e8e3 | 573 | crypt_stat->tfm = crypto_alloc_skcipher(full_alg_name, 0, 0); |
de88777e AM |
574 | if (IS_ERR(crypt_stat->tfm)) { |
575 | rc = PTR_ERR(crypt_stat->tfm); | |
b0105eae | 576 | crypt_stat->tfm = NULL; |
237fead6 MH |
577 | ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): " |
578 | "Error initializing cipher [%s]\n", | |
cb69f36b KC |
579 | full_alg_name); |
580 | goto out_free; | |
237fead6 | 581 | } |
231baecd EB |
582 | crypto_skcipher_set_flags(crypt_stat->tfm, |
583 | CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); | |
237fead6 | 584 | rc = 0; |
cb69f36b KC |
585 | out_free: |
586 | kfree(full_alg_name); | |
c8161f64 ES |
587 | out_unlock: |
588 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
237fead6 MH |
589 | return rc; |
590 | } | |
591 | ||
592 | static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat) | |
593 | { | |
594 | int extent_size_tmp; | |
595 | ||
596 | crypt_stat->extent_mask = 0xFFFFFFFF; | |
597 | crypt_stat->extent_shift = 0; | |
598 | if (crypt_stat->extent_size == 0) | |
599 | return; | |
600 | extent_size_tmp = crypt_stat->extent_size; | |
601 | while ((extent_size_tmp & 0x01) == 0) { | |
602 | extent_size_tmp >>= 1; | |
603 | crypt_stat->extent_mask <<= 1; | |
604 | crypt_stat->extent_shift++; | |
605 | } | |
606 | } | |
607 | ||
608 | void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) | |
609 | { | |
610 | /* Default values; may be overwritten as we are parsing the | |
611 | * packets. */ | |
612 | crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; | |
613 | set_extent_mask_and_shift(crypt_stat); | |
614 | crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES; | |
dd2a3b7a | 615 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
fa3ef1cb | 616 | crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
45eaab79 | 617 | else { |
09cbfeaf | 618 | if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) |
fa3ef1cb | 619 | crypt_stat->metadata_size = |
cc11beff | 620 | ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
45eaab79 | 621 | else |
09cbfeaf | 622 | crypt_stat->metadata_size = PAGE_SIZE; |
45eaab79 | 623 | } |
237fead6 MH |
624 | } |
625 | ||
5da877ea | 626 | /* |
237fead6 | 627 | * ecryptfs_compute_root_iv |
237fead6 MH |
628 | * |
629 | * On error, sets the root IV to all 0's. | |
630 | */ | |
631 | int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat) | |
632 | { | |
633 | int rc = 0; | |
634 | char dst[MD5_DIGEST_SIZE]; | |
635 | ||
636 | BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE); | |
637 | BUG_ON(crypt_stat->iv_bytes <= 0); | |
e2bd99ec | 638 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { |
237fead6 MH |
639 | rc = -EINVAL; |
640 | ecryptfs_printk(KERN_WARNING, "Session key not valid; " | |
641 | "cannot generate root IV\n"); | |
642 | goto out; | |
643 | } | |
644 | rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key, | |
645 | crypt_stat->key_size); | |
646 | if (rc) { | |
647 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " | |
648 | "MD5 while generating root IV\n"); | |
649 | goto out; | |
650 | } | |
651 | memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes); | |
652 | out: | |
653 | if (rc) { | |
654 | memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes); | |
e2bd99ec | 655 | crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING; |
237fead6 MH |
656 | } |
657 | return rc; | |
658 | } | |
659 | ||
660 | static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat) | |
661 | { | |
662 | get_random_bytes(crypt_stat->key, crypt_stat->key_size); | |
e2bd99ec | 663 | crypt_stat->flags |= ECRYPTFS_KEY_VALID; |
237fead6 MH |
664 | ecryptfs_compute_root_iv(crypt_stat); |
665 | if (unlikely(ecryptfs_verbosity > 0)) { | |
666 | ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n"); | |
667 | ecryptfs_dump_hex(crypt_stat->key, | |
668 | crypt_stat->key_size); | |
669 | } | |
670 | } | |
671 | ||
17398957 MH |
672 | /** |
673 | * ecryptfs_copy_mount_wide_flags_to_inode_flags | |
22e78faf MH |
674 | * @crypt_stat: The inode's cryptographic context |
675 | * @mount_crypt_stat: The mount point's cryptographic context | |
17398957 MH |
676 | * |
677 | * This function propagates the mount-wide flags to individual inode | |
678 | * flags. | |
679 | */ | |
680 | static void ecryptfs_copy_mount_wide_flags_to_inode_flags( | |
681 | struct ecryptfs_crypt_stat *crypt_stat, | |
682 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
683 | { | |
684 | if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) | |
685 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
686 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) | |
687 | crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED; | |
addd65ad MH |
688 | if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) { |
689 | crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES; | |
690 | if (mount_crypt_stat->flags | |
691 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK) | |
692 | crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK; | |
693 | else if (mount_crypt_stat->flags | |
694 | & ECRYPTFS_GLOBAL_ENCFN_USE_FEK) | |
695 | crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK; | |
696 | } | |
17398957 MH |
697 | } |
698 | ||
f4aad16a MH |
699 | static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs( |
700 | struct ecryptfs_crypt_stat *crypt_stat, | |
701 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
702 | { | |
703 | struct ecryptfs_global_auth_tok *global_auth_tok; | |
704 | int rc = 0; | |
705 | ||
aa06117f | 706 | mutex_lock(&crypt_stat->keysig_list_mutex); |
f4aad16a | 707 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
aa06117f | 708 | |
f4aad16a MH |
709 | list_for_each_entry(global_auth_tok, |
710 | &mount_crypt_stat->global_auth_tok_list, | |
711 | mount_crypt_stat_list) { | |
84814d64 TH |
712 | if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK) |
713 | continue; | |
f4aad16a MH |
714 | rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig); |
715 | if (rc) { | |
716 | printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc); | |
f4aad16a MH |
717 | goto out; |
718 | } | |
719 | } | |
aa06117f | 720 | |
f4aad16a | 721 | out: |
aa06117f RD |
722 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
723 | mutex_unlock(&crypt_stat->keysig_list_mutex); | |
f4aad16a MH |
724 | return rc; |
725 | } | |
726 | ||
237fead6 MH |
727 | /** |
728 | * ecryptfs_set_default_crypt_stat_vals | |
22e78faf MH |
729 | * @crypt_stat: The inode's cryptographic context |
730 | * @mount_crypt_stat: The mount point's cryptographic context | |
237fead6 MH |
731 | * |
732 | * Default values in the event that policy does not override them. | |
733 | */ | |
734 | static void ecryptfs_set_default_crypt_stat_vals( | |
735 | struct ecryptfs_crypt_stat *crypt_stat, | |
736 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
737 | { | |
17398957 MH |
738 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
739 | mount_crypt_stat); | |
237fead6 MH |
740 | ecryptfs_set_default_sizes(crypt_stat); |
741 | strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER); | |
742 | crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES; | |
e2bd99ec | 743 | crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID); |
237fead6 MH |
744 | crypt_stat->file_version = ECRYPTFS_FILE_VERSION; |
745 | crypt_stat->mount_crypt_stat = mount_crypt_stat; | |
746 | } | |
747 | ||
748 | /** | |
749 | * ecryptfs_new_file_context | |
b59db43a | 750 | * @ecryptfs_inode: The eCryptfs inode |
237fead6 MH |
751 | * |
752 | * If the crypto context for the file has not yet been established, | |
753 | * this is where we do that. Establishing a new crypto context | |
754 | * involves the following decisions: | |
755 | * - What cipher to use? | |
756 | * - What set of authentication tokens to use? | |
757 | * Here we just worry about getting enough information into the | |
758 | * authentication tokens so that we know that they are available. | |
