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1/**
2 * eCryptfs: Linux filesystem encryption layer
3 * In-kernel key management code. Includes functions to parse and
4 * write authentication token-related packets with the underlying
5 * file.
6 *
7 * Copyright (C) 2004-2006 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
9 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * Trevor S. Highland <trevor.highland@gmail.com>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
25 * 02111-1307, USA.
26 */
27
28#include <crypto/hash.h>
29#include <crypto/skcipher.h>
30#include <linux/string.h>
31#include <linux/pagemap.h>
32#include <linux/key.h>
33#include <linux/random.h>
34#include <linux/scatterlist.h>
35#include <linux/slab.h>
36#include "ecryptfs_kernel.h"
37
38/**
39 * request_key returned an error instead of a valid key address;
40 * determine the type of error, make appropriate log entries, and
41 * return an error code.
42 */
43static int process_request_key_err(long err_code)
44{
45 int rc = 0;
46
47 switch (err_code) {
48 case -ENOKEY:
49 ecryptfs_printk(KERN_WARNING, "No key\n");
50 rc = -ENOENT;
51 break;
52 case -EKEYEXPIRED:
53 ecryptfs_printk(KERN_WARNING, "Key expired\n");
54 rc = -ETIME;
55 break;
56 case -EKEYREVOKED:
57 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
58 rc = -EINVAL;
59 break;
60 default:
61 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
62 "[0x%.16lx]\n", err_code);
63 rc = -EINVAL;
64 }
65 return rc;
66}
67
68static int process_find_global_auth_tok_for_sig_err(int err_code)
69{
70 int rc = err_code;
71
72 switch (err_code) {
73 case -ENOENT:
74 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
75 break;
76 case -EINVAL:
77 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
78 break;
79 default:
80 rc = process_request_key_err(err_code);
81 break;
82 }
83 return rc;
84}
85
86/**
87 * ecryptfs_parse_packet_length
88 * @data: Pointer to memory containing length at offset
89 * @size: This function writes the decoded size to this memory
90 * address; zero on error
91 * @length_size: The number of bytes occupied by the encoded length
92 *
93 * Returns zero on success; non-zero on error
94 */
95int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
96 size_t *length_size)
97{
98 int rc = 0;
99
100 (*length_size) = 0;
101 (*size) = 0;
102 if (data[0] < 192) {
103 /* One-byte length */
104 (*size) = data[0];
105 (*length_size) = 1;
106 } else if (data[0] < 224) {
107 /* Two-byte length */
108 (*size) = (data[0] - 192) * 256;
109 (*size) += data[1] + 192;
110 (*length_size) = 2;
111 } else if (data[0] == 255) {
112 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
113 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
114 "supported\n");
115 rc = -EINVAL;
116 goto out;
117 } else {
118 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
119 rc = -EINVAL;
120 goto out;
121 }
122out:
123 return rc;
124}
125
126/**
127 * ecryptfs_write_packet_length
128 * @dest: The byte array target into which to write the length. Must
129 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
130 * @size: The length to write.
131 * @packet_size_length: The number of bytes used to encode the packet
132 * length is written to this address.
133 *
134 * Returns zero on success; non-zero on error.
135 */
136int ecryptfs_write_packet_length(char *dest, size_t size,
137 size_t *packet_size_length)
138{
139 int rc = 0;
140
141 if (size < 192) {
142 dest[0] = size;
143 (*packet_size_length) = 1;
144 } else if (size < 65536) {
145 dest[0] = (((size - 192) / 256) + 192);
146 dest[1] = ((size - 192) % 256);
147 (*packet_size_length) = 2;
148 } else {
149 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
150 rc = -EINVAL;
151 ecryptfs_printk(KERN_WARNING,
152 "Unsupported packet size: [%zd]\n", size);
153 }
154 return rc;
155}
156
157static int
158write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
159 char **packet, size_t *packet_len)
160{
161 size_t i = 0;
162 size_t data_len;
163 size_t packet_size_len;
164 char *message;
165 int rc;
166
167 /*
168 * ***** TAG 64 Packet Format *****
169 * | Content Type | 1 byte |
170 * | Key Identifier Size | 1 or 2 bytes |
171 * | Key Identifier | arbitrary |
172 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
173 * | Encrypted File Encryption Key | arbitrary |
174 */
175 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
176 + session_key->encrypted_key_size);
177 *packet = kmalloc(data_len, GFP_KERNEL);
178 message = *packet;
179 if (!message) {
180 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
181 rc = -ENOMEM;
182 goto out;
183 }
184 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
185 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
186 &packet_size_len);
187 if (rc) {
188 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
189 "header; cannot generate packet length\n");
190 goto out;
191 }
192 i += packet_size_len;
193 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
194 i += ECRYPTFS_SIG_SIZE_HEX;
195 rc = ecryptfs_write_packet_length(&message[i],
196 session_key->encrypted_key_size,
197 &packet_size_len);
198 if (rc) {
199 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
200 "header; cannot generate packet length\n");
201 goto out;
202 }
203 i += packet_size_len;
204 memcpy(&message[i], session_key->encrypted_key,
205 session_key->encrypted_key_size);
206 i += session_key->encrypted_key_size;
207 *packet_len = i;
208out:
209 return rc;
210}
211
212static int
213parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
214 struct ecryptfs_message *msg)
215{
216 size_t i = 0;
217 char *data;
218 size_t data_len;
219 size_t m_size;
220 size_t message_len;
221 u16 checksum = 0;
222 u16 expected_checksum = 0;
223 int rc;
224
225 /*
226 * ***** TAG 65 Packet Format *****
227 * | Content Type | 1 byte |
228 * | Status Indicator | 1 byte |
229 * | File Encryption Key Size | 1 or 2 bytes |
230 * | File Encryption Key | arbitrary |
231 */
232 message_len = msg->data_len;
233 data = msg->data;
234 if (message_len < 4) {
235 rc = -EIO;
236 goto out;
237 }
238 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
239 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
240 rc = -EIO;
241 goto out;
242 }
243 if (data[i++]) {
244 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
245 "[%d]\n", data[i-1]);
246 rc = -EIO;
247 goto out;
248 }
249 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
250 if (rc) {
251 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
252 "rc = [%d]\n", rc);
253 goto out;
254 }
255 i += data_len;
256 if (message_len < (i + m_size)) {
257 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
258 "is shorter than expected\n");
259 rc = -EIO;
260 goto out;
261 }
262 if (m_size < 3) {
263 ecryptfs_printk(KERN_ERR,
264 "The decrypted key is not long enough to "
265 "include a cipher code and checksum\n");
266 rc = -EIO;
267 goto out;
268 }
269 *cipher_code = data[i++];
270 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
271 session_key->decrypted_key_size = m_size - 3;
272 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
273 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
274 "the maximum key size [%d]\n",
275 session_key->decrypted_key_size,
276 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
277 rc = -EIO;
278 goto out;
279 }
280 memcpy(session_key->decrypted_key, &data[i],
281 session_key->decrypted_key_size);
282 i += session_key->decrypted_key_size;
283 expected_checksum += (unsigned char)(data[i++]) << 8;
284 expected_checksum += (unsigned char)(data[i++]);
285 for (i = 0; i < session_key->decrypted_key_size; i++)
286 checksum += session_key->decrypted_key[i];
287 if (expected_checksum != checksum) {
288 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
289 "encryption key; expected [%x]; calculated "
290 "[%x]\n", expected_checksum, checksum);
291 rc = -EIO;
292 }
293out:
294 return rc;
295}
296
297
298static int
299write_tag_66_packet(char *signature, u8 cipher_code,
300 struct ecryptfs_crypt_stat *crypt_stat, char **packet,
301 size_t *packet_len)
302{
303 size_t i = 0;
304 size_t j;
305 size_t data_len;
306 size_t checksum = 0;
307 size_t packet_size_len;
308 char *message;
309 int rc;
310
311 /*
312 * ***** TAG 66 Packet Format *****
313 * | Content Type | 1 byte |
314 * | Key Identifier Size | 1 or 2 bytes |
315 * | Key Identifier | arbitrary |
316 * | File Encryption Key Size | 1 or 2 bytes |
317 * | File Encryption Key | arbitrary |
318 */
319 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
320 *packet = kmalloc(data_len, GFP_KERNEL);
321 message = *packet;
322 if (!message) {
323 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
324 rc = -ENOMEM;
325 goto out;
326 }
327 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
328 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
329 &packet_size_len);
330 if (rc) {
331 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
332 "header; cannot generate packet length\n");
333 goto out;
334 }
335 i += packet_size_len;
336 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
337 i += ECRYPTFS_SIG_SIZE_HEX;
338 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
339 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
340 &packet_size_len);
341 if (rc) {
342 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
343 "header; cannot generate packet length\n");
344 goto out;
345 }
346 i += packet_size_len;
347 message[i++] = cipher_code;
348 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
349 i += crypt_stat->key_size;
350 for (j = 0; j < crypt_stat->key_size; j++)
351 checksum += crypt_stat->key[j];
352 message[i++] = (checksum / 256) % 256;
353 message[i++] = (checksum % 256);
354 *packet_len = i;
355out:
356 return rc;
357}
358
359static int
360parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
361 struct ecryptfs_message *msg)
362{
363 size_t i = 0;
364 char *data;
365 size_t data_len;
366 size_t message_len;
367 int rc;
368
369 /*
370 * ***** TAG 65 Packet Format *****
371 * | Content Type | 1 byte |
372 * | Status Indicator | 1 byte |
373 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
374 * | Encrypted File Encryption Key | arbitrary |
375 */
376 message_len = msg->data_len;
377 data = msg->data;
378 /* verify that everything through the encrypted FEK size is present */
379 if (message_len < 4) {
380 rc = -EIO;
381 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
382 "message length is [%d]\n", __func__, message_len, 4);
383 goto out;
384 }
385 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
386 rc = -EIO;
387 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
388 __func__);
389 goto out;
390 }
391 if (data[i++]) {
392 rc = -EIO;
393 printk(KERN_ERR "%s: Status indicator has non zero "
394 "value [%d]\n", __func__, data[i-1]);
395
396 goto out;
397 }
398 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
399 &data_len);
400 if (rc) {
401 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
402 "rc = [%d]\n", rc);
403 goto out;
404 }
405 i += data_len;
406 if (message_len < (i + key_rec->enc_key_size)) {
407 rc = -EIO;
408 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
409 __func__, message_len, (i + key_rec->enc_key_size));
410 goto out;
411 }
412 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
413 rc = -EIO;
414 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
415 "the maximum key size [%d]\n", __func__,
416 key_rec->enc_key_size,
417 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
418 goto out;
419 }
420 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
421out:
422 return rc;
423}
424
425/**
426 * ecryptfs_verify_version
427 * @version: The version number to confirm
428 *
429 * Returns zero on good version; non-zero otherwise
430 */
431static int ecryptfs_verify_version(u16 version)
432{
433 int rc = 0;
434 unsigned char major;
435 unsigned char minor;
436
437 major = ((version >> 8) & 0xFF);
438 minor = (version & 0xFF);
439 if (major != ECRYPTFS_VERSION_MAJOR) {
440 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
441 "Expected [%d]; got [%d]\n",
442 ECRYPTFS_VERSION_MAJOR, major);
443 rc = -EINVAL;
444 goto out;
445 }
446 if (minor != ECRYPTFS_VERSION_MINOR) {
447 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
448 "Expected [%d]; got [%d]\n",
449 ECRYPTFS_VERSION_MINOR, minor);
450 rc = -EINVAL;
451 goto out;
452 }
453out:
454 return rc;
455}
456
457/**
458 * ecryptfs_verify_auth_tok_from_key
459 * @auth_tok_key: key containing the authentication token
460 * @auth_tok: authentication token
461 *
462 * Returns zero on valid auth tok; -EINVAL otherwise
463 */
464static int
465ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
466 struct ecryptfs_auth_tok **auth_tok)
467{
468 int rc = 0;
469
470 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
471 if (ecryptfs_verify_version((*auth_tok)->version)) {
472 printk(KERN_ERR "Data structure version mismatch. Userspace "
473 "tools must match eCryptfs kernel module with major "
474 "version [%d] and minor version [%d]\n",
475 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
476 rc = -EINVAL;
477 goto out;
478 }
479 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
480 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
481 printk(KERN_ERR "Invalid auth_tok structure "
482 "returned from key query\n");
483 rc = -EINVAL;
484 goto out;
485 }
486out:
487 return rc;
488}
489
490static int
491ecryptfs_find_global_auth_tok_for_sig(
492 struct key **auth_tok_key,
493 struct ecryptfs_auth_tok **auth_tok,
494 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
495{
496 struct ecryptfs_global_auth_tok *walker;
497 int rc = 0;
498
499 (*auth_tok_key) = NULL;
500 (*auth_tok) = NULL;
501 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
502 list_for_each_entry(walker,
503 &mount_crypt_stat->global_auth_tok_list,
504 mount_crypt_stat_list) {
505 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
506 continue;
507
508 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
509 rc = -EINVAL;
510 goto out;
511 }
512
513 rc = key_validate(walker->global_auth_tok_key);
514 if (rc) {
515 if (rc == -EKEYEXPIRED)
516 goto out;
517 goto out_invalid_auth_tok;
518 }
519
520 down_write(&(walker->global_auth_tok_key->sem));
521 rc = ecryptfs_verify_auth_tok_from_key(
522 walker->global_auth_tok_key, auth_tok);
523 if (rc)
524 goto out_invalid_auth_tok_unlock;
525
526 (*auth_tok_key) = walker->global_auth_tok_key;
527 key_get(*auth_tok_key);
528 goto out;
529 }
530 rc = -ENOENT;
531 goto out;
532out_invalid_auth_tok_unlock:
533 up_write(&(walker->global_auth_tok_key->sem));
534out_invalid_auth_tok:
535 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
536 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
537 key_put(walker->global_auth_tok_key);
538 walker->global_auth_tok_key = NULL;
539out:
540 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
541 return rc;
542}
543
544/**
545 * ecryptfs_find_auth_tok_for_sig
546 * @auth_tok: Set to the matching auth_tok; NULL if not found
547 * @crypt_stat: inode crypt_stat crypto context
548 * @sig: Sig of auth_tok to find
549 *
550 * For now, this function simply looks at the registered auth_tok's
551 * linked off the mount_crypt_stat, so all the auth_toks that can be
552 * used must be registered at mount time. This function could
553 * potentially try a lot harder to find auth_tok's (e.g., by calling
554 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
555 * that static registration of auth_tok's will no longer be necessary.
