1 /**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2007 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 * 02111-1307, USA.
24 */
25
26 #include <linux/fs.h>
27 #include <linux/mount.h>
28 #include <linux/pagemap.h>
29 #include <linux/random.h>
30 #include <linux/compiler.h>
31 #include <linux/key.h>
32 #include <linux/namei.h>
33 #include <linux/crypto.h>
34 #include <linux/file.h>
35 #include <linux/scatterlist.h>
36 #include <linux/slab.h>
37 #include <asm/unaligned.h>
38 #include "ecryptfs_kernel.h"
39
40 static int
41 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
42 struct page *dst_page, int dst_offset,
43 struct page *src_page, int src_offset, int size,
44 unsigned char *iv);
45 static int
46 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
47 struct page *dst_page, int dst_offset,
48 struct page *src_page, int src_offset, int size,
49 unsigned char *iv);
50
51 /**
52 * ecryptfs_to_hex
53 * @dst: Buffer to take hex character representation of contents of
54 * src; must be at least of size (src_size * 2)
55 * @src: Buffer to be converted to a hex string respresentation
56 * @src_size: number of bytes to convert
57 */
ecryptfs_to_hex(char * dst,char * src,size_t src_size)58 void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
59 {
60 int x;
61
62 for (x = 0; x < src_size; x++)
63 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
64 }
65
66 /**
67 * ecryptfs_from_hex
68 * @dst: Buffer to take the bytes from src hex; must be at least of
69 * size (src_size / 2)
70 * @src: Buffer to be converted from a hex string respresentation to raw value
71 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
72 */
ecryptfs_from_hex(char * dst,char * src,int dst_size)73 void ecryptfs_from_hex(char *dst, char *src, int dst_size)
74 {
75 int x;
76 char tmp[3] = { 0, };
77
78 for (x = 0; x < dst_size; x++) {
79 tmp[0] = src[x * 2];
80 tmp[1] = src[x * 2 + 1];
81 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
82 }
83 }
84
85 /**
86 * ecryptfs_calculate_md5 - calculates the md5 of @src
87 * @dst: Pointer to 16 bytes of allocated memory
88 * @crypt_stat: Pointer to crypt_stat struct for the current inode
89 * @src: Data to be md5'd
90 * @len: Length of @src
91 *
92 * Uses the allocated crypto context that crypt_stat references to
93 * generate the MD5 sum of the contents of src.
94 */
ecryptfs_calculate_md5(char * dst,struct ecryptfs_crypt_stat * crypt_stat,char * src,int len)95 static int ecryptfs_calculate_md5(char *dst,
96 struct ecryptfs_crypt_stat *crypt_stat,
97 char *src, int len)
98 {
99 struct scatterlist sg;
100 struct hash_desc desc = {
101 .tfm = crypt_stat->hash_tfm,
102 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
103 };
104 int rc = 0;
105
106 mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
107 sg_init_one(&sg, (u8 *)src, len);
108 if (!desc.tfm) {
109 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
110 CRYPTO_ALG_ASYNC);
111 if (IS_ERR(desc.tfm)) {
112 rc = PTR_ERR(desc.tfm);
113 ecryptfs_printk(KERN_ERR, "Error attempting to "
114 "allocate crypto context; rc = [%d]\n",
115 rc);
116 goto out;
117 }
118 crypt_stat->hash_tfm = desc.tfm;
119 }
120 rc = crypto_hash_init(&desc);
121 if (rc) {
122 printk(KERN_ERR
123 "%s: Error initializing crypto hash; rc = [%d]\n",
124 __func__, rc);
125 goto out;
126 }
127 rc = crypto_hash_update(&desc, &sg, len);
128 if (rc) {
129 printk(KERN_ERR
130 "%s: Error updating crypto hash; rc = [%d]\n",
131 __func__, rc);
132 goto out;
133 }
134 rc = crypto_hash_final(&desc, dst);
135 if (rc) {
136 printk(KERN_ERR
137 "%s: Error finalizing crypto hash; rc = [%d]\n",
138 __func__, rc);
139 goto out;
140 }
141 out:
142 mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
143 return rc;
144 }
145
ecryptfs_crypto_api_algify_cipher_name(char ** algified_name,char * cipher_name,char * chaining_modifier)146 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
147 char *cipher_name,
148 char *chaining_modifier)
149 {
150 int cipher_name_len = strlen(cipher_name);
151 int chaining_modifier_len = strlen(chaining_modifier);
152 int algified_name_len;
153 int rc;
154
155 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
156 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
157 if (!(*algified_name)) {
158 rc = -ENOMEM;
159 goto out;
160 }
161 snprintf((*algified_name), algified_name_len, "%s(%s)",
162 chaining_modifier, cipher_name);
163 rc = 0;
164 out:
165 return rc;
166 }
167
168 /**
169 * ecryptfs_derive_iv
170 * @iv: destination for the derived iv vale
171 * @crypt_stat: Pointer to crypt_stat struct for the current inode
172 * @offset: Offset of the extent whose IV we are to derive
173 *
174 * Generate the initialization vector from the given root IV and page
175 * offset.
176 *
177 * Returns zero on success; non-zero on error.
178 */
ecryptfs_derive_iv(char * iv,struct ecryptfs_crypt_stat * crypt_stat,loff_t offset)179 int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
180 loff_t offset)
181 {
182 int rc = 0;
183 char dst[MD5_DIGEST_SIZE];
184 char src[ECRYPTFS_MAX_IV_BYTES + 16];
185
186 if (unlikely(ecryptfs_verbosity > 0)) {
187 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
188 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
189 }
190 /* TODO: It is probably secure to just cast the least
191 * significant bits of the root IV into an unsigned long and
192 * add the offset to that rather than go through all this
193 * hashing business. -Halcrow */
194 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
195 memset((src + crypt_stat->iv_bytes), 0, 16);
196 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
197 if (unlikely(ecryptfs_verbosity > 0)) {
198 ecryptfs_printk(KERN_DEBUG, "source:\n");
199 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
200 }
201 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
202 (crypt_stat->iv_bytes + 16));
203 if (rc) {
204 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
205 "MD5 while generating IV for a page\n");
206 goto out;
207 }
208 memcpy(iv, dst, crypt_stat->iv_bytes);
209 if (unlikely(ecryptfs_verbosity > 0)) {
210 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
211 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
212 }
213 out:
214 return rc;
215 }
216
217 /**
218 * ecryptfs_init_crypt_stat
219 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
220 *
221 * Initialize the crypt_stat structure.
222 */
223 void
ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat * crypt_stat)224 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
225 {
226 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
227 INIT_LIST_HEAD(&crypt_stat->keysig_list);
228 mutex_init(&crypt_stat->keysig_list_mutex);
229 mutex_init(&crypt_stat->cs_mutex);
230 mutex_init(&crypt_stat->cs_tfm_mutex);
231 mutex_init(&crypt_stat->cs_hash_tfm_mutex);
232 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
233 }
234
235 /**
236 * ecryptfs_destroy_crypt_stat
237 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
238 *
239 * Releases all memory associated with a crypt_stat struct.
240 */
ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat * crypt_stat)241 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
242 {
243 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
244
245 if (crypt_stat->tfm)
246 crypto_free_blkcipher(crypt_stat->tfm);
247 if (crypt_stat->hash_tfm)
248 crypto_free_hash(crypt_stat->hash_tfm);
249 list_for_each_entry_safe(key_sig, key_sig_tmp,
250 &crypt_stat->keysig_list, crypt_stat_list) {
251 list_del(&key_sig->crypt_stat_list);
252 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
253 }
254 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
255 }
256
ecryptfs_destroy_mount_crypt_stat(struct ecryptfs_mount_crypt_stat * mount_crypt_stat)257 void ecryptfs_destroy_mount_crypt_stat(
258 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
259 {
260 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
261
262 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
263 return;
264 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
265 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
266 &mount_crypt_stat->global_auth_tok_list,
267 mount_crypt_stat_list) {
268 list_del(&auth_tok->mount_crypt_stat_list);
269 if (auth_tok->global_auth_tok_key
270 && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
271 key_put(auth_tok->global_auth_tok_key);
272 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
273 }
274 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
275 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
276 }
277
278 /**
279 * virt_to_scatterlist
280 * @addr: Virtual address
281 * @size: Size of data; should be an even multiple of the block size
282 * @sg: Pointer to scatterlist array; set to NULL to obtain only
283 * the number of scatterlist structs required in array
284 * @sg_size: Max array size
285 *
286 * Fills in a scatterlist array with page references for a passed
287 * virtual address.