759 | * We associate the available authentication tokens with the new file | |
760 | * via the set of signatures in the crypt_stat struct. Later, when | |
761 | * the headers are actually written out, we may again defer to | |
762 | * userspace to perform the encryption of the session key; for the | |
763 | * foreseeable future, this will be the case with public key packets. | |
764 | * | |
765 | * Returns zero on success; non-zero otherwise | |
766 | */ | |
b59db43a | 767 | int ecryptfs_new_file_context(struct inode *ecryptfs_inode) |
237fead6 | 768 | { |
237fead6 | 769 | struct ecryptfs_crypt_stat *crypt_stat = |
b59db43a | 770 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
237fead6 MH |
771 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
772 | &ecryptfs_superblock_to_private( | |
b59db43a | 773 | ecryptfs_inode->i_sb)->mount_crypt_stat; |
237fead6 | 774 | int cipher_name_len; |
f4aad16a | 775 | int rc = 0; |
237fead6 MH |
776 | |
777 | ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat); | |
af655dc6 | 778 | crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID); |
f4aad16a MH |
779 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
780 | mount_crypt_stat); | |
781 | rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat, | |
782 | mount_crypt_stat); | |
783 | if (rc) { | |
784 | printk(KERN_ERR "Error attempting to copy mount-wide key sigs " | |
785 | "to the inode key sigs; rc = [%d]\n", rc); | |
786 | goto out; | |
787 | } | |
788 | cipher_name_len = | |
789 | strlen(mount_crypt_stat->global_default_cipher_name); | |
790 | memcpy(crypt_stat->cipher, | |
791 | mount_crypt_stat->global_default_cipher_name, | |
792 | cipher_name_len); | |
793 | crypt_stat->cipher[cipher_name_len] = '\0'; | |
794 | crypt_stat->key_size = | |
795 | mount_crypt_stat->global_default_cipher_key_size; | |
796 | ecryptfs_generate_new_key(crypt_stat); | |
237fead6 MH |
797 | rc = ecryptfs_init_crypt_ctx(crypt_stat); |
798 | if (rc) | |
799 | ecryptfs_printk(KERN_ERR, "Error initializing cryptographic " | |
800 | "context for cipher [%s]: rc = [%d]\n", | |
801 | crypt_stat->cipher, rc); | |
f4aad16a | 802 | out: |
237fead6 MH |
803 | return rc; |
804 | } | |
805 | ||
806 | /** | |
7a86617e | 807 | * ecryptfs_validate_marker - check for the ecryptfs marker |
237fead6 MH |
808 | * @data: The data block in which to check |
809 | * | |
7a86617e | 810 | * Returns zero if marker found; -EINVAL if not found |
237fead6 | 811 | */ |
7a86617e | 812 | static int ecryptfs_validate_marker(char *data) |
237fead6 MH |
813 | { |
814 | u32 m_1, m_2; | |
815 | ||
29335c6a HH |
816 | m_1 = get_unaligned_be32(data); |
817 | m_2 = get_unaligned_be32(data + 4); | |
237fead6 | 818 | if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2) |
7a86617e | 819 | return 0; |
237fead6 MH |
820 | ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; " |
821 | "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2, | |
822 | MAGIC_ECRYPTFS_MARKER); | |
823 | ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = " | |
824 | "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER)); | |
7a86617e | 825 | return -EINVAL; |
237fead6 MH |
826 | } |
827 | ||
828 | struct ecryptfs_flag_map_elem { | |
829 | u32 file_flag; | |
830 | u32 local_flag; | |
831 | }; | |
832 | ||
833 | /* Add support for additional flags by adding elements here. */ | |
834 | static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = { | |
835 | {0x00000001, ECRYPTFS_ENABLE_HMAC}, | |
dd2a3b7a | 836 | {0x00000002, ECRYPTFS_ENCRYPTED}, |
addd65ad MH |
837 | {0x00000004, ECRYPTFS_METADATA_IN_XATTR}, |
838 | {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES} | |
237fead6 MH |
839 | }; |
840 | ||
841 | /** | |
842 | * ecryptfs_process_flags | |
22e78faf | 843 | * @crypt_stat: The cryptographic context |
237fead6 MH |
844 | * @page_virt: Source data to be parsed |
845 | * @bytes_read: Updated with the number of bytes read | |
237fead6 | 846 | */ |
7451c54a | 847 | static void ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat, |
237fead6 MH |
848 | char *page_virt, int *bytes_read) |
849 | { | |
237fead6 MH |
850 | int i; |
851 | u32 flags; | |
852 | ||
29335c6a | 853 | flags = get_unaligned_be32(page_virt); |
02f9876e | 854 | for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++) |
237fead6 | 855 | if (flags & ecryptfs_flag_map[i].file_flag) { |
e2bd99ec | 856 | crypt_stat->flags |= ecryptfs_flag_map[i].local_flag; |
237fead6 | 857 | } else |
e2bd99ec | 858 | crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag); |
237fead6 MH |
859 | /* Version is in top 8 bits of the 32-bit flag vector */ |
860 | crypt_stat->file_version = ((flags >> 24) & 0xFF); | |
861 | (*bytes_read) = 4; | |
237fead6 MH |
862 | } |
863 | ||
864 | /** | |
865 | * write_ecryptfs_marker | |
866 | * @page_virt: The pointer to in a page to begin writing the marker | |
867 | * @written: Number of bytes written | |
868 | * | |
869 | * Marker = 0x3c81b7f5 | |
870 | */ | |
871 | static void write_ecryptfs_marker(char *page_virt, size_t *written) | |
872 | { | |
873 | u32 m_1, m_2; | |
874 | ||
875 | get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); | |
876 | m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER); | |
29335c6a HH |
877 | put_unaligned_be32(m_1, page_virt); |
878 | page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2); | |
879 | put_unaligned_be32(m_2, page_virt); | |
237fead6 MH |
880 | (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
881 | } | |
882 | ||
f4e60e6b TH |
883 | void ecryptfs_write_crypt_stat_flags(char *page_virt, |
884 | struct ecryptfs_crypt_stat *crypt_stat, | |
885 | size_t *written) | |
237fead6 MH |
886 | { |
887 | u32 flags = 0; | |
888 | int i; | |
889 | ||
02f9876e | 890 | for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++) |
e2bd99ec | 891 | if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag) |
237fead6 MH |
892 | flags |= ecryptfs_flag_map[i].file_flag; |
893 | /* Version is in top 8 bits of the 32-bit flag vector */ | |
894 | flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000); | |
29335c6a | 895 | put_unaligned_be32(flags, page_virt); |
237fead6 MH |
896 | (*written) = 4; |
897 | } | |
898 | ||
899 | struct ecryptfs_cipher_code_str_map_elem { | |
900 | char cipher_str[16]; | |
19e66a67 | 901 | u8 cipher_code; |
237fead6 MH |
902 | }; |
903 | ||
904 | /* Add support for additional ciphers by adding elements here. The | |
40f0fd37 | 905 | * cipher_code is whatever OpenPGP applications use to identify the |
237fead6 MH |
906 | * ciphers. List in order of probability. */ |
907 | static struct ecryptfs_cipher_code_str_map_elem | |
908 | ecryptfs_cipher_code_str_map[] = { | |
909 | {"aes",RFC2440_CIPHER_AES_128 }, | |
910 | {"blowfish", RFC2440_CIPHER_BLOWFISH}, | |
911 | {"des3_ede", RFC2440_CIPHER_DES3_EDE}, | |
912 | {"cast5", RFC2440_CIPHER_CAST_5}, | |
913 | {"twofish", RFC2440_CIPHER_TWOFISH}, | |
914 | {"cast6", RFC2440_CIPHER_CAST_6}, | |
915 | {"aes", RFC2440_CIPHER_AES_192}, | |
916 | {"aes", RFC2440_CIPHER_AES_256} | |
917 | }; | |
918 | ||
919 | /** | |
920 | * ecryptfs_code_for_cipher_string | |
9c79f34f MH |
921 | * @cipher_name: The string alias for the cipher |
922 | * @key_bytes: Length of key in bytes; used for AES code selection | |
237fead6 MH |
923 | * |
924 | * Returns zero on no match, or the cipher code on match | |
925 | */ | |
9c79f34f | 926 | u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes) |
237fead6 MH |
927 | { |
928 | int i; | |
19e66a67 | 929 | u8 code = 0; |
237fead6 MH |
930 | struct ecryptfs_cipher_code_str_map_elem *map = |
931 | ecryptfs_cipher_code_str_map; | |
932 | ||
9c79f34f MH |
933 | if (strcmp(cipher_name, "aes") == 0) { |
934 | switch (key_bytes) { | |
237fead6 MH |
935 | case 16: |
936 | code = RFC2440_CIPHER_AES_128; | |
937 | break; | |
938 | case 24: | |
939 | code = RFC2440_CIPHER_AES_192; | |
940 | break; | |
941 | case 32: | |
942 | code = RFC2440_CIPHER_AES_256; | |
943 | } | |