556 *
557 * Returns zero on no error; non-zero on error
558 */
559static int
560ecryptfs_find_auth_tok_for_sig(
561 struct key **auth_tok_key,
562 struct ecryptfs_auth_tok **auth_tok,
563 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
564 char *sig)
565{
566 int rc = 0;
567
568 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
569 mount_crypt_stat, sig);
570 if (rc == -ENOENT) {
571 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
572 * mount_crypt_stat structure, we prevent to use auth toks that
573 * are not inserted through the ecryptfs_add_global_auth_tok
574 * function.
575 */
576 if (mount_crypt_stat->flags
577 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
578 return -EINVAL;
579
580 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
581 sig);
582 }
583 return rc;
584}
585
586/**
587 * write_tag_70_packet can gobble a lot of stack space. We stuff most
588 * of the function's parameters in a kmalloc'd struct to help reduce
589 * eCryptfs' overall stack usage.
590 */
591struct ecryptfs_write_tag_70_packet_silly_stack {
592 u8 cipher_code;
593 size_t max_packet_size;
594 size_t packet_size_len;
595 size_t block_aligned_filename_size;
596 size_t block_size;
597 size_t i;
598 size_t j;
599 size_t num_rand_bytes;
600 struct mutex *tfm_mutex;
601 char *block_aligned_filename;
602 struct ecryptfs_auth_tok *auth_tok;
603 struct scatterlist src_sg[2];
604 struct scatterlist dst_sg[2];
605 struct crypto_skcipher *skcipher_tfm;
606 struct skcipher_request *skcipher_req;
607 char iv[ECRYPTFS_MAX_IV_BYTES];
608 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
609 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
610 struct crypto_shash *hash_tfm;
611 struct shash_desc *hash_desc;
612};
613
614/**
615 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
616 * @filename: NULL-terminated filename string
617 *
618 * This is the simplest mechanism for achieving filename encryption in
619 * eCryptfs. It encrypts the given filename with the mount-wide
620 * filename encryption key (FNEK) and stores it in a packet to @dest,
621 * which the callee will encode and write directly into the dentry
622 * name.
623 */
624int
625ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
626 size_t *packet_size,
627 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
628 char *filename, size_t filename_size)
629{
630 struct ecryptfs_write_tag_70_packet_silly_stack *s;
631 struct key *auth_tok_key = NULL;
632 int rc = 0;
633
634 s = kzalloc(sizeof(*s), GFP_KERNEL);
635 if (!s) {
636 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
637 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
638 return -ENOMEM;
639 }
640 (*packet_size) = 0;
641 rc = ecryptfs_find_auth_tok_for_sig(
642 &auth_tok_key,
643 &s->auth_tok, mount_crypt_stat,
644 mount_crypt_stat->global_default_fnek_sig);
645 if (rc) {
646 printk(KERN_ERR "%s: Error attempting to find auth tok for "
647 "fnek sig [%s]; rc = [%d]\n", __func__,
648 mount_crypt_stat->global_default_fnek_sig, rc);
649 goto out;
650 }
651 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
652 &s->skcipher_tfm,
653 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
654 if (unlikely(rc)) {
655 printk(KERN_ERR "Internal error whilst attempting to get "
656 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
657 mount_crypt_stat->global_default_fn_cipher_name, rc);
658 goto out;
659 }
660 mutex_lock(s->tfm_mutex);
661 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
662 /* Plus one for the \0 separator between the random prefix
663 * and the plaintext filename */
664 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
665 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
666 if ((s->block_aligned_filename_size % s->block_size) != 0) {
667 s->num_rand_bytes += (s->block_size
668 - (s->block_aligned_filename_size
669 % s->block_size));
670 s->block_aligned_filename_size = (s->num_rand_bytes
671 + filename_size);
672 }
673 /* Octet 0: Tag 70 identifier
674 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
675 * and block-aligned encrypted filename size)
676 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
677 * Octet N2-N3: Cipher identifier (1 octet)
678 * Octets N3-N4: Block-aligned encrypted filename
679 * - Consists of a minimum number of random characters, a \0
680 * separator, and then the filename */
681 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
682 + s->block_aligned_filename_size);
683 if (dest == NULL) {
684 (*packet_size) = s->max_packet_size;
685 goto out_unlock;
686 }
687 if (s->max_packet_size > (*remaining_bytes)) {
688 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
689 "[%zd] available\n", __func__, s->max_packet_size,
690 (*remaining_bytes));
691 rc = -EINVAL;
692 goto out_unlock;
693 }
694
695 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
696 if (!s->skcipher_req) {
697 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
698 "skcipher_request_alloc for %s\n", __func__,
699 crypto_skcipher_driver_name(s->skcipher_tfm));
700 rc = -ENOMEM;
701 goto out_unlock;
702 }
703
704 skcipher_request_set_callback(s->skcipher_req,
705 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
706
707 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
708 GFP_KERNEL);
709 if (!s->block_aligned_filename) {
710 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
711 "kzalloc [%zd] bytes\n", __func__,
712 s->block_aligned_filename_size);
713 rc = -ENOMEM;
714 goto out_unlock;
715 }
716 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
717 rc = ecryptfs_write_packet_length(&dest[s->i],
718 (ECRYPTFS_SIG_SIZE
719 + 1 /* Cipher code */
720 + s->block_aligned_filename_size),
721 &s->packet_size_len);
722 if (rc) {
723 printk(KERN_ERR "%s: Error generating tag 70 packet "
724 "header; cannot generate packet length; rc = [%d]\n",
725 __func__, rc);
726 goto out_free_unlock;
727 }
728 s->i += s->packet_size_len;
729 ecryptfs_from_hex(&dest[s->i],
730 mount_crypt_stat->global_default_fnek_sig,
731 ECRYPTFS_SIG_SIZE);
732 s->i += ECRYPTFS_SIG_SIZE;
733 s->cipher_code = ecryptfs_code_for_cipher_string(
734 mount_crypt_stat->global_default_fn_cipher_name,
735 mount_crypt_stat->global_default_fn_cipher_key_bytes);
736 if (s->cipher_code == 0) {
737 printk(KERN_WARNING "%s: Unable to generate code for "
738 "cipher [%s] with key bytes [%zd]\n", __func__,
739 mount_crypt_stat->global_default_fn_cipher_name,
740 mount_crypt_stat->global_default_fn_cipher_key_bytes);
741 rc = -EINVAL;
742 goto out_free_unlock;
743 }
744 dest[s->i++] = s->cipher_code;
745 /* TODO: Support other key modules than passphrase for
746 * filename encryption */
747 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
748 rc = -EOPNOTSUPP;
749 printk(KERN_INFO "%s: Filename encryption only supports "
750 "password tokens\n", __func__);
751 goto out_free_unlock;
752 }
753 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
754 if (IS_ERR(s->hash_tfm)) {
755 rc = PTR_ERR(s->hash_tfm);
756 printk(KERN_ERR "%s: Error attempting to "
757 "allocate hash crypto context; rc = [%d]\n",
758 __func__, rc);
759 goto out_free_unlock;
760 }
761
762 s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
763 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
764 if (!s->hash_desc) {
765 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
766 "kmalloc [%zd] bytes\n", __func__,
767 sizeof(*s->hash_desc) +
768 crypto_shash_descsize(s->hash_tfm));
769 rc = -ENOMEM;
770 goto out_release_free_unlock;
771 }
772
773 s->hash_desc->tfm = s->hash_tfm;
774 s->hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
775
776 rc = crypto_shash_digest(s->hash_desc,
777 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
778 s->auth_tok->token.password.session_key_encryption_key_bytes,
779 s->hash);
780 if (rc) {
781 printk(KERN_ERR
782 "%s: Error computing crypto hash; rc = [%d]\n",
783 __func__, rc);
784 goto out_release_free_unlock;
785 }
786 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
787 s->block_aligned_filename[s->j] =
788 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
789 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
790 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
791 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
792 ECRYPTFS_TAG_70_DIGEST_SIZE,
793 s->tmp_hash);
794 if (rc) {
795 printk(KERN_ERR
796 "%s: Error computing crypto hash; "
797 "rc = [%d]\n", __func__, rc);
798 goto out_release_free_unlock;
799 }
800 memcpy(s->hash, s->tmp_hash,
801 ECRYPTFS_TAG_70_DIGEST_SIZE);
802 }
803 if (s->block_aligned_filename[s->j] == '\0')
804 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
805 }
806 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
807 filename_size);
808 rc = virt_to_scatterlist(s->block_aligned_filename,
809 s->block_aligned_filename_size, s->src_sg, 2);
810 if (rc < 1) {
811 printk(KERN_ERR "%s: Internal error whilst attempting to "
812 "convert filename memory to scatterlist; rc = [%d]. "
813 "block_aligned_filename_size = [%zd]\n", __func__, rc,
814 s->block_aligned_filename_size);
815 goto out_release_free_unlock;
816 }
817 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
818 s->dst_sg, 2);
819 if (rc < 1) {
820 printk(KERN_ERR "%s: Internal error whilst attempting to "
821 "convert encrypted filename memory to scatterlist; "
822 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
823 __func__, rc, s->block_aligned_filename_size);
824 goto out_release_free_unlock;
825 }
826 /* The characters in the first block effectively do the job
827 * of the IV here, so we just use 0's for the IV. Note the
828 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
829 * >= ECRYPTFS_MAX_IV_BYTES. */
830 rc = crypto_skcipher_setkey(
831 s->skcipher_tfm,
832 s->auth_tok->token.password.session_key_encryption_key,
833 mount_crypt_stat->global_default_fn_cipher_key_bytes);
834 if (rc < 0) {
835 printk(KERN_ERR "%s: Error setting key for crypto context; "
836 "rc = [%d]. s->auth_tok->token.password.session_key_"
837 "encryption_key = [0x%p]; mount_crypt_stat->"
838 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
839 rc,
840 s->auth_tok->token.password.session_key_encryption_key,
841 mount_crypt_stat->global_default_fn_cipher_key_bytes);
842 goto out_release_free_unlock;
843 }
844 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
845 s->block_aligned_filename_size, s->iv);
846 rc = crypto_skcipher_encrypt(s->skcipher_req);
847 if (rc) {
848 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
849 "rc = [%d]\n", __func__, rc);
850 goto out_release_free_unlock;
851 }
852 s->i += s->block_aligned_filename_size;
853 (*packet_size) = s->i;
854 (*remaining_bytes) -= (*packet_size);
855out_release_free_unlock:
856 crypto_free_shash(s->hash_tfm);
857out_free_unlock:
858 kzfree(s->block_aligned_filename);
859out_unlock:
860 mutex_unlock(s->tfm_mutex);
861out:
862 if (auth_tok_key) {
863 up_write(&(auth_tok_key->sem));
864 key_put(auth_tok_key);
865 }
866 skcipher_request_free(s->skcipher_req);
867 kzfree(s->hash_desc);
868 kfree(s);
869 return rc;
870}
871
872struct ecryptfs_parse_tag_70_packet_silly_stack {
873 u8 cipher_code;
874 size_t max_packet_size;
875 size_t packet_size_len;
876 size_t parsed_tag_70_packet_size;
877 size_t block_aligned_filename_size;
878 size_t block_size;
879 size_t i;
880 struct mutex *tfm_mutex;
881 char *decrypted_filename;
882 struct ecryptfs_auth_tok *auth_tok;
883 struct scatterlist src_sg[2];
884 struct scatterlist dst_sg[2];
885 struct crypto_skcipher *skcipher_tfm;
886 struct skcipher_request *skcipher_req;
887 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
888 char iv[ECRYPTFS_MAX_IV_BYTES];
889 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
890};
891
892/**
893 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
894 * @filename: This function kmalloc's the memory for the filename
895 * @filename_size: This function sets this to the amount of memory
896 * kmalloc'd for the filename
897 * @packet_size: This function sets this to the the number of octets
898 * in the packet parsed
899 * @mount_crypt_stat: The mount-wide cryptographic context
900 * @data: The memory location containing the start of the tag 70
901 * packet
902 * @max_packet_size: The maximum legal size of the packet to be parsed
903 * from @data
904 *
905 * Returns zero on success; non-zero otherwise
906 */
907int
908ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
909 size_t *packet_size,
910 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
911 char *data, size_t max_packet_size)
912{
913 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
914 struct key *auth_tok_key = NULL;
915 int rc = 0;
916
917 (*packet_size) = 0;
918 (*filename_size) = 0;
919 (*filename) = NULL;
920 s = kzalloc(sizeof(*s), GFP_KERNEL);
921 if (!s) {
922 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
923 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
924 return -ENOMEM;
925 }
926 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
927 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
928 "at least [%d]\n", __func__, max_packet_size,
929 ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
930 rc = -EINVAL;
931 goto out;
932 }
933 /* Octet 0: Tag 70 identifier
934 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
935 * and block-aligned encrypted filename size)
936 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
937 * Octet N2-N3: Cipher identifier (1 octet)
938 * Octets N3-N4: Block-aligned encrypted filename
939 * - Consists of a minimum number of random numbers, a \0
940 * separator, and then the filename */
941 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
942 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
943 "tag [0x%.2x]\n", __func__,
944 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
945 rc = -EINVAL;
946 goto out;
947 }
948 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
949 &s->parsed_tag_70_packet_size,
950 &s->packet_size_len);
951 if (rc) {
952 printk(KERN_WARNING "%s: Error parsing packet length; "
953 "rc = [%d]\n", __func__, rc);
954 goto out;
955 }
956 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
957 - ECRYPTFS_SIG_SIZE - 1);
958 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
959 > max_packet_size) {
960 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