288 *
289 * Returns the number of scatterlist structs in array used
290 */
virt_to_scatterlist(const void * addr,int size,struct scatterlist * sg,int sg_size)291 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
292 int sg_size)
293 {
294 int i = 0;
295 struct page *pg;
296 int offset;
297 int remainder_of_page;
298
299 sg_init_table(sg, sg_size);
300
301 while (size > 0 && i < sg_size) {
302 pg = virt_to_page(addr);
303 offset = offset_in_page(addr);
304 if (sg)
305 sg_set_page(&sg[i], pg, 0, offset);
306 remainder_of_page = PAGE_CACHE_SIZE - offset;
307 if (size >= remainder_of_page) {
308 if (sg)
309 sg[i].length = remainder_of_page;
310 addr += remainder_of_page;
311 size -= remainder_of_page;
312 } else {
313 if (sg)
314 sg[i].length = size;
315 addr += size;
316 size = 0;
317 }
318 i++;
319 }
320 if (size > 0)
321 return -ENOMEM;
322 return i;
323 }
324
325 /**
326 * encrypt_scatterlist
327 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
328 * @dest_sg: Destination of encrypted data
329 * @src_sg: Data to be encrypted
330 * @size: Length of data to be encrypted
331 * @iv: iv to use during encryption
332 *
333 * Returns the number of bytes encrypted; negative value on error
334 */
encrypt_scatterlist(struct ecryptfs_crypt_stat * crypt_stat,struct scatterlist * dest_sg,struct scatterlist * src_sg,int size,unsigned char * iv)335 static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
336 struct scatterlist *dest_sg,
337 struct scatterlist *src_sg, int size,
338 unsigned char *iv)
339 {
340 struct blkcipher_desc desc = {
341 .tfm = crypt_stat->tfm,
342 .info = iv,
343 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
344 };
345 int rc = 0;
346
347 BUG_ON(!crypt_stat || !crypt_stat->tfm
348 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
349 if (unlikely(ecryptfs_verbosity > 0)) {
350 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
351 crypt_stat->key_size);
352 ecryptfs_dump_hex(crypt_stat->key,
353 crypt_stat->key_size);
354 }
355 /* Consider doing this once, when the file is opened */
356 mutex_lock(&crypt_stat->cs_tfm_mutex);
357 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
358 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
359 crypt_stat->key_size);
360 crypt_stat->flags |= ECRYPTFS_KEY_SET;
361 }
362 if (rc) {
363 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
364 rc);
365 mutex_unlock(&crypt_stat->cs_tfm_mutex);
366 rc = -EINVAL;
367 goto out;
368 }
369 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
370 crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
371 mutex_unlock(&crypt_stat->cs_tfm_mutex);
372 out:
373 return rc;
374 }
375
376 /**
377 * ecryptfs_lower_offset_for_extent
378 *
379 * Convert an eCryptfs page index into a lower byte offset
380 */
ecryptfs_lower_offset_for_extent(loff_t * offset,loff_t extent_num,struct ecryptfs_crypt_stat * crypt_stat)381 static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
382 struct ecryptfs_crypt_stat *crypt_stat)
383 {
384 (*offset) = ecryptfs_lower_header_size(crypt_stat)
385 + (crypt_stat->extent_size * extent_num);
386 }
387
388 /**
389 * ecryptfs_encrypt_extent
390 * @enc_extent_page: Allocated page into which to encrypt the data in
391 * @page
392 * @crypt_stat: crypt_stat containing cryptographic context for the
393 * encryption operation
394 * @page: Page containing plaintext data extent to encrypt
395 * @extent_offset: Page extent offset for use in generating IV
396 *
397 * Encrypts one extent of data.
398 *
399 * Return zero on success; non-zero otherwise
400 */
ecryptfs_encrypt_extent(struct page * enc_extent_page,struct ecryptfs_crypt_stat * crypt_stat,struct page * page,unsigned long extent_offset)401 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
402 struct ecryptfs_crypt_stat *crypt_stat,
403 struct page *page,
404 unsigned long extent_offset)
405 {
406 loff_t extent_base;
407 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
408 int rc;
409
410 extent_base = (((loff_t)page->index)
411 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
412 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
413 (extent_base + extent_offset));
414 if (rc) {
415 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
416 "extent [0x%.16llx]; rc = [%d]\n",
417 (unsigned long long)(extent_base + extent_offset), rc);
418 goto out;
419 }
420 if (unlikely(ecryptfs_verbosity > 0)) {
421 ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
422 "with iv:\n");
423 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
424 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
425 "encryption:\n");
426 ecryptfs_dump_hex((char *)
427 (page_address(page)
428 + (extent_offset * crypt_stat->extent_size)),
429 8);
430 }
431 rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
432 page, (extent_offset
433 * crypt_stat->extent_size),
434 crypt_stat->extent_size, extent_iv);
435 if (rc < 0) {
436 printk(KERN_ERR "%s: Error attempting to encrypt page with "
437 "page->index = [%ld], extent_offset = [%ld]; "
438 "rc = [%d]\n", __func__, page->index, extent_offset,
439 rc);
440 goto out;
441 }
442 rc = 0;
443 if (unlikely(ecryptfs_verbosity > 0)) {
444 ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16llx]; "
445 "rc = [%d]\n",
446 (unsigned long long)(extent_base + extent_offset), rc);
447 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
448 "encryption:\n");
449 ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
450 }
451 out:
452 return rc;
453 }
454
455 /**
456 * ecryptfs_encrypt_page
457 * @page: Page mapped from the eCryptfs inode for the file; contains
458 * decrypted content that needs to be encrypted (to a temporary
459 * page; not in place) and written out to the lower file
460 *
461 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
462 * that eCryptfs pages may straddle the lower pages -- for instance,
463 * if the file was created on a machine with an 8K page size
464 * (resulting in an 8K header), and then the file is copied onto a
465 * host with a 32K page size, then when reading page 0 of the eCryptfs
466 * file, 24K of page 0 of the lower file will be read and decrypted,
467 * and then 8K of page 1 of the lower file will be read and decrypted.
468 *
469 * Returns zero on success; negative on error
470 */
ecryptfs_encrypt_page(struct page * page)471 int ecryptfs_encrypt_page(struct page *page)
472 {
473 struct inode *ecryptfs_inode;
474 struct ecryptfs_crypt_stat *crypt_stat;
475 char *enc_extent_virt;
476 struct page *enc_extent_page = NULL;
477 loff_t extent_offset;
478 int rc = 0;
479
480 ecryptfs_inode = page->mapping->host;
481 crypt_stat =
482 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
483 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
484 enc_extent_page = alloc_page(GFP_USER);
485 if (!enc_extent_page) {
486 rc = -ENOMEM;
487 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
488 "encrypted extent\n");
489 goto out;
490 }
491 enc_extent_virt = kmap(enc_extent_page);
492 for (extent_offset = 0;
493 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
494 extent_offset++) {
495 loff_t offset;
496
497 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
498 extent_offset);
499 if (rc) {
500 printk(KERN_ERR "%s: Error encrypting extent; "
501 "rc = [%d]\n", __func__, rc);
502 goto out;
503 }
504 ecryptfs_lower_offset_for_extent(
505 &offset, ((((loff_t)page->index)
506 * (PAGE_CACHE_SIZE
507 / crypt_stat->extent_size))
508 + extent_offset), crypt_stat);
509 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
510 offset, crypt_stat->extent_size);
511 if (rc < 0) {
512 ecryptfs_printk(KERN_ERR, "Error attempting "
513 "to write lower page; rc = [%d]"
514 "\n", rc);
515 goto out;
516 }
517 }
518 rc = 0;
519 out:
520 if (enc_extent_page) {
521 kunmap(enc_extent_page);
522 __free_page(enc_extent_page);
523 }
524 return rc;
525 }
526
ecryptfs_decrypt_extent(struct page * page,struct ecryptfs_crypt_stat * crypt_stat,struct page * enc_extent_page,unsigned long extent_offset)527 static int ecryptfs_decrypt_extent(struct page *page,
528 struct ecryptfs_crypt_stat *crypt_stat,
529 struct page *enc_extent_page,
530 unsigned long extent_offset)
531 {
532 loff_t extent_base;
533 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
534 int rc;
535
536 extent_base = (((loff_t)page->index)
537 * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
538 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
539 (extent_base + extent_offset));
540 if (rc) {
541 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
542 "extent [0x%.16llx]; rc = [%d]\n",
543 (unsigned long long)(extent_base + extent_offset), rc);
544 goto out;
545 }
546 if (unlikely(ecryptfs_verbosity > 0)) {
547 ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
548 "with iv:\n");
549 ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
550 ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
551 "decryption:\n");
552 ecryptfs_dump_hex((char *)
553 (page_address(enc_extent_page)
554 + (extent_offset * crypt_stat->extent_size)),
555 8);
556 }
557 rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
558 (extent_offset
559 * crypt_stat->extent_size),
560 enc_extent_page, 0,
561 crypt_stat->extent_size, extent_iv);
562 if (rc < 0) {
563 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
564 "page->index = [%ld], extent_offset = [%ld]; "
565 "rc = [%d]\n", __func__, page->index, extent_offset,
566 rc);
567 goto out;
568 }
569 rc = 0;
570 if (unlikely(ecryptfs_verbosity > 0)) {
571 ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16llx]; "
572 "rc = [%d]\n",
573 (unsigned long long)(extent_base + extent_offset), rc);
574 ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
575 "decryption:\n");
576 ecryptfs_dump_hex((char *)(page_address(page)
577 + (extent_offset
578 * crypt_stat->extent_size)), 8);
579 }
580 out:
581 return rc;
582 }
583
584 /**
585 * ecryptfs_decrypt_page
586 * @page: Page mapped from the eCryptfs inode for the file; data read
587 * and decrypted from the lower file will be written into this
588 * page
589 *
590 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
591 * that eCryptfs pages may straddle the lower pages -- for instance,
592 * if the file was created on a machine with an 8K page size
593 * (resulting in an 8K header), and then the file is copied onto a
594 * host with a 32K page size, then when reading page 0 of the eCryptfs
595 * file, 24K of page 0 of the lower file will be read and decrypted,
596 * and then 8K of page 1 of the lower file will be read and decrypted.