944 | } else { | |
945 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) | |
9c79f34f | 946 | if (strcmp(cipher_name, map[i].cipher_str) == 0) { |
237fead6 MH |
947 | code = map[i].cipher_code; |
948 | break; | |
949 | } | |
950 | } | |
951 | return code; | |
952 | } | |
953 | ||
954 | /** | |
955 | * ecryptfs_cipher_code_to_string | |
956 | * @str: Destination to write out the cipher name | |
957 | * @cipher_code: The code to convert to cipher name string | |
958 | * | |
959 | * Returns zero on success | |
960 | */ | |
19e66a67 | 961 | int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code) |
237fead6 MH |
962 | { |
963 | int rc = 0; | |
964 | int i; | |
965 | ||
966 | str[0] = '\0'; | |
967 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) | |
968 | if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code) | |
969 | strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str); | |
970 | if (str[0] == '\0') { | |
971 | ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: " | |
972 | "[%d]\n", cipher_code); | |
973 | rc = -EINVAL; | |
974 | } | |
975 | return rc; | |
976 | } | |
977 | ||
778aeb42 | 978 | int ecryptfs_read_and_validate_header_region(struct inode *inode) |
dd2a3b7a | 979 | { |
778aeb42 TH |
980 | u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
981 | u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; | |
dd2a3b7a MH |
982 | int rc; |
983 | ||
778aeb42 TH |
984 | rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES, |
985 | inode); | |
0bdf8a82 DC |
986 | if (rc < 0) |
987 | return rc; | |
988 | else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) | |
989 | return -EINVAL; | |
778aeb42 TH |
990 | rc = ecryptfs_validate_marker(marker); |
991 | if (!rc) | |
992 | ecryptfs_i_size_init(file_size, inode); | |
dd2a3b7a MH |
993 | return rc; |
994 | } | |
995 | ||
e77a56dd MH |
996 | void |
997 | ecryptfs_write_header_metadata(char *virt, | |
998 | struct ecryptfs_crypt_stat *crypt_stat, | |
999 | size_t *written) | |
237fead6 MH |
1000 | { |
1001 | u32 header_extent_size; | |
1002 | u16 num_header_extents_at_front; | |
1003 | ||
45eaab79 | 1004 | header_extent_size = (u32)crypt_stat->extent_size; |
237fead6 | 1005 | num_header_extents_at_front = |
fa3ef1cb | 1006 | (u16)(crypt_stat->metadata_size / crypt_stat->extent_size); |
29335c6a | 1007 | put_unaligned_be32(header_extent_size, virt); |
237fead6 | 1008 | virt += 4; |
29335c6a | 1009 | put_unaligned_be16(num_header_extents_at_front, virt); |
237fead6 MH |
1010 | (*written) = 6; |
1011 | } | |
1012 | ||
30632870 | 1013 | struct kmem_cache *ecryptfs_header_cache; |
237fead6 MH |
1014 | |
1015 | /** | |
1016 | * ecryptfs_write_headers_virt | |
22e78faf | 1017 | * @page_virt: The virtual address to write the headers to |
87b811c3 | 1018 | * @max: The size of memory allocated at page_virt |
22e78faf MH |
1019 | * @size: Set to the number of bytes written by this function |
1020 | * @crypt_stat: The cryptographic context | |
1021 | * @ecryptfs_dentry: The eCryptfs dentry | |
237fead6 MH |
1022 | * |
1023 | * Format version: 1 | |
1024 | * | |
1025 | * Header Extent: | |
1026 | * Octets 0-7: Unencrypted file size (big-endian) | |
1027 | * Octets 8-15: eCryptfs special marker | |
1028 | * Octets 16-19: Flags | |
1029 | * Octet 16: File format version number (between 0 and 255) | |
1030 | * Octets 17-18: Reserved | |
1031 | * Octet 19: Bit 1 (lsb): Reserved | |
1032 | * Bit 2: Encrypted? | |
1033 | * Bits 3-8: Reserved | |
1034 | * Octets 20-23: Header extent size (big-endian) | |
1035 | * Octets 24-25: Number of header extents at front of file | |
1036 | * (big-endian) | |
1037 | * Octet 26: Begin RFC 2440 authentication token packet set | |
1038 | * Data Extent 0: | |
1039 | * Lower data (CBC encrypted) | |
1040 | * Data Extent 1: | |
1041 | * Lower data (CBC encrypted) | |
1042 | * ... | |
1043 | * | |
1044 | * Returns zero on success | |
1045 | */ | |
87b811c3 ES |
1046 | static int ecryptfs_write_headers_virt(char *page_virt, size_t max, |
1047 | size_t *size, | |
dd2a3b7a MH |
1048 | struct ecryptfs_crypt_stat *crypt_stat, |
1049 | struct dentry *ecryptfs_dentry) | |
237fead6 MH |
1050 | { |
1051 | int rc; | |
1052 | size_t written; | |
1053 | size_t offset; | |
1054 | ||
1055 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
1056 | write_ecryptfs_marker((page_virt + offset), &written); | |
1057 | offset += written; | |
f4e60e6b TH |
1058 | ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat, |
1059 | &written); | |
237fead6 | 1060 | offset += written; |
e77a56dd MH |
1061 | ecryptfs_write_header_metadata((page_virt + offset), crypt_stat, |
1062 | &written); | |
237fead6 MH |
1063 | offset += written; |
1064 | rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat, | |
1065 | ecryptfs_dentry, &written, | |
87b811c3 | 1066 | max - offset); |
237fead6 MH |
1067 | if (rc) |
1068 | ecryptfs_printk(KERN_WARNING, "Error generating key packet " | |
1069 | "set; rc = [%d]\n", rc); | |
dd2a3b7a MH |
1070 | if (size) { |
1071 | offset += written; | |
1072 | *size = offset; | |
1073 | } | |
1074 | return rc; | |
1075 | } | |
1076 | ||
22e78faf | 1077 | static int |
b59db43a | 1078 | ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode, |
8faece5f | 1079 | char *virt, size_t virt_len) |
dd2a3b7a | 1080 | { |
d7cdc5fe | 1081 | int rc; |
dd2a3b7a | 1082 | |
b59db43a | 1083 | rc = ecryptfs_write_lower(ecryptfs_inode, virt, |
8faece5f | 1084 | 0, virt_len); |
96a7b9c2 | 1085 | if (rc < 0) |
d7cdc5fe | 1086 | printk(KERN_ERR "%s: Error attempting to write header " |
96a7b9c2 TH |
1087 | "information to lower file; rc = [%d]\n", __func__, rc); |
1088 | else | |
1089 | rc = 0; | |
70456600 | 1090 | return rc; |
dd2a3b7a MH |
1091 | } |
1092 | ||
22e78faf MH |
1093 | static int |
1094 | ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry, | |
3767e255 | 1095 | struct inode *ecryptfs_inode, |
22e78faf | 1096 | char *page_virt, size_t size) |
dd2a3b7a MH |
1097 | { |
1098 | int rc; | |
d43388de RK |
1099 | struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); |
1100 | struct inode *lower_inode = d_inode(lower_dentry); | |
dd2a3b7a | 1101 | |
d43388de RK |
1102 | if (!(lower_inode->i_opflags & IOP_XATTR)) { |
1103 | rc = -EOPNOTSUPP; | |
1104 | goto out; | |
1105 | } | |
dd2a3b7a | 1106 | |
d43388de | 1107 | inode_lock(lower_inode); |
c7c7a1a1 TA |
1108 | rc = __vfs_setxattr(&init_user_ns, lower_dentry, lower_inode, |
1109 | ECRYPTFS_XATTR_NAME, page_virt, size, 0); | |
d43388de RK |
1110 | if (!rc && ecryptfs_inode) |
1111 | fsstack_copy_attr_all(ecryptfs_inode, lower_inode); | |
1112 | inode_unlock(lower_inode); | |
1113 | out: | |
237fead6 MH |
1114 | return rc; |
1115 | } | |
1116 | ||
8faece5f TH |
1117 | static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask, |
1118 | unsigned int order) | |
1119 | { | |
1120 | struct page *page; | |
1121 | ||
1122 | page = alloc_pages(gfp_mask | __GFP_ZERO, order); | |
1123 | if (page) | |
1124 | return (unsigned long) page_address(page); | |
1125 | return 0; | |
1126 | } | |
1127 | ||
237fead6 | 1128 | /** |
dd2a3b7a | 1129 | * ecryptfs_write_metadata |
b59db43a TH |
1130 | * @ecryptfs_dentry: The eCryptfs dentry, which should be negative |
1131 | * @ecryptfs_inode: The newly created eCryptfs inode | |
237fead6 MH |
1132 | * |
1133 | * Write the file headers out. This will likely involve a userspace | |
1134 | * callout, in which the session key is encrypted with one or more | |
1135 | * public keys and/or the passphrase necessary to do the encryption is | |
1136 | * retrieved via a prompt. Exactly what happens at this point should | |
1137 | * be policy-dependent. | |
1138 | * | |
1139 | * Returns zero on success; non-zero on error | |
1140 | */ | |
b59db43a TH |
1141 | int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry, |
1142 | struct inode *ecryptfs_inode) | |
237fead6 | 1143 | { |
d7cdc5fe | 1144 | struct ecryptfs_crypt_stat *crypt_stat = |
b59db43a | 1145 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