961 "size is [%zd]\n", __func__, max_packet_size,
962 (1 + s->packet_size_len + 1
963 + s->block_aligned_filename_size));
964 rc = -EINVAL;
965 goto out;
966 }
967 (*packet_size) += s->packet_size_len;
968 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
969 ECRYPTFS_SIG_SIZE);
970 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
971 (*packet_size) += ECRYPTFS_SIG_SIZE;
972 s->cipher_code = data[(*packet_size)++];
973 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
974 if (rc) {
975 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
976 __func__, s->cipher_code);
977 goto out;
978 }
979 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
980 &s->auth_tok, mount_crypt_stat,
981 s->fnek_sig_hex);
982 if (rc) {
983 printk(KERN_ERR "%s: Error attempting to find auth tok for "
984 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
985 rc);
986 goto out;
987 }
988 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
989 &s->tfm_mutex,
990 s->cipher_string);
991 if (unlikely(rc)) {
992 printk(KERN_ERR "Internal error whilst attempting to get "
993 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
994 s->cipher_string, rc);
995 goto out;
996 }
997 mutex_lock(s->tfm_mutex);
998 rc = virt_to_scatterlist(&data[(*packet_size)],
999 s->block_aligned_filename_size, s->src_sg, 2);
1000 if (rc < 1) {
1001 printk(KERN_ERR "%s: Internal error whilst attempting to "
1002 "convert encrypted filename memory to scatterlist; "
1003 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1004 __func__, rc, s->block_aligned_filename_size);
1005 goto out_unlock;
1006 }
1007 (*packet_size) += s->block_aligned_filename_size;
1008 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1009 GFP_KERNEL);
1010 if (!s->decrypted_filename) {
1011 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1012 "kmalloc [%zd] bytes\n", __func__,
1013 s->block_aligned_filename_size);
1014 rc = -ENOMEM;
1015 goto out_unlock;
1016 }
1017 rc = virt_to_scatterlist(s->decrypted_filename,
1018 s->block_aligned_filename_size, s->dst_sg, 2);
1019 if (rc < 1) {
1020 printk(KERN_ERR "%s: Internal error whilst attempting to "
1021 "convert decrypted filename memory to scatterlist; "
1022 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1023 __func__, rc, s->block_aligned_filename_size);
1024 goto out_free_unlock;
1025 }
1026
1027 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
1028 if (!s->skcipher_req) {
1029 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1030 "skcipher_request_alloc for %s\n", __func__,
1031 crypto_skcipher_driver_name(s->skcipher_tfm));
1032 rc = -ENOMEM;
1033 goto out_free_unlock;
1034 }
1035
1036 skcipher_request_set_callback(s->skcipher_req,
1037 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
1038
1039 /* The characters in the first block effectively do the job of
1040 * the IV here, so we just use 0's for the IV. Note the
1041 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1042 * >= ECRYPTFS_MAX_IV_BYTES. */
1043 /* TODO: Support other key modules than passphrase for
1044 * filename encryption */
1045 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1046 rc = -EOPNOTSUPP;
1047 printk(KERN_INFO "%s: Filename encryption only supports "
1048 "password tokens\n", __func__);
1049 goto out_free_unlock;
1050 }
1051 rc = crypto_skcipher_setkey(
1052 s->skcipher_tfm,
1053 s->auth_tok->token.password.session_key_encryption_key,
1054 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1055 if (rc < 0) {
1056 printk(KERN_ERR "%s: Error setting key for crypto context; "
1057 "rc = [%d]. s->auth_tok->token.password.session_key_"
1058 "encryption_key = [0x%p]; mount_crypt_stat->"
1059 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1060 rc,
1061 s->auth_tok->token.password.session_key_encryption_key,
1062 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1063 goto out_free_unlock;
1064 }
1065 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
1066 s->block_aligned_filename_size, s->iv);
1067 rc = crypto_skcipher_decrypt(s->skcipher_req);
1068 if (rc) {
1069 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1070 "rc = [%d]\n", __func__, rc);
1071 goto out_free_unlock;
1072 }
1073 while (s->decrypted_filename[s->i] != '\0'
1074 && s->i < s->block_aligned_filename_size)
1075 s->i++;
1076 if (s->i == s->block_aligned_filename_size) {
1077 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1078 "find valid separator between random characters and "
1079 "the filename\n", __func__);
1080 rc = -EINVAL;
1081 goto out_free_unlock;
1082 }
1083 s->i++;
1084 (*filename_size) = (s->block_aligned_filename_size - s->i);
1085 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1086 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1087 "invalid\n", __func__, (*filename_size));
1088 rc = -EINVAL;
1089 goto out_free_unlock;
1090 }
1091 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1092 if (!(*filename)) {
1093 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1094 "kmalloc [%zd] bytes\n", __func__,
1095 ((*filename_size) + 1));
1096 rc = -ENOMEM;
1097 goto out_free_unlock;
1098 }
1099 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1100 (*filename)[(*filename_size)] = '\0';
1101out_free_unlock:
1102 kfree(s->decrypted_filename);
1103out_unlock:
1104 mutex_unlock(s->tfm_mutex);
1105out:
1106 if (rc) {
1107 (*packet_size) = 0;
1108 (*filename_size) = 0;
1109 (*filename) = NULL;
1110 }
1111 if (auth_tok_key) {
1112 up_write(&(auth_tok_key->sem));
1113 key_put(auth_tok_key);
1114 }
1115 skcipher_request_free(s->skcipher_req);
1116 kfree(s);
1117 return rc;
1118}
1119
1120static int
1121ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1122{
1123 int rc = 0;
1124
1125 (*sig) = NULL;
1126 switch (auth_tok->token_type) {
1127 case ECRYPTFS_PASSWORD:
1128 (*sig) = auth_tok->token.password.signature;
1129 break;
1130 case ECRYPTFS_PRIVATE_KEY:
1131 (*sig) = auth_tok->token.private_key.signature;
1132 break;
1133 default:
1134 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1135 auth_tok->token_type);
1136 rc = -EINVAL;
1137 }
1138 return rc;
1139}
1140
1141/**
1142 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1143 * @auth_tok: The key authentication token used to decrypt the session key
1144 * @crypt_stat: The cryptographic context
1145 *
1146 * Returns zero on success; non-zero error otherwise.
1147 */
1148static int
1149decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1150 struct ecryptfs_crypt_stat *crypt_stat)
1151{
1152 u8 cipher_code = 0;
1153 struct ecryptfs_msg_ctx *msg_ctx;
1154 struct ecryptfs_message *msg = NULL;
1155 char *auth_tok_sig;
1156 char *payload = NULL;
1157 size_t payload_len = 0;
1158 int rc;
1159
1160 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1161 if (rc) {
1162 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1163 auth_tok->token_type);
1164 goto out;
1165 }
1166 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1167 &payload, &payload_len);
1168 if (rc) {
1169 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1170 goto out;
1171 }
1172 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1173 if (rc) {
1174 ecryptfs_printk(KERN_ERR, "Error sending message to "
1175 "ecryptfsd: %d\n", rc);
1176 goto out;
1177 }
1178 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1179 if (rc) {
1180 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1181 "from the user space daemon\n");
1182 rc = -EIO;
1183 goto out;
1184 }
1185 rc = parse_tag_65_packet(&(auth_tok->session_key),
1186 &cipher_code, msg);
1187 if (rc) {
1188 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1189 rc);
1190 goto out;
1191 }
1192 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1193 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1194 auth_tok->session_key.decrypted_key_size);
1195 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1196 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1197 if (rc) {
1198 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1199 cipher_code)
1200 goto out;
1201 }
1202 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1203 if (ecryptfs_verbosity > 0) {
1204 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1205 ecryptfs_dump_hex(crypt_stat->key,
1206 crypt_stat->key_size);
1207 }
1208out:
1209 kfree(msg);
1210 kfree(payload);
1211 return rc;
1212}
1213
1214static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1215{
1216 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1217 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1218
1219 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1220 auth_tok_list_head, list) {
1221 list_del(&auth_tok_list_item->list);
1222 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1223 auth_tok_list_item);
1224 }
1225}
1226
1227struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1228
1229/**
1230 * parse_tag_1_packet
1231 * @crypt_stat: The cryptographic context to modify based on packet contents
1232 * @data: The raw bytes of the packet.
1233 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1234 * a new authentication token will be placed at the
1235 * end of this list for this packet.
1236 * @new_auth_tok: Pointer to a pointer to memory that this function
1237 * allocates; sets the memory address of the pointer to
1238 * NULL on error. This object is added to the
1239 * auth_tok_list.
1240 * @packet_size: This function writes the size of the parsed packet
1241 * into this memory location; zero on error.
1242 * @max_packet_size: The maximum allowable packet size
1243 *
1244 * Returns zero on success; non-zero on error.
1245 */
1246static int
1247parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1248 unsigned char *data, struct list_head *auth_tok_list,
1249 struct ecryptfs_auth_tok **new_auth_tok,
1250 size_t *packet_size, size_t max_packet_size)
1251{
1252 size_t body_size;
1253 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1254 size_t length_size;
1255 int rc = 0;
1256
1257 (*packet_size) = 0;
1258 (*new_auth_tok) = NULL;
1259 /**
1260 * This format is inspired by OpenPGP; see RFC 2440
1261 * packet tag 1
1262 *
1263 * Tag 1 identifier (1 byte)
1264 * Max Tag 1 packet size (max 3 bytes)
1265 * Version (1 byte)
1266 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1267 * Cipher identifier (1 byte)
1268 * Encrypted key size (arbitrary)
1269 *
1270 * 12 bytes minimum packet size
1271 */
1272 if (unlikely(max_packet_size < 12)) {
1273 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1274 rc = -EINVAL;
1275 goto out;
1276 }
1277 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1278 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1279 ECRYPTFS_TAG_1_PACKET_TYPE);
1280 rc = -EINVAL;
1281 goto out;
1282 }
1283 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1284 * at end of function upon failure */
1285 auth_tok_list_item =
1286 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1287 GFP_KERNEL);
1288 if (!auth_tok_list_item) {
1289 printk(KERN_ERR "Unable to allocate memory\n");
1290 rc = -ENOMEM;
1291 goto out;
1292 }
1293 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1294 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1295 &length_size);
1296 if (rc) {
1297 printk(KERN_WARNING "Error parsing packet length; "
1298 "rc = [%d]\n", rc);
1299 goto out_free;
1300 }
1301 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1302 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1303 rc = -EINVAL;
1304 goto out_free;
1305 }
1306 (*packet_size) += length_size;
1307 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1308 printk(KERN_WARNING "Packet size exceeds max\n");
1309 rc = -EINVAL;
1310 goto out_free;
1311 }
1312 if (unlikely(data[(*packet_size)++] != 0x03)) {
1313 printk(KERN_WARNING "Unknown version number [%d]\n",
1314 data[(*packet_size) - 1]);
1315 rc = -EINVAL;
1316 goto out_free;
1317 }
1318 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1319 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1320 *packet_size += ECRYPTFS_SIG_SIZE;
1321 /* This byte is skipped because the kernel does not need to
1322 * know which public key encryption algorithm was used */
1323 (*packet_size)++;
1324 (*new_auth_tok)->session_key.encrypted_key_size =
1325 body_size - (ECRYPTFS_SIG_SIZE + 2);
1326 if ((*new_auth_tok)->session_key.encrypted_key_size
1327 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1328 printk(KERN_WARNING "Tag 1 packet contains key larger "
1329 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1330 rc = -EINVAL;
1331 goto out;
1332 }
1333 memcpy((*new_auth_tok)->session_key.encrypted_key,
1334 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1335 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1336 (*new_auth_tok)->session_key.flags &=
1337 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1338 (*new_auth_tok)->session_key.flags |=
1339 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1340 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1341 (*new_auth_tok)->flags = 0;
1342 (*new_auth_tok)->session_key.flags &=
1343 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1344 (*new_auth_tok)->session_key.flags &=
1345 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1346 list_add(&auth_tok_list_item->list, auth_tok_list);
1347 goto out;
1348out_free:
1349 (*new_auth_tok) = NULL;
1350 memset(auth_tok_list_item, 0,
1351 sizeof(struct ecryptfs_auth_tok_list_item));
1352 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1353 auth_tok_list_item);
1354out:
1355 if (rc)
1356 (*packet_size) = 0;
1357 return rc;
1358}
1359
1360/**
1361 * parse_tag_3_packet
1362 * @crypt_stat: The cryptographic context to modify based on packet
1363 * contents.
1364 * @data: The raw bytes of the packet.
1365 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1366 * a new authentication token will be placed at the end
1367 * of this list for this packet.
1368 * @new_auth_tok: Pointer to a pointer to memory that this function
1369 * allocates; sets the memory address of the pointer to
1370 * NULL on error. This object is added to the
1371 * auth_tok_list.
1372 * @packet_size: This function writes the size of the parsed packet
1373 * into this memory location; zero on error.
1374 * @max_packet_size: maximum number of bytes to parse
1375 *
1376 * Returns zero on success; non-zero on error.
