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 | ||
263 | /** | |
00a69940 | 264 | * crypt_scatterlist |
237fead6 | 265 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
0df5ed65 | 266 | * @dst_sg: Destination of the data after performing the crypto operation |
00a69940 TH |
267 | * @src_sg: Data to be encrypted or decrypted |
268 | * @size: Length of data | |
269 | * @iv: IV to use | |
270 | * @op: ENCRYPT or DECRYPT to indicate the desired operation | |
237fead6 | 271 | * |
00a69940 | 272 | * Returns the number of bytes encrypted or decrypted; negative value on error |
237fead6 | 273 | */ |
00a69940 | 274 | static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, |
0df5ed65 | 275 | struct scatterlist *dst_sg, |
00a69940 TH |
276 | struct scatterlist *src_sg, int size, |
277 | unsigned char *iv, int op) | |
237fead6 | 278 | { |
3095e8e3 | 279 | struct skcipher_request *req = NULL; |
20066bf7 | 280 | DECLARE_CRYPTO_WAIT(ecr); |
237fead6 MH |
281 | int rc = 0; |
282 | ||
237fead6 | 283 | if (unlikely(ecryptfs_verbosity > 0)) { |
f24b3887 | 284 | ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n", |
237fead6 MH |
285 | crypt_stat->key_size); |
286 | ecryptfs_dump_hex(crypt_stat->key, | |
287 | crypt_stat->key_size); | |
288 | } | |
4dfea4f0 | 289 | |
237fead6 | 290 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
3095e8e3 | 291 | req = skcipher_request_alloc(crypt_stat->tfm, GFP_NOFS); |
4dfea4f0 | 292 | if (!req) { |
237fead6 | 293 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
4dfea4f0 | 294 | rc = -ENOMEM; |
237fead6 MH |
295 | goto out; |
296 | } | |
4dfea4f0 | 297 | |
3095e8e3 | 298 | skcipher_request_set_callback(req, |
4dfea4f0 | 299 | CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, |
20066bf7 | 300 | crypto_req_done, &ecr); |
4dfea4f0 TH |
301 | /* Consider doing this once, when the file is opened */ |
302 | if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) { | |
3095e8e3 HX |
303 | rc = crypto_skcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
304 | crypt_stat->key_size); | |
4dfea4f0 TH |
305 | if (rc) { |
306 | ecryptfs_printk(KERN_ERR, | |
307 | "Error setting key; rc = [%d]\n", | |
308 | rc); | |
309 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
310 | rc = -EINVAL; | |
311 | goto out; | |
312 | } | |
313 | crypt_stat->flags |= ECRYPTFS_KEY_SET; | |
314 | } | |
237fead6 | 315 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
3095e8e3 HX |
316 | skcipher_request_set_crypt(req, src_sg, dst_sg, size, iv); |
317 | rc = op == ENCRYPT ? crypto_skcipher_encrypt(req) : | |
318 | crypto_skcipher_decrypt(req); | |
20066bf7 | 319 | rc = crypto_wait_req(rc, &ecr); |
237fead6 | 320 | out: |
3095e8e3 | 321 | skcipher_request_free(req); |
237fead6 MH |
322 | return rc; |
323 | } | |
324 | ||
5da877ea | 325 | /* |
24d15266 | 326 | * lower_offset_for_page |
0216f7f7 MH |
327 | * |
328 | * Convert an eCryptfs page index into a lower byte offset | |
329 | */ | |
24d15266 TH |
330 | static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat, |
331 | struct page *page) | |
0216f7f7 | 332 | { |
24d15266 | 333 | return ecryptfs_lower_header_size(crypt_stat) + |
09cbfeaf | 334 | ((loff_t)page->index << PAGE_SHIFT); |
0216f7f7 MH |
335 | } |
336 | ||
337 | /** | |
d78de618 | 338 | * crypt_extent |
0216f7f7 MH |
339 | * @crypt_stat: crypt_stat containing cryptographic context for the |
340 | * encryption operation | |
0df5ed65 | 341 | * @dst_page: The page to write the result into |
d78de618 | 342 | * @src_page: The page to read from |
0216f7f7 | 343 | * @extent_offset: Page extent offset for use in generating IV |
d78de618 | 344 | * @op: ENCRYPT or DECRYPT to indicate the desired operation |
0216f7f7 | 345 | * |
d78de618 | 346 | * Encrypts or decrypts one extent of data. |
0216f7f7 MH |
347 | * |
348 | * Return zero on success; non-zero otherwise | |
349 | */ | |
0df5ed65 TH |
350 | static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat, |
351 | struct page *dst_page, | |
d78de618 TH |
352 | struct page *src_page, |
353 | unsigned long extent_offset, int op) | |
0216f7f7 | 354 | { |
d78de618 | 355 | pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index; |
d6a13c17 | 356 | loff_t extent_base; |
0216f7f7 | 357 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
406c93df TH |
358 | struct scatterlist src_sg, dst_sg; |
359 | size_t extent_size = crypt_stat->extent_size; | |
0216f7f7 MH |
360 | int rc; |
361 | ||
09cbfeaf | 362 | extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size)); |
0216f7f7 MH |
363 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, |
364 | (extent_base + extent_offset)); | |
365 | if (rc) { | |
888d57bb JP |
366 | ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for " |
367 | "extent [0x%.16llx]; rc = [%d]\n", | |
368 | (unsigned long long)(extent_base + extent_offset), rc); | |
0216f7f7 MH |
369 | goto out; |
370 | } | |
406c93df TH |
371 | |
372 | sg_init_table(&src_sg, 1); | |
373 | sg_init_table(&dst_sg, 1); | |
374 | ||
375 | sg_set_page(&src_sg, src_page, extent_size, | |
376 | extent_offset * extent_size); | |
377 | sg_set_page(&dst_sg, dst_page, extent_size, | |
378 | extent_offset * extent_size); | |
379 | ||
380 | rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size, | |
381 | extent_iv, op); | |
0216f7f7 | 382 | if (rc < 0) { |
d78de618 TH |
383 | printk(KERN_ERR "%s: Error attempting to crypt page with " |
384 | "page_index = [%ld], extent_offset = [%ld]; " | |
385 | "rc = [%d]\n", __func__, page_index, extent_offset, rc); | |
0216f7f7 MH |
386 | goto out; |
387 | } | |
388 | rc = 0; | |
0216f7f7 MH |
389 | out: |
390 | return rc; | |
391 | } | |
392 | ||
237fead6 MH |
393 | /** |
394 | * ecryptfs_encrypt_page | |
0216f7f7 MH |
395 | * @page: Page mapped from the eCryptfs inode for the file; contains |
396 | * decrypted content that needs to be encrypted (to a temporary | |
397 | * page; not in place) and written out to the lower file | |
237fead6 MH |
398 | * |
399 | * Encrypt an eCryptfs page. This is done on a per-extent basis. Note | |
400 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
401 | * if the file was created on a machine with an 8K page size | |
402 | * (resulting in an 8K header), and then the file is copied onto a | |
403 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
404 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
405 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
406 | * | |
237fead6 MH |
407 | * Returns zero on success; negative on error |
408 | */ | |
0216f7f7 | 409 | int ecryptfs_encrypt_page(struct page *page) |
237fead6 | 410 | { |
0216f7f7 | 411 | struct inode *ecryptfs_inode; |
237fead6 | 412 | struct ecryptfs_crypt_stat *crypt_stat; |
7fcba054 ES |
413 | char *enc_extent_virt; |
414 | struct page *enc_extent_page = NULL; | |
0216f7f7 | 415 | loff_t extent_offset; |
0f896176 | 416 | loff_t lower_offset; |
237fead6 | 417 | int rc = 0; |
0216f7f7 MH |
418 | |
419 | ecryptfs_inode = page->mapping->host; | |
420 | crypt_stat = | |
421 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
13a791b4 | 422 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
7fcba054 ES |
423 | enc_extent_page = alloc_page(GFP_USER); |
424 | if (!enc_extent_page) { | |
0216f7f7 MH |
425 | rc = -ENOMEM; |
426 | ecryptfs_printk(KERN_ERR, "Error allocating memory for " | |
427 | "encrypted extent\n"); | |
428 | goto out; | |
429 | } | |
0f896176 | 430 | |
0216f7f7 | 431 | for (extent_offset = 0; |
09cbfeaf | 432 | extent_offset < (PAGE_SIZE / crypt_stat->extent_size); |
0216f7f7 | 433 | extent_offset++) { |
0df5ed65 | 434 | rc = crypt_extent(crypt_stat, enc_extent_page, page, |
d78de618 | 435 | extent_offset, ENCRYPT); |
237fead6 | 436 | if (rc) { |
0216f7f7 | 437 | printk(KERN_ERR "%s: Error encrypting extent; " |
18d1dbf1 | 438 | "rc = [%d]\n", __func__, rc); |
237fead6 MH |
439 | goto out; |
440 | } | |
7fcba054 | 441 | } |
0216f7f7 | 442 | |
24d15266 | 443 | lower_offset = lower_offset_for_page(crypt_stat, page); |
8b70deb8 | 444 | enc_extent_virt = kmap_local_page(enc_extent_page); |
0f896176 | 445 | rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset, |
09cbfeaf | 446 | PAGE_SIZE); |
8b70deb8 | 447 | kunmap_local(enc_extent_virt); |
0216f7f7 | 448 | if (rc < 0) { |
0f896176 TH |
449 | ecryptfs_printk(KERN_ERR, |
450 | "Error attempting to write lower page; rc = [%d]\n", | |
451 | rc); | |
0216f7f7 MH |
452 | goto out; |
453 | } | |
454 | rc = 0; | |
237fead6 | 455 | out: |
7fcba054 | 456 | if (enc_extent_page) { |
7fcba054 ES |
457 | __free_page(enc_extent_page); |
458 | } | |
237fead6 MH |
459 | return rc; |
460 | } | |
461 | ||
462 | /** | |
463 | * ecryptfs_decrypt_page | |
0216f7f7 MH |
464 | * @page: Page mapped from the eCryptfs inode for the file; data read |
465 | * and decrypted from the lower file will be written into this | |
466 | * page | |
237fead6 MH |
467 | * |
468 | * Decrypt an eCryptfs page. This is done on a per-extent basis. Note | |
469 | * that eCryptfs pages may straddle the lower pages -- for instance, | |
470 | * if the file was created on a machine with an 8K page size | |
471 | * (resulting in an 8K header), and then the file is copied onto a | |
472 | * host with a 32K page size, then when reading page 0 of the eCryptfs | |
473 | * file, 24K of page 0 of the lower file will be read and decrypted, | |
474 | * and then 8K of page 1 of the lower file will be read and decrypted. | |
475 | * | |
476 | * Returns zero on success; negative on error | |
477 | */ | |
