Commit | Line | Data |
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1a59d1b8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
237fead6 MH |
2 | /** |
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 | ||
3095e8e3 HX |
51 | static int ecryptfs_hash_digest(struct crypto_shash *tfm, |
52 | char *src, int len, char *dst) | |
53 | { | |
54 | SHASH_DESC_ON_STACK(desc, tfm); | |
55 | int err; | |
56 | ||
57 | desc->tfm = tfm; | |
3095e8e3 HX |
58 | err = crypto_shash_digest(desc, src, len, dst); |
59 | shash_desc_zero(desc); | |
60 | return err; | |
61 | } | |
62 | ||
237fead6 MH |
63 | /** |
64 | * ecryptfs_calculate_md5 - calculates the md5 of @src | |
65 | * @dst: Pointer to 16 bytes of allocated memory | |
66 | * @crypt_stat: Pointer to crypt_stat struct for the current inode | |
67 | * @src: Data to be md5'd | |
68 | * @len: Length of @src | |
69 | * | |
70 | * Uses the allocated crypto context that crypt_stat references to | |
71 | * generate the MD5 sum of the contents of src. | |
72 | */ | |
73 | static int ecryptfs_calculate_md5(char *dst, | |
74 | struct ecryptfs_crypt_stat *crypt_stat, | |
75 | char *src, int len) | |
76 | { | |
3095e8e3 | 77 | struct crypto_shash *tfm; |
565d9724 | 78 | int rc = 0; |
237fead6 | 79 | |
3095e8e3 | 80 | tfm = crypt_stat->hash_tfm; |
3095e8e3 | 81 | rc = ecryptfs_hash_digest(tfm, src, len, dst); |
8a29f2b0 MH |
82 | if (rc) { |
83 | printk(KERN_ERR | |
3095e8e3 | 84 | "%s: Error computing crypto hash; rc = [%d]\n", |
18d1dbf1 | 85 | __func__, rc); |
8a29f2b0 MH |
86 | goto out; |
87 | } | |
237fead6 MH |
88 | out: |
89 | return rc; | |
90 | } | |
91 | ||
cd9d67df MH |
92 | static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name, |
93 | char *cipher_name, | |
94 | char *chaining_modifier) | |
8bba066f MH |
95 | { |
96 | int cipher_name_len = strlen(cipher_name); | |
97 | int chaining_modifier_len = strlen(chaining_modifier); | |
98 | int algified_name_len; | |
99 | int rc; | |
100 | ||
101 | algified_name_len = (chaining_modifier_len + cipher_name_len + 3); | |
102 | (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL); | |
7bd473fc | 103 | if (!(*algified_name)) { |
8bba066f MH |
104 | rc = -ENOMEM; |
105 | goto out; | |
106 | } | |
107 | snprintf((*algified_name), algified_name_len, "%s(%s)", | |
108 | chaining_modifier, cipher_name); | |
109 | rc = 0; | |
110 | out: | |
111 | return rc; | |
112 | } | |
113 | ||
237fead6 MH |
114 | /** |
115 | * ecryptfs_derive_iv | |
116 | * @iv: destination for the derived iv vale | |
117 | * @crypt_stat: Pointer to crypt_stat struct for the current inode | |
d6a13c17 | 118 | * @offset: Offset of the extent whose IV we are to derive |
237fead6 MH |
119 | * |
120 | * Generate the initialization vector from the given root IV and page | |
121 | * offset. | |
122 | * | |
123 | * Returns zero on success; non-zero on error. | |
124 | */ | |
a34f60f7 MH |
125 | int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat, |
126 | loff_t offset) | |
237fead6 MH |
127 | { |
128 | int rc = 0; | |
129 | char dst[MD5_DIGEST_SIZE]; | |
130 | char src[ECRYPTFS_MAX_IV_BYTES + 16]; | |
131 | ||
132 | if (unlikely(ecryptfs_verbosity > 0)) { | |
133 | ecryptfs_printk(KERN_DEBUG, "root iv:\n"); | |
134 | ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes); | |
135 | } | |
136 | /* TODO: It is probably secure to just cast the least | |
137 | * significant bits of the root IV into an unsigned long and | |
138 | * add the offset to that rather than go through all this | |
139 | * hashing business. -Halcrow */ | |
140 | memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes); | |
141 | memset((src + crypt_stat->iv_bytes), 0, 16); | |
d6a13c17 | 142 | snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset); |
237fead6 MH |
143 | if (unlikely(ecryptfs_verbosity > 0)) { |
144 | ecryptfs_printk(KERN_DEBUG, "source:\n"); | |
145 | ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16)); | |
146 | } | |
147 | rc = ecryptfs_calculate_md5(dst, crypt_stat, src, | |
148 | (crypt_stat->iv_bytes + 16)); | |
149 | if (rc) { | |
150 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " | |
151 | "MD5 while generating IV for a page\n"); | |
152 | goto out; | |
153 | } | |
154 | memcpy(iv, dst, crypt_stat->iv_bytes); | |
155 | if (unlikely(ecryptfs_verbosity > 0)) { | |
156 | ecryptfs_printk(KERN_DEBUG, "derived iv:\n"); | |
157 | ecryptfs_dump_hex(iv, crypt_stat->iv_bytes); | |
158 | } | |
159 | out: | |
160 | return rc; | |
161 | } | |
162 | ||
163 | /** | |
164 | * ecryptfs_init_crypt_stat | |
165 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. | |
166 | * | |
167 | * Initialize the crypt_stat structure. | |
168 | */ | |
e81f3340 | 169 | int ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
237fead6 | 170 | { |
e81f3340 HX |
171 | struct crypto_shash *tfm; |
172 | int rc; | |
173 | ||
174 | tfm = crypto_alloc_shash(ECRYPTFS_DEFAULT_HASH, 0, 0); | |
175 | if (IS_ERR(tfm)) { | |
176 | rc = PTR_ERR(tfm); | |
177 | ecryptfs_printk(KERN_ERR, "Error attempting to " | |
178 | "allocate crypto context; rc = [%d]\n", | |
179 | rc); | |
180 | return rc; | |
181 | } | |
182 | ||
237fead6 | 183 | memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
f4aad16a MH |
184 | INIT_LIST_HEAD(&crypt_stat->keysig_list); |
185 | mutex_init(&crypt_stat->keysig_list_mutex); | |
237fead6 MH |
186 | mutex_init(&crypt_stat->cs_mutex); |
187 | mutex_init(&crypt_stat->cs_tfm_mutex); | |
e81f3340 | 188 | crypt_stat->hash_tfm = tfm; |
e2bd99ec | 189 | crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED; |
e81f3340 HX |
190 | |
191 | return 0; | |
237fead6 MH |
192 | } |
193 | ||
194 | /** | |
fcd12835 | 195 | * ecryptfs_destroy_crypt_stat |
237fead6 MH |
196 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
197 | * | |
198 | * Releases all memory associated with a crypt_stat struct. | |
199 | */ | |
fcd12835 | 200 | void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
237fead6 | 201 | { |
f4aad16a MH |
202 | struct ecryptfs_key_sig *key_sig, *key_sig_tmp; |
203 | ||
3095e8e3 HX |
204 | crypto_free_skcipher(crypt_stat->tfm); |
205 | crypto_free_shash(crypt_stat->hash_tfm); | |
f4aad16a MH |
206 | list_for_each_entry_safe(key_sig, key_sig_tmp, |
207 | &crypt_stat->keysig_list, crypt_stat_list) { | |
208 | list_del(&key_sig->crypt_stat_list); | |
209 | kmem_cache_free(ecryptfs_key_sig_cache, key_sig); | |
210 | } | |
237fead6 MH |
211 | memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
212 | } | |
213 | ||
fcd12835 | 214 | void ecryptfs_destroy_mount_crypt_stat( |
237fead6 MH |
215 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
216 | { | |
f4aad16a MH |
217 | struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp; |
218 | ||
219 | if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED)) | |
220 | return; | |
221 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
222 | list_for_each_entry_safe(auth_tok, auth_tok_tmp, | |
223 | &mount_crypt_stat->global_auth_tok_list, | |
224 | mount_crypt_stat_list) { | |
225 | list_del(&auth_tok->mount_crypt_stat_list); | |
0dad87fc | 226 | if (!(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID)) |
f4aad16a MH |
227 | key_put(auth_tok->global_auth_tok_key); |
228 | kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok); | |
229 | } | |
230 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
237fead6 MH |
231 | memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat)); |
232 | } | |
233 | ||
234 | /** | |
235 | * virt_to_scatterlist | |
236 | * @addr: Virtual address | |
237 | * @size: Size of data; should be an even multiple of the block size | |
238 | * @sg: Pointer to scatterlist array; set to NULL to obtain only | |
239 | * the number of scatterlist structs required in array | |
240 | * @sg_size: Max array size | |
241 | * | |
242 | * Fills in a scatterlist array with page references for a passed | |
243 | * virtual address. | |
244 | * | |
245 | * Returns the number of scatterlist structs in array used | |
246 | */ | |
247 | int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg, | |
248 | int sg_size) | |
249 | { | |
250 | int i = 0; | |
251 | struct page *pg; | |
252 | int offset; | |
253 | int remainder_of_page; | |
254 | ||
68e3f5dd HX |
255 | sg_init_table(sg, sg_size); |
256 | ||
237fead6 MH |
257 | while (size > 0 && i < sg_size) { |
258 | pg = virt_to_page(addr); | |
259 | offset = offset_in_page(addr); | |
a07c48ad | 260 | sg_set_page(&sg[i], pg, 0, offset); |
09cbfeaf | 261 | remainder_of_page = PAGE_SIZE - offset; |
237fead6 | 262 | if (size >= remainder_of_page) { |
a07c48ad | 263 | sg[i].length = remainder_of_page; |
237fead6 MH |
264 | addr += remainder_of_page; |
265 | size -= remainder_of_page; | |
266 | } else { | |
a07c48ad | 267 | sg[i].length = size; |
237fead6 MH |
268 | addr += size; |
269 | size = 0; | |
270 | } | |
271 | i++; | |
272 | } | |
273 | if (size > 0) | |
274 | return -ENOMEM; | |
275 | return i; | |
276 | } | |
277 | ||
4dfea4f0 TH |
278 | struct extent_crypt_result { |
279 | struct completion completion; | |
280 | int rc; | |
281 | }; | |
282 | ||
283 | static void extent_crypt_complete(struct crypto_async_request *req, int rc) | |
284 | { | |
285 | struct extent_crypt_result *ecr = req->data; | |
286 | ||
287 | if (rc == -EINPROGRESS) | |
288 | return; | |
289 | ||
290 | ecr->rc = rc; | |
291 | complete(&ecr->completion); | |
292 | } | |
293 | ||
237fead6 | 294 | /** |
00a69940 | 295 | * crypt_scatterlist |
237fead6 | 296 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
0df5ed65 | 297 | * @dst_sg: Destination of the data after performing the crypto operation |
00a69940 TH |
298 | * @src_sg: Data to be encrypted or decrypted |
299 | * @size: Length of data | |
300 | * @iv: IV to use | |
301 | * @op: ENCRYPT or DECRYPT to indicate the desired operation | |
237fead6 | 302 | * |
00a69940 | 303 | * Returns the number of bytes encrypted or decrypted; negative value on error |
237fead6 | 304 | */ |
00a69940 | 305 | static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, |
0df5ed65 | 306 | struct scatterlist *dst_sg, |
00a69940 TH |
307 | struct scatterlist *src_sg, int size, |
308 | unsigned char *iv, int op) | |
237fead6 | 309 | { |
3095e8e3 | 310 | struct skcipher_request *req = NULL; |
4dfea4f0 | 311 | struct extent_crypt_result ecr; |
237fead6 MH |
312 | int rc = 0; |
313 | ||
314 | BUG_ON(!crypt_stat || !crypt_stat->tfm | |
e2bd99ec | 315 | || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)); |
237fead6 | 316 | if (unlikely(ecryptfs_verbosity > 0)) { |
f24b3887 | 317 | ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n", |
237fead6 MH |
318 | crypt_stat->key_size); |
319 | ecryptfs_dump_hex(crypt_stat->key, | |