597 *
598 * Returns zero on success; negative on error
599 */
ecryptfs_decrypt_page(struct page * page)600 int ecryptfs_decrypt_page(struct page *page)
601 {
602 struct inode *ecryptfs_inode;
603 struct ecryptfs_crypt_stat *crypt_stat;
604 char *enc_extent_virt;
605 struct page *enc_extent_page = NULL;
606 unsigned long extent_offset;
607 int rc = 0;
608
609 ecryptfs_inode = page->mapping->host;
610 crypt_stat =
611 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
612 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
613 enc_extent_page = alloc_page(GFP_USER);
614 if (!enc_extent_page) {
615 rc = -ENOMEM;
616 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
617 "encrypted extent\n");
618 goto out;
619 }
620 enc_extent_virt = kmap(enc_extent_page);
621 for (extent_offset = 0;
622 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
623 extent_offset++) {
624 loff_t offset;
625
626 ecryptfs_lower_offset_for_extent(
627 &offset, ((page->index * (PAGE_CACHE_SIZE
628 / crypt_stat->extent_size))
629 + extent_offset), crypt_stat);
630 rc = ecryptfs_read_lower(enc_extent_virt, offset,
631 crypt_stat->extent_size,
632 ecryptfs_inode);
633 if (rc < 0) {
634 ecryptfs_printk(KERN_ERR, "Error attempting "
635 "to read lower page; rc = [%d]"
636 "\n", rc);
637 goto out;
638 }
639 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
640 extent_offset);
641 if (rc) {
642 printk(KERN_ERR "%s: Error encrypting extent; "
643 "rc = [%d]\n", __func__, rc);
644 goto out;
645 }
646 }
647 out:
648 if (enc_extent_page) {
649 kunmap(enc_extent_page);
650 __free_page(enc_extent_page);
651 }
652 return rc;
653 }
654
655 /**
656 * decrypt_scatterlist
657 * @crypt_stat: Cryptographic context
658 * @dest_sg: The destination scatterlist to decrypt into
659 * @src_sg: The source scatterlist to decrypt from
660 * @size: The number of bytes to decrypt
661 * @iv: The initialization vector to use for the decryption
662 *
663 * Returns the number of bytes decrypted; negative value on error
664 */
decrypt_scatterlist(struct ecryptfs_crypt_stat * crypt_stat,struct scatterlist * dest_sg,struct scatterlist * src_sg,int size,unsigned char * iv)665 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
666 struct scatterlist *dest_sg,
667 struct scatterlist *src_sg, int size,
668 unsigned char *iv)
669 {
670 struct blkcipher_desc desc = {
671 .tfm = crypt_stat->tfm,
672 .info = iv,
673 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
674 };
675 int rc = 0;
676
677 /* Consider doing this once, when the file is opened */
678 mutex_lock(&crypt_stat->cs_tfm_mutex);
679 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
680 crypt_stat->key_size);
681 if (rc) {
682 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
683 rc);
684 mutex_unlock(&crypt_stat->cs_tfm_mutex);
685 rc = -EINVAL;
686 goto out;
687 }
688 ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
689 rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
690 mutex_unlock(&crypt_stat->cs_tfm_mutex);
691 if (rc) {
692 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
693 rc);
694 goto out;
695 }
696 rc = size;
697 out:
698 return rc;
699 }
700
701 /**
702 * ecryptfs_encrypt_page_offset
703 * @crypt_stat: The cryptographic context
704 * @dst_page: The page to encrypt into
705 * @dst_offset: The offset in the page to encrypt into
706 * @src_page: The page to encrypt from
707 * @src_offset: The offset in the page to encrypt from
708 * @size: The number of bytes to encrypt
709 * @iv: The initialization vector to use for the encryption
710 *
711 * Returns the number of bytes encrypted
712 */
713 static int
ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat * crypt_stat,struct page * dst_page,int dst_offset,struct page * src_page,int src_offset,int size,unsigned char * iv)714 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
715 struct page *dst_page, int dst_offset,
716 struct page *src_page, int src_offset, int size,
717 unsigned char *iv)
718 {
719 struct scatterlist src_sg, dst_sg;
720
721 sg_init_table(&src_sg, 1);
722 sg_init_table(&dst_sg, 1);
723
724 sg_set_page(&src_sg, src_page, size, src_offset);
725 sg_set_page(&dst_sg, dst_page, size, dst_offset);
726 return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
727 }
728
729 /**
730 * ecryptfs_decrypt_page_offset
731 * @crypt_stat: The cryptographic context
732 * @dst_page: The page to decrypt into
733 * @dst_offset: The offset in the page to decrypt into
734 * @src_page: The page to decrypt from
735 * @src_offset: The offset in the page to decrypt from
736 * @size: The number of bytes to decrypt
737 * @iv: The initialization vector to use for the decryption
738 *
739 * Returns the number of bytes decrypted
740 */
741 static int
ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat * crypt_stat,struct page * dst_page,int dst_offset,struct page * src_page,int src_offset,int size,unsigned char * iv)742 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
743 struct page *dst_page, int dst_offset,
744 struct page *src_page, int src_offset, int size,
745 unsigned char *iv)
746 {
747 struct scatterlist src_sg, dst_sg;
748
749 sg_init_table(&src_sg, 1);
750 sg_set_page(&src_sg, src_page, size, src_offset);
751
752 sg_init_table(&dst_sg, 1);
753 sg_set_page(&dst_sg, dst_page, size, dst_offset);
754
755 return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
756 }
757
758 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
759
760 /**
761 * ecryptfs_init_crypt_ctx
762 * @crypt_stat: Uninitialized crypt stats structure
763 *
764 * Initialize the crypto context.
765 *
766 * TODO: Performance: Keep a cache of initialized cipher contexts;
767 * only init if needed
768 */
ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat * crypt_stat)769 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
770 {
771 char *full_alg_name;
772 int rc = -EINVAL;
773
774 if (!crypt_stat->cipher) {
775 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
776 goto out;
777 }
778 ecryptfs_printk(KERN_DEBUG,
779 "Initializing cipher [%s]; strlen = [%d]; "
780 "key_size_bits = [%zd]\n",
781 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
782 crypt_stat->key_size << 3);
783 if (crypt_stat->tfm) {
784 rc = 0;
785 goto out;
786 }
787 mutex_lock(&crypt_stat->cs_tfm_mutex);
788 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
789 crypt_stat->cipher, "cbc");
790 if (rc)
791 goto out_unlock;
792 crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
793 CRYPTO_ALG_ASYNC);
794 kfree(full_alg_name);
795 if (IS_ERR(crypt_stat->tfm)) {
796 rc = PTR_ERR(crypt_stat->tfm);
797 crypt_stat->tfm = NULL;
798 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
799 "Error initializing cipher [%s]\n",
800 crypt_stat->cipher);
801 goto out_unlock;
802 }
803 crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
804 rc = 0;
805 out_unlock:
806 mutex_unlock(&crypt_stat->cs_tfm_mutex);
807 out:
808 return rc;
809 }
810
set_extent_mask_and_shift(struct ecryptfs_crypt_stat * crypt_stat)811 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
812 {
813 int extent_size_tmp;
814
815 crypt_stat->extent_mask = 0xFFFFFFFF;
816 crypt_stat->extent_shift = 0;
817 if (crypt_stat->extent_size == 0)
818 return;
819 extent_size_tmp = crypt_stat->extent_size;
820 while ((extent_size_tmp & 0x01) == 0) {
821 extent_size_tmp >>= 1;
822 crypt_stat->extent_mask <<= 1;
823 crypt_stat->extent_shift++;
824 }
825 }
826
ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat * crypt_stat)827 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
828 {
829 /* Default values; may be overwritten as we are parsing the
830 * packets. */
831 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
832 set_extent_mask_and_shift(crypt_stat);
833 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
834 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
835 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
836 else {
837 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
838 crypt_stat->metadata_size =
839 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
840 else
841 crypt_stat->metadata_size = PAGE_CACHE_SIZE;
842 }
843 }
844
845 /**
846 * ecryptfs_compute_root_iv
847 * @crypt_stats
848 *
849 * On error, sets the root IV to all 0's.
