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