320 | crypt_stat->key_size); | |
321 | } | |
4dfea4f0 TH |
322 | |
323 | init_completion(&ecr.completion); | |
324 | ||
237fead6 | 325 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
3095e8e3 | 326 | req = skcipher_request_alloc(crypt_stat->tfm, GFP_NOFS); |
4dfea4f0 | 327 | if (!req) { |
237fead6 | 328 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
4dfea4f0 | 329 | rc = -ENOMEM; |
237fead6 MH |
330 | goto out; |
331 | } | |
4dfea4f0 | 332 | |
3095e8e3 | 333 | skcipher_request_set_callback(req, |
4dfea4f0 TH |
334 | CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, |
335 | extent_crypt_complete, &ecr); | |
336 | /* Consider doing this once, when the file is opened */ | |
337 | if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) { | |
3095e8e3 HX |
338 | rc = crypto_skcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
339 | crypt_stat->key_size); | |
4dfea4f0 TH |
340 | if (rc) { |
341 | ecryptfs_printk(KERN_ERR, | |
342 | "Error setting key; rc = [%d]\n", | |
343 | rc); | |
344 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
345 | rc = -EINVAL; | |
346 | goto out; | |
347 | } | |
348 | crypt_stat->flags |= ECRYPTFS_KEY_SET; | |
349 | } | |
237fead6 | 350 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
3095e8e3 HX |
351 | skcipher_request_set_crypt(req, src_sg, dst_sg, size, iv); |
352 | rc = op == ENCRYPT ? crypto_skcipher_encrypt(req) : | |
353 | crypto_skcipher_decrypt(req); | |
4dfea4f0 TH |
354 | if (rc == -EINPROGRESS || rc == -EBUSY) { |
355 | struct extent_crypt_result *ecr = req->base.data; | |
356 | ||
357 | wait_for_completion(&ecr->completion); | |
358 | rc = ecr->rc; | |
16735d02 | 359 | reinit_completion(&ecr->completion); |
4dfea4f0 | 360 | } |
237fead6 | 361 | out: |
3095e8e3 | 362 | skcipher_request_free(req); |
237fead6 MH |
363 | return rc; |
364 | } | |
365 | ||
0216f7f7 | 366 | /** |
24d15266 | 367 | * lower_offset_for_page |
0216f7f7 MH |
368 | * |
369 | * Convert an eCryptfs page index into a lower byte offset | |
370 | */ | |
24d15266 TH |
371 | static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat, |
372 | struct page *page) | |
0216f7f7 | 373 | { |
24d15266 | 374 | return ecryptfs_lower_header_size(crypt_stat) + |
09cbfeaf | 375 | ((loff_t)page->index << PAGE_SHIFT); |
0216f7f7 MH |
376 | } |
377 | ||
378 | /** | |
d78de618 | 379 | * crypt_extent |
0216f7f7 MH |
380 | * @crypt_stat: crypt_stat containing cryptographic context for the |
381 | * encryption operation | |
0df5ed65 | 382 | * @dst_page: The page to write the result into |
d78de618 | 383 | * @src_page: The page to read from |
0216f7f7 | 384 | * @extent_offset: Page extent offset for use in generating IV |
d78de618 | 385 | * @op: ENCRYPT or DECRYPT to indicate the desired operation |
0216f7f7 | 386 | * |
d78de618 | 387 | * Encrypts or decrypts one extent of data. |
0216f7f7 MH |
388 | * |
389 | * Return zero on success; non-zero otherwise | |
390 | */ | |
0df5ed65 TH |
391 | static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat, |
392 | struct page *dst_page, | |
d78de618 TH |
393 | struct page *src_page, |
394 | unsigned long extent_offset, int op) | |
0216f7f7 | 395 | { |
d78de618 | 396 | pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index; |
d6a13c17 | 397 | loff_t extent_base; |
0216f7f7 | 398 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
406c93df TH |
399 | struct scatterlist src_sg, dst_sg; |
400 | size_t extent_size = crypt_stat->extent_size; | |
0216f7f7 MH |
401 | int rc; |
402 | ||
09cbfeaf | 403 | extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size)); |
0216f7f7 MH |
404 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, |
405 | (extent_base + extent_offset)); | |
406 | if (rc) { | |
888d57bb JP |
407 | ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for " |
408 | "extent [0x%.16llx]; rc = [%d]\n", | |
409 | (unsigned long long)(extent_base + extent_offset), rc); | |
0216f7f7 MH |
410 | goto out; |
411 | } | |
406c93df TH |
412 | |
413 | sg_init_table(&src_sg, 1); | |
414 | sg_init_table(&dst_sg, 1); | |
415 | ||
416 | sg_set_page(&src_sg, src_page, extent_size, | |
417 | extent_offset * extent_size); | |
418 | sg_set_page(&dst_sg, dst_page, extent_size, | |
419 | extent_offset * extent_size); | |
420 | ||
421 | rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size, | |
422 | extent_iv, op); | |
0216f7f7 | 423 | if (rc < 0) { |
d78de618 TH |
424 | printk(KERN_ERR "%s: Error attempting to crypt page with " |
425 | "page_index = [%ld], extent_offset = [%ld]; " | |
426 | "rc = [%d]\n", __func__, page_index, extent_offset, rc); | |
0216f7f7 MH |
427 | goto out; |
428 | } | |
429 | rc = 0; | |
0216f7f7 MH |
430 | out: |
431 | return rc; | |
432 | } | |
433 | ||
237fead6 MH |
434 | /** |
435 | * ecryptfs_encrypt_page | |
0216f7f7 MH |
436 | * @page: Page mapped from the eCryptfs inode for the file; contains |
437 | * decrypted content that needs to be encrypted (to a temporary | |
438 | * page; not in place) and written out to the lower file | |
237fead6 MH |
439 | * |
440 | * Encrypt an eCryptfs page. This is done on a per-extent basis. Note | |
441 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
442 | * if the file was created on a machine with an 8K page size | |
443 | * (resulting in an 8K header), and then the file is copied onto a | |
444 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
445 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
446 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
447 | * | |
237fead6 MH |
448 | * Returns zero on success; negative on error |
449 | */ | |
0216f7f7 | 450 | int ecryptfs_encrypt_page(struct page *page) |
237fead6 | 451 | { |
0216f7f7 | 452 | struct inode *ecryptfs_inode; |
237fead6 | 453 | struct ecryptfs_crypt_stat *crypt_stat; |
7fcba054 ES |
454 | char *enc_extent_virt; |
455 | struct page *enc_extent_page = NULL; | |
0216f7f7 | 456 | loff_t extent_offset; |
0f896176 | 457 | loff_t lower_offset; |
237fead6 | 458 | int rc = 0; |
0216f7f7 MH |
459 | |
460 | ecryptfs_inode = page->mapping->host; | |
461 | crypt_stat = | |
462 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
13a791b4 | 463 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
7fcba054 ES |
464 | enc_extent_page = alloc_page(GFP_USER); |
465 | if (!enc_extent_page) { | |
0216f7f7 MH |
466 | rc = -ENOMEM; |
467 | ecryptfs_printk(KERN_ERR, "Error allocating memory for " | |
468 | "encrypted extent\n"); | |
469 | goto out; | |
470 | } | |
0f896176 | 471 | |
0216f7f7 | 472 | for (extent_offset = 0; |
09cbfeaf | 473 | extent_offset < (PAGE_SIZE / crypt_stat->extent_size); |
0216f7f7 | 474 | extent_offset++) { |
0df5ed65 | 475 | rc = crypt_extent(crypt_stat, enc_extent_page, page, |
d78de618 | 476 | extent_offset, ENCRYPT); |
237fead6 | 477 | if (rc) { |
0216f7f7 | 478 | printk(KERN_ERR "%s: Error encrypting extent; " |
18d1dbf1 | 479 | "rc = [%d]\n", __func__, rc); |
237fead6 MH |
480 | goto out; |
481 | } | |
7fcba054 | 482 | } |
0216f7f7 | 483 | |
24d15266 | 484 | lower_offset = lower_offset_for_page(crypt_stat, page); |
0f896176 TH |
485 | enc_extent_virt = kmap(enc_extent_page); |
486 | rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset, | |
09cbfeaf | 487 | PAGE_SIZE); |
0f896176 | 488 | kunmap(enc_extent_page); |
0216f7f7 | 489 | if (rc < 0) { |
0f896176 TH |
490 | ecryptfs_printk(KERN_ERR, |
491 | "Error attempting to write lower page; rc = [%d]\n", | |
492 | rc); | |
0216f7f7 MH |
493 | goto out; |
494 | } | |
495 | rc = 0; | |
237fead6 | 496 | out: |
7fcba054 | 497 | if (enc_extent_page) { |
7fcba054 ES |
498 | __free_page(enc_extent_page); |
499 | } | |
237fead6 MH |
500 | return rc; |
501 | } | |
502 | ||
503 | /** | |
504 | * ecryptfs_decrypt_page | |
0216f7f7 MH |
505 | * @page: Page mapped from the eCryptfs inode for the file; data read |
506 | * and decrypted from the lower file will be written into this | |
507 | * page | |
237fead6 MH |
508 | * |
509 | * Decrypt an eCryptfs page. This is done on a per-extent basis. Note | |
510 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
511 | * if the file was created on a machine with an 8K page size | |
512 | * (resulting in an 8K header), and then the file is copied onto a | |
513 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
514 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
515 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
516 | * | |
517 | * Returns zero on success; negative on error | |
518 | */ | |
0216f7f7 | 519 | int ecryptfs_decrypt_page(struct page *page) |
237fead6 | 520 | { |
0216f7f7 | 521 | struct inode *ecryptfs_inode; |
237fead6 | 522 | struct ecryptfs_crypt_stat *crypt_stat; |
9c6043f4 | 523 | char *page_virt; |
0216f7f7 | 524 | unsigned long extent_offset; |
0f896176 | 525 | loff_t lower_offset; |
237fead6 | 526 | int rc = 0; |
237fead6 | 527 | |
0216f7f7 MH |
528 | ecryptfs_inode = page->mapping->host; |
529 | crypt_stat = | |
530 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
13a791b4 | 531 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
0f896176 | 532 | |
24d15266 | 533 | lower_offset = lower_offset_for_page(crypt_stat, page); |
9c6043f4 | 534 | page_virt = kmap(page); |
09cbfeaf | 535 | rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE, |
0f896176 | 536 | ecryptfs_inode); |
9c6043f4 | 537 | kunmap(page); |
0f896176 TH |
538 | if (rc < 0) { |
539 | ecryptfs_printk(KERN_ERR, | |
540 | "Error attempting to read lower page; rc = [%d]\n", | |
541 | rc); | |
16a72c45 | 542 | goto out; |
237fead6 | 543 | } |
0f896176 | 544 | |
0216f7f7 | 545 | for (extent_offset = 0; |
09cbfeaf | 546 | extent_offset < (PAGE_SIZE / crypt_stat->extent_size); |
0216f7f7 | 547 | extent_offset++) { |
0df5ed65 | 548 | rc = crypt_extent(crypt_stat, page, page, |
d78de618 | 549 | extent_offset, DECRYPT); |
0216f7f7 MH |
550 | if (rc) { |
551 | printk(KERN_ERR "%s: Error encrypting extent; " | |
18d1dbf1 | 552 | "rc = [%d]\n", __func__, rc); |
16a72c45 | 553 | goto out; |
237fead6 | 554 | } |
237fead6 MH |
555 | } |
556 | out: | |
237fead6 | 557 | return rc; |
237fead6 MH |
558 | } |
559 | ||
560 | #define ECRYPTFS_MAX_SCATTERLIST_LEN 4 | |
561 | ||
562 | /** | |
563 | * ecryptfs_init_crypt_ctx | |
421f91d2 | 564 | * @crypt_stat: Uninitialized crypt stats structure |
237fead6 MH |
565 | * |
566 | * Initialize the crypto context. | |
567 | * | |
568 | * TODO: Performance: Keep a cache of initialized cipher contexts; | |
569 | * only init if needed | |
570 | */ | |
571 | int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat) | |
572 | { | |
8bba066f | 573 | char *full_alg_name; |
237fead6 MH |
574 | int rc = -EINVAL; |
575 | ||
237fead6 MH |
576 | ecryptfs_printk(KERN_DEBUG, |
577 | "Initializing cipher [%s]; strlen = [%d]; " | |