850 */
ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat * crypt_stat)851 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
852 {
853 int rc = 0;
854 char dst[MD5_DIGEST_SIZE];
855
856 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
857 BUG_ON(crypt_stat->iv_bytes <= 0);
858 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
859 rc = -EINVAL;
860 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
861 "cannot generate root IV\n");
862 goto out;
863 }
864 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
865 crypt_stat->key_size);
866 if (rc) {
867 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
868 "MD5 while generating root IV\n");
869 goto out;
870 }
871 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
872 out:
873 if (rc) {
874 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
875 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
876 }
877 return rc;
878 }
879
ecryptfs_generate_new_key(struct ecryptfs_crypt_stat * crypt_stat)880 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
881 {
882 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
883 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
884 ecryptfs_compute_root_iv(crypt_stat);
885 if (unlikely(ecryptfs_verbosity > 0)) {
886 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
887 ecryptfs_dump_hex(crypt_stat->key,
888 crypt_stat->key_size);
889 }
890 }
891
892 /**
893 * ecryptfs_copy_mount_wide_flags_to_inode_flags
894 * @crypt_stat: The inode's cryptographic context
895 * @mount_crypt_stat: The mount point's cryptographic context
896 *
897 * This function propagates the mount-wide flags to individual inode
898 * flags.
899 */
ecryptfs_copy_mount_wide_flags_to_inode_flags(struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_mount_crypt_stat * mount_crypt_stat)900 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
901 struct ecryptfs_crypt_stat *crypt_stat,
902 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
903 {
904 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
905 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
906 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
907 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
908 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
909 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
910 if (mount_crypt_stat->flags
911 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
912 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
913 else if (mount_crypt_stat->flags
914 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
915 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
916 }
917 }
918
ecryptfs_copy_mount_wide_sigs_to_inode_sigs(struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_mount_crypt_stat * mount_crypt_stat)919 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
920 struct ecryptfs_crypt_stat *crypt_stat,
921 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
922 {
923 struct ecryptfs_global_auth_tok *global_auth_tok;
924 int rc = 0;
925
926 mutex_lock(&crypt_stat->keysig_list_mutex);
927 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
928
929 list_for_each_entry(global_auth_tok,
930 &mount_crypt_stat->global_auth_tok_list,
931 mount_crypt_stat_list) {
932 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
933 continue;
934 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
935 if (rc) {
936 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
937 goto out;
938 }
939 }
940
941 out:
942 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
943 mutex_unlock(&crypt_stat->keysig_list_mutex);
944 return rc;
945 }
946
947 /**
948 * ecryptfs_set_default_crypt_stat_vals
949 * @crypt_stat: The inode's cryptographic context
950 * @mount_crypt_stat: The mount point's cryptographic context
951 *
952 * Default values in the event that policy does not override them.
953 */
ecryptfs_set_default_crypt_stat_vals(struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_mount_crypt_stat * mount_crypt_stat)954 static void ecryptfs_set_default_crypt_stat_vals(
955 struct ecryptfs_crypt_stat *crypt_stat,
956 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
957 {
958 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
959 mount_crypt_stat);
960 ecryptfs_set_default_sizes(crypt_stat);
961 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
962 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
963 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
964 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
965 crypt_stat->mount_crypt_stat = mount_crypt_stat;
966 }
967
968 /**
969 * ecryptfs_new_file_context
970 * @ecryptfs_dentry: The eCryptfs dentry
971 *
972 * If the crypto context for the file has not yet been established,
973 * this is where we do that. Establishing a new crypto context
974 * involves the following decisions:
975 * - What cipher to use?
976 * - What set of authentication tokens to use?
977 * Here we just worry about getting enough information into the
978 * authentication tokens so that we know that they are available.
979 * We associate the available authentication tokens with the new file
980 * via the set of signatures in the crypt_stat struct. Later, when
981 * the headers are actually written out, we may again defer to
982 * userspace to perform the encryption of the session key; for the
983 * foreseeable future, this will be the case with public key packets.
984 *
985 * Returns zero on success; non-zero otherwise
986 */
ecryptfs_new_file_context(struct dentry * ecryptfs_dentry)987 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
988 {
989 struct ecryptfs_crypt_stat *crypt_stat =
990 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
991 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
992 &ecryptfs_superblock_to_private(
993 ecryptfs_dentry->d_sb)->mount_crypt_stat;
994 int cipher_name_len;
995 int rc = 0;
996
997 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
998 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
999 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1000 mount_crypt_stat);
1001 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1002 mount_crypt_stat);
1003 if (rc) {
1004 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1005 "to the inode key sigs; rc = [%d]\n", rc);
1006 goto out;
1007 }
1008 cipher_name_len =
1009 strlen(mount_crypt_stat->global_default_cipher_name);
1010 memcpy(crypt_stat->cipher,
1011 mount_crypt_stat->global_default_cipher_name,
1012 cipher_name_len);
1013 crypt_stat->cipher[cipher_name_len] = '\0';
1014 crypt_stat->key_size =
1015 mount_crypt_stat->global_default_cipher_key_size;
1016 ecryptfs_generate_new_key(crypt_stat);
1017 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1018 if (rc)
1019 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1020 "context for cipher [%s]: rc = [%d]\n",
1021 crypt_stat->cipher, rc);
1022 out:
1023 return rc;
1024 }
1025
1026 /**
1027 * contains_ecryptfs_marker - check for the ecryptfs marker
1028 * @data: The data block in which to check
1029 *
1030 * Returns one if marker found; zero if not found
1031 */
contains_ecryptfs_marker(char * data)1032 static int contains_ecryptfs_marker(char *data)
1033 {
1034 u32 m_1, m_2;
1035
1036 m_1 = get_unaligned_be32(data);
1037 m_2 = get_unaligned_be32(data + 4);
1038 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1039 return 1;
1040 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1041 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1042 MAGIC_ECRYPTFS_MARKER);
1043 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1044 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1045 return 0;
1046 }
1047
1048 struct ecryptfs_flag_map_elem {
1049 u32 file_flag;
1050 u32 local_flag;
1051 };
1052
1053 /* Add support for additional flags by adding elements here. */
1054 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1055 {0x00000001, ECRYPTFS_ENABLE_HMAC},
1056 {0x00000002, ECRYPTFS_ENCRYPTED},
1057 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1058 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
1059 };
1060
1061 /**
1062 * ecryptfs_process_flags
1063 * @crypt_stat: The cryptographic context
1064 * @page_virt: Source data to be parsed
1065 * @bytes_read: Updated with the number of bytes read
1066 *
1067 * Returns zero on success; non-zero if the flag set is invalid
1068 */
ecryptfs_process_flags(struct ecryptfs_crypt_stat * crypt_stat,char * page_virt,int * bytes_read)1069 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1070 char *page_virt, int *bytes_read)
1071 {
1072 int rc = 0;
1073 int i;
1074 u32 flags;
1075
1076 flags = get_unaligned_be32(page_virt);
1077 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1078 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1079 if (flags & ecryptfs_flag_map[i].file_flag) {
1080 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1081 } else
1082 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1083 /* Version is in top 8 bits of the 32-bit flag vector */
1084 crypt_stat->file_version = ((flags >> 24) & 0xFF);
1085 (*bytes_read) = 4;
1086 return rc;
1087 }
1088
1089 /**
1090 * write_ecryptfs_marker
1091 * @page_virt: The pointer to in a page to begin writing the marker
1092 * @written: Number of bytes written
1093 *
1094 * Marker = 0x3c81b7f5
1095 */
write_ecryptfs_marker(char * page_virt,size_t * written)1096 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1097 {
1098 u32 m_1, m_2;
1099
1100 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1101 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1102 put_unaligned_be32(m_1, page_virt);
1103 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1104 put_unaligned_be32(m_2, page_virt);
1105 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1106 }
1107
ecryptfs_write_crypt_stat_flags(char * page_virt,struct ecryptfs_crypt_stat * crypt_stat,size_t * written)1108 void ecryptfs_write_crypt_stat_flags(char *page_virt,
1109 struct ecryptfs_crypt_stat *crypt_stat,
1110 size_t *written)
1111 {
1112 u32 flags = 0;
1113 int i;
1114
1115 for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1116 / sizeof(struct ecryptfs_flag_map_elem))); i++)
1117 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1118 flags |= ecryptfs_flag_map[i].file_flag;
1119 /* Version is in top 8 bits of the 32-bit flag vector */
1120 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1121 put_unaligned_be32(flags, page_virt);
1122 (*written) = 4;
1123 }
1124
1125 struct ecryptfs_cipher_code_str_map_elem {