1377 */
1378static int
1379parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1380 unsigned char *data, struct list_head *auth_tok_list,
1381 struct ecryptfs_auth_tok **new_auth_tok,
1382 size_t *packet_size, size_t max_packet_size)
1383{
1384 size_t body_size;
1385 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1386 size_t length_size;
1387 int rc = 0;
1388
1389 (*packet_size) = 0;
1390 (*new_auth_tok) = NULL;
1391 /**
1392 *This format is inspired by OpenPGP; see RFC 2440
1393 * packet tag 3
1394 *
1395 * Tag 3 identifier (1 byte)
1396 * Max Tag 3 packet size (max 3 bytes)
1397 * Version (1 byte)
1398 * Cipher code (1 byte)
1399 * S2K specifier (1 byte)
1400 * Hash identifier (1 byte)
1401 * Salt (ECRYPTFS_SALT_SIZE)
1402 * Hash iterations (1 byte)
1403 * Encrypted key (arbitrary)
1404 *
1405 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1406 */
1407 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1408 printk(KERN_ERR "Max packet size too large\n");
1409 rc = -EINVAL;
1410 goto out;
1411 }
1412 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1413 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1414 ECRYPTFS_TAG_3_PACKET_TYPE);
1415 rc = -EINVAL;
1416 goto out;
1417 }
1418 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1419 * at end of function upon failure */
1420 auth_tok_list_item =
1421 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1422 if (!auth_tok_list_item) {
1423 printk(KERN_ERR "Unable to allocate memory\n");
1424 rc = -ENOMEM;
1425 goto out;
1426 }
1427 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1428 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1429 &length_size);
1430 if (rc) {
1431 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1432 rc);
1433 goto out_free;
1434 }
1435 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1436 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1437 rc = -EINVAL;
1438 goto out_free;
1439 }
1440 (*packet_size) += length_size;
1441 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1442 printk(KERN_ERR "Packet size exceeds max\n");
1443 rc = -EINVAL;
1444 goto out_free;
1445 }
1446 (*new_auth_tok)->session_key.encrypted_key_size =
1447 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1448 if ((*new_auth_tok)->session_key.encrypted_key_size
1449 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1450 printk(KERN_WARNING "Tag 3 packet contains key larger "
1451 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1452 rc = -EINVAL;
1453 goto out_free;
1454 }
1455 if (unlikely(data[(*packet_size)++] != 0x04)) {
1456 printk(KERN_WARNING "Unknown version number [%d]\n",
1457 data[(*packet_size) - 1]);
1458 rc = -EINVAL;
1459 goto out_free;
1460 }
1461 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1462 (u16)data[(*packet_size)]);
1463 if (rc)
1464 goto out_free;
1465 /* A little extra work to differentiate among the AES key
1466 * sizes; see RFC2440 */
1467 switch(data[(*packet_size)++]) {
1468 case RFC2440_CIPHER_AES_192:
1469 crypt_stat->key_size = 24;
1470 break;
1471 default:
1472 crypt_stat->key_size =
1473 (*new_auth_tok)->session_key.encrypted_key_size;
1474 }
1475 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1476 if (rc)
1477 goto out_free;
1478 if (unlikely(data[(*packet_size)++] != 0x03)) {
1479 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1480 rc = -ENOSYS;
1481 goto out_free;
1482 }
1483 /* TODO: finish the hash mapping */
1484 switch (data[(*packet_size)++]) {
1485 case 0x01: /* See RFC2440 for these numbers and their mappings */
1486 /* Choose MD5 */
1487 memcpy((*new_auth_tok)->token.password.salt,
1488 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1489 (*packet_size) += ECRYPTFS_SALT_SIZE;
1490 /* This conversion was taken straight from RFC2440 */
1491 (*new_auth_tok)->token.password.hash_iterations =
1492 ((u32) 16 + (data[(*packet_size)] & 15))
1493 << ((data[(*packet_size)] >> 4) + 6);
1494 (*packet_size)++;
1495 /* Friendly reminder:
1496 * (*new_auth_tok)->session_key.encrypted_key_size =
1497 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1498 memcpy((*new_auth_tok)->session_key.encrypted_key,
1499 &data[(*packet_size)],
1500 (*new_auth_tok)->session_key.encrypted_key_size);
1501 (*packet_size) +=
1502 (*new_auth_tok)->session_key.encrypted_key_size;
1503 (*new_auth_tok)->session_key.flags &=
1504 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1505 (*new_auth_tok)->session_key.flags |=
1506 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1507 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1508 break;
1509 default:
1510 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1511 "[%d]\n", data[(*packet_size) - 1]);
1512 rc = -ENOSYS;
1513 goto out_free;
1514 }
1515 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1516 /* TODO: Parametarize; we might actually want userspace to
1517 * decrypt the session key. */
1518 (*new_auth_tok)->session_key.flags &=
1519 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1520 (*new_auth_tok)->session_key.flags &=
1521 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1522 list_add(&auth_tok_list_item->list, auth_tok_list);
1523 goto out;
1524out_free:
1525 (*new_auth_tok) = NULL;
1526 memset(auth_tok_list_item, 0,
1527 sizeof(struct ecryptfs_auth_tok_list_item));
1528 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1529 auth_tok_list_item);
1530out:
1531 if (rc)
1532 (*packet_size) = 0;
1533 return rc;
1534}
1535
1536/**
1537 * parse_tag_11_packet
1538 * @data: The raw bytes of the packet
1539 * @contents: This function writes the data contents of the literal
1540 * packet into this memory location
1541 * @max_contents_bytes: The maximum number of bytes that this function
1542 * is allowed to write into contents
1543 * @tag_11_contents_size: This function writes the size of the parsed
1544 * contents into this memory location; zero on
1545 * error
1546 * @packet_size: This function writes the size of the parsed packet
1547 * into this memory location; zero on error
1548 * @max_packet_size: maximum number of bytes to parse
1549 *
1550 * Returns zero on success; non-zero on error.
1551 */
1552static int
1553parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1554 size_t max_contents_bytes, size_t *tag_11_contents_size,
1555 size_t *packet_size, size_t max_packet_size)
1556{
1557 size_t body_size;
1558 size_t length_size;
1559 int rc = 0;
1560
1561 (*packet_size) = 0;
1562 (*tag_11_contents_size) = 0;
1563 /* This format is inspired by OpenPGP; see RFC 2440
1564 * packet tag 11
1565 *
1566 * Tag 11 identifier (1 byte)
1567 * Max Tag 11 packet size (max 3 bytes)
1568 * Binary format specifier (1 byte)
1569 * Filename length (1 byte)
1570 * Filename ("_CONSOLE") (8 bytes)
1571 * Modification date (4 bytes)
1572 * Literal data (arbitrary)
1573 *
1574 * We need at least 16 bytes of data for the packet to even be
1575 * valid.
1576 */
1577 if (max_packet_size < 16) {
1578 printk(KERN_ERR "Maximum packet size too small\n");
1579 rc = -EINVAL;
1580 goto out;
1581 }
1582 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1583 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1584 rc = -EINVAL;
1585 goto out;
1586 }
1587 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1588 &length_size);
1589 if (rc) {
1590 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1591 goto out;
1592 }
1593 if (body_size < 14) {
1594 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1595 rc = -EINVAL;
1596 goto out;
1597 }
1598 (*packet_size) += length_size;
1599 (*tag_11_contents_size) = (body_size - 14);
1600 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1601 printk(KERN_ERR "Packet size exceeds max\n");
1602 rc = -EINVAL;
1603 goto out;
1604 }
1605 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1606 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1607 "expected size\n");
1608 rc = -EINVAL;
1609 goto out;
1610 }
1611 if (data[(*packet_size)++] != 0x62) {
1612 printk(KERN_WARNING "Unrecognizable packet\n");
1613 rc = -EINVAL;
1614 goto out;
1615 }
1616 if (data[(*packet_size)++] != 0x08) {
1617 printk(KERN_WARNING "Unrecognizable packet\n");
1618 rc = -EINVAL;
1619 goto out;
1620 }
1621 (*packet_size) += 12; /* Ignore filename and modification date */
1622 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1623 (*packet_size) += (*tag_11_contents_size);
1624out:
1625 if (rc) {
1626 (*packet_size) = 0;
1627 (*tag_11_contents_size) = 0;
1628 }
1629 return rc;
1630}
1631
1632int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1633 struct ecryptfs_auth_tok **auth_tok,
1634 char *sig)
1635{
1636 int rc = 0;
1637
1638 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1639 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1640 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1641 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1642 printk(KERN_ERR "Could not find key with description: [%s]\n",
1643 sig);
1644 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1645 (*auth_tok_key) = NULL;
1646 goto out;
1647 }
1648 }
1649 down_write(&(*auth_tok_key)->sem);
1650 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1651 if (rc) {
1652 up_write(&(*auth_tok_key)->sem);
1653 key_put(*auth_tok_key);
1654 (*auth_tok_key) = NULL;
1655 goto out;
1656 }
1657out:
1658 return rc;
1659}
1660
1661/**
1662 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1663 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1664 * @crypt_stat: The cryptographic context
1665 *
1666 * Returns zero on success; non-zero error otherwise
1667 */
1668static int
1669decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1670 struct ecryptfs_crypt_stat *crypt_stat)
1671{
1672 struct scatterlist dst_sg[2];
1673 struct scatterlist src_sg[2];
1674 struct mutex *tfm_mutex;
1675 struct crypto_skcipher *tfm;
1676 struct skcipher_request *req = NULL;
1677 int rc = 0;
1678
1679 if (unlikely(ecryptfs_verbosity > 0)) {
1680 ecryptfs_printk(
1681 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1682 auth_tok->token.password.session_key_encryption_key_bytes);
1683 ecryptfs_dump_hex(
1684 auth_tok->token.password.session_key_encryption_key,
1685 auth_tok->token.password.session_key_encryption_key_bytes);
1686 }
1687 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
1688 crypt_stat->cipher);
1689 if (unlikely(rc)) {
1690 printk(KERN_ERR "Internal error whilst attempting to get "
1691 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1692 crypt_stat->cipher, rc);
1693 goto out;
1694 }
1695 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1696 auth_tok->session_key.encrypted_key_size,
1697 src_sg, 2);
1698 if (rc < 1 || rc > 2) {
1699 printk(KERN_ERR "Internal error whilst attempting to convert "
1700 "auth_tok->session_key.encrypted_key to scatterlist; "
1701 "expected rc = 1; got rc = [%d]. "
1702 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1703 auth_tok->session_key.encrypted_key_size);
1704 goto out;
1705 }
1706 auth_tok->session_key.decrypted_key_size =
1707 auth_tok->session_key.encrypted_key_size;
1708 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1709 auth_tok->session_key.decrypted_key_size,
1710 dst_sg, 2);
1711 if (rc < 1 || rc > 2) {
1712 printk(KERN_ERR "Internal error whilst attempting to convert "
1713 "auth_tok->session_key.decrypted_key to scatterlist; "
1714 "expected rc = 1; got rc = [%d]\n", rc);
1715 goto out;
1716 }
1717 mutex_lock(tfm_mutex);
1718 req = skcipher_request_alloc(tfm, GFP_KERNEL);
1719 if (!req) {
1720 mutex_unlock(tfm_mutex);
1721 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1722 "skcipher_request_alloc for %s\n", __func__,
1723 crypto_skcipher_driver_name(tfm));
1724 rc = -ENOMEM;
1725 goto out;
1726 }
1727
1728 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
1729 NULL, NULL);
1730 rc = crypto_skcipher_setkey(
1731 tfm, auth_tok->token.password.session_key_encryption_key,
1732 crypt_stat->key_size);
1733 if (unlikely(rc < 0)) {
1734 mutex_unlock(tfm_mutex);
1735 printk(KERN_ERR "Error setting key for crypto context\n");
1736 rc = -EINVAL;
1737 goto out;
1738 }
1739 skcipher_request_set_crypt(req, src_sg, dst_sg,
1740 auth_tok->session_key.encrypted_key_size,
1741 NULL);
1742 rc = crypto_skcipher_decrypt(req);
1743 mutex_unlock(tfm_mutex);
1744 if (unlikely(rc)) {
1745 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1746 goto out;
1747 }
1748 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1749 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1750 auth_tok->session_key.decrypted_key_size);
1751 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1752 if (unlikely(ecryptfs_verbosity > 0)) {
1753 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1754 crypt_stat->key_size);
1755 ecryptfs_dump_hex(crypt_stat->key,
1756 crypt_stat->key_size);
1757 }
1758out:
1759 skcipher_request_free(req);
1760 return rc;
1761}
1762
1763/**
1764 * ecryptfs_parse_packet_set
1765 * @crypt_stat: The cryptographic context
1766 * @src: Virtual address of region of memory containing the packets
1767 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1768 *
1769 * Get crypt_stat to have the file's session key if the requisite key
1770 * is available to decrypt the session key.
1771 *
1772 * Returns Zero if a valid authentication token was retrieved and
1773 * processed; negative value for file not encrypted or for error
1774 * conditions.