f24b3887 | 578 | "key_size_bits = [%zd]\n", |
237fead6 MH |
579 | crypt_stat->cipher, (int)strlen(crypt_stat->cipher), |
580 | crypt_stat->key_size << 3); | |
cb69f36b | 581 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
237fead6 MH |
582 | if (crypt_stat->tfm) { |
583 | rc = 0; | |
cb69f36b | 584 | goto out_unlock; |
237fead6 | 585 | } |
8bba066f MH |
586 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, |
587 | crypt_stat->cipher, "cbc"); | |
588 | if (rc) | |
c8161f64 | 589 | goto out_unlock; |
3095e8e3 | 590 | crypt_stat->tfm = crypto_alloc_skcipher(full_alg_name, 0, 0); |
de88777e AM |
591 | if (IS_ERR(crypt_stat->tfm)) { |
592 | rc = PTR_ERR(crypt_stat->tfm); | |
b0105eae | 593 | crypt_stat->tfm = NULL; |
237fead6 MH |
594 | ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): " |
595 | "Error initializing cipher [%s]\n", | |
cb69f36b KC |
596 | full_alg_name); |
597 | goto out_free; | |
237fead6 | 598 | } |
231baecd EB |
599 | crypto_skcipher_set_flags(crypt_stat->tfm, |
600 | CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); | |
237fead6 | 601 | rc = 0; |
cb69f36b KC |
602 | out_free: |
603 | kfree(full_alg_name); | |
c8161f64 ES |
604 | out_unlock: |
605 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
237fead6 MH |
606 | return rc; |
607 | } | |
608 | ||
609 | static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat) | |
610 | { | |
611 | int extent_size_tmp; | |
612 | ||
613 | crypt_stat->extent_mask = 0xFFFFFFFF; | |
614 | crypt_stat->extent_shift = 0; | |
615 | if (crypt_stat->extent_size == 0) | |
616 | return; | |
617 | extent_size_tmp = crypt_stat->extent_size; | |
618 | while ((extent_size_tmp & 0x01) == 0) { | |
619 | extent_size_tmp >>= 1; | |
620 | crypt_stat->extent_mask <<= 1; | |
621 | crypt_stat->extent_shift++; | |
622 | } | |
623 | } | |
624 | ||
625 | void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) | |
626 | { | |
627 | /* Default values; may be overwritten as we are parsing the | |
628 | * packets. */ | |
629 | crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; | |
630 | set_extent_mask_and_shift(crypt_stat); | |
631 | crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES; | |
dd2a3b7a | 632 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
fa3ef1cb | 633 | crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
45eaab79 | 634 | else { |
09cbfeaf | 635 | if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) |
fa3ef1cb | 636 | crypt_stat->metadata_size = |
cc11beff | 637 | ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
45eaab79 | 638 | else |
09cbfeaf | 639 | crypt_stat->metadata_size = PAGE_SIZE; |
45eaab79 | 640 | } |
237fead6 MH |
641 | } |
642 | ||
643 | /** | |
644 | * ecryptfs_compute_root_iv | |
645 | * @crypt_stats | |
646 | * | |
647 | * On error, sets the root IV to all 0's. | |
648 | */ | |
649 | int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat) | |
650 | { | |
651 | int rc = 0; | |
652 | char dst[MD5_DIGEST_SIZE]; | |
653 | ||
654 | BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE); | |
655 | BUG_ON(crypt_stat->iv_bytes <= 0); | |
e2bd99ec | 656 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { |
237fead6 MH |
657 | rc = -EINVAL; |
658 | ecryptfs_printk(KERN_WARNING, "Session key not valid; " | |
659 | "cannot generate root IV\n"); | |
660 | goto out; | |
661 | } | |
662 | rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key, | |
663 | crypt_stat->key_size); | |
664 | if (rc) { | |
665 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " | |
666 | "MD5 while generating root IV\n"); | |
667 | goto out; | |
668 | } | |
669 | memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes); | |
670 | out: | |
671 | if (rc) { | |
672 | memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes); | |
e2bd99ec | 673 | crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING; |
237fead6 MH |
674 | } |
675 | return rc; | |
676 | } | |
677 | ||
678 | static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat) | |
679 | { | |
680 | get_random_bytes(crypt_stat->key, crypt_stat->key_size); | |
e2bd99ec | 681 | crypt_stat->flags |= ECRYPTFS_KEY_VALID; |
237fead6 MH |
682 | ecryptfs_compute_root_iv(crypt_stat); |
683 | if (unlikely(ecryptfs_verbosity > 0)) { | |
684 | ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n"); | |
685 | ecryptfs_dump_hex(crypt_stat->key, | |
686 | crypt_stat->key_size); | |
687 | } | |
688 | } | |
689 | ||
17398957 MH |
690 | /** |
691 | * ecryptfs_copy_mount_wide_flags_to_inode_flags | |
22e78faf MH |
692 | * @crypt_stat: The inode's cryptographic context |
693 | * @mount_crypt_stat: The mount point's cryptographic context | |
17398957 MH |
694 | * |
695 | * This function propagates the mount-wide flags to individual inode | |
696 | * flags. | |
697 | */ | |
698 | static void ecryptfs_copy_mount_wide_flags_to_inode_flags( | |
699 | struct ecryptfs_crypt_stat *crypt_stat, | |
700 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
701 | { | |
702 | if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) | |
703 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
704 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) | |
705 | crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED; | |
addd65ad MH |
706 | if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) { |
707 | crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES; | |
708 | if (mount_crypt_stat->flags | |
709 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK) | |
710 | crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK; | |
711 | else if (mount_crypt_stat->flags | |
712 | & ECRYPTFS_GLOBAL_ENCFN_USE_FEK) | |
713 | crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK; | |
714 | } | |
17398957 MH |
715 | } |
716 | ||
f4aad16a MH |
717 | static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs( |
718 | struct ecryptfs_crypt_stat *crypt_stat, | |
719 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
720 | { | |
721 | struct ecryptfs_global_auth_tok *global_auth_tok; | |
722 | int rc = 0; | |
723 | ||
aa06117f | 724 | mutex_lock(&crypt_stat->keysig_list_mutex); |
f4aad16a | 725 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
aa06117f | 726 | |
f4aad16a MH |
727 | list_for_each_entry(global_auth_tok, |
728 | &mount_crypt_stat->global_auth_tok_list, | |
729 | mount_crypt_stat_list) { | |
84814d64 TH |
730 | if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK) |
731 | continue; | |
f4aad16a MH |
732 | rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig); |
733 | if (rc) { | |
734 | printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc); | |
f4aad16a MH |
735 | goto out; |
736 | } | |
737 | } | |
aa06117f | 738 | |
f4aad16a | 739 | out: |
aa06117f RD |
740 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
741 | mutex_unlock(&crypt_stat->keysig_list_mutex); | |
f4aad16a MH |
742 | return rc; |
743 | } | |
744 | ||
237fead6 MH |
745 | /** |
746 | * ecryptfs_set_default_crypt_stat_vals | |
22e78faf MH |
747 | * @crypt_stat: The inode's cryptographic context |
748 | * @mount_crypt_stat: The mount point's cryptographic context | |
237fead6 MH |
749 | * |
750 | * Default values in the event that policy does not override them. | |
751 | */ | |
752 | static void ecryptfs_set_default_crypt_stat_vals( | |
753 | struct ecryptfs_crypt_stat *crypt_stat, | |
754 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
755 | { | |
17398957 MH |
756 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
757 | mount_crypt_stat); | |
237fead6 MH |
758 | ecryptfs_set_default_sizes(crypt_stat); |
759 | strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER); | |
760 | crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES; | |
e2bd99ec | 761 | crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID); |
237fead6 MH |
762 | crypt_stat->file_version = ECRYPTFS_FILE_VERSION; |
763 | crypt_stat->mount_crypt_stat = mount_crypt_stat; | |
764 | } | |
765 | ||
766 | /** | |
767 | * ecryptfs_new_file_context | |
b59db43a | 768 | * @ecryptfs_inode: The eCryptfs inode |
237fead6 MH |
769 | * |
770 | * If the crypto context for the file has not yet been established, | |
771 | * this is where we do that. Establishing a new crypto context | |
772 | * involves the following decisions: | |
773 | * - What cipher to use? | |
774 | * - What set of authentication tokens to use? | |
775 | * Here we just worry about getting enough information into the | |
776 | * authentication tokens so that we know that they are available. | |
777 | * We associate the available authentication tokens with the new file | |
778 | * via the set of signatures in the crypt_stat struct. Later, when | |
779 | * the headers are actually written out, we may again defer to | |
780 | * userspace to perform the encryption of the session key; for the | |
781 | * foreseeable future, this will be the case with public key packets. | |
782 | * | |
783 | * Returns zero on success; non-zero otherwise | |
784 | */ | |
b59db43a | 785 | int ecryptfs_new_file_context(struct inode *ecryptfs_inode) |
237fead6 | 786 | { |
237fead6 | 787 | struct ecryptfs_crypt_stat *crypt_stat = |
b59db43a | 788 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
237fead6 MH |
789 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
790 | &ecryptfs_superblock_to_private( | |
b59db43a | 791 | ecryptfs_inode->i_sb)->mount_crypt_stat; |
237fead6 | 792 | int cipher_name_len; |
f4aad16a | 793 | int rc = 0; |
237fead6 MH |
794 | |
795 | ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat); | |
af655dc6 | 796 | crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID); |
f4aad16a MH |
797 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
798 | mount_crypt_stat); | |
799 | rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat, | |
800 | mount_crypt_stat); | |
801 | if (rc) { | |
802 | printk(KERN_ERR "Error attempting to copy mount-wide key sigs " | |
803 | "to the inode key sigs; rc = [%d]\n", rc); | |
804 | goto out; | |
805 | } | |
806 | cipher_name_len = | |
807 | strlen(mount_crypt_stat->global_default_cipher_name); | |
808 | memcpy(crypt_stat->cipher, | |
809 | mount_crypt_stat->global_default_cipher_name, | |
810 | cipher_name_len); | |
811 | crypt_stat->cipher[cipher_name_len] = '\0'; | |
812 | crypt_stat->key_size = | |
813 | mount_crypt_stat->global_default_cipher_key_size; | |
814 | ecryptfs_generate_new_key(crypt_stat); | |
237fead6 MH |
815 | rc = ecryptfs_init_crypt_ctx(crypt_stat); |
816 | if (rc) | |
817 | ecryptfs_printk(KERN_ERR, "Error initializing cryptographic " | |
818 | "context for cipher [%s]: rc = [%d]\n", | |
819 | crypt_stat->cipher, rc); | |
f4aad16a | 820 | out: |
237fead6 MH |
821 | return rc; |
822 | } | |
823 | ||
824 | /** | |