1126 char cipher_str[16];
1127 u8 cipher_code;
1128 };
1129
1130 /* Add support for additional ciphers by adding elements here. The
1131 * cipher_code is whatever OpenPGP applicatoins use to identify the
1132 * ciphers. List in order of probability. */
1133 static struct ecryptfs_cipher_code_str_map_elem
1134 ecryptfs_cipher_code_str_map[] = {
1135 {"aes",RFC2440_CIPHER_AES_128 },
1136 {"blowfish", RFC2440_CIPHER_BLOWFISH},
1137 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1138 {"cast5", RFC2440_CIPHER_CAST_5},
1139 {"twofish", RFC2440_CIPHER_TWOFISH},
1140 {"cast6", RFC2440_CIPHER_CAST_6},
1141 {"aes", RFC2440_CIPHER_AES_192},
1142 {"aes", RFC2440_CIPHER_AES_256}
1143 };
1144
1145 /**
1146 * ecryptfs_code_for_cipher_string
1147 * @cipher_name: The string alias for the cipher
1148 * @key_bytes: Length of key in bytes; used for AES code selection
1149 *
1150 * Returns zero on no match, or the cipher code on match
1151 */
ecryptfs_code_for_cipher_string(char * cipher_name,size_t key_bytes)1152 u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
1153 {
1154 int i;
1155 u8 code = 0;
1156 struct ecryptfs_cipher_code_str_map_elem *map =
1157 ecryptfs_cipher_code_str_map;
1158
1159 if (strcmp(cipher_name, "aes") == 0) {
1160 switch (key_bytes) {
1161 case 16:
1162 code = RFC2440_CIPHER_AES_128;
1163 break;
1164 case 24:
1165 code = RFC2440_CIPHER_AES_192;
1166 break;
1167 case 32:
1168 code = RFC2440_CIPHER_AES_256;
1169 }
1170 } else {
1171 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1172 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
1173 code = map[i].cipher_code;
1174 break;
1175 }
1176 }
1177 return code;
1178 }
1179
1180 /**
1181 * ecryptfs_cipher_code_to_string
1182 * @str: Destination to write out the cipher name
1183 * @cipher_code: The code to convert to cipher name string
1184 *
1185 * Returns zero on success
1186 */
ecryptfs_cipher_code_to_string(char * str,u8 cipher_code)1187 int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
1188 {
1189 int rc = 0;
1190 int i;
1191
1192 str[0] = '\0';
1193 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1194 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1195 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1196 if (str[0] == '\0') {
1197 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1198 "[%d]\n", cipher_code);
1199 rc = -EINVAL;
1200 }
1201 return rc;
1202 }
1203
ecryptfs_read_and_validate_header_region(char * data,struct inode * ecryptfs_inode)1204 int ecryptfs_read_and_validate_header_region(char *data,
1205 struct inode *ecryptfs_inode)
1206 {
1207 struct ecryptfs_crypt_stat *crypt_stat =
1208 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
1209 int rc;
1210
1211 if (crypt_stat->extent_size == 0)
1212 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
1213 rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
1214 ecryptfs_inode);
1215 if (rc < 0) {
1216 printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
1217 __func__, rc);
1218 goto out;
1219 }
1220 if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
1221 rc = -EINVAL;
1222 } else
1223 rc = 0;
1224 out:
1225 return rc;
1226 }
1227
1228 void
ecryptfs_write_header_metadata(char * virt,struct ecryptfs_crypt_stat * crypt_stat,size_t * written)1229 ecryptfs_write_header_metadata(char *virt,
1230 struct ecryptfs_crypt_stat *crypt_stat,
1231 size_t *written)
1232 {
1233 u32 header_extent_size;
1234 u16 num_header_extents_at_front;
1235
1236 header_extent_size = (u32)crypt_stat->extent_size;
1237 num_header_extents_at_front =
1238 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
1239 put_unaligned_be32(header_extent_size, virt);
1240 virt += 4;
1241 put_unaligned_be16(num_header_extents_at_front, virt);
1242 (*written) = 6;
1243 }
1244
1245 struct kmem_cache *ecryptfs_header_cache_1;
1246 struct kmem_cache *ecryptfs_header_cache_2;
1247
1248 /**
1249 * ecryptfs_write_headers_virt
1250 * @page_virt: The virtual address to write the headers to
1251 * @max: The size of memory allocated at page_virt
1252 * @size: Set to the number of bytes written by this function
1253 * @crypt_stat: The cryptographic context
1254 * @ecryptfs_dentry: The eCryptfs dentry
1255 *
1256 * Format version: 1
1257 *
1258 * Header Extent:
1259 * Octets 0-7: Unencrypted file size (big-endian)
1260 * Octets 8-15: eCryptfs special marker
1261 * Octets 16-19: Flags
1262 * Octet 16: File format version number (between 0 and 255)
1263 * Octets 17-18: Reserved
1264 * Octet 19: Bit 1 (lsb): Reserved
1265 * Bit 2: Encrypted?
1266 * Bits 3-8: Reserved
1267 * Octets 20-23: Header extent size (big-endian)
1268 * Octets 24-25: Number of header extents at front of file
1269 * (big-endian)
1270 * Octet 26: Begin RFC 2440 authentication token packet set
1271 * Data Extent 0:
1272 * Lower data (CBC encrypted)
1273 * Data Extent 1:
1274 * Lower data (CBC encrypted)
1275 * ...
1276 *
1277 * Returns zero on success
1278 */
ecryptfs_write_headers_virt(char * page_virt,size_t max,size_t * size,struct ecryptfs_crypt_stat * crypt_stat,struct dentry * ecryptfs_dentry)1279 static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1280 size_t *size,
1281 struct ecryptfs_crypt_stat *crypt_stat,
1282 struct dentry *ecryptfs_dentry)
1283 {
1284 int rc;
1285 size_t written;
1286 size_t offset;
1287
1288 offset = ECRYPTFS_FILE_SIZE_BYTES;
1289 write_ecryptfs_marker((page_virt + offset), &written);
1290 offset += written;
1291 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1292 &written);
1293 offset += written;
1294 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1295 &written);
1296 offset += written;
1297 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1298 ecryptfs_dentry, &written,
1299 max - offset);
1300 if (rc)
1301 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1302 "set; rc = [%d]\n", rc);
1303 if (size) {
1304 offset += written;
1305 *size = offset;
1306 }
1307 return rc;
1308 }
1309
1310 static int
ecryptfs_write_metadata_to_contents(struct dentry * ecryptfs_dentry,char * virt,size_t virt_len)1311 ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
1312 char *virt, size_t virt_len)
1313 {
1314 int rc;
1315
1316 rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
1317 0, virt_len);
1318 if (rc < 0)
1319 printk(KERN_ERR "%s: Error attempting to write header "
1320 "information to lower file; rc = [%d]\n", __func__, rc);
1321 else
1322 rc = 0;
1323 return rc;
1324 }
1325
1326 static int
ecryptfs_write_metadata_to_xattr(struct dentry * ecryptfs_dentry,char * page_virt,size_t size)1327 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1328 char *page_virt, size_t size)
1329 {
1330 int rc;
1331
1332 rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1333 size, 0);
1334 return rc;
1335 }
1336
ecryptfs_get_zeroed_pages(gfp_t gfp_mask,unsigned int order)1337 static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1338 unsigned int order)
1339 {
1340 struct page *page;
1341
1342 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1343 if (page)
1344 return (unsigned long) page_address(page);
1345 return 0;
1346 }
1347
1348 /**
1349 * ecryptfs_write_metadata
1350 * @ecryptfs_dentry: The eCryptfs dentry
1351 *
1352 * Write the file headers out. This will likely involve a userspace
1353 * callout, in which the session key is encrypted with one or more
1354 * public keys and/or the passphrase necessary to do the encryption is
1355 * retrieved via a prompt. Exactly what happens at this point should
1356 * be policy-dependent.
1357 *
1358 * Returns zero on success; non-zero on error
1359 */
ecryptfs_write_metadata(struct dentry * ecryptfs_dentry)1360 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
1361 {
1362 struct ecryptfs_crypt_stat *crypt_stat =
1363 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1364 unsigned int order;
1365 char *virt;
1366 size_t virt_len;
1367 size_t size = 0;
1368 int rc = 0;
1369
1370 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1371 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1372 printk(KERN_ERR "Key is invalid; bailing out\n");
1373 rc = -EINVAL;
1374 goto out;
1375 }
1376 } else {
1377 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1378 __func__);
1379 rc = -EINVAL;
1380 goto out;
1381 }
1382 virt_len = crypt_stat->metadata_size;
1383 order = get_order(virt_len);
1384 /* Released in this function */
1385 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1386 if (!virt) {
1387 printk(KERN_ERR "%s: Out of memory\n", __func__);
1388 rc = -ENOMEM;
1389 goto out;
1390 }
1391 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
1392 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1393 ecryptfs_dentry);
1394 if (unlikely(rc)) {
1395 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1396 __func__, rc);
1397 goto out_free;
1398 }
1399 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1400 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1401 size);
1402 else
1403 rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
1404 virt_len);
1405 if (rc) {
1406 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1407 "rc = [%d]\n", __func__, rc);
1408 goto out_free;
1409 }
1410 out_free:
1411 free_pages((unsigned long)virt, order);
1412 out:
1413 return rc;
1414 }
1415
1416 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1417 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
parse_header_metadata(struct ecryptfs_crypt_stat * crypt_stat,char * virt,int * bytes_read,int validate_header_size)1418 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1419 char *virt, int *bytes_read,
1420 int validate_header_size)
1421 {
1422 int rc = 0;
1423 u32 header_extent_size;
1424 u16 num_header_extents_at_front;
1425
1426 header_extent_size = get_unaligned_be32(virt);
1427 virt += sizeof(__be32);
1428 num_header_extents_at_front = get_unaligned_be16(virt);
1429 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1430 * (size_t)header_extent_size));
1431 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1432 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1433 && (crypt_stat->metadata_size
1434 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1435 rc = -EINVAL;
1436 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1437 crypt_stat->metadata_size);
1438 }
1439 return rc;
1440 }
1441
1442 /**
1443 * set_default_header_data
1444 * @crypt_stat: The cryptographic context
1445 *
1446 * For version 0 file format; this function is only for backwards
1447 * compatibility for files created with the prior versions of
1448 * eCryptfs.