0216f7f7 | 478 | int ecryptfs_decrypt_page(struct page *page) |
237fead6 | 479 | { |
0216f7f7 | 480 | struct inode *ecryptfs_inode; |
237fead6 | 481 | struct ecryptfs_crypt_stat *crypt_stat; |
9c6043f4 | 482 | char *page_virt; |
0216f7f7 | 483 | unsigned long extent_offset; |
0f896176 | 484 | loff_t lower_offset; |
237fead6 | 485 | int rc = 0; |
237fead6 | 486 | |
0216f7f7 MH |
487 | ecryptfs_inode = page->mapping->host; |
488 | crypt_stat = | |
489 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); | |
13a791b4 | 490 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
0f896176 | 491 | |
24d15266 | 492 | lower_offset = lower_offset_for_page(crypt_stat, page); |
8b70deb8 | 493 | page_virt = kmap_local_page(page); |
09cbfeaf | 494 | rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE, |
0f896176 | 495 | ecryptfs_inode); |
8b70deb8 | 496 | kunmap_local(page_virt); |
0f896176 TH |
497 | if (rc < 0) { |
498 | ecryptfs_printk(KERN_ERR, | |
499 | "Error attempting to read lower page; rc = [%d]\n", | |
500 | rc); | |
16a72c45 | 501 | goto out; |
237fead6 | 502 | } |
0f896176 | 503 | |
0216f7f7 | 504 | for (extent_offset = 0; |
09cbfeaf | 505 | extent_offset < (PAGE_SIZE / crypt_stat->extent_size); |
0216f7f7 | 506 | extent_offset++) { |
0df5ed65 | 507 | rc = crypt_extent(crypt_stat, page, page, |
d78de618 | 508 | extent_offset, DECRYPT); |
0216f7f7 | 509 | if (rc) { |
1abbe110 | 510 | printk(KERN_ERR "%s: Error decrypting extent; " |
18d1dbf1 | 511 | "rc = [%d]\n", __func__, rc); |
16a72c45 | 512 | goto out; |
237fead6 | 513 | } |
237fead6 MH |
514 | } |
515 | out: | |
237fead6 | 516 | return rc; |
237fead6 MH |
517 | } |
518 | ||
519 | #define ECRYPTFS_MAX_SCATTERLIST_LEN 4 | |
520 | ||
521 | /** | |
522 | * ecryptfs_init_crypt_ctx | |
421f91d2 | 523 | * @crypt_stat: Uninitialized crypt stats structure |
237fead6 MH |
524 | * |
525 | * Initialize the crypto context. | |
526 | * | |
527 | * TODO: Performance: Keep a cache of initialized cipher contexts; | |
528 | * only init if needed | |
529 | */ | |
530 | int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat) | |
531 | { | |
8bba066f | 532 | char *full_alg_name; |
237fead6 MH |
533 | int rc = -EINVAL; |
534 | ||
237fead6 MH |
535 | ecryptfs_printk(KERN_DEBUG, |
536 | "Initializing cipher [%s]; strlen = [%d]; " | |
f24b3887 | 537 | "key_size_bits = [%zd]\n", |
237fead6 MH |
538 | crypt_stat->cipher, (int)strlen(crypt_stat->cipher), |
539 | crypt_stat->key_size << 3); | |
cb69f36b | 540 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
237fead6 MH |
541 | if (crypt_stat->tfm) { |
542 | rc = 0; | |
cb69f36b | 543 | goto out_unlock; |
237fead6 | 544 | } |
8bba066f MH |
545 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, |
546 | crypt_stat->cipher, "cbc"); | |
547 | if (rc) | |
c8161f64 | 548 | goto out_unlock; |
3095e8e3 | 549 | crypt_stat->tfm = crypto_alloc_skcipher(full_alg_name, 0, 0); |
de88777e AM |
550 | if (IS_ERR(crypt_stat->tfm)) { |
551 | rc = PTR_ERR(crypt_stat->tfm); | |
b0105eae | 552 | crypt_stat->tfm = NULL; |
237fead6 MH |
553 | ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): " |
554 | "Error initializing cipher [%s]\n", | |
cb69f36b KC |
555 | full_alg_name); |
556 | goto out_free; | |
237fead6 | 557 | } |
231baecd EB |
558 | crypto_skcipher_set_flags(crypt_stat->tfm, |
559 | CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); | |
237fead6 | 560 | rc = 0; |
cb69f36b KC |
561 | out_free: |
562 | kfree(full_alg_name); | |
c8161f64 ES |
563 | out_unlock: |
564 | mutex_unlock(&crypt_stat->cs_tfm_mutex); | |
237fead6 MH |
565 | return rc; |
566 | } | |
567 | ||
568 | static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat) | |
569 | { | |
570 | int extent_size_tmp; | |
571 | ||
572 | crypt_stat->extent_mask = 0xFFFFFFFF; | |
573 | crypt_stat->extent_shift = 0; | |
574 | if (crypt_stat->extent_size == 0) | |
575 | return; | |
576 | extent_size_tmp = crypt_stat->extent_size; | |
577 | while ((extent_size_tmp & 0x01) == 0) { | |
578 | extent_size_tmp >>= 1; | |
579 | crypt_stat->extent_mask <<= 1; | |
580 | crypt_stat->extent_shift++; | |
581 | } | |
582 | } | |
583 | ||
584 | void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) | |
585 | { | |
586 | /* Default values; may be overwritten as we are parsing the | |
587 | * packets. */ | |
588 | crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; | |
589 | set_extent_mask_and_shift(crypt_stat); | |
590 | crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES; | |
dd2a3b7a | 591 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
fa3ef1cb | 592 | crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
45eaab79 | 593 | else { |
09cbfeaf | 594 | if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) |
fa3ef1cb | 595 | crypt_stat->metadata_size = |
cc11beff | 596 | ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
45eaab79 | 597 | else |
09cbfeaf | 598 | crypt_stat->metadata_size = PAGE_SIZE; |
45eaab79 | 599 | } |
237fead6 MH |
600 | } |
601 | ||
5da877ea | 602 | /* |
237fead6 | 603 | * ecryptfs_compute_root_iv |
237fead6 MH |
604 | * |
605 | * On error, sets the root IV to all 0's. | |
606 | */ | |
607 | int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat) | |
608 | { | |
609 | int rc = 0; | |
610 | char dst[MD5_DIGEST_SIZE]; | |
611 | ||
612 | BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE); | |
613 | BUG_ON(crypt_stat->iv_bytes <= 0); | |
e2bd99ec | 614 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { |
237fead6 MH |
615 | rc = -EINVAL; |
616 | ecryptfs_printk(KERN_WARNING, "Session key not valid; " | |
617 | "cannot generate root IV\n"); | |
618 | goto out; | |
619 | } | |
620 | rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key, | |
621 | crypt_stat->key_size); | |
622 | if (rc) { | |
623 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " | |
624 | "MD5 while generating root IV\n"); | |
625 | goto out; | |
626 | } | |
627 | memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes); | |
628 | out: | |
629 | if (rc) { | |
630 | memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes); | |
e2bd99ec | 631 | crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING; |
237fead6 MH |
632 | } |
633 | return rc; | |
634 | } | |
635 | ||
636 | static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat) | |
637 | { | |
638 | get_random_bytes(crypt_stat->key, crypt_stat->key_size); | |
e2bd99ec | 639 | crypt_stat->flags |= ECRYPTFS_KEY_VALID; |
237fead6 MH |
640 | ecryptfs_compute_root_iv(crypt_stat); |
641 | if (unlikely(ecryptfs_verbosity > 0)) { | |
642 | ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n"); | |
643 | ecryptfs_dump_hex(crypt_stat->key, | |
644 | crypt_stat->key_size); | |
645 | } | |
646 | } | |
647 | ||
17398957 MH |
648 | /** |
649 | * ecryptfs_copy_mount_wide_flags_to_inode_flags | |
22e78faf MH |
650 | * @crypt_stat: The inode's cryptographic context |
651 | * @mount_crypt_stat: The mount point's cryptographic context | |
17398957 MH |
652 | * |
653 | * This function propagates the mount-wide flags to individual inode | |
654 | * flags. | |
655 | */ | |
656 | static void ecryptfs_copy_mount_wide_flags_to_inode_flags( | |
657 | struct ecryptfs_crypt_stat *crypt_stat, | |
658 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
659 | { | |
660 | if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) | |
661 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
662 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) | |
663 | crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED; | |
addd65ad MH |
664 | if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) { |
665 | crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES; | |
666 | if (mount_crypt_stat->flags | |
667 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK) | |
668 | crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK; | |
669 | else if (mount_crypt_stat->flags | |
670 | & ECRYPTFS_GLOBAL_ENCFN_USE_FEK) | |
671 | crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK; | |
672 | } | |
17398957 MH |
673 | } |
674 | ||
f4aad16a MH |
675 | static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs( |
676 | struct ecryptfs_crypt_stat *crypt_stat, | |
677 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
678 | { | |
679 | struct ecryptfs_global_auth_tok *global_auth_tok; | |
680 | int rc = 0; | |
681 | ||
aa06117f | 682 | mutex_lock(&crypt_stat->keysig_list_mutex); |
f4aad16a | 683 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
aa06117f | 684 | |
f4aad16a MH |
685 | list_for_each_entry(global_auth_tok, |
686 | &mount_crypt_stat->global_auth_tok_list, | |
687 | mount_crypt_stat_list) { | |
84814d64 TH |
688 | if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK) |
689 | continue; | |
f4aad16a MH |
690 | rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig); |
691 | if (rc) { | |
692 | printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc); | |
f4aad16a MH |
693 | goto out; |
694 | } | |
695 | } | |
aa06117f | 696 | |
f4aad16a | 697 | out: |
aa06117f RD |
698 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
699 | mutex_unlock(&crypt_stat->keysig_list_mutex); | |
f4aad16a MH |
700 | return rc; |
701 | } | |
702 | ||
237fead6 MH |
703 | /** |
704 | * ecryptfs_set_default_crypt_stat_vals | |
22e78faf MH |
705 | * @crypt_stat: The inode's cryptographic context |
706 | * @mount_crypt_stat: The mount point's cryptographic context | |
237fead6 MH |
707 | * |
708 | * Default values in the event that policy does not override them. | |
709 | */ | |