1775 */
1776int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1777 unsigned char *src,
1778 struct dentry *ecryptfs_dentry)
1779{
1780 size_t i = 0;
1781 size_t found_auth_tok;
1782 size_t next_packet_is_auth_tok_packet;
1783 struct list_head auth_tok_list;
1784 struct ecryptfs_auth_tok *matching_auth_tok;
1785 struct ecryptfs_auth_tok *candidate_auth_tok;
1786 char *candidate_auth_tok_sig;
1787 size_t packet_size;
1788 struct ecryptfs_auth_tok *new_auth_tok;
1789 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1790 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1791 size_t tag_11_contents_size;
1792 size_t tag_11_packet_size;
1793 struct key *auth_tok_key = NULL;
1794 int rc = 0;
1795
1796 INIT_LIST_HEAD(&auth_tok_list);
1797 /* Parse the header to find as many packets as we can; these will be
1798 * added the our &auth_tok_list */
1799 next_packet_is_auth_tok_packet = 1;
1800 while (next_packet_is_auth_tok_packet) {
1801 size_t max_packet_size = ((PAGE_SIZE - 8) - i);
1802
1803 switch (src[i]) {
1804 case ECRYPTFS_TAG_3_PACKET_TYPE:
1805 rc = parse_tag_3_packet(crypt_stat,
1806 (unsigned char *)&src[i],
1807 &auth_tok_list, &new_auth_tok,
1808 &packet_size, max_packet_size);
1809 if (rc) {
1810 ecryptfs_printk(KERN_ERR, "Error parsing "
1811 "tag 3 packet\n");
1812 rc = -EIO;
1813 goto out_wipe_list;
1814 }
1815 i += packet_size;
1816 rc = parse_tag_11_packet((unsigned char *)&src[i],
1817 sig_tmp_space,
1818 ECRYPTFS_SIG_SIZE,
1819 &tag_11_contents_size,
1820 &tag_11_packet_size,
1821 max_packet_size);
1822 if (rc) {
1823 ecryptfs_printk(KERN_ERR, "No valid "
1824 "(ecryptfs-specific) literal "
1825 "packet containing "
1826 "authentication token "
1827 "signature found after "
1828 "tag 3 packet\n");
1829 rc = -EIO;
1830 goto out_wipe_list;
1831 }
1832 i += tag_11_packet_size;
1833 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1834 ecryptfs_printk(KERN_ERR, "Expected "
1835 "signature of size [%d]; "
1836 "read size [%zd]\n",
1837 ECRYPTFS_SIG_SIZE,
1838 tag_11_contents_size);
1839 rc = -EIO;
1840 goto out_wipe_list;
1841 }
1842 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1843 sig_tmp_space, tag_11_contents_size);
1844 new_auth_tok->token.password.signature[
1845 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1846 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1847 break;
1848 case ECRYPTFS_TAG_1_PACKET_TYPE:
1849 rc = parse_tag_1_packet(crypt_stat,
1850 (unsigned char *)&src[i],
1851 &auth_tok_list, &new_auth_tok,
1852 &packet_size, max_packet_size);
1853 if (rc) {
1854 ecryptfs_printk(KERN_ERR, "Error parsing "
1855 "tag 1 packet\n");
1856 rc = -EIO;
1857 goto out_wipe_list;
1858 }
1859 i += packet_size;
1860 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1861 break;
1862 case ECRYPTFS_TAG_11_PACKET_TYPE:
1863 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1864 "(Tag 11 not allowed by itself)\n");
1865 rc = -EIO;
1866 goto out_wipe_list;
1867 default:
1868 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1869 "of the file header; hex value of "
1870 "character is [0x%.2x]\n", i, src[i]);
1871 next_packet_is_auth_tok_packet = 0;
1872 }
1873 }
1874 if (list_empty(&auth_tok_list)) {
1875 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1876 "eCryptfs file; this is not supported in this version "
1877 "of the eCryptfs kernel module\n");
1878 rc = -EINVAL;
1879 goto out;
1880 }
1881 /* auth_tok_list contains the set of authentication tokens
1882 * parsed from the metadata. We need to find a matching
1883 * authentication token that has the secret component(s)
1884 * necessary to decrypt the EFEK in the auth_tok parsed from
1885 * the metadata. There may be several potential matches, but
1886 * just one will be sufficient to decrypt to get the FEK. */
1887find_next_matching_auth_tok:
1888 found_auth_tok = 0;
1889 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1890 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1891 if (unlikely(ecryptfs_verbosity > 0)) {
1892 ecryptfs_printk(KERN_DEBUG,
1893 "Considering cadidate auth tok:\n");
1894 ecryptfs_dump_auth_tok(candidate_auth_tok);
1895 }
1896 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1897 candidate_auth_tok);
1898 if (rc) {
1899 printk(KERN_ERR
1900 "Unrecognized candidate auth tok type: [%d]\n",
1901 candidate_auth_tok->token_type);
1902 rc = -EINVAL;
1903 goto out_wipe_list;
1904 }
1905 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1906 &matching_auth_tok,
1907 crypt_stat->mount_crypt_stat,
1908 candidate_auth_tok_sig);
1909 if (!rc) {
1910 found_auth_tok = 1;
1911 goto found_matching_auth_tok;
1912 }
1913 }
1914 if (!found_auth_tok) {
1915 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1916 "authentication token\n");
1917 rc = -EIO;
1918 goto out_wipe_list;
1919 }
1920found_matching_auth_tok:
1921 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1922 memcpy(&(candidate_auth_tok->token.private_key),
1923 &(matching_auth_tok->token.private_key),
1924 sizeof(struct ecryptfs_private_key));
1925 up_write(&(auth_tok_key->sem));
1926 key_put(auth_tok_key);
1927 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1928 crypt_stat);
1929 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1930 memcpy(&(candidate_auth_tok->token.password),
1931 &(matching_auth_tok->token.password),
1932 sizeof(struct ecryptfs_password));
1933 up_write(&(auth_tok_key->sem));
1934 key_put(auth_tok_key);
1935 rc = decrypt_passphrase_encrypted_session_key(
1936 candidate_auth_tok, crypt_stat);
1937 } else {
1938 up_write(&(auth_tok_key->sem));
1939 key_put(auth_tok_key);
1940 rc = -EINVAL;
1941 }
1942 if (rc) {
1943 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1944
1945 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1946 "session key for authentication token with sig "
1947 "[%.*s]; rc = [%d]. Removing auth tok "
1948 "candidate from the list and searching for "
1949 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1950 candidate_auth_tok_sig, rc);
1951 list_for_each_entry_safe(auth_tok_list_item,
1952 auth_tok_list_item_tmp,
1953 &auth_tok_list, list) {
1954 if (candidate_auth_tok
1955 == &auth_tok_list_item->auth_tok) {
1956 list_del(&auth_tok_list_item->list);
1957 kmem_cache_free(
1958 ecryptfs_auth_tok_list_item_cache,
1959 auth_tok_list_item);
1960 goto find_next_matching_auth_tok;
1961 }
1962 }
1963 BUG();
1964 }
1965 rc = ecryptfs_compute_root_iv(crypt_stat);
1966 if (rc) {
1967 ecryptfs_printk(KERN_ERR, "Error computing "
1968 "the root IV\n");
1969 goto out_wipe_list;
1970 }
1971 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1972 if (rc) {
1973 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1974 "context for cipher [%s]; rc = [%d]\n",
1975 crypt_stat->cipher, rc);
1976 }
1977out_wipe_list:
1978 wipe_auth_tok_list(&auth_tok_list);
1979out:
1980 return rc;
1981}
1982
1983static int
1984pki_encrypt_session_key(struct key *auth_tok_key,
1985 struct ecryptfs_auth_tok *auth_tok,
1986 struct ecryptfs_crypt_stat *crypt_stat,
1987 struct ecryptfs_key_record *key_rec)
1988{
1989 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1990 char *payload = NULL;
1991 size_t payload_len = 0;
1992 struct ecryptfs_message *msg;
1993 int rc;
1994
1995 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1996 ecryptfs_code_for_cipher_string(
1997 crypt_stat->cipher,
1998 crypt_stat->key_size),
1999 crypt_stat, &payload, &payload_len);
2000 up_write(&(auth_tok_key->sem));
2001 key_put(auth_tok_key);
2002 if (rc) {
2003 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
2004 goto out;
2005 }
2006 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
2007 if (rc) {
2008 ecryptfs_printk(KERN_ERR, "Error sending message to "
2009 "ecryptfsd: %d\n", rc);
2010 goto out;
2011 }
2012 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
2013 if (rc) {
2014 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2015 "from the user space daemon\n");
2016 rc = -EIO;
2017 goto out;
2018 }
2019 rc = parse_tag_67_packet(key_rec, msg);
2020 if (rc)
2021 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2022 kfree(msg);
2023out:
2024 kfree(payload);
2025 return rc;
2026}
2027/**
2028 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2029 * @dest: Buffer into which to write the packet
2030 * @remaining_bytes: Maximum number of bytes that can be writtn
2031 * @auth_tok_key: The authentication token key to unlock and put when done with
2032 * @auth_tok
2033 * @auth_tok: The authentication token used for generating the tag 1 packet
2034 * @crypt_stat: The cryptographic context
2035 * @key_rec: The key record struct for the tag 1 packet
2036 * @packet_size: This function will write the number of bytes that end
2037 * up constituting the packet; set to zero on error
2038 *
2039 * Returns zero on success; non-zero on error.
2040 */
2041static int
2042write_tag_1_packet(char *dest, size_t *remaining_bytes,
2043 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2044 struct ecryptfs_crypt_stat *crypt_stat,
2045 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2046{
2047 size_t i;
2048 size_t encrypted_session_key_valid = 0;
2049 size_t packet_size_length;
2050 size_t max_packet_size;
2051 int rc = 0;
2052
2053 (*packet_size) = 0;
2054 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2055 ECRYPTFS_SIG_SIZE);
2056 encrypted_session_key_valid = 0;
2057 for (i = 0; i < crypt_stat->key_size; i++)
2058 encrypted_session_key_valid |=
2059 auth_tok->session_key.encrypted_key[i];
2060 if (encrypted_session_key_valid) {
2061 memcpy(key_rec->enc_key,
2062 auth_tok->session_key.encrypted_key,
2063 auth_tok->session_key.encrypted_key_size);
2064 up_write(&(auth_tok_key->sem));
2065 key_put(auth_tok_key);
2066 goto encrypted_session_key_set;
2067 }
2068 if (auth_tok->session_key.encrypted_key_size == 0)
2069 auth_tok->session_key.encrypted_key_size =
2070 auth_tok->token.private_key.key_size;
2071 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2072 key_rec);
2073 if (rc) {
2074 printk(KERN_ERR "Failed to encrypt session key via a key "
2075 "module; rc = [%d]\n", rc);
2076 goto out;
2077 }
2078 if (ecryptfs_verbosity > 0) {
2079 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2080 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2081 }
2082encrypted_session_key_set:
2083 /* This format is inspired by OpenPGP; see RFC 2440
2084 * packet tag 1 */
2085 max_packet_size = (1 /* Tag 1 identifier */
2086 + 3 /* Max Tag 1 packet size */
2087 + 1 /* Version */
2088 + ECRYPTFS_SIG_SIZE /* Key identifier */
2089 + 1 /* Cipher identifier */
2090 + key_rec->enc_key_size); /* Encrypted key size */
2091 if (max_packet_size > (*remaining_bytes)) {
2092 printk(KERN_ERR "Packet length larger than maximum allowable; "
2093 "need up to [%td] bytes, but there are only [%td] "
2094 "available\n", max_packet_size, (*remaining_bytes));
2095 rc = -EINVAL;
2096 goto out;
2097 }
2098 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2099 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2100 (max_packet_size - 4),
2101 &packet_size_length);
2102 if (rc) {
2103 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2104 "header; cannot generate packet length\n");
2105 goto out;
2106 }
2107 (*packet_size) += packet_size_length;
2108 dest[(*packet_size)++] = 0x03; /* version 3 */
2109 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2110 (*packet_size) += ECRYPTFS_SIG_SIZE;
2111 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2112 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2113 key_rec->enc_key_size);
2114 (*packet_size) += key_rec->enc_key_size;
2115out:
2116 if (rc)
2117 (*packet_size) = 0;
2118 else
2119 (*remaining_bytes) -= (*packet_size);
2120 return rc;
2121}
2122
2123/**
2124 * write_tag_11_packet
2125 * @dest: Target into which Tag 11 packet is to be written
2126 * @remaining_bytes: Maximum packet length
2127 * @contents: Byte array of contents to copy in
2128 * @contents_length: Number of bytes in contents
2129 * @packet_length: Length of the Tag 11 packet written; zero on error
2130 *
2131 * Returns zero on success; non-zero on error.
2132 */
2133static int
2134write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2135 size_t contents_length, size_t *packet_length)
2136{
2137 size_t packet_size_length;
2138 size_t max_packet_size;
2139 int rc = 0;
2140
2141 (*packet_length) = 0;
2142 /* This format is inspired by OpenPGP; see RFC 2440
2143 * packet tag 11 */
2144 max_packet_size = (1 /* Tag 11 identifier */
2145 + 3 /* Max Tag 11 packet size */
2146 + 1 /* Binary format specifier */
2147 + 1 /* Filename length */
2148 + 8 /* Filename ("_CONSOLE") */
2149 + 4 /* Modification date */
2150 + contents_length); /* Literal data */
2151 if (max_packet_size > (*remaining_bytes)) {
2152 printk(KERN_ERR "Packet length larger than maximum allowable; "
2153 "need up to [%td] bytes, but there are only [%td] "
2154 "available\n", max_packet_size, (*remaining_bytes));
2155 rc = -EINVAL;
2156 goto out;
2157 }
2158 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2159 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2160 (max_packet_size - 4),
2161 &packet_size_length);
2162 if (rc) {
2163 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2164 "generate packet length. rc = [%d]\n", rc);
2165 goto out;
2166 }
2167 (*packet_length) += packet_size_length;
2168 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2169 dest[(*packet_length)++] = 8;
2170 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2171 (*packet_length) += 8;
2172 memset(&dest[(*packet_length)], 0x00, 4);
2173 (*packet_length) += 4;
2174 memcpy(&dest[(*packet_length)], contents, contents_length);
2175 (*packet_length) += contents_length;
2176 out:
2177 if (rc)
2178 (*packet_length) = 0;
2179 else
2180 (*remaining_bytes) -= (*packet_length);
2181 return rc;
2182}
2183
2184/**
2185 * write_tag_3_packet
2186 * @dest: Buffer into which to write the packet
2187 * @remaining_bytes: Maximum number of bytes that can be written
2188 * @auth_tok: Authentication token
2189 * @crypt_stat: The cryptographic context
2190 * @key_rec: encrypted key
2191 * @packet_size: This function will write the number of bytes that end
2192 * up constituting the packet; set to zero on error
2193 *
2194 * Returns zero on success; non-zero on error.
2195 */
2196static int
2197write_tag_3_packet(char *dest, size_t *remaining_bytes,
2198 struct ecryptfs_auth_tok *auth_tok,
2199 struct ecryptfs_crypt_stat *crypt_stat,
2200 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2201{
2202 size_t i;
2203 size_t encrypted_session_key_valid = 0;
2204 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2205 struct scatterlist dst_sg[2];
2206 struct scatterlist src_sg[2];
2207 struct mutex *tfm_mutex = NULL;
2208 u8 cipher_code;
2209 size_t packet_size_length;
2210 size_t max_packet_size;
2211 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2212 crypt_stat->mount_crypt_stat;
2213 struct crypto_skcipher *tfm;
2214 struct skcipher_request *req;
2215 int rc = 0;
2216
2217 (*packet_size) = 0;
2218 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2219 ECRYPTFS_SIG_SIZE);
2220 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
2221 crypt_stat->cipher);
2222 if (unlikely(rc)) {
2223 printk(KERN_ERR "Internal error whilst attempting to get "
2224 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2225 crypt_stat->cipher, rc);
2226 goto out;
2227 }
2228 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2229 printk(KERN_WARNING "No key size specified at mount; "
2230 "defaulting to [%d]\n",
2231 crypto_skcipher_default_keysize(tfm));
2232 mount_crypt_stat->global_default_cipher_key_size =
2233 crypto_skcipher_default_keysize(tfm);
2234 }
2235 if (crypt_stat->key_size == 0)
2236 crypt_stat->key_size =
2237 mount_crypt_stat->global_default_cipher_key_size;
2238 if (auth_tok->session_key.encrypted_key_size == 0)
2239 auth_tok->session_key.encrypted_key_size =
2240 crypt_stat->key_size;
2241 if (crypt_stat->key_size == 24
2242 && strcmp("aes", crypt_stat->cipher) == 0) {
2243 memset((crypt_stat->key + 24), 0, 8);
2244 auth_tok->session_key.encrypted_key_size = 32;
2245 } else
2246 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2247 key_rec->enc_key_size =
2248 auth_tok->session_key.encrypted_key_size;
2249 encrypted_session_key_valid = 0;
2250 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2251 encrypted_session_key_valid |=
2252 auth_tok->session_key.encrypted_key[i];
2253 if (encrypted_session_key_valid) {
2254 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2255 "using auth_tok->session_key.encrypted_key, "
2256 "where key_rec->enc_key_size = [%zd]\n",
2257 key_rec->enc_key_size);
2258 memcpy(key_rec->enc_key,
2259 auth_tok->session_key.encrypted_key,
2260 key_rec->enc_key_size);
2261 goto encrypted_session_key_set;
2262 }
2263 if (auth_tok->token.password.flags &
2264 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2265 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2266 "session key encryption key of size [%d]\n",
2267 auth_tok->token.password.