1449 */
set_default_header_data(struct ecryptfs_crypt_stat * crypt_stat)1450 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1451 {
1452 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1453 }
1454
ecryptfs_i_size_init(const char * page_virt,struct inode * inode)1455 void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1456 {
1457 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1458 struct ecryptfs_crypt_stat *crypt_stat;
1459 u64 file_size;
1460
1461 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1462 mount_crypt_stat =
1463 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1464 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1465 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1466 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1467 file_size += crypt_stat->metadata_size;
1468 } else
1469 file_size = get_unaligned_be64(page_virt);
1470 i_size_write(inode, (loff_t)file_size);
1471 crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1472 }
1473
1474 /**
1475 * ecryptfs_read_headers_virt
1476 * @page_virt: The virtual address into which to read the headers
1477 * @crypt_stat: The cryptographic context
1478 * @ecryptfs_dentry: The eCryptfs dentry
1479 * @validate_header_size: Whether to validate the header size while reading
1480 *
1481 * Read/parse the header data. The header format is detailed in the
1482 * comment block for the ecryptfs_write_headers_virt() function.
1483 *
1484 * Returns zero on success
1485 */
ecryptfs_read_headers_virt(char * page_virt,struct ecryptfs_crypt_stat * crypt_stat,struct dentry * ecryptfs_dentry,int validate_header_size)1486 static int ecryptfs_read_headers_virt(char *page_virt,
1487 struct ecryptfs_crypt_stat *crypt_stat,
1488 struct dentry *ecryptfs_dentry,
1489 int validate_header_size)
1490 {
1491 int rc = 0;
1492 int offset;
1493 int bytes_read;
1494
1495 ecryptfs_set_default_sizes(crypt_stat);
1496 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1497 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1498 offset = ECRYPTFS_FILE_SIZE_BYTES;
1499 rc = contains_ecryptfs_marker(page_virt + offset);
1500 if (rc == 0) {
1501 rc = -EINVAL;
1502 goto out;
1503 }
1504 if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1505 ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
1506 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1507 rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1508 &bytes_read);
1509 if (rc) {
1510 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1511 goto out;
1512 }
1513 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1514 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1515 "file version [%d] is supported by this "
1516 "version of eCryptfs\n",
1517 crypt_stat->file_version,
1518 ECRYPTFS_SUPPORTED_FILE_VERSION);
1519 rc = -EINVAL;
1520 goto out;
1521 }
1522 offset += bytes_read;
1523 if (crypt_stat->file_version >= 1) {
1524 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1525 &bytes_read, validate_header_size);
1526 if (rc) {
1527 ecryptfs_printk(KERN_WARNING, "Error reading header "
1528 "metadata; rc = [%d]\n", rc);
1529 }
1530 offset += bytes_read;
1531 } else
1532 set_default_header_data(crypt_stat);
1533 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1534 ecryptfs_dentry);
1535 out:
1536 return rc;
1537 }
1538
1539 /**
1540 * ecryptfs_read_xattr_region
1541 * @page_virt: The vitual address into which to read the xattr data
1542 * @ecryptfs_inode: The eCryptfs inode
1543 *
1544 * Attempts to read the crypto metadata from the extended attribute
1545 * region of the lower file.
1546 *
1547 * Returns zero on success; non-zero on error
1548 */
ecryptfs_read_xattr_region(char * page_virt,struct inode * ecryptfs_inode)1549 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1550 {
1551 struct dentry *lower_dentry =
1552 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1553 ssize_t size;
1554 int rc = 0;
1555
1556 size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1557 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1558 if (size < 0) {
1559 if (unlikely(ecryptfs_verbosity > 0))
1560 printk(KERN_INFO "Error attempting to read the [%s] "
1561 "xattr from the lower file; return value = "
1562 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1563 rc = -EINVAL;
1564 goto out;
1565 }
1566 out:
1567 return rc;
1568 }
1569
ecryptfs_read_and_validate_xattr_region(char * page_virt,struct dentry * ecryptfs_dentry)1570 int ecryptfs_read_and_validate_xattr_region(char *page_virt,
1571 struct dentry *ecryptfs_dentry)
1572 {
1573 int rc;
1574
1575 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
1576 if (rc)
1577 goto out;
1578 if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
1579 printk(KERN_WARNING "Valid data found in [%s] xattr, but "
1580 "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
1581 rc = -EINVAL;
1582 }
1583 out:
1584 return rc;
1585 }
1586
1587 /**
1588 * ecryptfs_read_metadata
1589 *
1590 * Common entry point for reading file metadata. From here, we could
1591 * retrieve the header information from the header region of the file,
1592 * the xattr region of the file, or some other repostory that is
1593 * stored separately from the file itself. The current implementation
1594 * supports retrieving the metadata information from the file contents
1595 * and from the xattr region.
1596 *
1597 * Returns zero if valid headers found and parsed; non-zero otherwise
1598 */
ecryptfs_read_metadata(struct dentry * ecryptfs_dentry)1599 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1600 {
1601 int rc = 0;
1602 char *page_virt = NULL;
1603 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1604 struct ecryptfs_crypt_stat *crypt_stat =
1605 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1606 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1607 &ecryptfs_superblock_to_private(
1608 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1609
1610 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1611 mount_crypt_stat);
1612 /* Read the first page from the underlying file */
1613 page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
1614 if (!page_virt) {
1615 rc = -ENOMEM;
1616 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1617 __func__);
1618 goto out;
1619 }
1620 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1621 ecryptfs_inode);
1622 if (rc >= 0)
1623 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1624 ecryptfs_dentry,
1625 ECRYPTFS_VALIDATE_HEADER_SIZE);
1626 if (rc) {
1627 memset(page_virt, 0, PAGE_CACHE_SIZE);
1628 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1629 if (rc) {
1630 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1631 "file header region or xattr region\n");
1632 rc = -EINVAL;
1633 goto out;
1634 }
1635 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1636 ecryptfs_dentry,
1637 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1638 if (rc) {
1639 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1640 "file xattr region either\n");
1641 rc = -EINVAL;
1642 }
1643 if (crypt_stat->mount_crypt_stat->flags
1644 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1645 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1646 } else {
1647 printk(KERN_WARNING "Attempt to access file with "
1648 "crypto metadata only in the extended attribute "
1649 "region, but eCryptfs was mounted without "
1650 "xattr support enabled. eCryptfs will not treat "
1651 "this like an encrypted file.\n");
1652 rc = -EINVAL;
1653 }
1654 }
1655 out:
1656 if (page_virt) {
1657 memset(page_virt, 0, PAGE_CACHE_SIZE);
1658 kmem_cache_free(ecryptfs_header_cache_1, page_virt);
1659 }
1660 return rc;
1661 }
1662
1663 /**
1664 * ecryptfs_encrypt_filename - encrypt filename
1665 *
1666 * CBC-encrypts the filename. We do not want to encrypt the same
1667 * filename with the same key and IV, which may happen with hard
1668 * links, so we prepend random bits to each filename.
1669 *
1670 * Returns zero on success; non-zero otherwise
1671 */
1672 static int
ecryptfs_encrypt_filename(struct ecryptfs_filename * filename,struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_mount_crypt_stat * mount_crypt_stat)1673 ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1674 struct ecryptfs_crypt_stat *crypt_stat,
1675 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1676 {
1677 int rc = 0;
1678
1679 filename->encrypted_filename = NULL;
1680 filename->encrypted_filename_size = 0;
1681 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1682 || (mount_crypt_stat && (mount_crypt_stat->flags
1683 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1684 size_t packet_size;
1685 size_t remaining_bytes;
1686
1687 rc = ecryptfs_write_tag_70_packet(
1688 NULL, NULL,
1689 &filename->encrypted_filename_size,
1690 mount_crypt_stat, NULL,
1691 filename->filename_size);
1692 if (rc) {
1693 printk(KERN_ERR "%s: Error attempting to get packet "
1694 "size for tag 72; rc = [%d]\n", __func__,
1695 rc);
1696 filename->encrypted_filename_size = 0;
1697 goto out;
1698 }
1699 filename->encrypted_filename =
1700 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1701 if (!filename->encrypted_filename) {
1702 printk(KERN_ERR "%s: Out of memory whilst attempting "
1703 "to kmalloc [%zd] bytes\n", __func__,
1704 filename->encrypted_filename_size);
1705 rc = -ENOMEM;
1706 goto out;
1707 }
1708 remaining_bytes = filename->encrypted_filename_size;
1709 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1710 &remaining_bytes,
1711 &packet_size,
1712 mount_crypt_stat,
1713 filename->filename,
1714 filename->filename_size);
1715 if (rc) {
1716 printk(KERN_ERR "%s: Error attempting to generate "
1717 "tag 70 packet; rc = [%d]\n", __func__,
1718 rc);
1719 kfree(filename->encrypted_filename);
1720 filename->encrypted_filename = NULL;
1721 filename->encrypted_filename_size = 0;
1722 goto out;
1723 }
1724 filename->encrypted_filename_size = packet_size;
1725 } else {
1726 printk(KERN_ERR "%s: No support for requested filename "
1727 "encryption method in this release\n", __func__);
1728 rc = -EOPNOTSUPP;
1729 goto out;
1730 }
1731 out:
1732 return rc;
1733 }
1734
ecryptfs_copy_filename(char ** copied_name,size_t * copied_name_size,const char * name,size_t name_size)1735 static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1736 const char *name, size_t name_size)
1737 {
1738 int rc = 0;
1739
1740 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1741 if (!(*copied_name)) {
1742 rc = -ENOMEM;
1743 goto out;
1744 }
1745 memcpy((void *)(*copied_name), (void *)name, name_size);
1746 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1747 * in printing out the
1748 * string in debug
1749 * messages */
1750 (*copied_name_size) = name_size;
1751 out:
1752 return rc;
1753 }
1754
1755 /**
1756 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1757 * @key_tfm: Crypto context for key material, set by this function
1758 * @cipher_name: Name of the cipher
1759 * @key_size: Size of the key in bytes
1760 *
1761 * Returns zero on success. Any crypto_tfm structs allocated here
1762 * should be released by other functions, such as on a superblock put
1763 * event, regardless of whether this function succeeds for fails.