8faece5f | 1146 | unsigned int order; |
cc11beff | 1147 | char *virt; |
8faece5f | 1148 | size_t virt_len; |
d7cdc5fe | 1149 | size_t size = 0; |
237fead6 MH |
1150 | int rc = 0; |
1151 | ||
e2bd99ec MH |
1152 | if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
1153 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { | |
d7cdc5fe | 1154 | printk(KERN_ERR "Key is invalid; bailing out\n"); |
237fead6 MH |
1155 | rc = -EINVAL; |
1156 | goto out; | |
1157 | } | |
1158 | } else { | |
cc11beff | 1159 | printk(KERN_WARNING "%s: Encrypted flag not set\n", |
18d1dbf1 | 1160 | __func__); |
237fead6 | 1161 | rc = -EINVAL; |
237fead6 MH |
1162 | goto out; |
1163 | } | |
fa3ef1cb | 1164 | virt_len = crypt_stat->metadata_size; |
8faece5f | 1165 | order = get_order(virt_len); |
237fead6 | 1166 | /* Released in this function */ |
8faece5f | 1167 | virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order); |
cc11beff | 1168 | if (!virt) { |
18d1dbf1 | 1169 | printk(KERN_ERR "%s: Out of memory\n", __func__); |
237fead6 MH |
1170 | rc = -ENOMEM; |
1171 | goto out; | |
1172 | } | |
bd4f0fe8 | 1173 | /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */ |
8faece5f TH |
1174 | rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat, |
1175 | ecryptfs_dentry); | |
237fead6 | 1176 | if (unlikely(rc)) { |
cc11beff | 1177 | printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n", |
18d1dbf1 | 1178 | __func__, rc); |
237fead6 MH |
1179 | goto out_free; |
1180 | } | |
dd2a3b7a | 1181 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
3767e255 AV |
1182 | rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode, |
1183 | virt, size); | |
dd2a3b7a | 1184 | else |
b59db43a | 1185 | rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt, |
8faece5f | 1186 | virt_len); |
dd2a3b7a | 1187 | if (rc) { |
cc11beff | 1188 | printk(KERN_ERR "%s: Error writing metadata out to lower file; " |
18d1dbf1 | 1189 | "rc = [%d]\n", __func__, rc); |
dd2a3b7a | 1190 | goto out_free; |
237fead6 | 1191 | } |
237fead6 | 1192 | out_free: |
8faece5f | 1193 | free_pages((unsigned long)virt, order); |
237fead6 MH |
1194 | out: |
1195 | return rc; | |
1196 | } | |
1197 | ||
dd2a3b7a MH |
1198 | #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0 |
1199 | #define ECRYPTFS_VALIDATE_HEADER_SIZE 1 | |
237fead6 | 1200 | static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat, |
dd2a3b7a MH |
1201 | char *virt, int *bytes_read, |
1202 | int validate_header_size) | |
237fead6 MH |
1203 | { |
1204 | int rc = 0; | |
1205 | u32 header_extent_size; | |
1206 | u16 num_header_extents_at_front; | |
1207 | ||
29335c6a HH |
1208 | header_extent_size = get_unaligned_be32(virt); |
1209 | virt += sizeof(__be32); | |
1210 | num_header_extents_at_front = get_unaligned_be16(virt); | |
fa3ef1cb TH |
1211 | crypt_stat->metadata_size = (((size_t)num_header_extents_at_front |
1212 | * (size_t)header_extent_size)); | |
29335c6a | 1213 | (*bytes_read) = (sizeof(__be32) + sizeof(__be16)); |
dd2a3b7a | 1214 | if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE) |
fa3ef1cb | 1215 | && (crypt_stat->metadata_size |
dd2a3b7a | 1216 | < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) { |
237fead6 | 1217 | rc = -EINVAL; |
cc11beff | 1218 | printk(KERN_WARNING "Invalid header size: [%zd]\n", |
fa3ef1cb | 1219 | crypt_stat->metadata_size); |
237fead6 MH |
1220 | } |
1221 | return rc; | |
1222 | } | |
1223 | ||
1224 | /** | |
1225 | * set_default_header_data | |
22e78faf | 1226 | * @crypt_stat: The cryptographic context |
237fead6 MH |
1227 | * |
1228 | * For version 0 file format; this function is only for backwards | |
1229 | * compatibility for files created with the prior versions of | |
1230 | * eCryptfs. | |
1231 | */ | |
1232 | static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) | |
1233 | { | |
fa3ef1cb | 1234 | crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
237fead6 MH |
1235 | } |
1236 | ||
3aeb86ea TH |
1237 | void ecryptfs_i_size_init(const char *page_virt, struct inode *inode) |
1238 | { | |
1239 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat; | |
1240 | struct ecryptfs_crypt_stat *crypt_stat; | |
1241 | u64 file_size; | |
1242 | ||
1243 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; | |
1244 | mount_crypt_stat = | |
1245 | &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat; | |
1246 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { | |
1247 | file_size = i_size_read(ecryptfs_inode_to_lower(inode)); | |
1248 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) | |
1249 | file_size += crypt_stat->metadata_size; | |
1250 | } else | |
1251 | file_size = get_unaligned_be64(page_virt); | |
1252 | i_size_write(inode, (loff_t)file_size); | |
1253 | crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED; | |
1254 | } | |
1255 | ||
237fead6 MH |
1256 | /** |
1257 | * ecryptfs_read_headers_virt | |
22e78faf MH |
1258 | * @page_virt: The virtual address into which to read the headers |
1259 | * @crypt_stat: The cryptographic context | |
1260 | * @ecryptfs_dentry: The eCryptfs dentry | |
1261 | * @validate_header_size: Whether to validate the header size while reading | |
237fead6 MH |
1262 | * |
1263 | * Read/parse the header data. The header format is detailed in the | |
1264 | * comment block for the ecryptfs_write_headers_virt() function. | |
1265 | * | |
1266 | * Returns zero on success | |
1267 | */ | |
1268 | static int ecryptfs_read_headers_virt(char *page_virt, | |
1269 | struct ecryptfs_crypt_stat *crypt_stat, | |
dd2a3b7a MH |
1270 | struct dentry *ecryptfs_dentry, |
1271 | int validate_header_size) | |
237fead6 MH |
1272 | { |
1273 | int rc = 0; | |
1274 | int offset; | |
1275 | int bytes_read; | |
1276 | ||
1277 | ecryptfs_set_default_sizes(crypt_stat); | |
1278 | crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private( | |
1279 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
1280 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
7a86617e TH |
1281 | rc = ecryptfs_validate_marker(page_virt + offset); |
1282 | if (rc) | |
237fead6 | 1283 | goto out; |
3aeb86ea | 1284 | if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED)) |
2b0143b5 | 1285 | ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry)); |
237fead6 | 1286 | offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
7451c54a | 1287 | ecryptfs_process_flags(crypt_stat, (page_virt + offset), &bytes_read); |
237fead6 MH |
1288 | if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) { |
1289 | ecryptfs_printk(KERN_WARNING, "File version is [%d]; only " | |
1290 | "file version [%d] is supported by this " | |
1291 | "version of eCryptfs\n", | |
1292 | crypt_stat->file_version, | |
1293 | ECRYPTFS_SUPPORTED_FILE_VERSION); | |
1294 | rc = -EINVAL; | |
1295 | goto out; | |
1296 | } | |
1297 | offset += bytes_read; | |
1298 | if (crypt_stat->file_version >= 1) { | |
1299 | rc = parse_header_metadata(crypt_stat, (page_virt + offset), | |
dd2a3b7a | 1300 | &bytes_read, validate_header_size); |
237fead6 MH |
1301 | if (rc) { |
1302 | ecryptfs_printk(KERN_WARNING, "Error reading header " | |
1303 | "metadata; rc = [%d]\n", rc); | |
1304 | } | |
1305 | offset += bytes_read; | |
1306 | } else | |
1307 | set_default_header_data(crypt_stat); | |
1308 | rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), | |
1309 | ecryptfs_dentry); | |
1310 | out: | |
1311 | return rc; | |
1312 | } | |
1313 | ||
1314 | /** | |
dd2a3b7a | 1315 | * ecryptfs_read_xattr_region |
22e78faf | 1316 | * @page_virt: The vitual address into which to read the xattr data |
2ed92554 | 1317 | * @ecryptfs_inode: The eCryptfs inode |
dd2a3b7a MH |
1318 | * |
1319 | * Attempts to read the crypto metadata from the extended attribute | |
1320 | * region of the lower file. | |
22e78faf MH |
1321 | * |
1322 | * Returns zero on success; non-zero on error | |
dd2a3b7a | 1323 | */ |
d7cdc5fe | 1324 | int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode) |
dd2a3b7a | 1325 | { |