710 | static void ecryptfs_set_default_crypt_stat_vals( | |
711 | struct ecryptfs_crypt_stat *crypt_stat, | |
712 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
713 | { | |
17398957 MH |
714 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
715 | mount_crypt_stat); | |
237fead6 MH |
716 | ecryptfs_set_default_sizes(crypt_stat); |
717 | strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER); | |
718 | crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES; | |
e2bd99ec | 719 | crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID); |
237fead6 MH |
720 | crypt_stat->file_version = ECRYPTFS_FILE_VERSION; |
721 | crypt_stat->mount_crypt_stat = mount_crypt_stat; | |
722 | } | |
723 | ||
724 | /** | |
725 | * ecryptfs_new_file_context | |
b59db43a | 726 | * @ecryptfs_inode: The eCryptfs inode |
237fead6 MH |
727 | * |
728 | * If the crypto context for the file has not yet been established, | |
729 | * this is where we do that. Establishing a new crypto context | |
730 | * involves the following decisions: | |
731 | * - What cipher to use? | |
732 | * - What set of authentication tokens to use? | |
733 | * Here we just worry about getting enough information into the | |
734 | * authentication tokens so that we know that they are available. | |
735 | * We associate the available authentication tokens with the new file | |
736 | * via the set of signatures in the crypt_stat struct. Later, when | |
737 | * the headers are actually written out, we may again defer to | |
738 | * userspace to perform the encryption of the session key; for the | |
739 | * foreseeable future, this will be the case with public key packets. | |
740 | * | |
741 | * Returns zero on success; non-zero otherwise | |
742 | */ | |
b59db43a | 743 | int ecryptfs_new_file_context(struct inode *ecryptfs_inode) |
237fead6 | 744 | { |
237fead6 | 745 | struct ecryptfs_crypt_stat *crypt_stat = |
b59db43a | 746 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
237fead6 MH |
747 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
748 | &ecryptfs_superblock_to_private( | |
b59db43a | 749 | ecryptfs_inode->i_sb)->mount_crypt_stat; |
237fead6 | 750 | int cipher_name_len; |
f4aad16a | 751 | int rc = 0; |
237fead6 MH |
752 | |
753 | ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat); | |
af655dc6 | 754 | crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID); |
f4aad16a MH |
755 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
756 | mount_crypt_stat); | |
757 | rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat, | |
758 | mount_crypt_stat); | |
759 | if (rc) { | |
760 | printk(KERN_ERR "Error attempting to copy mount-wide key sigs " | |
761 | "to the inode key sigs; rc = [%d]\n", rc); | |
762 | goto out; | |
763 | } | |
764 | cipher_name_len = | |
765 | strlen(mount_crypt_stat->global_default_cipher_name); | |
766 | memcpy(crypt_stat->cipher, | |
767 | mount_crypt_stat->global_default_cipher_name, | |
768 | cipher_name_len); | |
769 | crypt_stat->cipher[cipher_name_len] = '\0'; | |
770 | crypt_stat->key_size = | |
771 | mount_crypt_stat->global_default_cipher_key_size; | |
772 | ecryptfs_generate_new_key(crypt_stat); | |
237fead6 MH |
773 | rc = ecryptfs_init_crypt_ctx(crypt_stat); |
774 | if (rc) | |
775 | ecryptfs_printk(KERN_ERR, "Error initializing cryptographic " | |
776 | "context for cipher [%s]: rc = [%d]\n", | |
777 | crypt_stat->cipher, rc); | |
f4aad16a | 778 | out: |
237fead6 MH |
779 | return rc; |
780 | } | |
781 | ||
782 | /** | |
7a86617e | 783 | * ecryptfs_validate_marker - check for the ecryptfs marker |
237fead6 MH |
784 | * @data: The data block in which to check |
785 | * | |
7a86617e | 786 | * Returns zero if marker found; -EINVAL if not found |
237fead6 | 787 | */ |
7a86617e | 788 | static int ecryptfs_validate_marker(char *data) |
237fead6 MH |
789 | { |
790 | u32 m_1, m_2; | |
791 | ||
29335c6a HH |
792 | m_1 = get_unaligned_be32(data); |
793 | m_2 = get_unaligned_be32(data + 4); | |
237fead6 | 794 | if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2) |
7a86617e | 795 | return 0; |
237fead6 MH |
796 | ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; " |
797 | "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2, | |
798 | MAGIC_ECRYPTFS_MARKER); | |
799 | ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = " | |
800 | "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER)); | |
7a86617e | 801 | return -EINVAL; |
237fead6 MH |
802 | } |
803 | ||
804 | struct ecryptfs_flag_map_elem { | |
805 | u32 file_flag; | |
806 | u32 local_flag; | |
807 | }; | |
808 | ||
809 | /* Add support for additional flags by adding elements here. */ | |
810 | static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = { | |
811 | {0x00000001, ECRYPTFS_ENABLE_HMAC}, | |
dd2a3b7a | 812 | {0x00000002, ECRYPTFS_ENCRYPTED}, |
addd65ad MH |
813 | {0x00000004, ECRYPTFS_METADATA_IN_XATTR}, |
814 | {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES} | |
237fead6 MH |
815 | }; |
816 | ||
817 | /** | |
818 | * ecryptfs_process_flags | |
22e78faf | 819 | * @crypt_stat: The cryptographic context |
237fead6 MH |
820 | * @page_virt: Source data to be parsed |
821 | * @bytes_read: Updated with the number of bytes read | |
237fead6 | 822 | */ |
7451c54a | 823 | static void ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat, |
237fead6 MH |
824 | char *page_virt, int *bytes_read) |
825 | { | |
237fead6 MH |
826 | int i; |
827 | u32 flags; | |
828 | ||
29335c6a | 829 | flags = get_unaligned_be32(page_virt); |
02f9876e | 830 | for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++) |
237fead6 | 831 | if (flags & ecryptfs_flag_map[i].file_flag) { |
e2bd99ec | 832 | crypt_stat->flags |= ecryptfs_flag_map[i].local_flag; |
237fead6 | 833 | } else |
e2bd99ec | 834 | crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag); |
237fead6 MH |
835 | /* Version is in top 8 bits of the 32-bit flag vector */ |
836 | crypt_stat->file_version = ((flags >> 24) & 0xFF); | |
837 | (*bytes_read) = 4; | |
237fead6 MH |
838 | } |
839 | ||
840 | /** | |
841 | * write_ecryptfs_marker | |
842 | * @page_virt: The pointer to in a page to begin writing the marker | |
843 | * @written: Number of bytes written | |
844 | * | |
845 | * Marker = 0x3c81b7f5 | |
846 | */ | |
847 | static void write_ecryptfs_marker(char *page_virt, size_t *written) | |
848 | { | |
849 | u32 m_1, m_2; | |
850 | ||
851 | get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); | |
852 | m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER); | |
29335c6a HH |
853 | put_unaligned_be32(m_1, page_virt); |
854 | page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2); | |
855 | put_unaligned_be32(m_2, page_virt); | |
237fead6 MH |
856 | (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
857 | } | |
858 | ||
f4e60e6b TH |
859 | void ecryptfs_write_crypt_stat_flags(char *page_virt, |
860 | struct ecryptfs_crypt_stat *crypt_stat, | |
861 | size_t *written) | |
237fead6 MH |
862 | { |
863 | u32 flags = 0; | |
864 | int i; | |
865 | ||
02f9876e | 866 | for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++) |
e2bd99ec | 867 | if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag) |
237fead6 MH |
868 | flags |= ecryptfs_flag_map[i].file_flag; |
869 | /* Version is in top 8 bits of the 32-bit flag vector */ | |
870 | flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000); | |
29335c6a | 871 | put_unaligned_be32(flags, page_virt); |
237fead6 MH |
872 | (*written) = 4; |
873 | } | |
874 | ||
875 | struct ecryptfs_cipher_code_str_map_elem { | |
876 | char cipher_str[16]; | |
19e66a67 | 877 | u8 cipher_code; |
237fead6 MH |
878 | }; |
879 | ||
880 | /* Add support for additional ciphers by adding elements here. The | |
40f0fd37 | 881 | * cipher_code is whatever OpenPGP applications use to identify the |
237fead6 MH |
882 | * ciphers. List in order of probability. */ |
883 | static struct ecryptfs_cipher_code_str_map_elem | |
884 | ecryptfs_cipher_code_str_map[] = { | |
885 | {"aes",RFC2440_CIPHER_AES_128 }, | |
886 | {"blowfish", RFC2440_CIPHER_BLOWFISH}, | |
887 | {"des3_ede", RFC2440_CIPHER_DES3_EDE}, | |
888 | {"cast5", RFC2440_CIPHER_CAST_5}, | |
889 | {"twofish", RFC2440_CIPHER_TWOFISH}, | |
890 | {"cast6", RFC2440_CIPHER_CAST_6}, | |
891 | {"aes", RFC2440_CIPHER_AES_192}, | |
892 | {"aes", RFC2440_CIPHER_AES_256} | |
893 | }; | |
894 | ||
895 | /** | |
896 | * ecryptfs_code_for_cipher_string | |
9c79f34f MH |
897 | * @cipher_name: The string alias for the cipher |
898 | * @key_bytes: Length of key in bytes; used for AES code selection | |
237fead6 MH |
899 | * |
900 | * Returns zero on no match, or the cipher code on match | |
901 | */ | |
9c79f34f | 902 | u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes) |
237fead6 MH |
903 | { |
904 | int i; | |
19e66a67 | 905 | u8 code = 0; |
237fead6 MH |
906 | struct ecryptfs_cipher_code_str_map_elem *map = |
907 | ecryptfs_cipher_code_str_map; | |
908 | ||
9c79f34f MH |
909 | if (strcmp(cipher_name, "aes") == 0) { |
910 | switch (key_bytes) { | |
237fead6 MH |
911 | case 16: |
912 | code = RFC2440_CIPHER_AES_128; | |
913 | break; | |
914 | case 24: | |
915 | code = RFC2440_CIPHER_AES_192; | |
916 | break; | |
917 | case 32: | |
918 | code = RFC2440_CIPHER_AES_256; | |
919 | } | |
920 | } else { | |
921 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) | |
9c79f34f | 922 | if (strcmp(cipher_name, map[i].cipher_str) == 0) { |
237fead6 MH |
923 | code = map[i].cipher_code; |
924 | break; | |
925 | } | |
926 | } | |
927 | return code; | |
928 | } | |