1764 */
1765 static int
ecryptfs_process_key_cipher(struct crypto_blkcipher ** key_tfm,char * cipher_name,size_t * key_size)1766 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1767 char *cipher_name, size_t *key_size)
1768 {
1769 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1770 char *full_alg_name = NULL;
1771 int rc;
1772
1773 *key_tfm = NULL;
1774 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1775 rc = -EINVAL;
1776 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1777 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1778 goto out;
1779 }
1780 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1781 "ecb");
1782 if (rc)
1783 goto out;
1784 *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1785 if (IS_ERR(*key_tfm)) {
1786 rc = PTR_ERR(*key_tfm);
1787 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1788 "[%s]; rc = [%d]\n", full_alg_name, rc);
1789 goto out;
1790 }
1791 crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1792 if (*key_size == 0) {
1793 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1794
1795 *key_size = alg->max_keysize;
1796 }
1797 get_random_bytes(dummy_key, *key_size);
1798 rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1799 if (rc) {
1800 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1801 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1802 rc);
1803 rc = -EINVAL;
1804 goto out;
1805 }
1806 out:
1807 kfree(full_alg_name);
1808 return rc;
1809 }
1810
1811 struct kmem_cache *ecryptfs_key_tfm_cache;
1812 static struct list_head key_tfm_list;
1813 struct mutex key_tfm_list_mutex;
1814
ecryptfs_init_crypto(void)1815 int __init ecryptfs_init_crypto(void)
1816 {
1817 mutex_init(&key_tfm_list_mutex);
1818 INIT_LIST_HEAD(&key_tfm_list);
1819 return 0;
1820 }
1821
1822 /**
1823 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1824 *
1825 * Called only at module unload time
1826 */
ecryptfs_destroy_crypto(void)1827 int ecryptfs_destroy_crypto(void)
1828 {
1829 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1830
1831 mutex_lock(&key_tfm_list_mutex);
1832 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1833 key_tfm_list) {
1834 list_del(&key_tfm->key_tfm_list);
1835 if (key_tfm->key_tfm)
1836 crypto_free_blkcipher(key_tfm->key_tfm);
1837 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1838 }
1839 mutex_unlock(&key_tfm_list_mutex);
1840 return 0;
1841 }
1842
1843 int
ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm ** key_tfm,char * cipher_name,size_t key_size)1844 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1845 size_t key_size)
1846 {
1847 struct ecryptfs_key_tfm *tmp_tfm;
1848 int rc = 0;
1849
1850 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1851
1852 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1853 if (key_tfm != NULL)
1854 (*key_tfm) = tmp_tfm;
1855 if (!tmp_tfm) {
1856 rc = -ENOMEM;
1857 printk(KERN_ERR "Error attempting to allocate from "
1858 "ecryptfs_key_tfm_cache\n");
1859 goto out;
1860 }
1861 mutex_init(&tmp_tfm->key_tfm_mutex);
1862 strncpy(tmp_tfm->cipher_name, cipher_name,
1863 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1864 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1865 tmp_tfm->key_size = key_size;
1866 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1867 tmp_tfm->cipher_name,
1868 &tmp_tfm->key_size);
1869 if (rc) {
1870 printk(KERN_ERR "Error attempting to initialize key TFM "
1871 "cipher with name = [%s]; rc = [%d]\n",
1872 tmp_tfm->cipher_name, rc);
1873 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1874 if (key_tfm != NULL)
1875 (*key_tfm) = NULL;
1876 goto out;
1877 }
1878 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1879 out:
1880 return rc;
1881 }
1882
1883 /**
1884 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1885 * @cipher_name: the name of the cipher to search for
1886 * @key_tfm: set to corresponding tfm if found
1887 *
1888 * Searches for cached key_tfm matching @cipher_name
1889 * Must be called with &key_tfm_list_mutex held
1890 * Returns 1 if found, with @key_tfm set
1891 * Returns 0 if not found, with @key_tfm set to NULL
1892 */
ecryptfs_tfm_exists(char * cipher_name,struct ecryptfs_key_tfm ** key_tfm)1893 int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1894 {
1895 struct ecryptfs_key_tfm *tmp_key_tfm;
1896
1897 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1898
1899 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1900 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1901 if (key_tfm)
1902 (*key_tfm) = tmp_key_tfm;
1903 return 1;
1904 }
1905 }
1906 if (key_tfm)
1907 (*key_tfm) = NULL;
1908 return 0;
1909 }
1910
1911 /**
1912 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1913 *
1914 * @tfm: set to cached tfm found, or new tfm created
1915 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1916 * @cipher_name: the name of the cipher to search for and/or add
1917 *
1918 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1919 * Searches for cached item first, and creates new if not found.
1920 * Returns 0 on success, non-zero if adding new cipher failed
1921 */
ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher ** tfm,struct mutex ** tfm_mutex,char * cipher_name)1922 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1923 struct mutex **tfm_mutex,
1924 char *cipher_name)
1925 {
1926 struct ecryptfs_key_tfm *key_tfm;
1927 int rc = 0;
1928
1929 (*tfm) = NULL;
1930 (*tfm_mutex) = NULL;
1931
1932 mutex_lock(&key_tfm_list_mutex);
1933 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1934 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1935 if (rc) {
1936 printk(KERN_ERR "Error adding new key_tfm to list; "
1937 "rc = [%d]\n", rc);
1938 goto out;
1939 }
1940 }
1941 (*tfm) = key_tfm->key_tfm;
1942 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1943 out:
1944 mutex_unlock(&key_tfm_list_mutex);
1945 return rc;
1946 }
1947
1948 /* 64 characters forming a 6-bit target field */
1949 static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1950 "EFGHIJKLMNOPQRST"
1951 "UVWXYZabcdefghij"
1952 "klmnopqrstuvwxyz");
1953
1954 /* We could either offset on every reverse map or just pad some 0x00's
1955 * at the front here */
1956 static const unsigned char filename_rev_map[] = {
1957 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1958 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1959 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1960 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1961 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1962 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1963 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1964 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1965 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1966 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1967 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1968 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1969 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1970 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1971 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1972 0x3D, 0x3E, 0x3F
1973 };
1974
1975 /**
1976 * ecryptfs_encode_for_filename
1977 * @dst: Destination location for encoded filename
1978 * @dst_size: Size of the encoded filename in bytes
1979 * @src: Source location for the filename to encode
1980 * @src_size: Size of the source in bytes
1981 */
ecryptfs_encode_for_filename(unsigned char * dst,size_t * dst_size,unsigned char * src,size_t src_size)1982 void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1983 unsigned char *src, size_t src_size)
1984 {
1985 size_t num_blocks;
1986 size_t block_num = 0;
1987 size_t dst_offset = 0;
1988 unsigned char last_block[3];
1989
1990 if (src_size == 0) {
1991 (*dst_size) = 0;
1992 goto out;
1993 }
1994 num_blocks = (src_size / 3);
1995 if ((src_size % 3) == 0) {
1996 memcpy(last_block, (&src[src_size - 3]), 3);
1997 } else {
1998 num_blocks++;
1999 last_block[2] = 0x00;
2000 switch (src_size % 3) {
2001 case 1:
2002 last_block[0] = src[src_size - 1];
2003 last_block[1] = 0x00;
2004 break;
2005 case 2:
2006 last_block[0] = src[src_size - 2];
2007 last_block[1] = src[src_size - 1];
2008 }
2009 }
2010 (*dst_size) = (num_blocks * 4);
2011 if (!dst)
2012 goto out;
2013 while (block_num < num_blocks) {
2014 unsigned char *src_block;
2015 unsigned char dst_block[4];
2016
2017 if (block_num == (num_blocks - 1))
2018 src_block = last_block;
2019 else
2020 src_block = &src[block_num * 3];
2021 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2022 dst_block[1] = (((src_block[0] << 4) & 0x30)
2023 | ((src_block[1] >> 4) & 0x0F));
2024 dst_block[2] = (((src_block[1] << 2) & 0x3C)
2025 | ((src_block[2] >> 6) & 0x03));
2026 dst_block[3] = (src_block[2] & 0x3F);
2027 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2028 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2029 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2030 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2031 block_num++;
2032 }
2033 out:
2034 return;
2035 }
2036
2037 /**
2038 * ecryptfs_decode_from_filename
2039 * @dst: If NULL, this function only sets @dst_size and returns. If
2040 * non-NULL, this function decodes the encoded octets in @src
2041 * into the memory that @dst points to.