7a86617e | 825 | * ecryptfs_validate_marker - check for the ecryptfs marker |
237fead6 MH |
826 | * @data: The data block in which to check |
827 | * | |
7a86617e | 828 | * Returns zero if marker found; -EINVAL if not found |
237fead6 | 829 | */ |
7a86617e | 830 | static int ecryptfs_validate_marker(char *data) |
237fead6 MH |
831 | { |
832 | u32 m_1, m_2; | |
833 | ||
29335c6a HH |
834 | m_1 = get_unaligned_be32(data); |
835 | m_2 = get_unaligned_be32(data + 4); | |
237fead6 | 836 | if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2) |
7a86617e | 837 | return 0; |
237fead6 MH |
838 | ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; " |
839 | "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2, | |
840 | MAGIC_ECRYPTFS_MARKER); | |
841 | ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = " | |
842 | "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER)); | |
7a86617e | 843 | return -EINVAL; |
237fead6 MH |
844 | } |
845 | ||
846 | struct ecryptfs_flag_map_elem { | |
847 | u32 file_flag; | |
848 | u32 local_flag; | |
849 | }; | |
850 | ||
851 | /* Add support for additional flags by adding elements here. */ | |
852 | static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = { | |
853 | {0x00000001, ECRYPTFS_ENABLE_HMAC}, | |
dd2a3b7a | 854 | {0x00000002, ECRYPTFS_ENCRYPTED}, |
addd65ad MH |
855 | {0x00000004, ECRYPTFS_METADATA_IN_XATTR}, |
856 | {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES} | |
237fead6 MH |
857 | }; |
858 | ||
859 | /** | |
860 | * ecryptfs_process_flags | |
22e78faf | 861 | * @crypt_stat: The cryptographic context |
237fead6 MH |
862 | * @page_virt: Source data to be parsed |
863 | * @bytes_read: Updated with the number of bytes read | |
237fead6 | 864 | */ |
7451c54a | 865 | static void ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat, |
237fead6 MH |
866 | char *page_virt, int *bytes_read) |
867 | { | |
237fead6 MH |
868 | int i; |
869 | u32 flags; | |
870 | ||
29335c6a | 871 | flags = get_unaligned_be32(page_virt); |
02f9876e | 872 | for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++) |
237fead6 | 873 | if (flags & ecryptfs_flag_map[i].file_flag) { |
e2bd99ec | 874 | crypt_stat->flags |= ecryptfs_flag_map[i].local_flag; |
237fead6 | 875 | } else |
e2bd99ec | 876 | crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag); |
237fead6 MH |
877 | /* Version is in top 8 bits of the 32-bit flag vector */ |
878 | crypt_stat->file_version = ((flags >> 24) & 0xFF); | |
879 | (*bytes_read) = 4; | |
237fead6 MH |
880 | } |
881 | ||
882 | /** | |
883 | * write_ecryptfs_marker | |
884 | * @page_virt: The pointer to in a page to begin writing the marker | |
885 | * @written: Number of bytes written | |
886 | * | |
887 | * Marker = 0x3c81b7f5 | |
888 | */ | |
889 | static void write_ecryptfs_marker(char *page_virt, size_t *written) | |
890 | { | |
891 | u32 m_1, m_2; | |
892 | ||
893 | get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); | |
894 | m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER); | |
29335c6a HH |
895 | put_unaligned_be32(m_1, page_virt); |
896 | page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2); | |
897 | put_unaligned_be32(m_2, page_virt); | |
237fead6 MH |
898 | (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
899 | } | |
900 | ||
f4e60e6b TH |
901 | void ecryptfs_write_crypt_stat_flags(char *page_virt, |
902 | struct ecryptfs_crypt_stat *crypt_stat, | |
903 | size_t *written) | |
237fead6 MH |
904 | { |
905 | u32 flags = 0; | |
906 | int i; | |
907 | ||
02f9876e | 908 | for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++) |
e2bd99ec | 909 | if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag) |
237fead6 MH |
910 | flags |= ecryptfs_flag_map[i].file_flag; |
911 | /* Version is in top 8 bits of the 32-bit flag vector */ | |
912 | flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000); | |
29335c6a | 913 | put_unaligned_be32(flags, page_virt); |
237fead6 MH |
914 | (*written) = 4; |
915 | } | |
916 | ||
917 | struct ecryptfs_cipher_code_str_map_elem { | |
918 | char cipher_str[16]; | |
19e66a67 | 919 | u8 cipher_code; |
237fead6 MH |
920 | }; |
921 | ||
922 | /* Add support for additional ciphers by adding elements here. The | |
40f0fd37 | 923 | * cipher_code is whatever OpenPGP applications use to identify the |
237fead6 MH |
924 | * ciphers. List in order of probability. */ |
925 | static struct ecryptfs_cipher_code_str_map_elem | |
926 | ecryptfs_cipher_code_str_map[] = { | |
927 | {"aes",RFC2440_CIPHER_AES_128 }, | |
928 | {"blowfish", RFC2440_CIPHER_BLOWFISH}, | |
929 | {"des3_ede", RFC2440_CIPHER_DES3_EDE}, | |
930 | {"cast5", RFC2440_CIPHER_CAST_5}, | |
931 | {"twofish", RFC2440_CIPHER_TWOFISH}, | |
932 | {"cast6", RFC2440_CIPHER_CAST_6}, | |
933 | {"aes", RFC2440_CIPHER_AES_192}, | |
934 | {"aes", RFC2440_CIPHER_AES_256} | |
935 | }; | |
936 | ||
937 | /** | |
938 | * ecryptfs_code_for_cipher_string | |
9c79f34f MH |
939 | * @cipher_name: The string alias for the cipher |
940 | * @key_bytes: Length of key in bytes; used for AES code selection | |
237fead6 MH |
941 | * |
942 | * Returns zero on no match, or the cipher code on match | |
943 | */ | |
9c79f34f | 944 | u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes) |
237fead6 MH |
945 | { |
946 | int i; | |
19e66a67 | 947 | u8 code = 0; |
237fead6 MH |
948 | struct ecryptfs_cipher_code_str_map_elem *map = |
949 | ecryptfs_cipher_code_str_map; | |
950 | ||
9c79f34f MH |
951 | if (strcmp(cipher_name, "aes") == 0) { |
952 | switch (key_bytes) { | |
237fead6 MH |
953 | case 16: |
954 | code = RFC2440_CIPHER_AES_128; | |
955 | break; | |
956 | case 24: | |
957 | code = RFC2440_CIPHER_AES_192; | |
958 | break; | |
959 | case 32: | |
960 | code = RFC2440_CIPHER_AES_256; | |
961 | } | |
962 | } else { | |
963 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) | |
9c79f34f | 964 | if (strcmp(cipher_name, map[i].cipher_str) == 0) { |
237fead6 MH |
965 | code = map[i].cipher_code; |
966 | break; | |
967 | } | |
968 | } | |
969 | return code; | |
970 | } | |
971 | ||
972 | /** | |
973 | * ecryptfs_cipher_code_to_string | |
974 | * @str: Destination to write out the cipher name | |
975 | * @cipher_code: The code to convert to cipher name string | |
976 | * | |
977 | * Returns zero on success | |
978 | */ | |
19e66a67 | 979 | int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code) |
237fead6 MH |
980 | { |
981 | int rc = 0; | |
982 | int i; | |
983 | ||
984 | str[0] = '\0'; | |
985 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) | |
986 | if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code) | |
987 | strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str); | |
988 | if (str[0] == '\0') { | |
989 | ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: " | |
990 | "[%d]\n", cipher_code); | |
991 | rc = -EINVAL; | |
992 | } | |
993 | return rc; | |
994 | } | |
995 | ||
778aeb42 | 996 | int ecryptfs_read_and_validate_header_region(struct inode *inode) |
dd2a3b7a | 997 | { |
778aeb42 TH |
998 | u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
999 | u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; | |
dd2a3b7a MH |
1000 | int rc; |
1001 | ||
778aeb42 TH |
1002 | rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES, |
1003 | inode); | |
0bdf8a82 DC |
1004 | if (rc < 0) |
1005 | return rc; | |
1006 | else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) | |
1007 | return -EINVAL; | |
778aeb42 TH |
1008 | rc = ecryptfs_validate_marker(marker); |
1009 | if (!rc) | |
1010 | ecryptfs_i_size_init(file_size, inode); | |
dd2a3b7a MH |
1011 | return rc; |
1012 | } | |
1013 | ||
e77a56dd MH |
1014 | void |
1015 | ecryptfs_write_header_metadata(char *virt, | |
1016 | struct ecryptfs_crypt_stat *crypt_stat, | |
1017 | size_t *written) | |
237fead6 MH |
1018 | { |
1019 | u32 header_extent_size; | |
1020 | u16 num_header_extents_at_front; | |
1021 | ||
45eaab79 | 1022 | header_extent_size = (u32)crypt_stat->extent_size; |
237fead6 | 1023 | num_header_extents_at_front = |
fa3ef1cb | 1024 | (u16)(crypt_stat->metadata_size / crypt_stat->extent_size); |
29335c6a | 1025 | put_unaligned_be32(header_extent_size, virt); |
237fead6 | 1026 | virt += 4; |
29335c6a | 1027 | put_unaligned_be16(num_header_extents_at_front, virt); |
237fead6 MH |
1028 | (*written) = 6; |
1029 | } | |
1030 | ||
30632870 | 1031 | struct kmem_cache *ecryptfs_header_cache; |
237fead6 MH |
1032 | |
1033 | /** | |
1034 | * ecryptfs_write_headers_virt | |
22e78faf | 1035 | * @page_virt: The virtual address to write the headers to |
87b811c3 | 1036 | * @max: The size of memory allocated at page_virt |
22e78faf MH |
1037 | * @size: Set to the number of bytes written by this function |
1038 | * @crypt_stat: The cryptographic context | |
1039 | * @ecryptfs_dentry: The eCryptfs dentry | |
237fead6 MH |
1040 | * |
1041 | * Format version: 1 | |
1042 | * | |
1043 | * Header Extent: | |
1044 | * Octets 0-7: Unencrypted file size (big-endian) | |
1045 | * Octets 8-15: eCryptfs special marker | |
1046 | * Octets 16-19: Flags | |
1047 | * Octet 16: File format version number (between 0 and 255) | |
1048 | * Octets 17-18: Reserved | |
1049 | * Octet 19: Bit 1 (lsb): Reserved | |
1050 | * Bit 2: Encrypted? | |
1051 | * Bits 3-8: Reserved | |
1052 | * Octets 20-23: Header extent size (big-endian) | |
1053 | * Octets 24-25: Number of header extents at front of file | |
1054 | * (big-endian) | |
1055 | * Octet 26: Begin RFC 2440 authentication token packet set | |
1056 | * Data Extent 0: | |
1057 | * Lower data (CBC encrypted) | |
1058 | * Data Extent 1: | |
1059 | * Lower data (CBC encrypted) | |
1060 | * ... | |
1061 | * | |
1062 | * Returns zero on success | |
1063 | */ | |
87b811c3 ES |
1064 | static int ecryptfs_write_headers_virt(char *page_virt, size_t max, |
1065 | size_t *size, | |
dd2a3b7a MH |
1066 | struct ecryptfs_crypt_stat *crypt_stat, |
1067 | struct dentry *ecryptfs_dentry) | |
237fead6 MH |
1068 | { |
1069 | int rc; | |
1070 | size_t written; | |
1071 | size_t offset; | |
1072 | ||
1073 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
1074 | write_ecryptfs_marker((page_virt + offset), &written); | |
1075 | offset += written; | |
f4e60e6b TH |
1076 | ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat, |
1077 | &written); | |
237fead6 | 1078 | offset += written; |
e77a56dd MH |
1079 | ecryptfs_write_header_metadata((page_virt + offset), crypt_stat, |
1080 | &written); | |
237fead6 MH |
1081 | offset += written; |
1082 | rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat, | |
1083 | ecryptfs_dentry, &written, | |
87b811c3 | 1084 | max - offset); |
237fead6 MH |
1085 | if (rc) |
1086 | ecryptfs_printk(KERN_WARNING, "Error generating key packet " | |