d7cdc5fe | 1326 | struct dentry *lower_dentry = |
b583043e | 1327 | ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry; |
dd2a3b7a MH |
1328 | ssize_t size; |
1329 | int rc = 0; | |
1330 | ||
ce23e640 AV |
1331 | size = ecryptfs_getxattr_lower(lower_dentry, |
1332 | ecryptfs_inode_to_lower(ecryptfs_inode), | |
1333 | ECRYPTFS_XATTR_NAME, | |
d7cdc5fe | 1334 | page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE); |
dd2a3b7a | 1335 | if (size < 0) { |
25bd8174 MH |
1336 | if (unlikely(ecryptfs_verbosity > 0)) |
1337 | printk(KERN_INFO "Error attempting to read the [%s] " | |
1338 | "xattr from the lower file; return value = " | |
1339 | "[%zd]\n", ECRYPTFS_XATTR_NAME, size); | |
dd2a3b7a MH |
1340 | rc = -EINVAL; |
1341 | goto out; | |
1342 | } | |
1343 | out: | |
1344 | return rc; | |
1345 | } | |
1346 | ||
778aeb42 | 1347 | int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry, |
3b06b3eb | 1348 | struct inode *inode) |
dd2a3b7a | 1349 | { |
778aeb42 TH |
1350 | u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
1351 | u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; | |
dd2a3b7a MH |
1352 | int rc; |
1353 | ||
778aeb42 | 1354 | rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), |
ce23e640 | 1355 | ecryptfs_inode_to_lower(inode), |
778aeb42 TH |
1356 | ECRYPTFS_XATTR_NAME, file_size, |
1357 | ECRYPTFS_SIZE_AND_MARKER_BYTES); | |
0bdf8a82 DC |
1358 | if (rc < 0) |
1359 | return rc; | |
1360 | else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) | |
1361 | return -EINVAL; | |
778aeb42 TH |
1362 | rc = ecryptfs_validate_marker(marker); |
1363 | if (!rc) | |
1364 | ecryptfs_i_size_init(file_size, inode); | |
dd2a3b7a MH |
1365 | return rc; |
1366 | } | |
1367 | ||
5da877ea | 1368 | /* |
dd2a3b7a MH |
1369 | * ecryptfs_read_metadata |
1370 | * | |
1371 | * Common entry point for reading file metadata. From here, we could | |
1372 | * retrieve the header information from the header region of the file, | |
40f0fd37 | 1373 | * the xattr region of the file, or some other repository that is |
dd2a3b7a MH |
1374 | * stored separately from the file itself. The current implementation |
1375 | * supports retrieving the metadata information from the file contents | |
1376 | * and from the xattr region. | |
237fead6 MH |
1377 | * |
1378 | * Returns zero if valid headers found and parsed; non-zero otherwise | |
1379 | */ | |
d7cdc5fe | 1380 | int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) |
237fead6 | 1381 | { |
bb450361 TG |
1382 | int rc; |
1383 | char *page_virt; | |
2b0143b5 | 1384 | struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry); |
237fead6 | 1385 | struct ecryptfs_crypt_stat *crypt_stat = |
d7cdc5fe | 1386 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
e77a56dd MH |
1387 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
1388 | &ecryptfs_superblock_to_private( | |
1389 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
237fead6 | 1390 | |
e77a56dd MH |
1391 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
1392 | mount_crypt_stat); | |
237fead6 | 1393 | /* Read the first page from the underlying file */ |
30632870 | 1394 | page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER); |
237fead6 MH |
1395 | if (!page_virt) { |
1396 | rc = -ENOMEM; | |
237fead6 MH |
1397 | goto out; |
1398 | } | |
d7cdc5fe MH |
1399 | rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size, |
1400 | ecryptfs_inode); | |
96a7b9c2 | 1401 | if (rc >= 0) |
d7cdc5fe MH |
1402 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
1403 | ecryptfs_dentry, | |
1404 | ECRYPTFS_VALIDATE_HEADER_SIZE); | |
237fead6 | 1405 | if (rc) { |
bb450361 | 1406 | /* metadata is not in the file header, so try xattrs */ |
09cbfeaf | 1407 | memset(page_virt, 0, PAGE_SIZE); |
d7cdc5fe | 1408 | rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode); |
dd2a3b7a MH |
1409 | if (rc) { |
1410 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " | |
30373dc0 TG |
1411 | "file header region or xattr region, inode %lu\n", |
1412 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1413 | rc = -EINVAL; |
1414 | goto out; | |
1415 | } | |
1416 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, | |
1417 | ecryptfs_dentry, | |
1418 | ECRYPTFS_DONT_VALIDATE_HEADER_SIZE); | |
1419 | if (rc) { | |
1420 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " | |
30373dc0 TG |
1421 | "file xattr region either, inode %lu\n", |
1422 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1423 | rc = -EINVAL; |
1424 | } | |
1425 | if (crypt_stat->mount_crypt_stat->flags | |
1426 | & ECRYPTFS_XATTR_METADATA_ENABLED) { | |
1427 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
1428 | } else { | |
1429 | printk(KERN_WARNING "Attempt to access file with " | |
1430 | "crypto metadata only in the extended attribute " | |
1431 | "region, but eCryptfs was mounted without " | |
1432 | "xattr support enabled. eCryptfs will not treat " | |
30373dc0 TG |
1433 | "this like an encrypted file, inode %lu\n", |
1434 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1435 | rc = -EINVAL; |
1436 | } | |
237fead6 MH |
1437 | } |
1438 | out: | |
1439 | if (page_virt) { | |
09cbfeaf | 1440 | memset(page_virt, 0, PAGE_SIZE); |
30632870 | 1441 | kmem_cache_free(ecryptfs_header_cache, page_virt); |
237fead6 MH |
1442 | } |
1443 | return rc; | |
1444 | } | |
1445 | ||
5da877ea | 1446 | /* |
51ca58dc MH |
1447 | * ecryptfs_encrypt_filename - encrypt filename |
1448 | * | |
1449 | * CBC-encrypts the filename. We do not want to encrypt the same | |
1450 | * filename with the same key and IV, which may happen with hard | |
1451 | * links, so we prepend random bits to each filename. | |
1452 | * | |
1453 | * Returns zero on success; non-zero otherwise | |
1454 | */ | |
1455 | static int | |
1456 | ecryptfs_encrypt_filename(struct ecryptfs_filename *filename, | |
51ca58dc MH |
1457 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
1458 | { | |
1459 | int rc = 0; | |
1460 | ||
1461 | filename->encrypted_filename = NULL; | |
1462 | filename->encrypted_filename_size = 0; | |
97c31606 AV |
1463 | if (mount_crypt_stat && (mount_crypt_stat->flags |
1464 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) { | |
51ca58dc MH |
1465 | size_t packet_size; |
1466 | size_t remaining_bytes; | |
1467 | ||
1468 | rc = ecryptfs_write_tag_70_packet( | |
1469 | NULL, NULL, | |
1470 | &filename->encrypted_filename_size, | |
1471 | mount_crypt_stat, NULL, | |
1472 | filename->filename_size); | |
1473 | if (rc) { | |
1474 | printk(KERN_ERR "%s: Error attempting to get packet " | |
1475 | "size for tag 72; rc = [%d]\n", __func__, | |
1476 | rc); | |
1477 | filename->encrypted_filename_size = 0; | |
1478 | goto out; | |
1479 | } | |
1480 | filename->encrypted_filename = | |
1481 | kmalloc(filename->encrypted_filename_size, GFP_KERNEL); | |
1482 | if (!filename->encrypted_filename) { | |
51ca58dc MH |
1483 | rc = -ENOMEM; |
1484 | goto out; | |
1485 | } | |
1486 | remaining_bytes = filename->encrypted_filename_size; | |
1487 | rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename, | |
1488 | &remaining_bytes, | |
1489 | &packet_size, | |
1490 | mount_crypt_stat, | |
1491 | filename->filename, | |
1492 | filename->filename_size); | |
1493 | if (rc) { | |
1494 | printk(KERN_ERR "%s: Error attempting to generate " | |
1495 | "tag 70 packet; rc = [%d]\n", __func__, | |
1496 | rc); | |
1497 | kfree(filename->encrypted_filename); | |
1498 | filename->encrypted_filename = NULL; | |
1499 | filename->encrypted_filename_size = 0; | |
1500 | goto out; | |
1501 | } | |
1502 | filename->encrypted_filename_size = packet_size; | |
1503 | } else { | |
1504 | printk(KERN_ERR "%s: No support for requested filename " | |
1505 | "encryption method in this release\n", __func__); | |
df6ad33b | 1506 | rc = -EOPNOTSUPP; |
51ca58dc MH |
1507 | goto out; |
1508 | } | |
1509 | out: | |
1510 | return rc; | |
1511 | } | |
1512 | ||
1513 | static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size, | |