2042 * @dst_size: Set to the size of the decoded string.
2043 * @src: The encoded set of octets to decode.
2044 * @src_size: The size of the encoded set of octets to decode.
2045 */
2046 static void
ecryptfs_decode_from_filename(unsigned char * dst,size_t * dst_size,const unsigned char * src,size_t src_size)2047 ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2048 const unsigned char *src, size_t src_size)
2049 {
2050 u8 current_bit_offset = 0;
2051 size_t src_byte_offset = 0;
2052 size_t dst_byte_offset = 0;
2053
2054 if (dst == NULL) {
2055 /* Not exact; conservatively long. Every block of 4
2056 * encoded characters decodes into a block of 3
2057 * decoded characters. This segment of code provides
2058 * the caller with the maximum amount of allocated
2059 * space that @dst will need to point to in a
2060 * subsequent call. */
2061 (*dst_size) = (((src_size + 1) * 3) / 4);
2062 goto out;
2063 }
2064 while (src_byte_offset < src_size) {
2065 unsigned char src_byte =
2066 filename_rev_map[(int)src[src_byte_offset]];
2067
2068 switch (current_bit_offset) {
2069 case 0:
2070 dst[dst_byte_offset] = (src_byte << 2);
2071 current_bit_offset = 6;
2072 break;
2073 case 6:
2074 dst[dst_byte_offset++] |= (src_byte >> 4);
2075 dst[dst_byte_offset] = ((src_byte & 0xF)
2076 << 4);
2077 current_bit_offset = 4;
2078 break;
2079 case 4:
2080 dst[dst_byte_offset++] |= (src_byte >> 2);
2081 dst[dst_byte_offset] = (src_byte << 6);
2082 current_bit_offset = 2;
2083 break;
2084 case 2:
2085 dst[dst_byte_offset++] |= (src_byte);
2086 dst[dst_byte_offset] = 0;
2087 current_bit_offset = 0;
2088 break;
2089 }
2090 src_byte_offset++;
2091 }
2092 (*dst_size) = dst_byte_offset;
2093 out:
2094 return;
2095 }
2096
2097 /**
2098 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2099 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2100 * @name: The plaintext name
2101 * @length: The length of the plaintext
2102 * @encoded_name: The encypted name
2103 *
2104 * Encrypts and encodes a filename into something that constitutes a
2105 * valid filename for a filesystem, with printable characters.
2106 *
2107 * We assume that we have a properly initialized crypto context,
2108 * pointed to by crypt_stat->tfm.
2109 *
2110 * Returns zero on success; non-zero on otherwise
2111 */
ecryptfs_encrypt_and_encode_filename(char ** encoded_name,size_t * encoded_name_size,struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_mount_crypt_stat * mount_crypt_stat,const char * name,size_t name_size)2112 int ecryptfs_encrypt_and_encode_filename(
2113 char **encoded_name,
2114 size_t *encoded_name_size,
2115 struct ecryptfs_crypt_stat *crypt_stat,
2116 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2117 const char *name, size_t name_size)
2118 {
2119 size_t encoded_name_no_prefix_size;
2120 int rc = 0;
2121
2122 (*encoded_name) = NULL;
2123 (*encoded_name_size) = 0;
2124 if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2125 || (mount_crypt_stat && (mount_crypt_stat->flags
2126 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2127 struct ecryptfs_filename *filename;
2128
2129 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2130 if (!filename) {
2131 printk(KERN_ERR "%s: Out of memory whilst attempting "
2132 "to kzalloc [%zd] bytes\n", __func__,
2133 sizeof(*filename));
2134 rc = -ENOMEM;
2135 goto out;
2136 }
2137 filename->filename = (char *)name;
2138 filename->filename_size = name_size;
2139 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2140 mount_crypt_stat);
2141 if (rc) {
2142 printk(KERN_ERR "%s: Error attempting to encrypt "
2143 "filename; rc = [%d]\n", __func__, rc);
2144 kfree(filename);
2145 goto out;
2146 }
2147 ecryptfs_encode_for_filename(
2148 NULL, &encoded_name_no_prefix_size,
2149 filename->encrypted_filename,
2150 filename->encrypted_filename_size);
2151 if ((crypt_stat && (crypt_stat->flags
2152 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2153 || (mount_crypt_stat
2154 && (mount_crypt_stat->flags
2155 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2156 (*encoded_name_size) =
2157 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2158 + encoded_name_no_prefix_size);
2159 else
2160 (*encoded_name_size) =
2161 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2162 + encoded_name_no_prefix_size);
2163 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2164 if (!(*encoded_name)) {
2165 printk(KERN_ERR "%s: Out of memory whilst attempting "
2166 "to kzalloc [%zd] bytes\n", __func__,
2167 (*encoded_name_size));
2168 rc = -ENOMEM;
2169 kfree(filename->encrypted_filename);
2170 kfree(filename);
2171 goto out;
2172 }
2173 if ((crypt_stat && (crypt_stat->flags
2174 & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2175 || (mount_crypt_stat
2176 && (mount_crypt_stat->flags
2177 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2178 memcpy((*encoded_name),
2179 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2180 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2181 ecryptfs_encode_for_filename(
2182 ((*encoded_name)
2183 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2184 &encoded_name_no_prefix_size,
2185 filename->encrypted_filename,
2186 filename->encrypted_filename_size);
2187 (*encoded_name_size) =
2188 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2189 + encoded_name_no_prefix_size);
2190 (*encoded_name)[(*encoded_name_size)] = '\0';
2191 } else {
2192 rc = -EOPNOTSUPP;
2193 }
2194 if (rc) {
2195 printk(KERN_ERR "%s: Error attempting to encode "
2196 "encrypted filename; rc = [%d]\n", __func__,
2197 rc);
2198 kfree((*encoded_name));
2199 (*encoded_name) = NULL;
2200 (*encoded_name_size) = 0;
2201 }
2202 kfree(filename->encrypted_filename);
2203 kfree(filename);
2204 } else {
2205 rc = ecryptfs_copy_filename(encoded_name,
2206 encoded_name_size,
2207 name, name_size);
2208 }
2209 out:
2210 return rc;
2211 }
2212
2213 /**
2214 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2215 * @plaintext_name: The plaintext name
2216 * @plaintext_name_size: The plaintext name size
2217 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2218 * @name: The filename in cipher text
2219 * @name_size: The cipher text name size
2220 *
2221 * Decrypts and decodes the filename.
2222 *
2223 * Returns zero on error; non-zero otherwise
2224 */
ecryptfs_decode_and_decrypt_filename(char ** plaintext_name,size_t * plaintext_name_size,struct dentry * ecryptfs_dir_dentry,const char * name,size_t name_size)2225 int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2226 size_t *plaintext_name_size,
2227 struct dentry *ecryptfs_dir_dentry,
2228 const char *name, size_t name_size)
2229 {
2230 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2231 &ecryptfs_superblock_to_private(
2232 ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
2233 char *decoded_name;
2234 size_t decoded_name_size;
2235 size_t packet_size;
2236 int rc = 0;
2237
2238 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2239 && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2240 && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
2241 && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2242 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
2243 const char *orig_name = name;
2244 size_t orig_name_size = name_size;
2245
2246 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2247 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2248 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2249 name, name_size);
2250 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2251 if (!decoded_name) {
2252 printk(KERN_ERR "%s: Out of memory whilst attempting "
2253 "to kmalloc [%zd] bytes\n", __func__,
2254 decoded_name_size);
2255 rc = -ENOMEM;
2256 goto out;
2257 }
2258 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2259 name, name_size);
2260 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2261 plaintext_name_size,
2262 &packet_size,
2263 mount_crypt_stat,
2264 decoded_name,
2265 decoded_name_size);
2266 if (rc) {
2267 printk(KERN_INFO "%s: Could not parse tag 70 packet "
2268 "from filename; copying through filename "
2269 "as-is\n", __func__);
2270 rc = ecryptfs_copy_filename(plaintext_name,
2271 plaintext_name_size,
2272 orig_name, orig_name_size);
2273 goto out_free;
2274 }
2275 } else {
2276 rc = ecryptfs_copy_filename(plaintext_name,
2277 plaintext_name_size,
2278 name, name_size);
2279 goto out;
2280 }
2281 out_free:
2282 kfree(decoded_name);
2283 out:
2284 return rc;
2285 }
2286