929 | ||
930 | /** | |
931 | * ecryptfs_cipher_code_to_string | |
932 | * @str: Destination to write out the cipher name | |
933 | * @cipher_code: The code to convert to cipher name string | |
934 | * | |
935 | * Returns zero on success | |
936 | */ | |
19e66a67 | 937 | int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code) |
237fead6 MH |
938 | { |
939 | int rc = 0; | |
940 | int i; | |
941 | ||
942 | str[0] = '\0'; | |
943 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) | |
944 | if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code) | |
945 | strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str); | |
946 | if (str[0] == '\0') { | |
947 | ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: " | |
948 | "[%d]\n", cipher_code); | |
949 | rc = -EINVAL; | |
950 | } | |
951 | return rc; | |
952 | } | |
953 | ||
778aeb42 | 954 | int ecryptfs_read_and_validate_header_region(struct inode *inode) |
dd2a3b7a | 955 | { |
778aeb42 TH |
956 | u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
957 | u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; | |
dd2a3b7a MH |
958 | int rc; |
959 | ||
778aeb42 TH |
960 | rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES, |
961 | inode); | |
0bdf8a82 DC |
962 | if (rc < 0) |
963 | return rc; | |
964 | else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) | |
965 | return -EINVAL; | |
778aeb42 TH |
966 | rc = ecryptfs_validate_marker(marker); |
967 | if (!rc) | |
968 | ecryptfs_i_size_init(file_size, inode); | |
dd2a3b7a MH |
969 | return rc; |
970 | } | |
971 | ||
e77a56dd MH |
972 | void |
973 | ecryptfs_write_header_metadata(char *virt, | |
974 | struct ecryptfs_crypt_stat *crypt_stat, | |
975 | size_t *written) | |
237fead6 MH |
976 | { |
977 | u32 header_extent_size; | |
978 | u16 num_header_extents_at_front; | |
979 | ||
45eaab79 | 980 | header_extent_size = (u32)crypt_stat->extent_size; |
237fead6 | 981 | num_header_extents_at_front = |
fa3ef1cb | 982 | (u16)(crypt_stat->metadata_size / crypt_stat->extent_size); |
29335c6a | 983 | put_unaligned_be32(header_extent_size, virt); |
237fead6 | 984 | virt += 4; |
29335c6a | 985 | put_unaligned_be16(num_header_extents_at_front, virt); |
237fead6 MH |
986 | (*written) = 6; |
987 | } | |
988 | ||
30632870 | 989 | struct kmem_cache *ecryptfs_header_cache; |
237fead6 MH |
990 | |
991 | /** | |
992 | * ecryptfs_write_headers_virt | |
22e78faf | 993 | * @page_virt: The virtual address to write the headers to |
87b811c3 | 994 | * @max: The size of memory allocated at page_virt |
22e78faf MH |
995 | * @size: Set to the number of bytes written by this function |
996 | * @crypt_stat: The cryptographic context | |
997 | * @ecryptfs_dentry: The eCryptfs dentry | |
237fead6 MH |
998 | * |
999 | * Format version: 1 | |
1000 | * | |
1001 | * Header Extent: | |
1002 | * Octets 0-7: Unencrypted file size (big-endian) | |
1003 | * Octets 8-15: eCryptfs special marker | |
1004 | * Octets 16-19: Flags | |
1005 | * Octet 16: File format version number (between 0 and 255) | |
1006 | * Octets 17-18: Reserved | |
1007 | * Octet 19: Bit 1 (lsb): Reserved | |
1008 | * Bit 2: Encrypted? | |
1009 | * Bits 3-8: Reserved | |
1010 | * Octets 20-23: Header extent size (big-endian) | |
1011 | * Octets 24-25: Number of header extents at front of file | |
1012 | * (big-endian) | |
1013 | * Octet 26: Begin RFC 2440 authentication token packet set | |
1014 | * Data Extent 0: | |
1015 | * Lower data (CBC encrypted) | |
1016 | * Data Extent 1: | |
1017 | * Lower data (CBC encrypted) | |
1018 | * ... | |
1019 | * | |
1020 | * Returns zero on success | |
1021 | */ | |
87b811c3 ES |
1022 | static int ecryptfs_write_headers_virt(char *page_virt, size_t max, |
1023 | size_t *size, | |
dd2a3b7a MH |
1024 | struct ecryptfs_crypt_stat *crypt_stat, |
1025 | struct dentry *ecryptfs_dentry) | |
237fead6 MH |
1026 | { |
1027 | int rc; | |
1028 | size_t written; | |
1029 | size_t offset; | |
1030 | ||
1031 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
1032 | write_ecryptfs_marker((page_virt + offset), &written); | |
1033 | offset += written; | |
f4e60e6b TH |
1034 | ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat, |
1035 | &written); | |
237fead6 | 1036 | offset += written; |
e77a56dd MH |
1037 | ecryptfs_write_header_metadata((page_virt + offset), crypt_stat, |
1038 | &written); | |
237fead6 MH |
1039 | offset += written; |
1040 | rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat, | |
1041 | ecryptfs_dentry, &written, | |
87b811c3 | 1042 | max - offset); |
237fead6 MH |
1043 | if (rc) |
1044 | ecryptfs_printk(KERN_WARNING, "Error generating key packet " | |
1045 | "set; rc = [%d]\n", rc); | |
dd2a3b7a MH |
1046 | if (size) { |
1047 | offset += written; | |
1048 | *size = offset; | |
1049 | } | |
1050 | return rc; | |
1051 | } | |
1052 | ||
22e78faf | 1053 | static int |
b59db43a | 1054 | ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode, |
8faece5f | 1055 | char *virt, size_t virt_len) |
dd2a3b7a | 1056 | { |
d7cdc5fe | 1057 | int rc; |
dd2a3b7a | 1058 | |
b59db43a | 1059 | rc = ecryptfs_write_lower(ecryptfs_inode, virt, |
8faece5f | 1060 | 0, virt_len); |
96a7b9c2 | 1061 | if (rc < 0) |
d7cdc5fe | 1062 | printk(KERN_ERR "%s: Error attempting to write header " |
96a7b9c2 TH |
1063 | "information to lower file; rc = [%d]\n", __func__, rc); |
1064 | else | |
1065 | rc = 0; | |
70456600 | 1066 | return rc; |
dd2a3b7a MH |
1067 | } |
1068 | ||
22e78faf MH |
1069 | static int |
1070 | ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry, | |
3767e255 | 1071 | struct inode *ecryptfs_inode, |
22e78faf | 1072 | char *page_virt, size_t size) |
dd2a3b7a MH |
1073 | { |
1074 | int rc; | |
d43388de RK |
1075 | struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); |
1076 | struct inode *lower_inode = d_inode(lower_dentry); | |
dd2a3b7a | 1077 | |
d43388de RK |
1078 | if (!(lower_inode->i_opflags & IOP_XATTR)) { |
1079 | rc = -EOPNOTSUPP; | |
1080 | goto out; | |
1081 | } | |
dd2a3b7a | 1082 | |
d43388de | 1083 | inode_lock(lower_inode); |
39f60c1c | 1084 | rc = __vfs_setxattr(&nop_mnt_idmap, lower_dentry, lower_inode, |
c7c7a1a1 | 1085 | ECRYPTFS_XATTR_NAME, page_virt, size, 0); |
d43388de RK |
1086 | if (!rc && ecryptfs_inode) |
1087 | fsstack_copy_attr_all(ecryptfs_inode, lower_inode); | |
1088 | inode_unlock(lower_inode); | |
1089 | out: | |
237fead6 MH |
1090 | return rc; |
1091 | } | |
1092 | ||
8faece5f TH |
1093 | static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask, |
1094 | unsigned int order) | |
1095 | { | |
1096 | struct page *page; | |
1097 | ||
1098 | page = alloc_pages(gfp_mask | __GFP_ZERO, order); | |
1099 | if (page) | |
1100 | return (unsigned long) page_address(page); | |
1101 | return 0; | |
1102 | } | |
1103 | ||
237fead6 | 1104 | /** |
dd2a3b7a | 1105 | * ecryptfs_write_metadata |
b59db43a TH |
1106 | * @ecryptfs_dentry: The eCryptfs dentry, which should be negative |
1107 | * @ecryptfs_inode: The newly created eCryptfs inode | |
237fead6 MH |
1108 | * |
1109 | * Write the file headers out. This will likely involve a userspace | |
1110 | * callout, in which the session key is encrypted with one or more | |
1111 | * public keys and/or the passphrase necessary to do the encryption is | |
1112 | * retrieved via a prompt. Exactly what happens at this point should | |
1113 | * be policy-dependent. | |
1114 | * | |
1115 | * Returns zero on success; non-zero on error | |
1116 | */ | |
b59db43a TH |
1117 | int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry, |
1118 | struct inode *ecryptfs_inode) | |
237fead6 | 1119 | { |
d7cdc5fe | 1120 | struct ecryptfs_crypt_stat *crypt_stat = |
b59db43a | 1121 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
8faece5f | 1122 | unsigned int order; |
cc11beff | 1123 | char *virt; |
8faece5f | 1124 | size_t virt_len; |
d7cdc5fe | 1125 | size_t size = 0; |
237fead6 MH |
1126 | int rc = 0; |
1127 | ||
e2bd99ec MH |
1128 | if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
1129 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { | |
d7cdc5fe | 1130 | printk(KERN_ERR "Key is invalid; bailing out\n"); |
237fead6 MH |
1131 | rc = -EINVAL; |
1132 | goto out; | |
1133 | } | |
1134 | } else { | |
cc11beff | 1135 | printk(KERN_WARNING "%s: Encrypted flag not set\n", |
18d1dbf1 | 1136 | __func__); |
237fead6 | 1137 | rc = -EINVAL; |
237fead6 MH |
1138 | goto out; |
1139 | } | |
fa3ef1cb | 1140 | virt_len = crypt_stat->metadata_size; |
8faece5f | 1141 | order = get_order(virt_len); |
237fead6 | 1142 | /* Released in this function */ |
8faece5f | 1143 | virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order); |
cc11beff | 1144 | if (!virt) { |
18d1dbf1 | 1145 | printk(KERN_ERR "%s: Out of memory\n", __func__); |
237fead6 MH |
1146 | rc = -ENOMEM; |
1147 | goto out; | |
1148 | } | |
bd4f0fe8 | 1149 | /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */ |
8faece5f TH |
1150 | rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat, |
1151 | ecryptfs_dentry); | |
237fead6 | 1152 | if (unlikely(rc)) { |
cc11beff | 1153 | printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n", |
18d1dbf1 | 1154 | __func__, rc); |
237fead6 MH |
1155 | goto out_free; |
1156 | } | |
dd2a3b7a | 1157 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
3767e255 AV |
1158 | rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode, |
1159 | virt, size); | |
dd2a3b7a | 1160 | else |
b59db43a | 1161 | rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt, |
8faece5f | 1162 | virt_len); |
dd2a3b7a | 1163 | if (rc) { |