2268 session_key_encryption_key_bytes);
2269 memcpy(session_key_encryption_key,
2270 auth_tok->token.password.session_key_encryption_key,
2271 crypt_stat->key_size);
2272 ecryptfs_printk(KERN_DEBUG,
2273 "Cached session key encryption key:\n");
2274 if (ecryptfs_verbosity > 0)
2275 ecryptfs_dump_hex(session_key_encryption_key, 16);
2276 }
2277 if (unlikely(ecryptfs_verbosity > 0)) {
2278 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2279 ecryptfs_dump_hex(session_key_encryption_key, 16);
2280 }
2281 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2282 src_sg, 2);
2283 if (rc < 1 || rc > 2) {
2284 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2285 "for crypt_stat session key; expected rc = 1; "
2286 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2287 rc, key_rec->enc_key_size);
2288 rc = -ENOMEM;
2289 goto out;
2290 }
2291 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2292 dst_sg, 2);
2293 if (rc < 1 || rc > 2) {
2294 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2295 "for crypt_stat encrypted session key; "
2296 "expected rc = 1; got rc = [%d]. "
2297 "key_rec->enc_key_size = [%zd]\n", rc,
2298 key_rec->enc_key_size);
2299 rc = -ENOMEM;
2300 goto out;
2301 }
2302 mutex_lock(tfm_mutex);
2303 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
2304 crypt_stat->key_size);
2305 if (rc < 0) {
2306 mutex_unlock(tfm_mutex);
2307 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2308 "context; rc = [%d]\n", rc);
2309 goto out;
2310 }
2311
2312 req = skcipher_request_alloc(tfm, GFP_KERNEL);
2313 if (!req) {
2314 mutex_unlock(tfm_mutex);
2315 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
2316 "attempting to skcipher_request_alloc for "
2317 "%s\n", crypto_skcipher_driver_name(tfm));
2318 rc = -ENOMEM;
2319 goto out;
2320 }
2321
2322 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
2323 NULL, NULL);
2324
2325 rc = 0;
2326 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2327 crypt_stat->key_size);
2328 skcipher_request_set_crypt(req, src_sg, dst_sg,
2329 (*key_rec).enc_key_size, NULL);
2330 rc = crypto_skcipher_encrypt(req);
2331 mutex_unlock(tfm_mutex);
2332 skcipher_request_free(req);
2333 if (rc) {
2334 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2335 goto out;
2336 }
2337 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2338 if (ecryptfs_verbosity > 0) {
2339 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2340 key_rec->enc_key_size);
2341 ecryptfs_dump_hex(key_rec->enc_key,
2342 key_rec->enc_key_size);
2343 }
2344encrypted_session_key_set:
2345 /* This format is inspired by OpenPGP; see RFC 2440
2346 * packet tag 3 */
2347 max_packet_size = (1 /* Tag 3 identifier */
2348 + 3 /* Max Tag 3 packet size */
2349 + 1 /* Version */
2350 + 1 /* Cipher code */
2351 + 1 /* S2K specifier */
2352 + 1 /* Hash identifier */
2353 + ECRYPTFS_SALT_SIZE /* Salt */
2354 + 1 /* Hash iterations */
2355 + key_rec->enc_key_size); /* Encrypted key size */
2356 if (max_packet_size > (*remaining_bytes)) {
2357 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2358 "there are only [%td] available\n", max_packet_size,
2359 (*remaining_bytes));
2360 rc = -EINVAL;
2361 goto out;
2362 }
2363 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2364 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2365 * to get the number of octets in the actual Tag 3 packet */
2366 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2367 (max_packet_size - 4),
2368 &packet_size_length);
2369 if (rc) {
2370 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2371 "generate packet length. rc = [%d]\n", rc);
2372 goto out;
2373 }
2374 (*packet_size) += packet_size_length;
2375 dest[(*packet_size)++] = 0x04; /* version 4 */
2376 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2377 * specified with strings */
2378 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2379 crypt_stat->key_size);
2380 if (cipher_code == 0) {
2381 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2382 "cipher [%s]\n", crypt_stat->cipher);
2383 rc = -EINVAL;
2384 goto out;
2385 }
2386 dest[(*packet_size)++] = cipher_code;
2387 dest[(*packet_size)++] = 0x03; /* S2K */
2388 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2389 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2390 ECRYPTFS_SALT_SIZE);
2391 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2392 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2393 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2394 key_rec->enc_key_size);
2395 (*packet_size) += key_rec->enc_key_size;
2396out:
2397 if (rc)
2398 (*packet_size) = 0;
2399 else
2400 (*remaining_bytes) -= (*packet_size);
2401 return rc;
2402}
2403
2404struct kmem_cache *ecryptfs_key_record_cache;
2405
2406/**
2407 * ecryptfs_generate_key_packet_set
2408 * @dest_base: Virtual address from which to write the key record set
2409 * @crypt_stat: The cryptographic context from which the
2410 * authentication tokens will be retrieved
2411 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2412 * for the global parameters
2413 * @len: The amount written
2414 * @max: The maximum amount of data allowed to be written
2415 *
2416 * Generates a key packet set and writes it to the virtual address
2417 * passed in.
2418 *
2419 * Returns zero on success; non-zero on error.
2420 */
2421int
2422ecryptfs_generate_key_packet_set(char *dest_base,
2423 struct ecryptfs_crypt_stat *crypt_stat,
2424 struct dentry *ecryptfs_dentry, size_t *len,
2425 size_t max)
2426{
2427 struct ecryptfs_auth_tok *auth_tok;
2428 struct key *auth_tok_key = NULL;
2429 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2430 &ecryptfs_superblock_to_private(
2431 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2432 size_t written;
2433 struct ecryptfs_key_record *key_rec;
2434 struct ecryptfs_key_sig *key_sig;
2435 int rc = 0;
2436
2437 (*len) = 0;
2438 mutex_lock(&crypt_stat->keysig_list_mutex);
2439 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2440 if (!key_rec) {
2441 rc = -ENOMEM;
2442 goto out;
2443 }
2444 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2445 crypt_stat_list) {
2446 memset(key_rec, 0, sizeof(*key_rec));
2447 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2448 &auth_tok,
2449 mount_crypt_stat,
2450 key_sig->keysig);
2451 if (rc) {
2452 printk(KERN_WARNING "Unable to retrieve auth tok with "
2453 "sig = [%s]\n", key_sig->keysig);
2454 rc = process_find_global_auth_tok_for_sig_err(rc);
2455 goto out_free;
2456 }
2457 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2458 rc = write_tag_3_packet((dest_base + (*len)),
2459 &max, auth_tok,
2460 crypt_stat, key_rec,
2461 &written);
2462 up_write(&(auth_tok_key->sem));
2463 key_put(auth_tok_key);
2464 if (rc) {
2465 ecryptfs_printk(KERN_WARNING, "Error "
2466 "writing tag 3 packet\n");
2467 goto out_free;
2468 }
2469 (*len) += written;
2470 /* Write auth tok signature packet */
2471 rc = write_tag_11_packet((dest_base + (*len)), &max,
2472 key_rec->sig,
2473 ECRYPTFS_SIG_SIZE, &written);
2474 if (rc) {
2475 ecryptfs_printk(KERN_ERR, "Error writing "
2476 "auth tok signature packet\n");
2477 goto out_free;
2478 }
2479 (*len) += written;
2480 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2481 rc = write_tag_1_packet(dest_base + (*len), &max,
2482 auth_tok_key, auth_tok,
2483 crypt_stat, key_rec, &written);
2484 if (rc) {
2485 ecryptfs_printk(KERN_WARNING, "Error "
2486 "writing tag 1 packet\n");
2487 goto out_free;
2488 }
2489 (*len) += written;
2490 } else {
2491 up_write(&(auth_tok_key->sem));
2492 key_put(auth_tok_key);
2493 ecryptfs_printk(KERN_WARNING, "Unsupported "
2494 "authentication token type\n");
2495 rc = -EINVAL;
2496 goto out_free;
2497 }
2498 }
2499 if (likely(max > 0)) {
2500 dest_base[(*len)] = 0x00;
2501 } else {
2502 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2503 rc = -EIO;
2504 }
2505out_free:
2506 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2507out:
2508 if (rc)
2509 (*len) = 0;
2510 mutex_unlock(&crypt_stat->keysig_list_mutex);
2511 return rc;
2512}
2513
2514struct kmem_cache *ecryptfs_key_sig_cache;
2515
2516int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2517{
2518 struct ecryptfs_key_sig *new_key_sig;
2519
2520 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2521 if (!new_key_sig) {
2522 printk(KERN_ERR
2523 "Error allocating from ecryptfs_key_sig_cache\n");
2524 return -ENOMEM;
2525 }
2526 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2527 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2528 /* Caller must hold keysig_list_mutex */
2529 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2530
2531 return 0;
2532}
2533
2534struct kmem_cache *ecryptfs_global_auth_tok_cache;
2535
2536int
2537ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2538 char *sig, u32 global_auth_tok_flags)
2539{
2540 struct ecryptfs_global_auth_tok *new_auth_tok;
2541 int rc = 0;
2542
2543 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2544 GFP_KERNEL);
2545 if (!new_auth_tok) {
2546 rc = -ENOMEM;
2547 printk(KERN_ERR "Error allocating from "
2548 "ecryptfs_global_auth_tok_cache\n");
2549 goto out;
2550 }
2551 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2552 new_auth_tok->flags = global_auth_tok_flags;
2553 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2554 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2555 list_add(&new_auth_tok->mount_crypt_stat_list,
2556 &mount_crypt_stat->global_auth_tok_list);
2557 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2558out:
2559 return rc;
2560}
2561
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * eCryptfs: Linux filesystem encryption layer
4 * In-kernel key management code. Includes functions to parse and
5 * write authentication token-related packets with the underlying
6 * file.
7 *
8 * Copyright (C) 2004-2006 International Business Machines Corp.
9 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
10 * Michael C. Thompson <mcthomps@us.ibm.com>
11 * Trevor S. Highland <trevor.highland@gmail.com>
12 */
13
14#include <crypto/hash.h>
15#include <crypto/skcipher.h>
16#include <linux/string.h>
17#include <linux/pagemap.h>
18#include <linux/key.h>
19#include <linux/random.h>
20#include <linux/scatterlist.h>
21#include <linux/slab.h>
22#include "ecryptfs_kernel.h"
23
24/*
25 * request_key returned an error instead of a valid key address;
26 * determine the type of error, make appropriate log entries, and
27 * return an error code.
28 */
29static int process_request_key_err(long err_code)
30{
31 int rc = 0;
32
33 switch (err_code) {
34 case -ENOKEY:
35 ecryptfs_printk(KERN_WARNING, "No key\n");
36 rc = -ENOENT;
37 break;
38 case -EKEYEXPIRED:
39 ecryptfs_printk(KERN_WARNING, "Key expired\n");
40 rc = -ETIME;
41 break;
42 case -EKEYREVOKED:
43 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
44 rc = -EINVAL;
45 break;
46 default:
47 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
48 "[0x%.16lx]\n", err_code);
49 rc = -EINVAL;
50 }
51 return rc;
52}
53
54static int process_find_global_auth_tok_for_sig_err(int err_code)
55{
56 int rc = err_code;
57
58 switch (err_code) {
59 case -ENOENT:
60 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
61 break;
62 case -EINVAL:
63 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
64 break;
65 default:
66 rc = process_request_key_err(err_code);
67 break;
68 }
69 return rc;
70}
71
72/**
73 * ecryptfs_parse_packet_length
74 * @data: Pointer to memory containing length at offset
75 * @size: This function writes the decoded size to this memory
76 * address; zero on error
77 * @length_size: The number of bytes occupied by the encoded length
78 *
79 * Returns zero on success; non-zero on error
80 */
81int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
82 size_t *length_size)
83{
84 int rc = 0;
85
86 (*length_size) = 0;
87 (*size) = 0;
88 if (data[0] < 192) {
89 /* One-byte length */
90 (*size) = data[0];
91 (*length_size) = 1;
92 } else if (data[0] < 224) {
93 /* Two-byte length */
94 (*size) = (data[0] - 192) * 256;
95 (*size) += data[1] + 192;
96 (*length_size) = 2;
97 } else if (data[0] == 255) {
98 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
99 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
100 "supported\n");
101 rc = -EINVAL;
102 goto out;
103 } else {
104 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
105 rc = -EINVAL;
106 goto out;
107 }
108out:
109 return rc;
110}
111
112/**
113 * ecryptfs_write_packet_length
114 * @dest: The byte array target into which to write the length. Must
115 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
116 * @size: The length to write.
117 * @packet_size_length: The number of bytes used to encode the packet
118 * length is written to this address.
119 *
120 * Returns zero on success; non-zero on error.