1087 | "set; rc = [%d]\n", rc); | |
dd2a3b7a MH |
1088 | if (size) { |
1089 | offset += written; | |
1090 | *size = offset; | |
1091 | } | |
1092 | return rc; | |
1093 | } | |
1094 | ||
22e78faf | 1095 | static int |
b59db43a | 1096 | ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode, |
8faece5f | 1097 | char *virt, size_t virt_len) |
dd2a3b7a | 1098 | { |
d7cdc5fe | 1099 | int rc; |
dd2a3b7a | 1100 | |
b59db43a | 1101 | rc = ecryptfs_write_lower(ecryptfs_inode, virt, |
8faece5f | 1102 | 0, virt_len); |
96a7b9c2 | 1103 | if (rc < 0) |
d7cdc5fe | 1104 | printk(KERN_ERR "%s: Error attempting to write header " |
96a7b9c2 TH |
1105 | "information to lower file; rc = [%d]\n", __func__, rc); |
1106 | else | |
1107 | rc = 0; | |
70456600 | 1108 | return rc; |
dd2a3b7a MH |
1109 | } |
1110 | ||
22e78faf MH |
1111 | static int |
1112 | ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry, | |
3767e255 | 1113 | struct inode *ecryptfs_inode, |
22e78faf | 1114 | char *page_virt, size_t size) |
dd2a3b7a MH |
1115 | { |
1116 | int rc; | |
d43388de RK |
1117 | struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); |
1118 | struct inode *lower_inode = d_inode(lower_dentry); | |
dd2a3b7a | 1119 | |
d43388de RK |
1120 | if (!(lower_inode->i_opflags & IOP_XATTR)) { |
1121 | rc = -EOPNOTSUPP; | |
1122 | goto out; | |
1123 | } | |
dd2a3b7a | 1124 | |
d43388de RK |
1125 | inode_lock(lower_inode); |
1126 | rc = __vfs_setxattr(lower_dentry, lower_inode, ECRYPTFS_XATTR_NAME, | |
1127 | page_virt, size, 0); | |
1128 | if (!rc && ecryptfs_inode) | |
1129 | fsstack_copy_attr_all(ecryptfs_inode, lower_inode); | |
1130 | inode_unlock(lower_inode); | |
1131 | out: | |
237fead6 MH |
1132 | return rc; |
1133 | } | |
1134 | ||
8faece5f TH |
1135 | static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask, |
1136 | unsigned int order) | |
1137 | { | |
1138 | struct page *page; | |
1139 | ||
1140 | page = alloc_pages(gfp_mask | __GFP_ZERO, order); | |
1141 | if (page) | |
1142 | return (unsigned long) page_address(page); | |
1143 | return 0; | |
1144 | } | |
1145 | ||
237fead6 | 1146 | /** |
dd2a3b7a | 1147 | * ecryptfs_write_metadata |
b59db43a TH |
1148 | * @ecryptfs_dentry: The eCryptfs dentry, which should be negative |
1149 | * @ecryptfs_inode: The newly created eCryptfs inode | |
237fead6 MH |
1150 | * |
1151 | * Write the file headers out. This will likely involve a userspace | |
1152 | * callout, in which the session key is encrypted with one or more | |
1153 | * public keys and/or the passphrase necessary to do the encryption is | |
1154 | * retrieved via a prompt. Exactly what happens at this point should | |
1155 | * be policy-dependent. | |
1156 | * | |
1157 | * Returns zero on success; non-zero on error | |
1158 | */ | |
b59db43a TH |
1159 | int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry, |
1160 | struct inode *ecryptfs_inode) | |
237fead6 | 1161 | { |
d7cdc5fe | 1162 | struct ecryptfs_crypt_stat *crypt_stat = |
b59db43a | 1163 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
8faece5f | 1164 | unsigned int order; |
cc11beff | 1165 | char *virt; |
8faece5f | 1166 | size_t virt_len; |
d7cdc5fe | 1167 | size_t size = 0; |
237fead6 MH |
1168 | int rc = 0; |
1169 | ||
e2bd99ec MH |
1170 | if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
1171 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { | |
d7cdc5fe | 1172 | printk(KERN_ERR "Key is invalid; bailing out\n"); |
237fead6 MH |
1173 | rc = -EINVAL; |
1174 | goto out; | |
1175 | } | |
1176 | } else { | |
cc11beff | 1177 | printk(KERN_WARNING "%s: Encrypted flag not set\n", |
18d1dbf1 | 1178 | __func__); |
237fead6 | 1179 | rc = -EINVAL; |
237fead6 MH |
1180 | goto out; |
1181 | } | |
fa3ef1cb | 1182 | virt_len = crypt_stat->metadata_size; |
8faece5f | 1183 | order = get_order(virt_len); |
237fead6 | 1184 | /* Released in this function */ |
8faece5f | 1185 | virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order); |
cc11beff | 1186 | if (!virt) { |
18d1dbf1 | 1187 | printk(KERN_ERR "%s: Out of memory\n", __func__); |
237fead6 MH |
1188 | rc = -ENOMEM; |
1189 | goto out; | |
1190 | } | |
bd4f0fe8 | 1191 | /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */ |
8faece5f TH |
1192 | rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat, |
1193 | ecryptfs_dentry); | |
237fead6 | 1194 | if (unlikely(rc)) { |
cc11beff | 1195 | printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n", |
18d1dbf1 | 1196 | __func__, rc); |
237fead6 MH |
1197 | goto out_free; |
1198 | } | |
dd2a3b7a | 1199 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
3767e255 AV |
1200 | rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode, |
1201 | virt, size); | |
dd2a3b7a | 1202 | else |
b59db43a | 1203 | rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt, |
8faece5f | 1204 | virt_len); |
dd2a3b7a | 1205 | if (rc) { |
cc11beff | 1206 | printk(KERN_ERR "%s: Error writing metadata out to lower file; " |
18d1dbf1 | 1207 | "rc = [%d]\n", __func__, rc); |
dd2a3b7a | 1208 | goto out_free; |
237fead6 | 1209 | } |
237fead6 | 1210 | out_free: |
8faece5f | 1211 | free_pages((unsigned long)virt, order); |
237fead6 MH |
1212 | out: |
1213 | return rc; | |
1214 | } | |
1215 | ||
dd2a3b7a MH |
1216 | #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0 |
1217 | #define ECRYPTFS_VALIDATE_HEADER_SIZE 1 | |
237fead6 | 1218 | static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat, |
dd2a3b7a MH |
1219 | char *virt, int *bytes_read, |
1220 | int validate_header_size) | |
237fead6 MH |
1221 | { |
1222 | int rc = 0; | |
1223 | u32 header_extent_size; | |
1224 | u16 num_header_extents_at_front; | |
1225 | ||
29335c6a HH |
1226 | header_extent_size = get_unaligned_be32(virt); |
1227 | virt += sizeof(__be32); | |
1228 | num_header_extents_at_front = get_unaligned_be16(virt); | |
fa3ef1cb TH |
1229 | crypt_stat->metadata_size = (((size_t)num_header_extents_at_front |
1230 | * (size_t)header_extent_size)); | |
29335c6a | 1231 | (*bytes_read) = (sizeof(__be32) + sizeof(__be16)); |
dd2a3b7a | 1232 | if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE) |
fa3ef1cb | 1233 | && (crypt_stat->metadata_size |
dd2a3b7a | 1234 | < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) { |
237fead6 | 1235 | rc = -EINVAL; |
cc11beff | 1236 | printk(KERN_WARNING "Invalid header size: [%zd]\n", |
fa3ef1cb | 1237 | crypt_stat->metadata_size); |
237fead6 MH |
1238 | } |
1239 | return rc; | |
1240 | } | |
1241 | ||
1242 | /** | |
1243 | * set_default_header_data | |
22e78faf | 1244 | * @crypt_stat: The cryptographic context |
237fead6 MH |
1245 | * |
1246 | * For version 0 file format; this function is only for backwards | |
1247 | * compatibility for files created with the prior versions of | |
1248 | * eCryptfs. | |
1249 | */ | |
1250 | static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) | |
1251 | { | |
fa3ef1cb | 1252 | crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
237fead6 MH |
1253 | } |
1254 | ||
3aeb86ea TH |
1255 | void ecryptfs_i_size_init(const char *page_virt, struct inode *inode) |
1256 | { | |
1257 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat; | |
1258 | struct ecryptfs_crypt_stat *crypt_stat; | |
1259 | u64 file_size; | |
1260 | ||
1261 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; | |
1262 | mount_crypt_stat = | |
1263 | &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat; | |
1264 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { | |
1265 | file_size = i_size_read(ecryptfs_inode_to_lower(inode)); | |
1266 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) | |
1267 | file_size += crypt_stat->metadata_size; | |
1268 | } else | |
1269 | file_size = get_unaligned_be64(page_virt); | |
1270 | i_size_write(inode, (loff_t)file_size); | |
1271 | crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED; | |
1272 | } | |
1273 | ||
237fead6 MH |
1274 | /** |
1275 | * ecryptfs_read_headers_virt | |
22e78faf MH |
1276 | * @page_virt: The virtual address into which to read the headers |
1277 | * @crypt_stat: The cryptographic context | |
1278 | * @ecryptfs_dentry: The eCryptfs dentry | |
1279 | * @validate_header_size: Whether to validate the header size while reading | |
237fead6 MH |
1280 | * |
1281 | * Read/parse the header data. The header format is detailed in the | |
1282 | * comment block for the ecryptfs_write_headers_virt() function. | |
1283 | * | |
1284 | * Returns zero on success | |
1285 | */ | |
1286 | static int ecryptfs_read_headers_virt(char *page_virt, | |
1287 | struct ecryptfs_crypt_stat *crypt_stat, | |
dd2a3b7a MH |
1288 | struct dentry *ecryptfs_dentry, |
1289 | int validate_header_size) | |
237fead6 MH |
1290 | { |
1291 | int rc = 0; | |
1292 | int offset; | |
1293 | int bytes_read; | |
1294 | ||
1295 | ecryptfs_set_default_sizes(crypt_stat); | |
1296 | crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private( | |
1297 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
1298 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
7a86617e TH |
1299 | rc = ecryptfs_validate_marker(page_virt + offset); |
1300 | if (rc) | |
237fead6 | 1301 | goto out; |
3aeb86ea | 1302 | if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED)) |
2b0143b5 | 1303 | ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry)); |
237fead6 | 1304 | offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
7451c54a | 1305 | ecryptfs_process_flags(crypt_stat, (page_virt + offset), &bytes_read); |
237fead6 MH |
1306 | if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) { |
1307 | ecryptfs_printk(KERN_WARNING, "File version is [%d]; only " | |
1308 | "file version [%d] is supported by this " | |
1309 | "version of eCryptfs\n", | |
1310 | crypt_stat->file_version, | |
1311 | ECRYPTFS_SUPPORTED_FILE_VERSION); | |
1312 | rc = -EINVAL; | |
1313 | goto out; | |
1314 | } | |
1315 | offset += bytes_read; | |
1316 | if (crypt_stat->file_version >= 1) { | |
1317 | rc = parse_header_metadata(crypt_stat, (page_virt + offset), | |
dd2a3b7a | 1318 | &bytes_read, validate_header_size); |
237fead6 MH |
1319 | if (rc) { |
1320 | ecryptfs_printk(KERN_WARNING, "Error reading header " | |
1321 | "metadata; rc = [%d]\n", rc); | |
1322 | } | |
1323 | offset += bytes_read; | |
1324 | } else | |
1325 | set_default_header_data(crypt_stat); | |
1326 | rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), | |
1327 | ecryptfs_dentry); | |
1328 | out: | |
1329 | return rc; | |
1330 | } | |
1331 | ||
1332 | /** | |
dd2a3b7a | 1333 | * ecryptfs_read_xattr_region |
22e78faf | 1334 | * @page_virt: The vitual address into which to read the xattr data |
2ed92554 | 1335 | * @ecryptfs_inode: The eCryptfs inode |
dd2a3b7a MH |
1336 | * |