1514 | const char *name, size_t name_size) | |
1515 | { | |
1516 | int rc = 0; | |
1517 | ||
fd9fc842 | 1518 | (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL); |
51ca58dc MH |
1519 | if (!(*copied_name)) { |
1520 | rc = -ENOMEM; | |
1521 | goto out; | |
1522 | } | |
1523 | memcpy((void *)(*copied_name), (void *)name, name_size); | |
1524 | (*copied_name)[(name_size)] = '\0'; /* Only for convenience | |
1525 | * in printing out the | |
1526 | * string in debug | |
1527 | * messages */ | |
fd9fc842 | 1528 | (*copied_name_size) = name_size; |
51ca58dc MH |
1529 | out: |
1530 | return rc; | |
1531 | } | |
1532 | ||
237fead6 | 1533 | /** |
f4aad16a | 1534 | * ecryptfs_process_key_cipher - Perform key cipher initialization. |
237fead6 | 1535 | * @key_tfm: Crypto context for key material, set by this function |
e5d9cbde MH |
1536 | * @cipher_name: Name of the cipher |
1537 | * @key_size: Size of the key in bytes | |
237fead6 MH |
1538 | * |
1539 | * Returns zero on success. Any crypto_tfm structs allocated here | |
1540 | * should be released by other functions, such as on a superblock put | |
1541 | * event, regardless of whether this function succeeds for fails. | |
1542 | */ | |
cd9d67df | 1543 | static int |
3095e8e3 | 1544 | ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm, |
f4aad16a | 1545 | char *cipher_name, size_t *key_size) |
237fead6 MH |
1546 | { |
1547 | char dummy_key[ECRYPTFS_MAX_KEY_BYTES]; | |
ece550f5 | 1548 | char *full_alg_name = NULL; |
237fead6 MH |
1549 | int rc; |
1550 | ||
e5d9cbde MH |
1551 | *key_tfm = NULL; |
1552 | if (*key_size > ECRYPTFS_MAX_KEY_BYTES) { | |
237fead6 | 1553 | rc = -EINVAL; |
df261c52 | 1554 | printk(KERN_ERR "Requested key size is [%zd] bytes; maximum " |
e5d9cbde | 1555 | "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES); |
237fead6 MH |
1556 | goto out; |
1557 | } | |
8bba066f MH |
1558 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name, |
1559 | "ecb"); | |
1560 | if (rc) | |
1561 | goto out; | |
3095e8e3 | 1562 | *key_tfm = crypto_alloc_skcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC); |
8bba066f MH |
1563 | if (IS_ERR(*key_tfm)) { |
1564 | rc = PTR_ERR(*key_tfm); | |
237fead6 | 1565 | printk(KERN_ERR "Unable to allocate crypto cipher with name " |
38268498 | 1566 | "[%s]; rc = [%d]\n", full_alg_name, rc); |
237fead6 MH |
1567 | goto out; |
1568 | } | |
231baecd | 1569 | crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); |
3095e8e3 | 1570 | if (*key_size == 0) |
9ac0d136 | 1571 | *key_size = crypto_skcipher_max_keysize(*key_tfm); |
e5d9cbde | 1572 | get_random_bytes(dummy_key, *key_size); |
3095e8e3 | 1573 | rc = crypto_skcipher_setkey(*key_tfm, dummy_key, *key_size); |
237fead6 | 1574 | if (rc) { |
df261c52 | 1575 | printk(KERN_ERR "Error attempting to set key of size [%zd] for " |
38268498 DH |
1576 | "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name, |
1577 | rc); | |
237fead6 MH |
1578 | rc = -EINVAL; |
1579 | goto out; | |
1580 | } | |
1581 | out: | |
ece550f5 | 1582 | kfree(full_alg_name); |
237fead6 MH |
1583 | return rc; |
1584 | } | |
f4aad16a MH |
1585 | |
1586 | struct kmem_cache *ecryptfs_key_tfm_cache; | |
7896b631 | 1587 | static struct list_head key_tfm_list; |
902af369 | 1588 | DEFINE_MUTEX(key_tfm_list_mutex); |
f4aad16a | 1589 | |
7371a382 | 1590 | int __init ecryptfs_init_crypto(void) |
f4aad16a | 1591 | { |
f4aad16a MH |
1592 | INIT_LIST_HEAD(&key_tfm_list); |
1593 | return 0; | |
1594 | } | |
1595 | ||
af440f52 ES |
1596 | /** |
1597 | * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list | |
1598 | * | |
1599 | * Called only at module unload time | |
1600 | */ | |
fcd12835 | 1601 | int ecryptfs_destroy_crypto(void) |
f4aad16a MH |
1602 | { |
1603 | struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp; | |
1604 | ||
1605 | mutex_lock(&key_tfm_list_mutex); | |
1606 | list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list, | |
1607 | key_tfm_list) { | |
1608 | list_del(&key_tfm->key_tfm_list); | |
3095e8e3 | 1609 | crypto_free_skcipher(key_tfm->key_tfm); |
f4aad16a MH |
1610 | kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm); |
1611 | } | |
1612 | mutex_unlock(&key_tfm_list_mutex); | |
1613 | return 0; | |
1614 | } | |
1615 | ||
1616 | int | |
1617 | ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name, | |
1618 | size_t key_size) | |
1619 | { | |
1620 | struct ecryptfs_key_tfm *tmp_tfm; | |
1621 | int rc = 0; | |
1622 | ||
af440f52 ES |
1623 | BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); |
1624 | ||
f4aad16a | 1625 | tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL); |
5032f360 | 1626 | if (key_tfm) |
f4aad16a MH |
1627 | (*key_tfm) = tmp_tfm; |
1628 | if (!tmp_tfm) { | |
1629 | rc = -ENOMEM; | |
f4aad16a MH |
1630 | goto out; |
1631 | } | |
1632 | mutex_init(&tmp_tfm->key_tfm_mutex); | |
1633 | strncpy(tmp_tfm->cipher_name, cipher_name, | |
1634 | ECRYPTFS_MAX_CIPHER_NAME_SIZE); | |
b8862906 | 1635 | tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; |
f4aad16a | 1636 | tmp_tfm->key_size = key_size; |
5dda6992 MH |
1637 | rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm, |
1638 | tmp_tfm->cipher_name, | |
1639 | &tmp_tfm->key_size); | |
1640 | if (rc) { | |
f4aad16a MH |
1641 | printk(KERN_ERR "Error attempting to initialize key TFM " |
1642 | "cipher with name = [%s]; rc = [%d]\n", | |
1643 | tmp_tfm->cipher_name, rc); | |
1644 | kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm); | |
5032f360 | 1645 | if (key_tfm) |
f4aad16a MH |
1646 | (*key_tfm) = NULL; |
1647 | goto out; | |
1648 | } | |
f4aad16a | 1649 | list_add(&tmp_tfm->key_tfm_list, &key_tfm_list); |
f4aad16a MH |
1650 | out: |
1651 | return rc; | |
1652 | } | |
1653 | ||
af440f52 ES |
1654 | /** |
1655 | * ecryptfs_tfm_exists - Search for existing tfm for cipher_name. | |
1656 | * @cipher_name: the name of the cipher to search for | |
1657 | * @key_tfm: set to corresponding tfm if found | |
1658 | * | |
1659 | * Searches for cached key_tfm matching @cipher_name | |
1660 | * Must be called with &key_tfm_list_mutex held | |
1661 | * Returns 1 if found, with @key_tfm set | |
1662 | * Returns 0 if not found, with @key_tfm set to NULL | |
1663 | */ | |
1664 | int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm) | |
1665 | { | |
1666 | struct ecryptfs_key_tfm *tmp_key_tfm; | |
1667 | ||
1668 | BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); | |
1669 | ||
1670 | list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) { | |
1671 | if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) { | |
1672 | if (key_tfm) | |
1673 | (*key_tfm) = tmp_key_tfm; | |
1674 | return 1; | |
1675 | } | |
1676 | } | |
1677 | if (key_tfm) | |
1678 | (*key_tfm) = NULL; | |
1679 | return 0; | |
1680 | } | |
1681 | ||
1682 | /** | |
1683 | * ecryptfs_get_tfm_and_mutex_for_cipher_name | |
1684 | * | |
1685 | * @tfm: set to cached tfm found, or new tfm created | |
1686 | * @tfm_mutex: set to mutex for cached tfm found, or new tfm created | |
1687 | * @cipher_name: the name of the cipher to search for and/or add | |
1688 | * | |
1689 | * Sets pointers to @tfm & @tfm_mutex matching @cipher_name. | |
1690 | * Searches for cached item first, and creates new if not found. | |
1691 | * Returns 0 on success, non-zero if adding new cipher failed | |
1692 | */ | |
3095e8e3 | 1693 | int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm, |
f4aad16a MH |
1694 | struct mutex **tfm_mutex, |
1695 | char *cipher_name) | |
1696 | { | |
1697 | struct ecryptfs_key_tfm *key_tfm; | |
1698 | int rc = 0; | |
1699 | ||
1700 | (*tfm) = NULL; | |
1701 | (*tfm_mutex) = NULL; | |
af440f52 | 1702 | |
f4aad16a | 1703 | mutex_lock(&key_tfm_list_mutex); |
af440f52 ES |
1704 | if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) { |
1705 | rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0); | |
1706 | if (rc) { | |
1707 | printk(KERN_ERR "Error adding new key_tfm to list; " | |
1708 | "rc = [%d]\n", rc); | |
f4aad16a MH |
1709 | goto out; |