cc11beff | 1164 | printk(KERN_ERR "%s: Error writing metadata out to lower file; " |
18d1dbf1 | 1165 | "rc = [%d]\n", __func__, rc); |
dd2a3b7a | 1166 | goto out_free; |
237fead6 | 1167 | } |
237fead6 | 1168 | out_free: |
8faece5f | 1169 | free_pages((unsigned long)virt, order); |
237fead6 MH |
1170 | out: |
1171 | return rc; | |
1172 | } | |
1173 | ||
dd2a3b7a MH |
1174 | #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0 |
1175 | #define ECRYPTFS_VALIDATE_HEADER_SIZE 1 | |
237fead6 | 1176 | static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat, |
dd2a3b7a MH |
1177 | char *virt, int *bytes_read, |
1178 | int validate_header_size) | |
237fead6 MH |
1179 | { |
1180 | int rc = 0; | |
1181 | u32 header_extent_size; | |
1182 | u16 num_header_extents_at_front; | |
1183 | ||
29335c6a HH |
1184 | header_extent_size = get_unaligned_be32(virt); |
1185 | virt += sizeof(__be32); | |
1186 | num_header_extents_at_front = get_unaligned_be16(virt); | |
fa3ef1cb TH |
1187 | crypt_stat->metadata_size = (((size_t)num_header_extents_at_front |
1188 | * (size_t)header_extent_size)); | |
29335c6a | 1189 | (*bytes_read) = (sizeof(__be32) + sizeof(__be16)); |
dd2a3b7a | 1190 | if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE) |
fa3ef1cb | 1191 | && (crypt_stat->metadata_size |
dd2a3b7a | 1192 | < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) { |
237fead6 | 1193 | rc = -EINVAL; |
cc11beff | 1194 | printk(KERN_WARNING "Invalid header size: [%zd]\n", |
fa3ef1cb | 1195 | crypt_stat->metadata_size); |
237fead6 MH |
1196 | } |
1197 | return rc; | |
1198 | } | |
1199 | ||
1200 | /** | |
1201 | * set_default_header_data | |
22e78faf | 1202 | * @crypt_stat: The cryptographic context |
237fead6 MH |
1203 | * |
1204 | * For version 0 file format; this function is only for backwards | |
1205 | * compatibility for files created with the prior versions of | |
1206 | * eCryptfs. | |
1207 | */ | |
1208 | static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) | |
1209 | { | |
fa3ef1cb | 1210 | crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
237fead6 MH |
1211 | } |
1212 | ||
3aeb86ea TH |
1213 | void ecryptfs_i_size_init(const char *page_virt, struct inode *inode) |
1214 | { | |
1215 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat; | |
1216 | struct ecryptfs_crypt_stat *crypt_stat; | |
1217 | u64 file_size; | |
1218 | ||
1219 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; | |
1220 | mount_crypt_stat = | |
1221 | &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat; | |
1222 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { | |
1223 | file_size = i_size_read(ecryptfs_inode_to_lower(inode)); | |
1224 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) | |
1225 | file_size += crypt_stat->metadata_size; | |
1226 | } else | |
1227 | file_size = get_unaligned_be64(page_virt); | |
1228 | i_size_write(inode, (loff_t)file_size); | |
1229 | crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED; | |
1230 | } | |
1231 | ||
237fead6 MH |
1232 | /** |
1233 | * ecryptfs_read_headers_virt | |
22e78faf MH |
1234 | * @page_virt: The virtual address into which to read the headers |
1235 | * @crypt_stat: The cryptographic context | |
1236 | * @ecryptfs_dentry: The eCryptfs dentry | |
1237 | * @validate_header_size: Whether to validate the header size while reading | |
237fead6 MH |
1238 | * |
1239 | * Read/parse the header data. The header format is detailed in the | |
1240 | * comment block for the ecryptfs_write_headers_virt() function. | |
1241 | * | |
1242 | * Returns zero on success | |
1243 | */ | |
1244 | static int ecryptfs_read_headers_virt(char *page_virt, | |
1245 | struct ecryptfs_crypt_stat *crypt_stat, | |
dd2a3b7a MH |
1246 | struct dentry *ecryptfs_dentry, |
1247 | int validate_header_size) | |
237fead6 MH |
1248 | { |
1249 | int rc = 0; | |
1250 | int offset; | |
1251 | int bytes_read; | |
1252 | ||
1253 | ecryptfs_set_default_sizes(crypt_stat); | |
1254 | crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private( | |
1255 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
1256 | offset = ECRYPTFS_FILE_SIZE_BYTES; | |
7a86617e TH |
1257 | rc = ecryptfs_validate_marker(page_virt + offset); |
1258 | if (rc) | |
237fead6 | 1259 | goto out; |
3aeb86ea | 1260 | if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED)) |
2b0143b5 | 1261 | ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry)); |
237fead6 | 1262 | offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
7451c54a | 1263 | ecryptfs_process_flags(crypt_stat, (page_virt + offset), &bytes_read); |
237fead6 MH |
1264 | if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) { |
1265 | ecryptfs_printk(KERN_WARNING, "File version is [%d]; only " | |
1266 | "file version [%d] is supported by this " | |
1267 | "version of eCryptfs\n", | |
1268 | crypt_stat->file_version, | |
1269 | ECRYPTFS_SUPPORTED_FILE_VERSION); | |
1270 | rc = -EINVAL; | |
1271 | goto out; | |
1272 | } | |
1273 | offset += bytes_read; | |
1274 | if (crypt_stat->file_version >= 1) { | |
1275 | rc = parse_header_metadata(crypt_stat, (page_virt + offset), | |
dd2a3b7a | 1276 | &bytes_read, validate_header_size); |
237fead6 MH |
1277 | if (rc) { |
1278 | ecryptfs_printk(KERN_WARNING, "Error reading header " | |
1279 | "metadata; rc = [%d]\n", rc); | |
1280 | } | |
1281 | offset += bytes_read; | |
1282 | } else | |
1283 | set_default_header_data(crypt_stat); | |
1284 | rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), | |
1285 | ecryptfs_dentry); | |
1286 | out: | |
1287 | return rc; | |
1288 | } | |
1289 | ||
1290 | /** | |
dd2a3b7a | 1291 | * ecryptfs_read_xattr_region |
22e78faf | 1292 | * @page_virt: The vitual address into which to read the xattr data |
2ed92554 | 1293 | * @ecryptfs_inode: The eCryptfs inode |
dd2a3b7a MH |
1294 | * |
1295 | * Attempts to read the crypto metadata from the extended attribute | |
1296 | * region of the lower file. | |
22e78faf MH |
1297 | * |
1298 | * Returns zero on success; non-zero on error | |
dd2a3b7a | 1299 | */ |
d7cdc5fe | 1300 | int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode) |
dd2a3b7a | 1301 | { |
d7cdc5fe | 1302 | struct dentry *lower_dentry = |
b583043e | 1303 | ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry; |
dd2a3b7a MH |
1304 | ssize_t size; |
1305 | int rc = 0; | |
1306 | ||
ce23e640 AV |
1307 | size = ecryptfs_getxattr_lower(lower_dentry, |
1308 | ecryptfs_inode_to_lower(ecryptfs_inode), | |
1309 | ECRYPTFS_XATTR_NAME, | |
d7cdc5fe | 1310 | page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE); |
dd2a3b7a | 1311 | if (size < 0) { |
25bd8174 MH |
1312 | if (unlikely(ecryptfs_verbosity > 0)) |
1313 | printk(KERN_INFO "Error attempting to read the [%s] " | |
1314 | "xattr from the lower file; return value = " | |
1315 | "[%zd]\n", ECRYPTFS_XATTR_NAME, size); | |
dd2a3b7a MH |
1316 | rc = -EINVAL; |
1317 | goto out; | |
1318 | } | |
1319 | out: | |
1320 | return rc; | |
1321 | } | |
1322 | ||
778aeb42 | 1323 | int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry, |
3b06b3eb | 1324 | struct inode *inode) |
dd2a3b7a | 1325 | { |
778aeb42 TH |
1326 | u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
1327 | u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; | |
dd2a3b7a MH |
1328 | int rc; |
1329 | ||
778aeb42 | 1330 | rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), |
ce23e640 | 1331 | ecryptfs_inode_to_lower(inode), |
778aeb42 TH |
1332 | ECRYPTFS_XATTR_NAME, file_size, |
1333 | ECRYPTFS_SIZE_AND_MARKER_BYTES); | |
0bdf8a82 DC |
1334 | if (rc < 0) |
1335 | return rc; | |
1336 | else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) | |
1337 | return -EINVAL; | |
778aeb42 TH |
1338 | rc = ecryptfs_validate_marker(marker); |
1339 | if (!rc) | |
1340 | ecryptfs_i_size_init(file_size, inode); | |
dd2a3b7a MH |
1341 | return rc; |
1342 | } | |
1343 | ||
5da877ea | 1344 | /* |
dd2a3b7a MH |
1345 | * ecryptfs_read_metadata |
1346 | * | |
1347 | * Common entry point for reading file metadata. From here, we could | |
1348 | * retrieve the header information from the header region of the file, | |
40f0fd37 | 1349 | * the xattr region of the file, or some other repository that is |
dd2a3b7a MH |
1350 | * stored separately from the file itself. The current implementation |
1351 | * supports retrieving the metadata information from the file contents | |
1352 | * and from the xattr region. | |
237fead6 MH |
1353 | * |
1354 | * Returns zero if valid headers found and parsed; non-zero otherwise | |
1355 | */ | |
d7cdc5fe | 1356 | int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) |
237fead6 | 1357 | { |
bb450361 TG |
1358 | int rc; |
1359 | char *page_virt; | |
2b0143b5 | 1360 | struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry); |
237fead6 | 1361 | struct ecryptfs_crypt_stat *crypt_stat = |
d7cdc5fe | 1362 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
e77a56dd MH |
1363 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
1364 | &ecryptfs_superblock_to_private( | |
1365 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
237fead6 | 1366 | |
e77a56dd MH |
1367 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
1368 | mount_crypt_stat); | |
237fead6 | 1369 | /* Read the first page from the underlying file */ |
30632870 | 1370 | page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER); |
237fead6 MH |
1371 | if (!page_virt) { |
1372 | rc = -ENOMEM; | |
237fead6 MH |
1373 | goto out; |
1374 | } | |
d7cdc5fe MH |
1375 | rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size, |