1337 | * Attempts to read the crypto metadata from the extended attribute | |
1338 | * region of the lower file. | |
22e78faf MH |
1339 | * |
1340 | * Returns zero on success; non-zero on error | |
dd2a3b7a | 1341 | */ |
d7cdc5fe | 1342 | int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode) |
dd2a3b7a | 1343 | { |
d7cdc5fe | 1344 | struct dentry *lower_dentry = |
b583043e | 1345 | ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry; |
dd2a3b7a MH |
1346 | ssize_t size; |
1347 | int rc = 0; | |
1348 | ||
ce23e640 AV |
1349 | size = ecryptfs_getxattr_lower(lower_dentry, |
1350 | ecryptfs_inode_to_lower(ecryptfs_inode), | |
1351 | ECRYPTFS_XATTR_NAME, | |
d7cdc5fe | 1352 | page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE); |
dd2a3b7a | 1353 | if (size < 0) { |
25bd8174 MH |
1354 | if (unlikely(ecryptfs_verbosity > 0)) |
1355 | printk(KERN_INFO "Error attempting to read the [%s] " | |
1356 | "xattr from the lower file; return value = " | |
1357 | "[%zd]\n", ECRYPTFS_XATTR_NAME, size); | |
dd2a3b7a MH |
1358 | rc = -EINVAL; |
1359 | goto out; | |
1360 | } | |
1361 | out: | |
1362 | return rc; | |
1363 | } | |
1364 | ||
778aeb42 | 1365 | int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry, |
3b06b3eb | 1366 | struct inode *inode) |
dd2a3b7a | 1367 | { |
778aeb42 TH |
1368 | u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
1369 | u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; | |
dd2a3b7a MH |
1370 | int rc; |
1371 | ||
778aeb42 | 1372 | rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), |
ce23e640 | 1373 | ecryptfs_inode_to_lower(inode), |
778aeb42 TH |
1374 | ECRYPTFS_XATTR_NAME, file_size, |
1375 | ECRYPTFS_SIZE_AND_MARKER_BYTES); | |
0bdf8a82 DC |
1376 | if (rc < 0) |
1377 | return rc; | |
1378 | else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) | |
1379 | return -EINVAL; | |
778aeb42 TH |
1380 | rc = ecryptfs_validate_marker(marker); |
1381 | if (!rc) | |
1382 | ecryptfs_i_size_init(file_size, inode); | |
dd2a3b7a MH |
1383 | return rc; |
1384 | } | |
1385 | ||
1386 | /** | |
1387 | * ecryptfs_read_metadata | |
1388 | * | |
1389 | * Common entry point for reading file metadata. From here, we could | |
1390 | * retrieve the header information from the header region of the file, | |
40f0fd37 | 1391 | * the xattr region of the file, or some other repository that is |
dd2a3b7a MH |
1392 | * stored separately from the file itself. The current implementation |
1393 | * supports retrieving the metadata information from the file contents | |
1394 | * and from the xattr region. | |
237fead6 MH |
1395 | * |
1396 | * Returns zero if valid headers found and parsed; non-zero otherwise | |
1397 | */ | |
d7cdc5fe | 1398 | int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) |
237fead6 | 1399 | { |
bb450361 TG |
1400 | int rc; |
1401 | char *page_virt; | |
2b0143b5 | 1402 | struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry); |
237fead6 | 1403 | struct ecryptfs_crypt_stat *crypt_stat = |
d7cdc5fe | 1404 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
e77a56dd MH |
1405 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
1406 | &ecryptfs_superblock_to_private( | |
1407 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
237fead6 | 1408 | |
e77a56dd MH |
1409 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
1410 | mount_crypt_stat); | |
237fead6 | 1411 | /* Read the first page from the underlying file */ |
30632870 | 1412 | page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER); |
237fead6 MH |
1413 | if (!page_virt) { |
1414 | rc = -ENOMEM; | |
237fead6 MH |
1415 | goto out; |
1416 | } | |
d7cdc5fe MH |
1417 | rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size, |
1418 | ecryptfs_inode); | |
96a7b9c2 | 1419 | if (rc >= 0) |
d7cdc5fe MH |
1420 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
1421 | ecryptfs_dentry, | |
1422 | ECRYPTFS_VALIDATE_HEADER_SIZE); | |
237fead6 | 1423 | if (rc) { |
bb450361 | 1424 | /* metadata is not in the file header, so try xattrs */ |
09cbfeaf | 1425 | memset(page_virt, 0, PAGE_SIZE); |
d7cdc5fe | 1426 | rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode); |
dd2a3b7a MH |
1427 | if (rc) { |
1428 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " | |
30373dc0 TG |
1429 | "file header region or xattr region, inode %lu\n", |
1430 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1431 | rc = -EINVAL; |
1432 | goto out; | |
1433 | } | |
1434 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, | |
1435 | ecryptfs_dentry, | |
1436 | ECRYPTFS_DONT_VALIDATE_HEADER_SIZE); | |
1437 | if (rc) { | |
1438 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " | |
30373dc0 TG |
1439 | "file xattr region either, inode %lu\n", |
1440 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1441 | rc = -EINVAL; |
1442 | } | |
1443 | if (crypt_stat->mount_crypt_stat->flags | |
1444 | & ECRYPTFS_XATTR_METADATA_ENABLED) { | |
1445 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
1446 | } else { | |
1447 | printk(KERN_WARNING "Attempt to access file with " | |
1448 | "crypto metadata only in the extended attribute " | |
1449 | "region, but eCryptfs was mounted without " | |
1450 | "xattr support enabled. eCryptfs will not treat " | |
30373dc0 TG |
1451 | "this like an encrypted file, inode %lu\n", |
1452 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1453 | rc = -EINVAL; |
1454 | } | |
237fead6 MH |
1455 | } |
1456 | out: | |
1457 | if (page_virt) { | |
09cbfeaf | 1458 | memset(page_virt, 0, PAGE_SIZE); |
30632870 | 1459 | kmem_cache_free(ecryptfs_header_cache, page_virt); |
237fead6 MH |
1460 | } |
1461 | return rc; | |
1462 | } | |
1463 | ||
51ca58dc MH |
1464 | /** |
1465 | * ecryptfs_encrypt_filename - encrypt filename | |
1466 | * | |
1467 | * CBC-encrypts the filename. We do not want to encrypt the same | |
1468 | * filename with the same key and IV, which may happen with hard | |
1469 | * links, so we prepend random bits to each filename. | |
1470 | * | |
1471 | * Returns zero on success; non-zero otherwise | |
1472 | */ | |
1473 | static int | |
1474 | ecryptfs_encrypt_filename(struct ecryptfs_filename *filename, | |
51ca58dc MH |
1475 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
1476 | { | |
1477 | int rc = 0; | |
1478 | ||
1479 | filename->encrypted_filename = NULL; | |
1480 | filename->encrypted_filename_size = 0; | |
97c31606 AV |
1481 | if (mount_crypt_stat && (mount_crypt_stat->flags |
1482 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) { | |
51ca58dc MH |
1483 | size_t packet_size; |
1484 | size_t remaining_bytes; | |
1485 | ||
1486 | rc = ecryptfs_write_tag_70_packet( | |
1487 | NULL, NULL, | |
1488 | &filename->encrypted_filename_size, | |
1489 | mount_crypt_stat, NULL, | |
1490 | filename->filename_size); | |
1491 | if (rc) { | |
1492 | printk(KERN_ERR "%s: Error attempting to get packet " | |
1493 | "size for tag 72; rc = [%d]\n", __func__, | |
1494 | rc); | |
1495 | filename->encrypted_filename_size = 0; | |
1496 | goto out; | |
1497 | } | |
1498 | filename->encrypted_filename = | |
1499 | kmalloc(filename->encrypted_filename_size, GFP_KERNEL); | |
1500 | if (!filename->encrypted_filename) { | |
51ca58dc MH |
1501 | rc = -ENOMEM; |
1502 | goto out; | |
1503 | } | |
1504 | remaining_bytes = filename->encrypted_filename_size; | |
1505 | rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename, | |
1506 | &remaining_bytes, | |
1507 | &packet_size, | |
1508 | mount_crypt_stat, | |
1509 | filename->filename, | |
1510 | filename->filename_size); | |
1511 | if (rc) { | |
1512 | printk(KERN_ERR "%s: Error attempting to generate " | |
1513 | "tag 70 packet; rc = [%d]\n", __func__, | |
1514 | rc); | |
1515 | kfree(filename->encrypted_filename); | |
1516 | filename->encrypted_filename = NULL; | |
1517 | filename->encrypted_filename_size = 0; | |
1518 | goto out; | |
1519 | } | |
1520 | filename->encrypted_filename_size = packet_size; | |
1521 | } else { | |
1522 | printk(KERN_ERR "%s: No support for requested filename " | |
1523 | "encryption method in this release\n", __func__); | |
df6ad33b | 1524 | rc = -EOPNOTSUPP; |
51ca58dc MH |
1525 | goto out; |
1526 | } | |
1527 | out: | |
1528 | return rc; | |
1529 | } | |
1530 | ||
1531 | static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size, | |
1532 | const char *name, size_t name_size) | |
1533 | { | |
1534 | int rc = 0; | |
1535 | ||
fd9fc842 | 1536 | (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL); |
51ca58dc MH |
1537 | if (!(*copied_name)) { |
1538 | rc = -ENOMEM; | |
1539 | goto out; | |
1540 | } | |
1541 | memcpy((void *)(*copied_name), (void *)name, name_size); | |
1542 | (*copied_name)[(name_size)] = '\0'; /* Only for convenience | |
1543 | * in printing out the | |
1544 | * string in debug | |
1545 | * messages */ | |
fd9fc842 | 1546 | (*copied_name_size) = name_size; |
51ca58dc MH |
1547 | out: |
1548 | return rc; | |
1549 | } | |
1550 | ||
237fead6 | 1551 | /** |
f4aad16a | 1552 | * ecryptfs_process_key_cipher - Perform key cipher initialization. |
237fead6 | 1553 | * @key_tfm: Crypto context for key material, set by this function |
e5d9cbde MH |
1554 | * @cipher_name: Name of the cipher |
1555 | * @key_size: Size of the key in bytes | |
237fead6 MH |
1556 | * |
1557 | * Returns zero on success. Any crypto_tfm structs allocated here | |
1558 | * should be released by other functions, such as on a superblock put | |
1559 | * event, regardless of whether this function succeeds for fails. | |
1560 | */ | |
cd9d67df | 1561 | static int |
3095e8e3 | 1562 | ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm, |
f4aad16a | 1563 | char *cipher_name, size_t *key_size) |
237fead6 MH |
1564 | { |
1565 | char dummy_key[ECRYPTFS_MAX_KEY_BYTES]; | |
ece550f5 | 1566 | char *full_alg_name = NULL; |
237fead6 MH |
1567 | int rc; |
1568 | ||
e5d9cbde MH |
1569 | *key_tfm = NULL; |
1570 | if (*key_size > ECRYPTFS_MAX_KEY_BYTES) { | |
237fead6 | 1571 | rc = -EINVAL; |
df261c52 | 1572 | printk(KERN_ERR "Requested key size is [%zd] bytes; maximum " |
e5d9cbde | 1573 | "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES); |
237fead6 MH |
1574 | goto out; |
1575 | } | |
8bba066f MH |
1576 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name, |
1577 | "ecb"); | |
1578 | if (rc) | |
1579 | goto out; | |
3095e8e3 | 1580 | *key_tfm = crypto_alloc_skcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC); |
8bba066f MH |
1581 | if (IS_ERR(*key_tfm)) { |
1582 | rc = PTR_ERR(*key_tfm); | |
237fead6 | 1583 | printk(KERN_ERR "Unable to allocate crypto cipher with name " |
38268498 | 1584 | "[%s]; rc = [%d]\n", full_alg_name, rc); |
237fead6 MH |
1585 | goto out; |
1586 | } | |
231baecd | 1587 | crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); |