1710 | } | |
1711 | } | |
f4aad16a MH |
1712 | (*tfm) = key_tfm->key_tfm; |
1713 | (*tfm_mutex) = &key_tfm->key_tfm_mutex; | |
1714 | out: | |
71fd5179 | 1715 | mutex_unlock(&key_tfm_list_mutex); |
f4aad16a MH |
1716 | return rc; |
1717 | } | |
51ca58dc MH |
1718 | |
1719 | /* 64 characters forming a 6-bit target field */ | |
1720 | static unsigned char *portable_filename_chars = ("-.0123456789ABCD" | |
1721 | "EFGHIJKLMNOPQRST" | |
1722 | "UVWXYZabcdefghij" | |
1723 | "klmnopqrstuvwxyz"); | |
1724 | ||
1725 | /* We could either offset on every reverse map or just pad some 0x00's | |
1726 | * at the front here */ | |
0f751e64 | 1727 | static const unsigned char filename_rev_map[256] = { |
51ca58dc MH |
1728 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */ |
1729 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */ | |
1730 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */ | |
1731 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */ | |
1732 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */ | |
1733 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */ | |
1734 | 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */ | |
1735 | 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */ | |
1736 | 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */ | |
1737 | 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */ | |
1738 | 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */ | |
1739 | 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */ | |
1740 | 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */ | |
1741 | 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */ | |
1742 | 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */ | |
0f751e64 | 1743 | 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */ |
51ca58dc MH |
1744 | }; |
1745 | ||
1746 | /** | |
1747 | * ecryptfs_encode_for_filename | |
1748 | * @dst: Destination location for encoded filename | |
1749 | * @dst_size: Size of the encoded filename in bytes | |
1750 | * @src: Source location for the filename to encode | |
1751 | * @src_size: Size of the source in bytes | |
1752 | */ | |
37028758 | 1753 | static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size, |
51ca58dc MH |
1754 | unsigned char *src, size_t src_size) |
1755 | { | |
1756 | size_t num_blocks; | |
1757 | size_t block_num = 0; | |
1758 | size_t dst_offset = 0; | |
1759 | unsigned char last_block[3]; | |
1760 | ||
1761 | if (src_size == 0) { | |
1762 | (*dst_size) = 0; | |
1763 | goto out; | |
1764 | } | |
1765 | num_blocks = (src_size / 3); | |
1766 | if ((src_size % 3) == 0) { | |
1767 | memcpy(last_block, (&src[src_size - 3]), 3); | |
1768 | } else { | |
1769 | num_blocks++; | |
1770 | last_block[2] = 0x00; | |
1771 | switch (src_size % 3) { | |
1772 | case 1: | |
1773 | last_block[0] = src[src_size - 1]; | |
1774 | last_block[1] = 0x00; | |
1775 | break; | |
1776 | case 2: | |
1777 | last_block[0] = src[src_size - 2]; | |
1778 | last_block[1] = src[src_size - 1]; | |
1779 | } | |
1780 | } | |
1781 | (*dst_size) = (num_blocks * 4); | |
1782 | if (!dst) | |
1783 | goto out; | |
1784 | while (block_num < num_blocks) { | |
1785 | unsigned char *src_block; | |
1786 | unsigned char dst_block[4]; | |
1787 | ||
1788 | if (block_num == (num_blocks - 1)) | |
1789 | src_block = last_block; | |
1790 | else | |
1791 | src_block = &src[block_num * 3]; | |
1792 | dst_block[0] = ((src_block[0] >> 2) & 0x3F); | |
1793 | dst_block[1] = (((src_block[0] << 4) & 0x30) | |
1794 | | ((src_block[1] >> 4) & 0x0F)); | |
1795 | dst_block[2] = (((src_block[1] << 2) & 0x3C) | |
1796 | | ((src_block[2] >> 6) & 0x03)); | |
1797 | dst_block[3] = (src_block[2] & 0x3F); | |
1798 | dst[dst_offset++] = portable_filename_chars[dst_block[0]]; | |
1799 | dst[dst_offset++] = portable_filename_chars[dst_block[1]]; | |
1800 | dst[dst_offset++] = portable_filename_chars[dst_block[2]]; | |
1801 | dst[dst_offset++] = portable_filename_chars[dst_block[3]]; | |
1802 | block_num++; | |
1803 | } | |
1804 | out: | |
1805 | return; | |
1806 | } | |
1807 | ||
4a26620d TH |
1808 | static size_t ecryptfs_max_decoded_size(size_t encoded_size) |
1809 | { | |
1810 | /* Not exact; conservatively long. Every block of 4 | |
1811 | * encoded characters decodes into a block of 3 | |
1812 | * decoded characters. This segment of code provides | |
1813 | * the caller with the maximum amount of allocated | |
1814 | * space that @dst will need to point to in a | |
1815 | * subsequent call. */ | |
1816 | return ((encoded_size + 1) * 3) / 4; | |
1817 | } | |
1818 | ||
71c11c37 MH |
1819 | /** |
1820 | * ecryptfs_decode_from_filename | |
1821 | * @dst: If NULL, this function only sets @dst_size and returns. If | |
1822 | * non-NULL, this function decodes the encoded octets in @src | |
1823 | * into the memory that @dst points to. | |
1824 | * @dst_size: Set to the size of the decoded string. | |
1825 | * @src: The encoded set of octets to decode. | |
1826 | * @src_size: The size of the encoded set of octets to decode. | |
1827 | */ | |
1828 | static void | |
1829 | ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size, | |
1830 | const unsigned char *src, size_t src_size) | |
51ca58dc MH |
1831 | { |
1832 | u8 current_bit_offset = 0; | |
1833 | size_t src_byte_offset = 0; | |
1834 | size_t dst_byte_offset = 0; | |
51ca58dc | 1835 | |
5032f360 | 1836 | if (!dst) { |
4a26620d | 1837 | (*dst_size) = ecryptfs_max_decoded_size(src_size); |
51ca58dc MH |
1838 | goto out; |
1839 | } | |
1840 | while (src_byte_offset < src_size) { | |
1841 | unsigned char src_byte = | |
1842 | filename_rev_map[(int)src[src_byte_offset]]; | |
1843 | ||
1844 | switch (current_bit_offset) { | |
1845 | case 0: | |
1846 | dst[dst_byte_offset] = (src_byte << 2); | |
1847 | current_bit_offset = 6; | |
1848 | break; | |
1849 | case 6: | |
1850 | dst[dst_byte_offset++] |= (src_byte >> 4); | |
1851 | dst[dst_byte_offset] = ((src_byte & 0xF) | |
1852 | << 4); | |
1853 | current_bit_offset = 4; | |
1854 | break; | |
1855 | case 4: | |
1856 | dst[dst_byte_offset++] |= (src_byte >> 2); | |
1857 | dst[dst_byte_offset] = (src_byte << 6); | |
1858 | current_bit_offset = 2; | |
1859 | break; | |
1860 | case 2: | |
1861 | dst[dst_byte_offset++] |= (src_byte); | |
51ca58dc MH |
1862 | current_bit_offset = 0; |
1863 | break; | |
1864 | } | |
1865 | src_byte_offset++; | |
1866 | } | |
1867 | (*dst_size) = dst_byte_offset; | |
1868 | out: | |
71c11c37 | 1869 | return; |
51ca58dc MH |
1870 | } |
1871 | ||
1872 | /** | |
1873 | * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text | |
5da877ea LJ |
1874 | * @encoded_name: The encrypted name |
1875 | * @encoded_name_size: Length of the encrypted name | |
1876 | * @mount_crypt_stat: The crypt_stat struct associated with the file name to encode | |
51ca58dc | 1877 | * @name: The plaintext name |
5da877ea | 1878 | * @name_size: The length of the plaintext name |
51ca58dc MH |
1879 | * |
1880 | * Encrypts and encodes a filename into something that constitutes a | |
1881 | * valid filename for a filesystem, with printable characters. | |
1882 | * | |
1883 | * We assume that we have a properly initialized crypto context, | |
1884 | * pointed to by crypt_stat->tfm. | |
1885 | * | |
1886 | * Returns zero on success; non-zero on otherwise | |
1887 | */ | |
1888 | int ecryptfs_encrypt_and_encode_filename( | |
1889 | char **encoded_name, | |
1890 | size_t *encoded_name_size, | |
51ca58dc MH |
1891 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat, |
1892 | const char *name, size_t name_size) | |
1893 | { | |
1894 | size_t encoded_name_no_prefix_size; | |
1895 | int rc = 0; | |
1896 | ||
1897 | (*encoded_name) = NULL; | |
1898 | (*encoded_name_size) = 0; | |
97c31606 AV |
1899 | if (mount_crypt_stat && (mount_crypt_stat->flags |
1900 | & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { | |
51ca58dc MH |
1901 | struct ecryptfs_filename *filename; |
1902 | ||
1903 | filename = kzalloc(sizeof(*filename), GFP_KERNEL); | |
1904 | if (!filename) { | |