121 */
122int ecryptfs_write_packet_length(char *dest, size_t size,
123 size_t *packet_size_length)
124{
125 int rc = 0;
126
127 if (size < 192) {
128 dest[0] = size;
129 (*packet_size_length) = 1;
130 } else if (size < 65536) {
131 dest[0] = (((size - 192) / 256) + 192);
132 dest[1] = ((size - 192) % 256);
133 (*packet_size_length) = 2;
134 } else {
135 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
136 rc = -EINVAL;
137 ecryptfs_printk(KERN_WARNING,
138 "Unsupported packet size: [%zd]\n", size);
139 }
140 return rc;
141}
142
143static int
144write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
145 char **packet, size_t *packet_len)
146{
147 size_t i = 0;
148 size_t data_len;
149 size_t packet_size_len;
150 char *message;
151 int rc;
152
153 /*
154 * ***** TAG 64 Packet Format *****
155 * | Content Type | 1 byte |
156 * | Key Identifier Size | 1 or 2 bytes |
157 * | Key Identifier | arbitrary |
158 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
159 * | Encrypted File Encryption Key | arbitrary |
160 */
161 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
162 + session_key->encrypted_key_size);
163 *packet = kmalloc(data_len, GFP_KERNEL);
164 message = *packet;
165 if (!message) {
166 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
167 rc = -ENOMEM;
168 goto out;
169 }
170 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
171 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
172 &packet_size_len);
173 if (rc) {
174 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
175 "header; cannot generate packet length\n");
176 goto out;
177 }
178 i += packet_size_len;
179 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
180 i += ECRYPTFS_SIG_SIZE_HEX;
181 rc = ecryptfs_write_packet_length(&message[i],
182 session_key->encrypted_key_size,
183 &packet_size_len);
184 if (rc) {
185 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
186 "header; cannot generate packet length\n");
187 goto out;
188 }
189 i += packet_size_len;
190 memcpy(&message[i], session_key->encrypted_key,
191 session_key->encrypted_key_size);
192 i += session_key->encrypted_key_size;
193 *packet_len = i;
194out:
195 return rc;
196}
197
198static int
199parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
200 struct ecryptfs_message *msg)
201{
202 size_t i = 0;
203 char *data;
204 size_t data_len;
205 size_t m_size;
206 size_t message_len;
207 u16 checksum = 0;
208 u16 expected_checksum = 0;
209 int rc;
210
211 /*
212 * ***** TAG 65 Packet Format *****
213 * | Content Type | 1 byte |
214 * | Status Indicator | 1 byte |
215 * | File Encryption Key Size | 1 or 2 bytes |
216 * | File Encryption Key | arbitrary |
217 */
218 message_len = msg->data_len;
219 data = msg->data;
220 if (message_len < 4) {
221 rc = -EIO;
222 goto out;
223 }
224 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
225 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
226 rc = -EIO;
227 goto out;
228 }
229 if (data[i++]) {
230 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
231 "[%d]\n", data[i-1]);
232 rc = -EIO;
233 goto out;
234 }
235 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
236 if (rc) {
237 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
238 "rc = [%d]\n", rc);
239 goto out;
240 }
241 i += data_len;
242 if (message_len < (i + m_size)) {
243 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
244 "is shorter than expected\n");
245 rc = -EIO;
246 goto out;
247 }
248 if (m_size < 3) {
249 ecryptfs_printk(KERN_ERR,
250 "The decrypted key is not long enough to "
251 "include a cipher code and checksum\n");
252 rc = -EIO;
253 goto out;
254 }
255 *cipher_code = data[i++];
256 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
257 session_key->decrypted_key_size = m_size - 3;
258 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
259 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
260 "the maximum key size [%d]\n",
261 session_key->decrypted_key_size,
262 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
263 rc = -EIO;
264 goto out;
265 }
266 memcpy(session_key->decrypted_key, &data[i],
267 session_key->decrypted_key_size);
268 i += session_key->decrypted_key_size;
269 expected_checksum += (unsigned char)(data[i++]) << 8;
270 expected_checksum += (unsigned char)(data[i++]);
271 for (i = 0; i < session_key->decrypted_key_size; i++)
272 checksum += session_key->decrypted_key[i];
273 if (expected_checksum != checksum) {
274 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
275 "encryption key; expected [%x]; calculated "
276 "[%x]\n", expected_checksum, checksum);
277 rc = -EIO;
278 }
279out:
280 return rc;
281}
282
283
284static int
285write_tag_66_packet(char *signature, u8 cipher_code,
286 struct ecryptfs_crypt_stat *crypt_stat, char **packet,
287 size_t *packet_len)
288{
289 size_t i = 0;
290 size_t j;
291 size_t data_len;
292 size_t checksum = 0;
293 size_t packet_size_len;
294 char *message;
295 int rc;
296
297 /*
298 * ***** TAG 66 Packet Format *****
299 * | Content Type | 1 byte |
300 * | Key Identifier Size | 1 or 2 bytes |
301 * | Key Identifier | arbitrary |
302 * | File Encryption Key Size | 1 or 2 bytes |
303 * | File Encryption Key | arbitrary |
304 */
305 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
306 *packet = kmalloc(data_len, GFP_KERNEL);
307 message = *packet;
308 if (!message) {
309 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
310 rc = -ENOMEM;
311 goto out;
312 }
313 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
314 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
315 &packet_size_len);
316 if (rc) {
317 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
318 "header; cannot generate packet length\n");
319 goto out;
320 }
321 i += packet_size_len;
322 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
323 i += ECRYPTFS_SIG_SIZE_HEX;
324 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
325 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
326 &packet_size_len);
327 if (rc) {
328 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
329 "header; cannot generate packet length\n");
330 goto out;
331 }
332 i += packet_size_len;
333 message[i++] = cipher_code;
334 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
335 i += crypt_stat->key_size;
336 for (j = 0; j < crypt_stat->key_size; j++)
337 checksum += crypt_stat->key[j];
338 message[i++] = (checksum / 256) % 256;
339 message[i++] = (checksum % 256);
340 *packet_len = i;
341out:
342 return rc;
343}
344
345static int
346parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
347 struct ecryptfs_message *msg)
348{
349 size_t i = 0;
350 char *data;
351 size_t data_len;
352 size_t message_len;
353 int rc;
354
355 /*
356 * ***** TAG 65 Packet Format *****
357 * | Content Type | 1 byte |
358 * | Status Indicator | 1 byte |
359 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
360 * | Encrypted File Encryption Key | arbitrary |
361 */
362 message_len = msg->data_len;
363 data = msg->data;
364 /* verify that everything through the encrypted FEK size is present */
365 if (message_len < 4) {
366 rc = -EIO;
367 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
368 "message length is [%d]\n", __func__, message_len, 4);
369 goto out;
370 }
371 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
372 rc = -EIO;
373 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
374 __func__);
375 goto out;
376 }
377 if (data[i++]) {
378 rc = -EIO;
379 printk(KERN_ERR "%s: Status indicator has non zero "
380 "value [%d]\n", __func__, data[i-1]);
381
382 goto out;
383 }
384 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
385 &data_len);
386 if (rc) {
387 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
388 "rc = [%d]\n", rc);
389 goto out;
390 }
391 i += data_len;
392 if (message_len < (i + key_rec->enc_key_size)) {
393 rc = -EIO;
394 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
395 __func__, message_len, (i + key_rec->enc_key_size));
396 goto out;
397 }
398 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
399 rc = -EIO;
400 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
401 "the maximum key size [%d]\n", __func__,
402 key_rec->enc_key_size,
403 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
404 goto out;
405 }
406 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
407out:
408 return rc;
409}
410
411/**
412 * ecryptfs_verify_version
413 * @version: The version number to confirm
414 *
415 * Returns zero on good version; non-zero otherwise
416 */
417static int ecryptfs_verify_version(u16 version)
418{
419 int rc = 0;
420 unsigned char major;
421 unsigned char minor;
422
423 major = ((version >> 8) & 0xFF);
424 minor = (version & 0xFF);
425 if (major != ECRYPTFS_VERSION_MAJOR) {
426 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
427 "Expected [%d]; got [%d]\n",
428 ECRYPTFS_VERSION_MAJOR, major);
429 rc = -EINVAL;
430 goto out;
431 }
432 if (minor != ECRYPTFS_VERSION_MINOR) {
433 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
434 "Expected [%d]; got [%d]\n",
435 ECRYPTFS_VERSION_MINOR, minor);
436 rc = -EINVAL;
437 goto out;
438 }
439out:
440 return rc;
441}
442
443/**
444 * ecryptfs_verify_auth_tok_from_key
445 * @auth_tok_key: key containing the authentication token
446 * @auth_tok: authentication token
447 *
448 * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
449 * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
450 */
451static int
452ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
453 struct ecryptfs_auth_tok **auth_tok)
454{
455 int rc = 0;
456
457 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
458 if (IS_ERR(*auth_tok)) {
459 rc = PTR_ERR(*auth_tok);
460 *auth_tok = NULL;
461 goto out;
462 }
463
464 if (ecryptfs_verify_version((*auth_tok)->version)) {
465 printk(KERN_ERR "Data structure version mismatch. Userspace "
466 "tools must match eCryptfs kernel module with major "
467 "version [%d] and minor version [%d]\n",
468 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
469 rc = -EINVAL;
470 goto out;
471 }
472 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
473 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
474 printk(KERN_ERR "Invalid auth_tok structure "
475 "returned from key query\n");
476 rc = -EINVAL;
477 goto out;
478 }
479out:
480 return rc;
481}
482
483static int
484ecryptfs_find_global_auth_tok_for_sig(
485 struct key **auth_tok_key,
486 struct ecryptfs_auth_tok **auth_tok,
487 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
488{
489 struct ecryptfs_global_auth_tok *walker;
490 int rc = 0;
491
492 (*auth_tok_key) = NULL;
493 (*auth_tok) = NULL;
494 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
495 list_for_each_entry(walker,
496 &mount_crypt_stat->global_auth_tok_list,
497 mount_crypt_stat_list) {
498 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
499 continue;
500
501 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
502 rc = -EINVAL;
503 goto out;
504 }
505
506 rc = key_validate(walker->global_auth_tok_key);
507 if (rc) {
508 if (rc == -EKEYEXPIRED)
509 goto out;
510 goto out_invalid_auth_tok;
511 }
512
513 down_write(&(walker->global_auth_tok_key->sem));
514 rc = ecryptfs_verify_auth_tok_from_key(
515 walker->global_auth_tok_key, auth_tok);
516 if (rc)
517 goto out_invalid_auth_tok_unlock;
518
519 (*auth_tok_key) = walker->global_auth_tok_key;
520 key_get(*auth_tok_key);
521 goto out;
522 }
523 rc = -ENOENT;
524 goto out;
525out_invalid_auth_tok_unlock:
526 up_write(&(walker->global_auth_tok_key->sem));
527out_invalid_auth_tok:
528 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
529 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
530 key_put(walker->global_auth_tok_key);
531 walker->global_auth_tok_key = NULL;
532out:
533 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
534 return rc;
535}
536
537/**
538 * ecryptfs_find_auth_tok_for_sig
539 * @auth_tok_key: key containing the authentication token
540 * @auth_tok: Set to the matching auth_tok; NULL if not found
541 * @mount_crypt_stat: inode crypt_stat crypto context
542 * @sig: Sig of auth_tok to find
543 *
544 * For now, this function simply looks at the registered auth_tok's
545 * linked off the mount_crypt_stat, so all the auth_toks that can be
546 * used must be registered at mount time. This function could
547 * potentially try a lot harder to find auth_tok's (e.g., by calling
548 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
549 * that static registration of auth_tok's will no longer be necessary.
550 *
551 * Returns zero on no error; non-zero on error
552 */
553static int
554ecryptfs_find_auth_tok_for_sig(
555 struct key **auth_tok_key,
556 struct ecryptfs_auth_tok **auth_tok,
557 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
558 char *sig)
559{
560 int rc = 0;
561
562 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
563 mount_crypt_stat, sig);
564 if (rc == -ENOENT) {
565 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
566 * mount_crypt_stat structure, we prevent to use auth toks that
567 * are not inserted through the ecryptfs_add_global_auth_tok
568 * function.
569 */
570 if (mount_crypt_stat->flags
571 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
572 return -EINVAL;
573
574 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
575 sig);
576 }
577 return rc;
578}
579
580/*
581 * write_tag_70_packet can gobble a lot of stack space. We stuff most
582 * of the function's parameters in a kmalloc'd struct to help reduce
583 * eCryptfs' overall stack usage.
584 */
585struct ecryptfs_write_tag_70_packet_silly_stack {
586 u8 cipher_code;
587 size_t max_packet_size;
588 size_t packet_size_len;
589 size_t block_aligned_filename_size;
590 size_t block_size;
591 size_t i;
592 size_t j;
593 size_t num_rand_bytes;
594 struct mutex *tfm_mutex;
595 char *block_aligned_filename;
596 struct ecryptfs_auth_tok *auth_tok;
597 struct scatterlist src_sg[2];
598 struct scatterlist dst_sg[2];
599 struct crypto_skcipher *skcipher_tfm;
600 struct skcipher_request *skcipher_req;
601 char iv[ECRYPTFS_MAX_IV_BYTES];
602 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
603 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
604 struct crypto_shash *hash_tfm;
605 struct shash_desc *hash_desc;
606};
607
608/*
609 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
610 * @filename: NULL-terminated filename string
611 *
612 * This is the simplest mechanism for achieving filename encryption in
613 * eCryptfs. It encrypts the given filename with the mount-wide
614 * filename encryption key (FNEK) and stores it in a packet to @dest,
615 * which the callee will encode and write directly into the dentry
616 * name.