1376 | ecryptfs_inode); | |
96a7b9c2 | 1377 | if (rc >= 0) |
d7cdc5fe MH |
1378 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
1379 | ecryptfs_dentry, | |
1380 | ECRYPTFS_VALIDATE_HEADER_SIZE); | |
237fead6 | 1381 | if (rc) { |
bb450361 | 1382 | /* metadata is not in the file header, so try xattrs */ |
09cbfeaf | 1383 | memset(page_virt, 0, PAGE_SIZE); |
d7cdc5fe | 1384 | rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode); |
dd2a3b7a MH |
1385 | if (rc) { |
1386 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " | |
30373dc0 TG |
1387 | "file header region or xattr region, inode %lu\n", |
1388 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1389 | rc = -EINVAL; |
1390 | goto out; | |
1391 | } | |
1392 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, | |
1393 | ecryptfs_dentry, | |
1394 | ECRYPTFS_DONT_VALIDATE_HEADER_SIZE); | |
1395 | if (rc) { | |
1396 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " | |
30373dc0 TG |
1397 | "file xattr region either, inode %lu\n", |
1398 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1399 | rc = -EINVAL; |
1400 | } | |
1401 | if (crypt_stat->mount_crypt_stat->flags | |
1402 | & ECRYPTFS_XATTR_METADATA_ENABLED) { | |
1403 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
1404 | } else { | |
1405 | printk(KERN_WARNING "Attempt to access file with " | |
1406 | "crypto metadata only in the extended attribute " | |
1407 | "region, but eCryptfs was mounted without " | |
1408 | "xattr support enabled. eCryptfs will not treat " | |
30373dc0 TG |
1409 | "this like an encrypted file, inode %lu\n", |
1410 | ecryptfs_inode->i_ino); | |
dd2a3b7a MH |
1411 | rc = -EINVAL; |
1412 | } | |
237fead6 MH |
1413 | } |
1414 | out: | |
1415 | if (page_virt) { | |
09cbfeaf | 1416 | memset(page_virt, 0, PAGE_SIZE); |
30632870 | 1417 | kmem_cache_free(ecryptfs_header_cache, page_virt); |
237fead6 MH |
1418 | } |
1419 | return rc; | |
1420 | } | |
1421 | ||
5da877ea | 1422 | /* |
51ca58dc MH |
1423 | * ecryptfs_encrypt_filename - encrypt filename |
1424 | * | |
1425 | * CBC-encrypts the filename. We do not want to encrypt the same | |
1426 | * filename with the same key and IV, which may happen with hard | |
1427 | * links, so we prepend random bits to each filename. | |
1428 | * | |
1429 | * Returns zero on success; non-zero otherwise | |
1430 | */ | |
1431 | static int | |
1432 | ecryptfs_encrypt_filename(struct ecryptfs_filename *filename, | |
51ca58dc MH |
1433 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
1434 | { | |
1435 | int rc = 0; | |
1436 | ||
1437 | filename->encrypted_filename = NULL; | |
1438 | filename->encrypted_filename_size = 0; | |
97c31606 AV |
1439 | if (mount_crypt_stat && (mount_crypt_stat->flags |
1440 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) { | |
51ca58dc MH |
1441 | size_t packet_size; |
1442 | size_t remaining_bytes; | |
1443 | ||
1444 | rc = ecryptfs_write_tag_70_packet( | |
1445 | NULL, NULL, | |
1446 | &filename->encrypted_filename_size, | |
1447 | mount_crypt_stat, NULL, | |
1448 | filename->filename_size); | |
1449 | if (rc) { | |
1450 | printk(KERN_ERR "%s: Error attempting to get packet " | |
1451 | "size for tag 72; rc = [%d]\n", __func__, | |
1452 | rc); | |
1453 | filename->encrypted_filename_size = 0; | |
1454 | goto out; | |
1455 | } | |
1456 | filename->encrypted_filename = | |
1457 | kmalloc(filename->encrypted_filename_size, GFP_KERNEL); | |
1458 | if (!filename->encrypted_filename) { | |
51ca58dc MH |
1459 | rc = -ENOMEM; |
1460 | goto out; | |
1461 | } | |
1462 | remaining_bytes = filename->encrypted_filename_size; | |
1463 | rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename, | |
1464 | &remaining_bytes, | |
1465 | &packet_size, | |
1466 | mount_crypt_stat, | |
1467 | filename->filename, | |
1468 | filename->filename_size); | |
1469 | if (rc) { | |
1470 | printk(KERN_ERR "%s: Error attempting to generate " | |
1471 | "tag 70 packet; rc = [%d]\n", __func__, | |
1472 | rc); | |
1473 | kfree(filename->encrypted_filename); | |
1474 | filename->encrypted_filename = NULL; | |
1475 | filename->encrypted_filename_size = 0; | |
1476 | goto out; | |
1477 | } | |
1478 | filename->encrypted_filename_size = packet_size; | |
1479 | } else { | |
1480 | printk(KERN_ERR "%s: No support for requested filename " | |
1481 | "encryption method in this release\n", __func__); | |
df6ad33b | 1482 | rc = -EOPNOTSUPP; |
51ca58dc MH |
1483 | goto out; |
1484 | } | |
1485 | out: | |
1486 | return rc; | |
1487 | } | |
1488 | ||
1489 | static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size, | |
1490 | const char *name, size_t name_size) | |
1491 | { | |
1492 | int rc = 0; | |
1493 | ||
fd9fc842 | 1494 | (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL); |
51ca58dc MH |
1495 | if (!(*copied_name)) { |
1496 | rc = -ENOMEM; | |
1497 | goto out; | |
1498 | } | |
1499 | memcpy((void *)(*copied_name), (void *)name, name_size); | |
1500 | (*copied_name)[(name_size)] = '\0'; /* Only for convenience | |
1501 | * in printing out the | |
1502 | * string in debug | |
1503 | * messages */ | |
fd9fc842 | 1504 | (*copied_name_size) = name_size; |
51ca58dc MH |
1505 | out: |
1506 | return rc; | |
1507 | } | |
1508 | ||
237fead6 | 1509 | /** |
f4aad16a | 1510 | * ecryptfs_process_key_cipher - Perform key cipher initialization. |
237fead6 | 1511 | * @key_tfm: Crypto context for key material, set by this function |
e5d9cbde MH |
1512 | * @cipher_name: Name of the cipher |
1513 | * @key_size: Size of the key in bytes | |
237fead6 MH |
1514 | * |
1515 | * Returns zero on success. Any crypto_tfm structs allocated here | |
1516 | * should be released by other functions, such as on a superblock put | |
1517 | * event, regardless of whether this function succeeds for fails. | |
1518 | */ | |
cd9d67df | 1519 | static int |
3095e8e3 | 1520 | ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm, |
f4aad16a | 1521 | char *cipher_name, size_t *key_size) |
237fead6 MH |
1522 | { |
1523 | char dummy_key[ECRYPTFS_MAX_KEY_BYTES]; | |
ece550f5 | 1524 | char *full_alg_name = NULL; |
237fead6 MH |
1525 | int rc; |
1526 | ||
e5d9cbde MH |
1527 | *key_tfm = NULL; |
1528 | if (*key_size > ECRYPTFS_MAX_KEY_BYTES) { | |
237fead6 | 1529 | rc = -EINVAL; |
df261c52 | 1530 | printk(KERN_ERR "Requested key size is [%zd] bytes; maximum " |
e5d9cbde | 1531 | "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES); |
237fead6 MH |
1532 | goto out; |
1533 | } | |
8bba066f MH |
1534 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name, |
1535 | "ecb"); | |
1536 | if (rc) | |
1537 | goto out; | |
3095e8e3 | 1538 | *key_tfm = crypto_alloc_skcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC); |
8bba066f MH |
1539 | if (IS_ERR(*key_tfm)) { |
1540 | rc = PTR_ERR(*key_tfm); | |
237fead6 | 1541 | printk(KERN_ERR "Unable to allocate crypto cipher with name " |
38268498 | 1542 | "[%s]; rc = [%d]\n", full_alg_name, rc); |
237fead6 MH |
1543 | goto out; |
1544 | } | |
231baecd | 1545 | crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); |
3095e8e3 | 1546 | if (*key_size == 0) |
9ac0d136 | 1547 | *key_size = crypto_skcipher_max_keysize(*key_tfm); |
e5d9cbde | 1548 | get_random_bytes(dummy_key, *key_size); |
3095e8e3 | 1549 | rc = crypto_skcipher_setkey(*key_tfm, dummy_key, *key_size); |
237fead6 | 1550 | if (rc) { |
df261c52 | 1551 | printk(KERN_ERR "Error attempting to set key of size [%zd] for " |
38268498 DH |
1552 | "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name, |
1553 | rc); | |
237fead6 MH |
1554 | rc = -EINVAL; |
1555 | goto out; | |
1556 | } | |
1557 | out: | |
ece550f5 | 1558 | kfree(full_alg_name); |
237fead6 MH |
1559 | return rc; |
1560 | } | |
f4aad16a MH |
1561 | |
1562 | struct kmem_cache *ecryptfs_key_tfm_cache; | |
7896b631 | 1563 | static struct list_head key_tfm_list; |
902af369 | 1564 | DEFINE_MUTEX(key_tfm_list_mutex); |
f4aad16a | 1565 | |
7371a382 | 1566 | int __init ecryptfs_init_crypto(void) |
f4aad16a | 1567 | { |
f4aad16a MH |
1568 | INIT_LIST_HEAD(&key_tfm_list); |
1569 | return 0; | |
1570 | } | |
1571 | ||
af440f52 ES |
1572 | /** |
1573 | * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list | |
1574 | * | |
1575 | * Called only at module unload time | |
1576 | */ | |
fcd12835 | 1577 | int ecryptfs_destroy_crypto(void) |
f4aad16a MH |
1578 | { |
1579 | struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp; | |
1580 | ||
1581 | mutex_lock(&key_tfm_list_mutex); | |
1582 | list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list, | |
1583 | key_tfm_list) { | |
1584 | list_del(&key_tfm->key_tfm_list); | |
3095e8e3 | 1585 | crypto_free_skcipher(key_tfm->key_tfm); |
f4aad16a MH |
1586 | kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm); |
1587 | } | |
1588 | mutex_unlock(&key_tfm_list_mutex); | |
1589 | return 0; | |
1590 | } | |
1591 | ||
1592 | int | |
1593 | ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name, | |
1594 | size_t key_size) | |
1595 | { | |
1596 | struct ecryptfs_key_tfm *tmp_tfm; | |
1597 | int rc = 0; | |
1598 | ||
af440f52 ES |
1599 | BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); |
1600 | ||
f4aad16a | 1601 | tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL); |
5032f360 | 1602 | if (key_tfm) |
f4aad16a MH |
1603 | (*key_tfm) = tmp_tfm; |
1604 | if (!tmp_tfm) { | |
1605 | rc = -ENOMEM; | |
f4aad16a MH |
1606 | goto out; |
1607 | } | |
1608 | mutex_init(&tmp_tfm->key_tfm_mutex); | |
1609 | strncpy(tmp_tfm->cipher_name, cipher_name, | |
1610 | ECRYPTFS_MAX_CIPHER_NAME_SIZE); | |