3095e8e3 HX |
1588 | if (*key_size == 0) |
1589 | *key_size = crypto_skcipher_default_keysize(*key_tfm); | |
e5d9cbde | 1590 | get_random_bytes(dummy_key, *key_size); |
3095e8e3 | 1591 | rc = crypto_skcipher_setkey(*key_tfm, dummy_key, *key_size); |
237fead6 | 1592 | if (rc) { |
df261c52 | 1593 | printk(KERN_ERR "Error attempting to set key of size [%zd] for " |
38268498 DH |
1594 | "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name, |
1595 | rc); | |
237fead6 MH |
1596 | rc = -EINVAL; |
1597 | goto out; | |
1598 | } | |
1599 | out: | |
ece550f5 | 1600 | kfree(full_alg_name); |
237fead6 MH |
1601 | return rc; |
1602 | } | |
f4aad16a MH |
1603 | |
1604 | struct kmem_cache *ecryptfs_key_tfm_cache; | |
7896b631 | 1605 | static struct list_head key_tfm_list; |
af440f52 | 1606 | struct mutex key_tfm_list_mutex; |
f4aad16a | 1607 | |
7371a382 | 1608 | int __init ecryptfs_init_crypto(void) |
f4aad16a MH |
1609 | { |
1610 | mutex_init(&key_tfm_list_mutex); | |
1611 | INIT_LIST_HEAD(&key_tfm_list); | |
1612 | return 0; | |
1613 | } | |
1614 | ||
af440f52 ES |
1615 | /** |
1616 | * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list | |
1617 | * | |
1618 | * Called only at module unload time | |
1619 | */ | |
fcd12835 | 1620 | int ecryptfs_destroy_crypto(void) |
f4aad16a MH |
1621 | { |
1622 | struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp; | |
1623 | ||
1624 | mutex_lock(&key_tfm_list_mutex); | |
1625 | list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list, | |
1626 | key_tfm_list) { | |
1627 | list_del(&key_tfm->key_tfm_list); | |
3095e8e3 | 1628 | crypto_free_skcipher(key_tfm->key_tfm); |
f4aad16a MH |
1629 | kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm); |
1630 | } | |
1631 | mutex_unlock(&key_tfm_list_mutex); | |
1632 | return 0; | |
1633 | } | |
1634 | ||
1635 | int | |
1636 | ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name, | |
1637 | size_t key_size) | |
1638 | { | |
1639 | struct ecryptfs_key_tfm *tmp_tfm; | |
1640 | int rc = 0; | |
1641 | ||
af440f52 ES |
1642 | BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); |
1643 | ||
f4aad16a | 1644 | tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL); |
5032f360 | 1645 | if (key_tfm) |
f4aad16a MH |
1646 | (*key_tfm) = tmp_tfm; |
1647 | if (!tmp_tfm) { | |
1648 | rc = -ENOMEM; | |
f4aad16a MH |
1649 | goto out; |
1650 | } | |
1651 | mutex_init(&tmp_tfm->key_tfm_mutex); | |
1652 | strncpy(tmp_tfm->cipher_name, cipher_name, | |
1653 | ECRYPTFS_MAX_CIPHER_NAME_SIZE); | |
b8862906 | 1654 | tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; |
f4aad16a | 1655 | tmp_tfm->key_size = key_size; |
5dda6992 MH |
1656 | rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm, |
1657 | tmp_tfm->cipher_name, | |
1658 | &tmp_tfm->key_size); | |
1659 | if (rc) { | |
f4aad16a MH |
1660 | printk(KERN_ERR "Error attempting to initialize key TFM " |
1661 | "cipher with name = [%s]; rc = [%d]\n", | |
1662 | tmp_tfm->cipher_name, rc); | |
1663 | kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm); | |
5032f360 | 1664 | if (key_tfm) |
f4aad16a MH |
1665 | (*key_tfm) = NULL; |
1666 | goto out; | |
1667 | } | |
f4aad16a | 1668 | list_add(&tmp_tfm->key_tfm_list, &key_tfm_list); |
f4aad16a MH |
1669 | out: |
1670 | return rc; | |
1671 | } | |
1672 | ||
af440f52 ES |
1673 | /** |
1674 | * ecryptfs_tfm_exists - Search for existing tfm for cipher_name. | |
1675 | * @cipher_name: the name of the cipher to search for | |
1676 | * @key_tfm: set to corresponding tfm if found | |
1677 | * | |
1678 | * Searches for cached key_tfm matching @cipher_name | |
1679 | * Must be called with &key_tfm_list_mutex held | |
1680 | * Returns 1 if found, with @key_tfm set | |
1681 | * Returns 0 if not found, with @key_tfm set to NULL | |
1682 | */ | |
1683 | int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm) | |
1684 | { | |
1685 | struct ecryptfs_key_tfm *tmp_key_tfm; | |
1686 | ||
1687 | BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); | |
1688 | ||
1689 | list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) { | |
1690 | if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) { | |
1691 | if (key_tfm) | |
1692 | (*key_tfm) = tmp_key_tfm; | |
1693 | return 1; | |
1694 | } | |
1695 | } | |
1696 | if (key_tfm) | |
1697 | (*key_tfm) = NULL; | |
1698 | return 0; | |
1699 | } | |
1700 | ||
1701 | /** | |
1702 | * ecryptfs_get_tfm_and_mutex_for_cipher_name | |
1703 | * | |
1704 | * @tfm: set to cached tfm found, or new tfm created | |
1705 | * @tfm_mutex: set to mutex for cached tfm found, or new tfm created | |
1706 | * @cipher_name: the name of the cipher to search for and/or add | |
1707 | * | |
1708 | * Sets pointers to @tfm & @tfm_mutex matching @cipher_name. | |
1709 | * Searches for cached item first, and creates new if not found. | |
1710 | * Returns 0 on success, non-zero if adding new cipher failed | |
1711 | */ | |
3095e8e3 | 1712 | int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm, |
f4aad16a MH |
1713 | struct mutex **tfm_mutex, |
1714 | char *cipher_name) | |
1715 | { | |
1716 | struct ecryptfs_key_tfm *key_tfm; | |
1717 | int rc = 0; | |
1718 | ||
1719 | (*tfm) = NULL; | |
1720 | (*tfm_mutex) = NULL; | |
af440f52 | 1721 | |
f4aad16a | 1722 | mutex_lock(&key_tfm_list_mutex); |
af440f52 ES |
1723 | if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) { |
1724 | rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0); | |
1725 | if (rc) { | |
1726 | printk(KERN_ERR "Error adding new key_tfm to list; " | |
1727 | "rc = [%d]\n", rc); | |
f4aad16a MH |
1728 | goto out; |
1729 | } | |
1730 | } | |
f4aad16a MH |
1731 | (*tfm) = key_tfm->key_tfm; |
1732 | (*tfm_mutex) = &key_tfm->key_tfm_mutex; | |
1733 | out: | |
71fd5179 | 1734 | mutex_unlock(&key_tfm_list_mutex); |
f4aad16a MH |
1735 | return rc; |
1736 | } | |
51ca58dc MH |
1737 | |
1738 | /* 64 characters forming a 6-bit target field */ | |
1739 | static unsigned char *portable_filename_chars = ("-.0123456789ABCD" | |
1740 | "EFGHIJKLMNOPQRST" | |
1741 | "UVWXYZabcdefghij" | |
1742 | "klmnopqrstuvwxyz"); | |
1743 | ||
1744 | /* We could either offset on every reverse map or just pad some 0x00's | |
1745 | * at the front here */ | |
0f751e64 | 1746 | static const unsigned char filename_rev_map[256] = { |
51ca58dc MH |
1747 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */ |
1748 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */ | |
1749 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */ | |
1750 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */ | |
1751 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */ | |
1752 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */ | |
1753 | 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */ | |
1754 | 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */ | |
1755 | 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */ | |
1756 | 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */ | |
1757 | 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */ | |
1758 | 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */ | |
1759 | 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */ | |
1760 | 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */ | |
1761 | 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */ | |
0f751e64 | 1762 | 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */ |
51ca58dc MH |
1763 | }; |
1764 | ||
1765 | /** | |
1766 | * ecryptfs_encode_for_filename | |
1767 | * @dst: Destination location for encoded filename | |
1768 | * @dst_size: Size of the encoded filename in bytes | |
1769 | * @src: Source location for the filename to encode | |
1770 | * @src_size: Size of the source in bytes | |
1771 | */ | |
37028758 | 1772 | static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size, |
51ca58dc MH |
1773 | unsigned char *src, size_t src_size) |
1774 | { | |
1775 | size_t num_blocks; | |
1776 | size_t block_num = 0; | |
1777 | size_t dst_offset = 0; | |
1778 | unsigned char last_block[3]; | |
1779 | ||
1780 | if (src_size == 0) { | |
1781 | (*dst_size) = 0; | |
1782 | goto out; | |
1783 | } | |
1784 | num_blocks = (src_size / 3); | |
1785 | if ((src_size % 3) == 0) { | |
1786 | memcpy(last_block, (&src[src_size - 3]), 3); | |
1787 | } else { | |
1788 | num_blocks++; | |
1789 | last_block[2] = 0x00; | |
1790 | switch (src_size % 3) { | |
1791 | case 1: | |
1792 | last_block[0] = src[src_size - 1]; | |
1793 | last_block[1] = 0x00; | |
1794 | break; | |
1795 | case 2: | |
1796 | last_block[0] = src[src_size - 2]; | |
1797 | last_block[1] = src[src_size - 1]; | |
1798 | } | |
1799 | } | |
1800 | (*dst_size) = (num_blocks * 4); | |
1801 | if (!dst) | |
1802 | goto out; | |
1803 | while (block_num < num_blocks) { | |
1804 | unsigned char *src_block; | |
1805 | unsigned char dst_block[4]; | |
1806 | ||
1807 | if (block_num == (num_blocks - 1)) | |
1808 | src_block = last_block; | |
1809 | else | |
1810 | src_block = &src[block_num * 3]; | |
1811 | dst_block[0] = ((src_block[0] >> 2) & 0x3F); | |
1812 | dst_block[1] = (((src_block[0] << 4) & 0x30) | |
1813 | | ((src_block[1] >> 4) & 0x0F)); | |
1814 | dst_block[2] = (((src_block[1] << 2) & 0x3C) | |
1815 | | ((src_block[2] >> 6) & 0x03)); | |
1816 | dst_block[3] = (src_block[2] & 0x3F); | |
1817 | dst[dst_offset++] = portable_filename_chars[dst_block[0]]; | |
1818 | dst[dst_offset++] = portable_filename_chars[dst_block[1]]; | |
1819 | dst[dst_offset++] = portable_filename_chars[dst_block[2]]; | |
1820 | dst[dst_offset++] = portable_filename_chars[dst_block[3]]; | |
1821 | block_num++; | |
1822 | } | |
1823 | out: | |
1824 | return; | |
1825 | } | |
1826 | ||
4a26620d TH |
1827 | static size_t ecryptfs_max_decoded_size(size_t encoded_size) |
1828 | { | |
1829 | /* Not exact; conservatively long. Every block of 4 | |
1830 | * encoded characters decodes into a block of 3 | |
1831 | * decoded characters. This segment of code provides | |
1832 | * the caller with the maximum amount of allocated | |
1833 | * space that @dst will need to point to in a | |
1834 | * subsequent call. */ | |
1835 | return ((encoded_size + 1) * 3) / 4; | |
1836 | } | |
1837 | ||
71c11c37 MH |
1838 | /** |
1839 | * ecryptfs_decode_from_filename | |
1840 | * @dst: If NULL, this function only sets @dst_size and returns. If | |
1841 | * non-NULL, this function decodes the encoded octets in @src | |
1842 | * into the memory that @dst points to. | |
1843 | * @dst_size: Set to the size of the decoded string. | |
1844 | * @src: The encoded set of octets to decode. | |
1845 | * @src_size: The size of the encoded set of octets to decode. | |
1846 | */ | |
1847 | static void | |
1848 | ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size, | |
1849 | const unsigned char *src, size_t src_size) | |