51ca58dc MH |
1905 | rc = -ENOMEM; |
1906 | goto out; | |
1907 | } | |
1908 | filename->filename = (char *)name; | |
1909 | filename->filename_size = name_size; | |
97c31606 | 1910 | rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat); |
51ca58dc MH |
1911 | if (rc) { |
1912 | printk(KERN_ERR "%s: Error attempting to encrypt " | |
1913 | "filename; rc = [%d]\n", __func__, rc); | |
1914 | kfree(filename); | |
1915 | goto out; | |
1916 | } | |
1917 | ecryptfs_encode_for_filename( | |
1918 | NULL, &encoded_name_no_prefix_size, | |
1919 | filename->encrypted_filename, | |
1920 | filename->encrypted_filename_size); | |
97c31606 | 1921 | if (mount_crypt_stat |
51ca58dc | 1922 | && (mount_crypt_stat->flags |
97c31606 | 1923 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) |
51ca58dc MH |
1924 | (*encoded_name_size) = |
1925 | (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1926 | + encoded_name_no_prefix_size); | |
1927 | else | |
1928 | (*encoded_name_size) = | |
1929 | (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1930 | + encoded_name_no_prefix_size); | |
1931 | (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL); | |
1932 | if (!(*encoded_name)) { | |
51ca58dc MH |
1933 | rc = -ENOMEM; |
1934 | kfree(filename->encrypted_filename); | |
1935 | kfree(filename); | |
1936 | goto out; | |
1937 | } | |
97c31606 | 1938 | if (mount_crypt_stat |
51ca58dc | 1939 | && (mount_crypt_stat->flags |
97c31606 | 1940 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) { |
51ca58dc MH |
1941 | memcpy((*encoded_name), |
1942 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, | |
1943 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE); | |
1944 | ecryptfs_encode_for_filename( | |
1945 | ((*encoded_name) | |
1946 | + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE), | |
1947 | &encoded_name_no_prefix_size, | |
1948 | filename->encrypted_filename, | |
1949 | filename->encrypted_filename_size); | |
1950 | (*encoded_name_size) = | |
1951 | (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1952 | + encoded_name_no_prefix_size); | |
1953 | (*encoded_name)[(*encoded_name_size)] = '\0'; | |
51ca58dc | 1954 | } else { |
df6ad33b | 1955 | rc = -EOPNOTSUPP; |
51ca58dc MH |
1956 | } |
1957 | if (rc) { | |
1958 | printk(KERN_ERR "%s: Error attempting to encode " | |
1959 | "encrypted filename; rc = [%d]\n", __func__, | |
1960 | rc); | |
1961 | kfree((*encoded_name)); | |
1962 | (*encoded_name) = NULL; | |
1963 | (*encoded_name_size) = 0; | |
1964 | } | |
1965 | kfree(filename->encrypted_filename); | |
1966 | kfree(filename); | |
1967 | } else { | |
1968 | rc = ecryptfs_copy_filename(encoded_name, | |
1969 | encoded_name_size, | |
1970 | name, name_size); | |
1971 | } | |
1972 | out: | |
1973 | return rc; | |
1974 | } | |
1975 | ||
e86281e7 TH |
1976 | static bool is_dot_dotdot(const char *name, size_t name_size) |
1977 | { | |
1978 | if (name_size == 1 && name[0] == '.') | |
1979 | return true; | |
1980 | else if (name_size == 2 && name[0] == '.' && name[1] == '.') | |
1981 | return true; | |
1982 | ||
1983 | return false; | |
1984 | } | |
1985 | ||
51ca58dc MH |
1986 | /** |
1987 | * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext | |
1988 | * @plaintext_name: The plaintext name | |
1989 | * @plaintext_name_size: The plaintext name size | |
5da877ea | 1990 | * @sb: Ecryptfs's super_block |
51ca58dc MH |
1991 | * @name: The filename in cipher text |
1992 | * @name_size: The cipher text name size | |
1993 | * | |
1994 | * Decrypts and decodes the filename. | |
1995 | * | |
1996 | * Returns zero on error; non-zero otherwise | |
1997 | */ | |
1998 | int ecryptfs_decode_and_decrypt_filename(char **plaintext_name, | |
1999 | size_t *plaintext_name_size, | |
0747fdb2 | 2000 | struct super_block *sb, |
51ca58dc MH |
2001 | const char *name, size_t name_size) |
2002 | { | |
2aac0cf8 | 2003 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
0747fdb2 | 2004 | &ecryptfs_superblock_to_private(sb)->mount_crypt_stat; |
51ca58dc MH |
2005 | char *decoded_name; |
2006 | size_t decoded_name_size; | |
2007 | size_t packet_size; | |
2008 | int rc = 0; | |
2009 | ||
e86281e7 TH |
2010 | if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) && |
2011 | !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)) { | |
2012 | if (is_dot_dotdot(name, name_size)) { | |
2013 | rc = ecryptfs_copy_filename(plaintext_name, | |
2014 | plaintext_name_size, | |
2015 | name, name_size); | |
2016 | goto out; | |
2017 | } | |
2018 | ||
2019 | if (name_size <= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE || | |
2020 | strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, | |
2021 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)) { | |
2022 | rc = -EINVAL; | |
2023 | goto out; | |
2024 | } | |
51ca58dc MH |
2025 | |
2026 | name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
2027 | name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
71c11c37 MH |
2028 | ecryptfs_decode_from_filename(NULL, &decoded_name_size, |
2029 | name, name_size); | |
51ca58dc MH |
2030 | decoded_name = kmalloc(decoded_name_size, GFP_KERNEL); |
2031 | if (!decoded_name) { | |
51ca58dc MH |
2032 | rc = -ENOMEM; |
2033 | goto out; | |
2034 | } | |
71c11c37 MH |
2035 | ecryptfs_decode_from_filename(decoded_name, &decoded_name_size, |
2036 | name, name_size); | |
51ca58dc MH |
2037 | rc = ecryptfs_parse_tag_70_packet(plaintext_name, |
2038 | plaintext_name_size, | |
2039 | &packet_size, | |
2040 | mount_crypt_stat, | |
2041 | decoded_name, | |
2042 | decoded_name_size); | |
2043 | if (rc) { | |
e86281e7 TH |
2044 | ecryptfs_printk(KERN_DEBUG, |
2045 | "%s: Could not parse tag 70 packet from filename\n", | |
2046 | __func__); | |
51ca58dc MH |
2047 | goto out_free; |
2048 | } | |
2049 | } else { | |
2050 | rc = ecryptfs_copy_filename(plaintext_name, | |
2051 | plaintext_name_size, | |
2052 | name, name_size); | |
2053 | goto out; | |
2054 | } | |
2055 | out_free: | |
2056 | kfree(decoded_name); | |
2057 | out: | |
2058 | return rc; | |
2059 | } | |
4a26620d TH |
2060 | |
2061 | #define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143 | |
2062 | ||
2063 | int ecryptfs_set_f_namelen(long *namelen, long lower_namelen, | |
2064 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
2065 | { | |
3095e8e3 | 2066 | struct crypto_skcipher *tfm; |
4a26620d TH |
2067 | struct mutex *tfm_mutex; |
2068 | size_t cipher_blocksize; | |
2069 | int rc; | |
2070 | ||
2071 | if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { | |
2072 | (*namelen) = lower_namelen; | |
2073 | return 0; | |
2074 | } | |
2075 | ||
3095e8e3 | 2076 | rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, |
4a26620d TH |
2077 | mount_crypt_stat->global_default_fn_cipher_name); |
2078 | if (unlikely(rc)) { | |
2079 | (*namelen) = 0; | |
2080 | return rc; | |
2081 | } | |
2082 | ||
2083 | mutex_lock(tfm_mutex); | |
3095e8e3 | 2084 | cipher_blocksize = crypto_skcipher_blocksize(tfm); |
4a26620d TH |
2085 | mutex_unlock(tfm_mutex); |
2086 | ||
2087 | /* Return an exact amount for the common cases */ | |
2088 | if (lower_namelen == NAME_MAX | |
2089 | && (cipher_blocksize == 8 || cipher_blocksize == 16)) { | |
2090 | (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16; | |
2091 | return 0; | |
2092 | } | |
2093 | ||
2094 | /* Return a safe estimate for the uncommon cases */ | |
2095 | (*namelen) = lower_namelen; | |
2096 | (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
2097 | /* Since this is the max decoded size, subtract 1 "decoded block" len */ | |
2098 | (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3; | |
2099 | (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE; | |
2100 | (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES; | |
2101 | /* Worst case is that the filename is padded nearly a full block size */ | |
2102 | (*namelen) -= cipher_blocksize - 1; | |
2103 | ||
2104 | if ((*namelen) < 0) | |
2105 | (*namelen) = 0; | |
2106 | ||
2107 | return 0; | |
2108 | } |