b8862906 | 1611 | tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; |
f4aad16a | 1612 | tmp_tfm->key_size = key_size; |
5dda6992 MH |
1613 | rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm, |
1614 | tmp_tfm->cipher_name, | |
1615 | &tmp_tfm->key_size); | |
1616 | if (rc) { | |
f4aad16a MH |
1617 | printk(KERN_ERR "Error attempting to initialize key TFM " |
1618 | "cipher with name = [%s]; rc = [%d]\n", | |
1619 | tmp_tfm->cipher_name, rc); | |
1620 | kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm); | |
5032f360 | 1621 | if (key_tfm) |
f4aad16a MH |
1622 | (*key_tfm) = NULL; |
1623 | goto out; | |
1624 | } | |
f4aad16a | 1625 | list_add(&tmp_tfm->key_tfm_list, &key_tfm_list); |
f4aad16a MH |
1626 | out: |
1627 | return rc; | |
1628 | } | |
1629 | ||
af440f52 ES |
1630 | /** |
1631 | * ecryptfs_tfm_exists - Search for existing tfm for cipher_name. | |
1632 | * @cipher_name: the name of the cipher to search for | |
1633 | * @key_tfm: set to corresponding tfm if found | |
1634 | * | |
1635 | * Searches for cached key_tfm matching @cipher_name | |
1636 | * Must be called with &key_tfm_list_mutex held | |
1637 | * Returns 1 if found, with @key_tfm set | |
1638 | * Returns 0 if not found, with @key_tfm set to NULL | |
1639 | */ | |
1640 | int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm) | |
1641 | { | |
1642 | struct ecryptfs_key_tfm *tmp_key_tfm; | |
1643 | ||
1644 | BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); | |
1645 | ||
1646 | list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) { | |
1647 | if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) { | |
1648 | if (key_tfm) | |
1649 | (*key_tfm) = tmp_key_tfm; | |
1650 | return 1; | |
1651 | } | |
1652 | } | |
1653 | if (key_tfm) | |
1654 | (*key_tfm) = NULL; | |
1655 | return 0; | |
1656 | } | |
1657 | ||
1658 | /** | |
1659 | * ecryptfs_get_tfm_and_mutex_for_cipher_name | |
1660 | * | |
1661 | * @tfm: set to cached tfm found, or new tfm created | |
1662 | * @tfm_mutex: set to mutex for cached tfm found, or new tfm created | |
1663 | * @cipher_name: the name of the cipher to search for and/or add | |
1664 | * | |
1665 | * Sets pointers to @tfm & @tfm_mutex matching @cipher_name. | |
1666 | * Searches for cached item first, and creates new if not found. | |
1667 | * Returns 0 on success, non-zero if adding new cipher failed | |
1668 | */ | |
3095e8e3 | 1669 | int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm, |
f4aad16a MH |
1670 | struct mutex **tfm_mutex, |
1671 | char *cipher_name) | |
1672 | { | |
1673 | struct ecryptfs_key_tfm *key_tfm; | |
1674 | int rc = 0; | |
1675 | ||
1676 | (*tfm) = NULL; | |
1677 | (*tfm_mutex) = NULL; | |
af440f52 | 1678 | |
f4aad16a | 1679 | mutex_lock(&key_tfm_list_mutex); |
af440f52 ES |
1680 | if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) { |
1681 | rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0); | |
1682 | if (rc) { | |
1683 | printk(KERN_ERR "Error adding new key_tfm to list; " | |
1684 | "rc = [%d]\n", rc); | |
f4aad16a MH |
1685 | goto out; |
1686 | } | |
1687 | } | |
f4aad16a MH |
1688 | (*tfm) = key_tfm->key_tfm; |
1689 | (*tfm_mutex) = &key_tfm->key_tfm_mutex; | |
1690 | out: | |
71fd5179 | 1691 | mutex_unlock(&key_tfm_list_mutex); |
f4aad16a MH |
1692 | return rc; |
1693 | } | |
51ca58dc MH |
1694 | |
1695 | /* 64 characters forming a 6-bit target field */ | |
1696 | static unsigned char *portable_filename_chars = ("-.0123456789ABCD" | |
1697 | "EFGHIJKLMNOPQRST" | |
1698 | "UVWXYZabcdefghij" | |
1699 | "klmnopqrstuvwxyz"); | |
1700 | ||
1701 | /* We could either offset on every reverse map or just pad some 0x00's | |
1702 | * at the front here */ | |
0f751e64 | 1703 | static const unsigned char filename_rev_map[256] = { |
51ca58dc MH |
1704 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */ |
1705 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */ | |
1706 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */ | |
1707 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */ | |
1708 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */ | |
1709 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */ | |
1710 | 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */ | |
1711 | 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */ | |
1712 | 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */ | |
1713 | 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */ | |
1714 | 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */ | |
1715 | 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */ | |
1716 | 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */ | |
1717 | 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */ | |
1718 | 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */ | |
0f751e64 | 1719 | 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */ |
51ca58dc MH |
1720 | }; |
1721 | ||
1722 | /** | |
1723 | * ecryptfs_encode_for_filename | |
1724 | * @dst: Destination location for encoded filename | |
1725 | * @dst_size: Size of the encoded filename in bytes | |
1726 | * @src: Source location for the filename to encode | |
1727 | * @src_size: Size of the source in bytes | |
1728 | */ | |
37028758 | 1729 | static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size, |
51ca58dc MH |
1730 | unsigned char *src, size_t src_size) |
1731 | { | |
1732 | size_t num_blocks; | |
1733 | size_t block_num = 0; | |
1734 | size_t dst_offset = 0; | |
1735 | unsigned char last_block[3]; | |
1736 | ||
1737 | if (src_size == 0) { | |
1738 | (*dst_size) = 0; | |
1739 | goto out; | |
1740 | } | |
1741 | num_blocks = (src_size / 3); | |
1742 | if ((src_size % 3) == 0) { | |
1743 | memcpy(last_block, (&src[src_size - 3]), 3); | |
1744 | } else { | |
1745 | num_blocks++; | |
1746 | last_block[2] = 0x00; | |
1747 | switch (src_size % 3) { | |
1748 | case 1: | |
1749 | last_block[0] = src[src_size - 1]; | |
1750 | last_block[1] = 0x00; | |
1751 | break; | |
1752 | case 2: | |
1753 | last_block[0] = src[src_size - 2]; | |
1754 | last_block[1] = src[src_size - 1]; | |
1755 | } | |
1756 | } | |
1757 | (*dst_size) = (num_blocks * 4); | |
1758 | if (!dst) | |
1759 | goto out; | |
1760 | while (block_num < num_blocks) { | |
1761 | unsigned char *src_block; | |
1762 | unsigned char dst_block[4]; | |
1763 | ||
1764 | if (block_num == (num_blocks - 1)) | |
1765 | src_block = last_block; | |
1766 | else | |
1767 | src_block = &src[block_num * 3]; | |
1768 | dst_block[0] = ((src_block[0] >> 2) & 0x3F); | |
1769 | dst_block[1] = (((src_block[0] << 4) & 0x30) | |
1770 | | ((src_block[1] >> 4) & 0x0F)); | |
1771 | dst_block[2] = (((src_block[1] << 2) & 0x3C) | |
1772 | | ((src_block[2] >> 6) & 0x03)); | |
1773 | dst_block[3] = (src_block[2] & 0x3F); | |
1774 | dst[dst_offset++] = portable_filename_chars[dst_block[0]]; | |
1775 | dst[dst_offset++] = portable_filename_chars[dst_block[1]]; | |
1776 | dst[dst_offset++] = portable_filename_chars[dst_block[2]]; | |
1777 | dst[dst_offset++] = portable_filename_chars[dst_block[3]]; | |
1778 | block_num++; | |
1779 | } | |
1780 | out: | |
1781 | return; | |
1782 | } | |
1783 | ||
4a26620d TH |
1784 | static size_t ecryptfs_max_decoded_size(size_t encoded_size) |
1785 | { | |
1786 | /* Not exact; conservatively long. Every block of 4 | |
1787 | * encoded characters decodes into a block of 3 | |
1788 | * decoded characters. This segment of code provides | |
1789 | * the caller with the maximum amount of allocated | |
1790 | * space that @dst will need to point to in a | |
1791 | * subsequent call. */ | |
1792 | return ((encoded_size + 1) * 3) / 4; | |
1793 | } | |
1794 | ||
71c11c37 MH |
1795 | /** |
1796 | * ecryptfs_decode_from_filename | |
1797 | * @dst: If NULL, this function only sets @dst_size and returns. If | |
1798 | * non-NULL, this function decodes the encoded octets in @src | |
1799 | * into the memory that @dst points to. | |
1800 | * @dst_size: Set to the size of the decoded string. | |
1801 | * @src: The encoded set of octets to decode. | |
1802 | * @src_size: The size of the encoded set of octets to decode. | |
1803 | */ | |
1804 | static void | |
1805 | ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size, | |
1806 | const unsigned char *src, size_t src_size) | |
51ca58dc MH |
1807 | { |
1808 | u8 current_bit_offset = 0; | |
1809 | size_t src_byte_offset = 0; | |
1810 | size_t dst_byte_offset = 0; | |
51ca58dc | 1811 | |
5032f360 | 1812 | if (!dst) { |
4a26620d | 1813 | (*dst_size) = ecryptfs_max_decoded_size(src_size); |
51ca58dc MH |
1814 | goto out; |
1815 | } | |
1816 | while (src_byte_offset < src_size) { | |
1817 | unsigned char src_byte = | |
1818 | filename_rev_map[(int)src[src_byte_offset]]; | |
1819 | ||
1820 | switch (current_bit_offset) { | |
1821 | case 0: | |
1822 | dst[dst_byte_offset] = (src_byte << 2); | |
1823 | current_bit_offset = 6; | |
1824 | break; | |
1825 | case 6: | |
1826 | dst[dst_byte_offset++] |= (src_byte >> 4); | |
1827 | dst[dst_byte_offset] = ((src_byte & 0xF) | |
1828 | << 4); | |
1829 | current_bit_offset = 4; | |
1830 | break; | |
1831 | case 4: | |
1832 | dst[dst_byte_offset++] |= (src_byte >> 2); | |
1833 | dst[dst_byte_offset] = (src_byte << 6); | |
1834 | current_bit_offset = 2; | |
1835 | break; | |
1836 | case 2: | |
1837 | dst[dst_byte_offset++] |= (src_byte); | |
51ca58dc MH |
1838 | current_bit_offset = 0; |
1839 | break; | |
1840 | } | |
1841 | src_byte_offset++; | |
1842 | } | |
1843 | (*dst_size) = dst_byte_offset; | |
1844 | out: | |
71c11c37 | 1845 | return; |
51ca58dc MH |
1846 | } |