51ca58dc MH |
1850 | { |
1851 | u8 current_bit_offset = 0; | |
1852 | size_t src_byte_offset = 0; | |
1853 | size_t dst_byte_offset = 0; | |
51ca58dc | 1854 | |
5032f360 | 1855 | if (!dst) { |
4a26620d | 1856 | (*dst_size) = ecryptfs_max_decoded_size(src_size); |
51ca58dc MH |
1857 | goto out; |
1858 | } | |
1859 | while (src_byte_offset < src_size) { | |
1860 | unsigned char src_byte = | |
1861 | filename_rev_map[(int)src[src_byte_offset]]; | |
1862 | ||
1863 | switch (current_bit_offset) { | |
1864 | case 0: | |
1865 | dst[dst_byte_offset] = (src_byte << 2); | |
1866 | current_bit_offset = 6; | |
1867 | break; | |
1868 | case 6: | |
1869 | dst[dst_byte_offset++] |= (src_byte >> 4); | |
1870 | dst[dst_byte_offset] = ((src_byte & 0xF) | |
1871 | << 4); | |
1872 | current_bit_offset = 4; | |
1873 | break; | |
1874 | case 4: | |
1875 | dst[dst_byte_offset++] |= (src_byte >> 2); | |
1876 | dst[dst_byte_offset] = (src_byte << 6); | |
1877 | current_bit_offset = 2; | |
1878 | break; | |
1879 | case 2: | |
1880 | dst[dst_byte_offset++] |= (src_byte); | |
51ca58dc MH |
1881 | current_bit_offset = 0; |
1882 | break; | |
1883 | } | |
1884 | src_byte_offset++; | |
1885 | } | |
1886 | (*dst_size) = dst_byte_offset; | |
1887 | out: | |
71c11c37 | 1888 | return; |
51ca58dc MH |
1889 | } |
1890 | ||
1891 | /** | |
1892 | * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text | |
1893 | * @crypt_stat: The crypt_stat struct associated with the file anem to encode | |
1894 | * @name: The plaintext name | |
1895 | * @length: The length of the plaintext | |
1896 | * @encoded_name: The encypted name | |
1897 | * | |
1898 | * Encrypts and encodes a filename into something that constitutes a | |
1899 | * valid filename for a filesystem, with printable characters. | |
1900 | * | |
1901 | * We assume that we have a properly initialized crypto context, | |
1902 | * pointed to by crypt_stat->tfm. | |
1903 | * | |
1904 | * Returns zero on success; non-zero on otherwise | |
1905 | */ | |
1906 | int ecryptfs_encrypt_and_encode_filename( | |
1907 | char **encoded_name, | |
1908 | size_t *encoded_name_size, | |
51ca58dc MH |
1909 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat, |
1910 | const char *name, size_t name_size) | |
1911 | { | |
1912 | size_t encoded_name_no_prefix_size; | |
1913 | int rc = 0; | |
1914 | ||
1915 | (*encoded_name) = NULL; | |
1916 | (*encoded_name_size) = 0; | |
97c31606 AV |
1917 | if (mount_crypt_stat && (mount_crypt_stat->flags |
1918 | & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { | |
51ca58dc MH |
1919 | struct ecryptfs_filename *filename; |
1920 | ||
1921 | filename = kzalloc(sizeof(*filename), GFP_KERNEL); | |
1922 | if (!filename) { | |
51ca58dc MH |
1923 | rc = -ENOMEM; |
1924 | goto out; | |
1925 | } | |
1926 | filename->filename = (char *)name; | |
1927 | filename->filename_size = name_size; | |
97c31606 | 1928 | rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat); |
51ca58dc MH |
1929 | if (rc) { |
1930 | printk(KERN_ERR "%s: Error attempting to encrypt " | |
1931 | "filename; rc = [%d]\n", __func__, rc); | |
1932 | kfree(filename); | |
1933 | goto out; | |
1934 | } | |
1935 | ecryptfs_encode_for_filename( | |
1936 | NULL, &encoded_name_no_prefix_size, | |
1937 | filename->encrypted_filename, | |
1938 | filename->encrypted_filename_size); | |
97c31606 | 1939 | if (mount_crypt_stat |
51ca58dc | 1940 | && (mount_crypt_stat->flags |
97c31606 | 1941 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) |
51ca58dc MH |
1942 | (*encoded_name_size) = |
1943 | (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1944 | + encoded_name_no_prefix_size); | |
1945 | else | |
1946 | (*encoded_name_size) = | |
1947 | (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1948 | + encoded_name_no_prefix_size); | |
1949 | (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL); | |
1950 | if (!(*encoded_name)) { | |
51ca58dc MH |
1951 | rc = -ENOMEM; |
1952 | kfree(filename->encrypted_filename); | |
1953 | kfree(filename); | |
1954 | goto out; | |
1955 | } | |
97c31606 | 1956 | if (mount_crypt_stat |
51ca58dc | 1957 | && (mount_crypt_stat->flags |
97c31606 | 1958 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) { |
51ca58dc MH |
1959 | memcpy((*encoded_name), |
1960 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, | |
1961 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE); | |
1962 | ecryptfs_encode_for_filename( | |
1963 | ((*encoded_name) | |
1964 | + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE), | |
1965 | &encoded_name_no_prefix_size, | |
1966 | filename->encrypted_filename, | |
1967 | filename->encrypted_filename_size); | |
1968 | (*encoded_name_size) = | |
1969 | (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1970 | + encoded_name_no_prefix_size); | |
1971 | (*encoded_name)[(*encoded_name_size)] = '\0'; | |
51ca58dc | 1972 | } else { |
df6ad33b | 1973 | rc = -EOPNOTSUPP; |
51ca58dc MH |
1974 | } |
1975 | if (rc) { | |
1976 | printk(KERN_ERR "%s: Error attempting to encode " | |
1977 | "encrypted filename; rc = [%d]\n", __func__, | |
1978 | rc); | |
1979 | kfree((*encoded_name)); | |
1980 | (*encoded_name) = NULL; | |
1981 | (*encoded_name_size) = 0; | |
1982 | } | |
1983 | kfree(filename->encrypted_filename); | |
1984 | kfree(filename); | |
1985 | } else { | |
1986 | rc = ecryptfs_copy_filename(encoded_name, | |
1987 | encoded_name_size, | |
1988 | name, name_size); | |
1989 | } | |
1990 | out: | |
1991 | return rc; | |
1992 | } | |
1993 | ||
e86281e7 TH |
1994 | static bool is_dot_dotdot(const char *name, size_t name_size) |
1995 | { | |
1996 | if (name_size == 1 && name[0] == '.') | |
1997 | return true; | |
1998 | else if (name_size == 2 && name[0] == '.' && name[1] == '.') | |
1999 | return true; | |
2000 | ||
2001 | return false; | |
2002 | } | |
2003 | ||
51ca58dc MH |
2004 | /** |
2005 | * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext | |
2006 | * @plaintext_name: The plaintext name | |
2007 | * @plaintext_name_size: The plaintext name size | |
2008 | * @ecryptfs_dir_dentry: eCryptfs directory dentry | |
2009 | * @name: The filename in cipher text | |
2010 | * @name_size: The cipher text name size | |
2011 | * | |
2012 | * Decrypts and decodes the filename. | |
2013 | * | |
2014 | * Returns zero on error; non-zero otherwise | |
2015 | */ | |
2016 | int ecryptfs_decode_and_decrypt_filename(char **plaintext_name, | |
2017 | size_t *plaintext_name_size, | |
0747fdb2 | 2018 | struct super_block *sb, |
51ca58dc MH |
2019 | const char *name, size_t name_size) |
2020 | { | |
2aac0cf8 | 2021 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
0747fdb2 | 2022 | &ecryptfs_superblock_to_private(sb)->mount_crypt_stat; |
51ca58dc MH |
2023 | char *decoded_name; |
2024 | size_t decoded_name_size; | |
2025 | size_t packet_size; | |
2026 | int rc = 0; | |
2027 | ||
e86281e7 TH |
2028 | if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) && |
2029 | !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)) { | |
2030 | if (is_dot_dotdot(name, name_size)) { | |
2031 | rc = ecryptfs_copy_filename(plaintext_name, | |
2032 | plaintext_name_size, | |
2033 | name, name_size); | |
2034 | goto out; | |
2035 | } | |
2036 | ||
2037 | if (name_size <= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE || | |
2038 | strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, | |
2039 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)) { | |
2040 | rc = -EINVAL; | |
2041 | goto out; | |
2042 | } | |
51ca58dc MH |
2043 | |
2044 | name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
2045 | name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
71c11c37 MH |
2046 | ecryptfs_decode_from_filename(NULL, &decoded_name_size, |
2047 | name, name_size); | |
51ca58dc MH |
2048 | decoded_name = kmalloc(decoded_name_size, GFP_KERNEL); |
2049 | if (!decoded_name) { | |
51ca58dc MH |
2050 | rc = -ENOMEM; |
2051 | goto out; | |
2052 | } | |
71c11c37 MH |
2053 | ecryptfs_decode_from_filename(decoded_name, &decoded_name_size, |
2054 | name, name_size); | |
51ca58dc MH |
2055 | rc = ecryptfs_parse_tag_70_packet(plaintext_name, |
2056 | plaintext_name_size, | |
2057 | &packet_size, | |
2058 | mount_crypt_stat, | |
2059 | decoded_name, | |
2060 | decoded_name_size); | |
2061 | if (rc) { | |
e86281e7 TH |
2062 | ecryptfs_printk(KERN_DEBUG, |
2063 | "%s: Could not parse tag 70 packet from filename\n", | |
2064 | __func__); | |
51ca58dc MH |
2065 | goto out_free; |
2066 | } | |
2067 | } else { | |
2068 | rc = ecryptfs_copy_filename(plaintext_name, | |
2069 | plaintext_name_size, | |
2070 | name, name_size); | |
2071 | goto out; | |
2072 | } | |
2073 | out_free: | |
2074 | kfree(decoded_name); | |
2075 | out: | |
2076 | return rc; | |
2077 | } | |
4a26620d TH |
2078 | |
2079 | #define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143 | |
2080 | ||
2081 | int ecryptfs_set_f_namelen(long *namelen, long lower_namelen, | |
2082 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
2083 | { | |
3095e8e3 | 2084 | struct crypto_skcipher *tfm; |
4a26620d TH |
2085 | struct mutex *tfm_mutex; |
2086 | size_t cipher_blocksize; | |
2087 | int rc; | |
2088 | ||
2089 | if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { | |
2090 | (*namelen) = lower_namelen; | |
2091 | return 0; | |
2092 | } | |
2093 | ||
3095e8e3 | 2094 | rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, |
4a26620d TH |
2095 | mount_crypt_stat->global_default_fn_cipher_name); |
2096 | if (unlikely(rc)) { | |
2097 | (*namelen) = 0; | |
2098 | return rc; | |
2099 | } | |
2100 | ||
2101 | mutex_lock(tfm_mutex); | |
3095e8e3 | 2102 | cipher_blocksize = crypto_skcipher_blocksize(tfm); |
4a26620d TH |
2103 | mutex_unlock(tfm_mutex); |
2104 | ||
2105 | /* Return an exact amount for the common cases */ | |
2106 | if (lower_namelen == NAME_MAX | |
2107 | && (cipher_blocksize == 8 || cipher_blocksize == 16)) { | |
2108 | (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16; | |
2109 | return 0; | |
2110 | } | |
2111 | ||
2112 | /* Return a safe estimate for the uncommon cases */ | |
2113 | (*namelen) = lower_namelen; | |
2114 | (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
2115 | /* Since this is the max decoded size, subtract 1 "decoded block" len */ | |
2116 | (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3; | |
2117 | (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE; | |
2118 | (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES; | |
2119 | /* Worst case is that the filename is padded nearly a full block size */ | |
2120 | (*namelen) -= cipher_blocksize - 1; | |
2121 | ||
2122 | if ((*namelen) < 0) | |
2123 | (*namelen) = 0; | |
2124 | ||
2125 | return 0; | |
2126 | } |