1847 | ||
1848 | /** | |
1849 | * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text | |
5da877ea LJ |
1850 | * @encoded_name: The encrypted name |
1851 | * @encoded_name_size: Length of the encrypted name | |
1852 | * @mount_crypt_stat: The crypt_stat struct associated with the file name to encode | |
51ca58dc | 1853 | * @name: The plaintext name |
5da877ea | 1854 | * @name_size: The length of the plaintext name |
51ca58dc MH |
1855 | * |
1856 | * Encrypts and encodes a filename into something that constitutes a | |
1857 | * valid filename for a filesystem, with printable characters. | |
1858 | * | |
1859 | * We assume that we have a properly initialized crypto context, | |
1860 | * pointed to by crypt_stat->tfm. | |
1861 | * | |
1862 | * Returns zero on success; non-zero on otherwise | |
1863 | */ | |
1864 | int ecryptfs_encrypt_and_encode_filename( | |
1865 | char **encoded_name, | |
1866 | size_t *encoded_name_size, | |
51ca58dc MH |
1867 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat, |
1868 | const char *name, size_t name_size) | |
1869 | { | |
1870 | size_t encoded_name_no_prefix_size; | |
1871 | int rc = 0; | |
1872 | ||
1873 | (*encoded_name) = NULL; | |
1874 | (*encoded_name_size) = 0; | |
97c31606 AV |
1875 | if (mount_crypt_stat && (mount_crypt_stat->flags |
1876 | & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { | |
51ca58dc MH |
1877 | struct ecryptfs_filename *filename; |
1878 | ||
1879 | filename = kzalloc(sizeof(*filename), GFP_KERNEL); | |
1880 | if (!filename) { | |
51ca58dc MH |
1881 | rc = -ENOMEM; |
1882 | goto out; | |
1883 | } | |
1884 | filename->filename = (char *)name; | |
1885 | filename->filename_size = name_size; | |
97c31606 | 1886 | rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat); |
51ca58dc MH |
1887 | if (rc) { |
1888 | printk(KERN_ERR "%s: Error attempting to encrypt " | |
1889 | "filename; rc = [%d]\n", __func__, rc); | |
1890 | kfree(filename); | |
1891 | goto out; | |
1892 | } | |
1893 | ecryptfs_encode_for_filename( | |
1894 | NULL, &encoded_name_no_prefix_size, | |
1895 | filename->encrypted_filename, | |
1896 | filename->encrypted_filename_size); | |
97c31606 | 1897 | if (mount_crypt_stat |
51ca58dc | 1898 | && (mount_crypt_stat->flags |
97c31606 | 1899 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) |
51ca58dc MH |
1900 | (*encoded_name_size) = |
1901 | (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1902 | + encoded_name_no_prefix_size); | |
1903 | else | |
1904 | (*encoded_name_size) = | |
1905 | (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1906 | + encoded_name_no_prefix_size); | |
1907 | (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL); | |
1908 | if (!(*encoded_name)) { | |
51ca58dc MH |
1909 | rc = -ENOMEM; |
1910 | kfree(filename->encrypted_filename); | |
1911 | kfree(filename); | |
1912 | goto out; | |
1913 | } | |
97c31606 | 1914 | if (mount_crypt_stat |
51ca58dc | 1915 | && (mount_crypt_stat->flags |
97c31606 | 1916 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) { |
51ca58dc MH |
1917 | memcpy((*encoded_name), |
1918 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, | |
1919 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE); | |
1920 | ecryptfs_encode_for_filename( | |
1921 | ((*encoded_name) | |
1922 | + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE), | |
1923 | &encoded_name_no_prefix_size, | |
1924 | filename->encrypted_filename, | |
1925 | filename->encrypted_filename_size); | |
1926 | (*encoded_name_size) = | |
1927 | (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE | |
1928 | + encoded_name_no_prefix_size); | |
1929 | (*encoded_name)[(*encoded_name_size)] = '\0'; | |
51ca58dc | 1930 | } else { |
df6ad33b | 1931 | rc = -EOPNOTSUPP; |
51ca58dc MH |
1932 | } |
1933 | if (rc) { | |
1934 | printk(KERN_ERR "%s: Error attempting to encode " | |
1935 | "encrypted filename; rc = [%d]\n", __func__, | |
1936 | rc); | |
1937 | kfree((*encoded_name)); | |
1938 | (*encoded_name) = NULL; | |
1939 | (*encoded_name_size) = 0; | |
1940 | } | |
1941 | kfree(filename->encrypted_filename); | |
1942 | kfree(filename); | |
1943 | } else { | |
1944 | rc = ecryptfs_copy_filename(encoded_name, | |
1945 | encoded_name_size, | |
1946 | name, name_size); | |
1947 | } | |
1948 | out: | |
1949 | return rc; | |
1950 | } | |
1951 | ||
e86281e7 TH |
1952 | static bool is_dot_dotdot(const char *name, size_t name_size) |
1953 | { | |
1954 | if (name_size == 1 && name[0] == '.') | |
1955 | return true; | |
1956 | else if (name_size == 2 && name[0] == '.' && name[1] == '.') | |
1957 | return true; | |
1958 | ||
1959 | return false; | |
1960 | } | |
1961 | ||
51ca58dc MH |
1962 | /** |
1963 | * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext | |
1964 | * @plaintext_name: The plaintext name | |
1965 | * @plaintext_name_size: The plaintext name size | |
5da877ea | 1966 | * @sb: Ecryptfs's super_block |
51ca58dc MH |
1967 | * @name: The filename in cipher text |
1968 | * @name_size: The cipher text name size | |
1969 | * | |
1970 | * Decrypts and decodes the filename. | |
1971 | * | |
1972 | * Returns zero on error; non-zero otherwise | |
1973 | */ | |
1974 | int ecryptfs_decode_and_decrypt_filename(char **plaintext_name, | |
1975 | size_t *plaintext_name_size, | |
0747fdb2 | 1976 | struct super_block *sb, |
51ca58dc MH |
1977 | const char *name, size_t name_size) |
1978 | { | |
2aac0cf8 | 1979 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
0747fdb2 | 1980 | &ecryptfs_superblock_to_private(sb)->mount_crypt_stat; |
51ca58dc MH |
1981 | char *decoded_name; |
1982 | size_t decoded_name_size; | |
1983 | size_t packet_size; | |
1984 | int rc = 0; | |
1985 | ||
e86281e7 TH |
1986 | if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) && |
1987 | !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)) { | |
1988 | if (is_dot_dotdot(name, name_size)) { | |
1989 | rc = ecryptfs_copy_filename(plaintext_name, | |
1990 | plaintext_name_size, | |
1991 | name, name_size); | |
1992 | goto out; | |
1993 | } | |
1994 | ||
1995 | if (name_size <= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE || | |
1996 | strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, | |
1997 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)) { | |
1998 | rc = -EINVAL; | |
1999 | goto out; | |
2000 | } | |
51ca58dc MH |
2001 | |
2002 | name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
2003 | name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
71c11c37 MH |
2004 | ecryptfs_decode_from_filename(NULL, &decoded_name_size, |
2005 | name, name_size); | |
51ca58dc MH |
2006 | decoded_name = kmalloc(decoded_name_size, GFP_KERNEL); |
2007 | if (!decoded_name) { | |
51ca58dc MH |
2008 | rc = -ENOMEM; |
2009 | goto out; | |
2010 | } | |
71c11c37 MH |
2011 | ecryptfs_decode_from_filename(decoded_name, &decoded_name_size, |
2012 | name, name_size); | |
51ca58dc MH |
2013 | rc = ecryptfs_parse_tag_70_packet(plaintext_name, |
2014 | plaintext_name_size, | |
2015 | &packet_size, | |
2016 | mount_crypt_stat, | |
2017 | decoded_name, | |
2018 | decoded_name_size); | |
2019 | if (rc) { | |
e86281e7 TH |
2020 | ecryptfs_printk(KERN_DEBUG, |
2021 | "%s: Could not parse tag 70 packet from filename\n", | |
2022 | __func__); | |
51ca58dc MH |
2023 | goto out_free; |
2024 | } | |
2025 | } else { | |
2026 | rc = ecryptfs_copy_filename(plaintext_name, | |
2027 | plaintext_name_size, | |
2028 | name, name_size); | |
2029 | goto out; | |
2030 | } | |
2031 | out_free: | |
2032 | kfree(decoded_name); | |
2033 | out: | |
2034 | return rc; | |
2035 | } | |
4a26620d TH |
2036 | |
2037 | #define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143 | |
2038 | ||
2039 | int ecryptfs_set_f_namelen(long *namelen, long lower_namelen, | |
2040 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) | |
2041 | { | |
3095e8e3 | 2042 | struct crypto_skcipher *tfm; |
4a26620d TH |
2043 | struct mutex *tfm_mutex; |
2044 | size_t cipher_blocksize; | |
2045 | int rc; | |
2046 | ||
2047 | if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { | |
2048 | (*namelen) = lower_namelen; | |
2049 | return 0; | |
2050 | } | |
2051 | ||
3095e8e3 | 2052 | rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, |
4a26620d TH |
2053 | mount_crypt_stat->global_default_fn_cipher_name); |
2054 | if (unlikely(rc)) { | |
2055 | (*namelen) = 0; | |
2056 | return rc; | |
2057 | } | |
2058 | ||
2059 | mutex_lock(tfm_mutex); | |
3095e8e3 | 2060 | cipher_blocksize = crypto_skcipher_blocksize(tfm); |
4a26620d TH |
2061 | mutex_unlock(tfm_mutex); |
2062 | ||
2063 | /* Return an exact amount for the common cases */ | |
2064 | if (lower_namelen == NAME_MAX | |
2065 | && (cipher_blocksize == 8 || cipher_blocksize == 16)) { | |
2066 | (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16; | |
2067 | return 0; | |
2068 | } | |
2069 | ||
2070 | /* Return a safe estimate for the uncommon cases */ | |
2071 | (*namelen) = lower_namelen; | |
2072 | (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; | |
2073 | /* Since this is the max decoded size, subtract 1 "decoded block" len */ | |
2074 | (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3; | |
2075 | (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE; | |
2076 | (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES; | |
2077 | /* Worst case is that the filename is padded nearly a full block size */ | |
2078 | (*namelen) -= cipher_blocksize - 1; | |
2079 | ||
2080 | if ((*namelen) < 0) | |
2081 | (*namelen) = 0; | |
2082 | ||
2083 | return 0; | |
2084 | } |