617 */
618int
619ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
620 size_t *packet_size,
621 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
622 char *filename, size_t filename_size)
623{
624 struct ecryptfs_write_tag_70_packet_silly_stack *s;
625 struct key *auth_tok_key = NULL;
626 int rc = 0;
627
628 s = kzalloc(sizeof(*s), GFP_KERNEL);
629 if (!s)
630 return -ENOMEM;
631
632 (*packet_size) = 0;
633 rc = ecryptfs_find_auth_tok_for_sig(
634 &auth_tok_key,
635 &s->auth_tok, mount_crypt_stat,
636 mount_crypt_stat->global_default_fnek_sig);
637 if (rc) {
638 printk(KERN_ERR "%s: Error attempting to find auth tok for "
639 "fnek sig [%s]; rc = [%d]\n", __func__,
640 mount_crypt_stat->global_default_fnek_sig, rc);
641 goto out;
642 }
643 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
644 &s->skcipher_tfm,
645 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
646 if (unlikely(rc)) {
647 printk(KERN_ERR "Internal error whilst attempting to get "
648 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
649 mount_crypt_stat->global_default_fn_cipher_name, rc);
650 goto out;
651 }
652 mutex_lock(s->tfm_mutex);
653 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
654 /* Plus one for the \0 separator between the random prefix
655 * and the plaintext filename */
656 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
657 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
658 if ((s->block_aligned_filename_size % s->block_size) != 0) {
659 s->num_rand_bytes += (s->block_size
660 - (s->block_aligned_filename_size
661 % s->block_size));
662 s->block_aligned_filename_size = (s->num_rand_bytes
663 + filename_size);
664 }
665 /* Octet 0: Tag 70 identifier
666 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
667 * and block-aligned encrypted filename size)
668 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
669 * Octet N2-N3: Cipher identifier (1 octet)
670 * Octets N3-N4: Block-aligned encrypted filename
671 * - Consists of a minimum number of random characters, a \0
672 * separator, and then the filename */
673 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
674 + s->block_aligned_filename_size);
675 if (!dest) {
676 (*packet_size) = s->max_packet_size;
677 goto out_unlock;
678 }
679 if (s->max_packet_size > (*remaining_bytes)) {
680 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
681 "[%zd] available\n", __func__, s->max_packet_size,
682 (*remaining_bytes));
683 rc = -EINVAL;
684 goto out_unlock;
685 }
686
687 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
688 if (!s->skcipher_req) {
689 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
690 "skcipher_request_alloc for %s\n", __func__,
691 crypto_skcipher_driver_name(s->skcipher_tfm));
692 rc = -ENOMEM;
693 goto out_unlock;
694 }
695
696 skcipher_request_set_callback(s->skcipher_req,
697 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
698
699 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
700 GFP_KERNEL);
701 if (!s->block_aligned_filename) {
702 rc = -ENOMEM;
703 goto out_unlock;
704 }
705 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
706 rc = ecryptfs_write_packet_length(&dest[s->i],
707 (ECRYPTFS_SIG_SIZE
708 + 1 /* Cipher code */
709 + s->block_aligned_filename_size),
710 &s->packet_size_len);
711 if (rc) {
712 printk(KERN_ERR "%s: Error generating tag 70 packet "
713 "header; cannot generate packet length; rc = [%d]\n",
714 __func__, rc);
715 goto out_free_unlock;
716 }
717 s->i += s->packet_size_len;
718 ecryptfs_from_hex(&dest[s->i],
719 mount_crypt_stat->global_default_fnek_sig,
720 ECRYPTFS_SIG_SIZE);
721 s->i += ECRYPTFS_SIG_SIZE;
722 s->cipher_code = ecryptfs_code_for_cipher_string(
723 mount_crypt_stat->global_default_fn_cipher_name,
724 mount_crypt_stat->global_default_fn_cipher_key_bytes);
725 if (s->cipher_code == 0) {
726 printk(KERN_WARNING "%s: Unable to generate code for "
727 "cipher [%s] with key bytes [%zd]\n", __func__,
728 mount_crypt_stat->global_default_fn_cipher_name,
729 mount_crypt_stat->global_default_fn_cipher_key_bytes);
730 rc = -EINVAL;
731 goto out_free_unlock;
732 }
733 dest[s->i++] = s->cipher_code;
734 /* TODO: Support other key modules than passphrase for
735 * filename encryption */
736 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
737 rc = -EOPNOTSUPP;
738 printk(KERN_INFO "%s: Filename encryption only supports "
739 "password tokens\n", __func__);
740 goto out_free_unlock;
741 }
742 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
743 if (IS_ERR(s->hash_tfm)) {
744 rc = PTR_ERR(s->hash_tfm);
745 printk(KERN_ERR "%s: Error attempting to "
746 "allocate hash crypto context; rc = [%d]\n",
747 __func__, rc);
748 goto out_free_unlock;
749 }
750
751 s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
752 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
753 if (!s->hash_desc) {
754 rc = -ENOMEM;
755 goto out_release_free_unlock;
756 }
757
758 s->hash_desc->tfm = s->hash_tfm;
759
760 rc = crypto_shash_digest(s->hash_desc,
761 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
762 s->auth_tok->token.password.session_key_encryption_key_bytes,
763 s->hash);
764 if (rc) {
765 printk(KERN_ERR
766 "%s: Error computing crypto hash; rc = [%d]\n",
767 __func__, rc);
768 goto out_release_free_unlock;
769 }
770 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
771 s->block_aligned_filename[s->j] =
772 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
773 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
774 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
775 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
776 ECRYPTFS_TAG_70_DIGEST_SIZE,
777 s->tmp_hash);
778 if (rc) {
779 printk(KERN_ERR
780 "%s: Error computing crypto hash; "
781 "rc = [%d]\n", __func__, rc);
782 goto out_release_free_unlock;
783 }
784 memcpy(s->hash, s->tmp_hash,
785 ECRYPTFS_TAG_70_DIGEST_SIZE);
786 }
787 if (s->block_aligned_filename[s->j] == '\0')
788 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
789 }
790 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
791 filename_size);
792 rc = virt_to_scatterlist(s->block_aligned_filename,
793 s->block_aligned_filename_size, s->src_sg, 2);
794 if (rc < 1) {
795 printk(KERN_ERR "%s: Internal error whilst attempting to "
796 "convert filename memory to scatterlist; rc = [%d]. "
797 "block_aligned_filename_size = [%zd]\n", __func__, rc,
798 s->block_aligned_filename_size);
799 goto out_release_free_unlock;
800 }
801 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
802 s->dst_sg, 2);
803 if (rc < 1) {
804 printk(KERN_ERR "%s: Internal error whilst attempting to "
805 "convert encrypted filename memory to scatterlist; "
806 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
807 __func__, rc, s->block_aligned_filename_size);
808 goto out_release_free_unlock;
809 }
810 /* The characters in the first block effectively do the job
811 * of the IV here, so we just use 0's for the IV. Note the
812 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
813 * >= ECRYPTFS_MAX_IV_BYTES. */
814 rc = crypto_skcipher_setkey(
815 s->skcipher_tfm,
816 s->auth_tok->token.password.session_key_encryption_key,
817 mount_crypt_stat->global_default_fn_cipher_key_bytes);
818 if (rc < 0) {
819 printk(KERN_ERR "%s: Error setting key for crypto context; "
820 "rc = [%d]. s->auth_tok->token.password.session_key_"
821 "encryption_key = [0x%p]; mount_crypt_stat->"
822 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
823 rc,
824 s->auth_tok->token.password.session_key_encryption_key,
825 mount_crypt_stat->global_default_fn_cipher_key_bytes);
826 goto out_release_free_unlock;
827 }
828 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
829 s->block_aligned_filename_size, s->iv);
830 rc = crypto_skcipher_encrypt(s->skcipher_req);
831 if (rc) {
832 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
833 "rc = [%d]\n", __func__, rc);
834 goto out_release_free_unlock;
835 }
836 s->i += s->block_aligned_filename_size;
837 (*packet_size) = s->i;
838 (*remaining_bytes) -= (*packet_size);
839out_release_free_unlock:
840 crypto_free_shash(s->hash_tfm);
841out_free_unlock:
842 kfree_sensitive(s->block_aligned_filename);
843out_unlock:
844 mutex_unlock(s->tfm_mutex);
845out:
846 if (auth_tok_key) {
847 up_write(&(auth_tok_key->sem));
848 key_put(auth_tok_key);
849 }
850 skcipher_request_free(s->skcipher_req);
851 kfree_sensitive(s->hash_desc);
852 kfree(s);
853 return rc;
854}
855
856struct ecryptfs_parse_tag_70_packet_silly_stack {
857 u8 cipher_code;
858 size_t max_packet_size;
859 size_t packet_size_len;
860 size_t parsed_tag_70_packet_size;
861 size_t block_aligned_filename_size;
862 size_t block_size;
863 size_t i;
864 struct mutex *tfm_mutex;
865 char *decrypted_filename;
866 struct ecryptfs_auth_tok *auth_tok;
867 struct scatterlist src_sg[2];
868 struct scatterlist dst_sg[2];
869 struct crypto_skcipher *skcipher_tfm;
870 struct skcipher_request *skcipher_req;
871 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
872 char iv[ECRYPTFS_MAX_IV_BYTES];
873 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
874};
875
876/**
877 * ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
878 * @filename: This function kmalloc's the memory for the filename
879 * @filename_size: This function sets this to the amount of memory
880 * kmalloc'd for the filename
881 * @packet_size: This function sets this to the the number of octets
882 * in the packet parsed
883 * @mount_crypt_stat: The mount-wide cryptographic context
884 * @data: The memory location containing the start of the tag 70
885 * packet
886 * @max_packet_size: The maximum legal size of the packet to be parsed
887 * from @data
888 *
889 * Returns zero on success; non-zero otherwise
890 */
891int
892ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
893 size_t *packet_size,
894 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
895 char *data, size_t max_packet_size)
896{
897 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
898 struct key *auth_tok_key = NULL;
899 int rc = 0;
900
901 (*packet_size) = 0;
902 (*filename_size) = 0;
903 (*filename) = NULL;
904 s = kzalloc(sizeof(*s), GFP_KERNEL);
905 if (!s)
906 return -ENOMEM;
907
908 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
909 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
910 "at least [%d]\n", __func__, max_packet_size,
911 ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
912 rc = -EINVAL;
913 goto out;
914 }
915 /* Octet 0: Tag 70 identifier
916 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
917 * and block-aligned encrypted filename size)
918 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
919 * Octet N2-N3: Cipher identifier (1 octet)
920 * Octets N3-N4: Block-aligned encrypted filename
921 * - Consists of a minimum number of random numbers, a \0
922 * separator, and then the filename */
923 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
924 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
925 "tag [0x%.2x]\n", __func__,
926 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
927 rc = -EINVAL;
928 goto out;
929 }
930 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
931 &s->parsed_tag_70_packet_size,
932 &s->packet_size_len);
933 if (rc) {
934 printk(KERN_WARNING "%s: Error parsing packet length; "
935 "rc = [%d]\n", __func__, rc);
936 goto out;
937 }
938 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
939 - ECRYPTFS_SIG_SIZE - 1);
940 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
941 > max_packet_size) {
942 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
943 "size is [%zd]\n", __func__, max_packet_size,
944 (1 + s->packet_size_len + 1
945 + s->block_aligned_filename_size));
946 rc = -EINVAL;
947 goto out;
948 }
949 (*packet_size) += s->packet_size_len;
950 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
951 ECRYPTFS_SIG_SIZE);
952 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
953 (*packet_size) += ECRYPTFS_SIG_SIZE;
954 s->cipher_code = data[(*packet_size)++];
955 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
956 if (rc) {
957 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
958 __func__, s->cipher_code);
959 goto out;
960 }
961 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
962 &s->auth_tok, mount_crypt_stat,
963 s->fnek_sig_hex);
964 if (rc) {
965 printk(KERN_ERR "%s: Error attempting to find auth tok for "
966 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
967 rc);
968 goto out;
969 }
970 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
971 &s->tfm_mutex,
972 s->cipher_string);
973 if (unlikely(rc)) {
974 printk(KERN_ERR "Internal error whilst attempting to get "
975 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
976 s->cipher_string, rc);
977 goto out;
978 }
979 mutex_lock(s->tfm_mutex);
980 rc = virt_to_scatterlist(&data[(*packet_size)],
981 s->block_aligned_filename_size, s->src_sg, 2);
982 if (rc < 1) {
983 printk(KERN_ERR "%s: Internal error whilst attempting to "
984 "convert encrypted filename memory to scatterlist; "
985 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
986 __func__, rc, s->block_aligned_filename_size);
987 goto out_unlock;
988 }
989 (*packet_size) += s->block_aligned_filename_size;
990 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
991 GFP_KERNEL);
992 if (!s->decrypted_filename) {
993 rc = -ENOMEM;
994 goto out_unlock;
995 }
996 rc = virt_to_scatterlist(s->decrypted_filename,
997 s->block_aligned_filename_size, s->dst_sg, 2);
998 if (rc < 1) {
999 printk(KERN_ERR "%s: Internal error whilst attempting to "
1000 "convert decrypted filename memory to scatterlist; "
1001 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1002 __func__, rc, s->block_aligned_filename_size);
1003 goto out_free_unlock;
1004 }
1005
1006 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
1007 if (!s->skcipher_req) {
1008 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1009 "skcipher_request_alloc for %s\n", __func__,
1010 crypto_skcipher_driver_name(s->skcipher_tfm));
1011 rc = -ENOMEM;
1012 goto out_free_unlock;
1013 }
1014
1015 skcipher_request_set_callback(s->skcipher_req,
1016 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
1017
1018 /* The characters in the first block effectively do the job of
1019 * the IV here, so we just use 0's for the IV. Note the
1020 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1021 * >= ECRYPTFS_MAX_IV_BYTES. */
1022 /* TODO: Support other key modules than passphrase for
1023 * filename encryption */
1024 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1025 rc = -EOPNOTSUPP;
1026 printk(KERN_INFO "%s: Filename encryption only supports "
1027 "password tokens\n", __func__);
1028 goto out_free_unlock;
1029 }
1030 rc = crypto_skcipher_setkey(
1031 s->skcipher_tfm,
1032 s->auth_tok->token.password.session_key_encryption_key,
1033 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1034 if (rc < 0) {
1035 printk(KERN_ERR "%s: Error setting key for crypto context; "
1036 "rc = [%d]. s->auth_tok->token.password.session_key_"
1037 "encryption_key = [0x%p]; mount_crypt_stat->"
1038 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1039 rc,
1040 s->auth_tok->token.password.session_key_encryption_key,
1041 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1042 goto out_free_unlock;
1043 }
1044 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
1045 s->block_aligned_filename_size, s->iv);
1046 rc = crypto_skcipher_decrypt(s->skcipher_req);
1047 if (rc) {
1048 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1049 "rc = [%d]\n", __func__, rc);
1050 goto out_free_unlock;
1051 }
1052
1053 while (s->i < s->block_aligned_filename_size &&
1054 s->decrypted_filename[s->i] != '\0')
1055 s->i++;
1056 if (s->i == s->block_aligned_filename_size) {
1057 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1058 "find valid separator between random characters and "
1059 "the filename\n", __func__);
1060 rc = -EINVAL;
1061 goto out_free_unlock;
1062 }
1063 s->i++;
1064 (*filename_size) = (s->block_aligned_filename_size - s->i);
1065 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1066 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1067 "invalid\n", __func__, (*filename_size));
1068 rc = -EINVAL;
1069 goto out_free_unlock;
1070 }
1071 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1072 if (!(*filename)) {
1073 rc = -ENOMEM;
1074 goto out_free_unlock;
1075 }
1076 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1077 (*filename)[(*filename_size)] = '\0';
1078out_free_unlock:
1079 kfree(s->decrypted_filename);
1080out_unlock:
1081 mutex_unlock(s->tfm_mutex);
1082out:
1083 if (rc) {
1084 (*packet_size) = 0;
1085 (*filename_size) = 0;
1086 (*filename) = NULL;
1087 }
1088 if (auth_tok_key) {
1089 up_write(&(auth_tok_key->sem));
1090 key_put(auth_tok_key);
1091 }
1092 skcipher_request_free(s->skcipher_req);
1093 kfree(s);
1094 return rc;
1095}
1096
1097static int
1098ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1099{
1100 int rc = 0;
1101
1102 (*sig) = NULL;
1103 switch (auth_tok->token_type) {
1104 case ECRYPTFS_PASSWORD:
1105 (*sig) = auth_tok->token.password.signature;
1106 break;
1107 case ECRYPTFS_PRIVATE_KEY:
1108 (*sig) = auth_tok->token.private_key.signature;
1109 break;
1110 default:
1111 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1112 auth_tok->token_type);
1113 rc = -EINVAL;
1114 }
1115 return rc;
1116}
1117
1118/**
1119 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1120 * @auth_tok: The key authentication token used to decrypt the session key
1121 * @crypt_stat: The cryptographic context
1122 *
1123 * Returns zero on success; non-zero error otherwise.
1124 */
1125static int
1126decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1127 struct ecryptfs_crypt_stat *crypt_stat)
1128{
1129 u8 cipher_code = 0;
1130 struct ecryptfs_msg_ctx *msg_ctx;
1131 struct ecryptfs_message *msg = NULL;
1132 char *auth_tok_sig;
1133 char *payload = NULL;
1134 size_t payload_len = 0;
1135 int rc;
1136
1137 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1138 if (rc) {
1139 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1140 auth_tok->token_type);
1141 goto out;
1142 }
1143 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1144 &payload, &payload_len);
1145 if (rc) {
1146 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1147 goto out;
1148 }
1149 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1150 if (rc) {
1151 ecryptfs_printk(KERN_ERR, "Error sending message to "
1152 "ecryptfsd: %d\n", rc);
1153 goto out;
1154 }
1155 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1156 if (rc) {
1157 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1158 "from the user space daemon\n");
1159 rc = -EIO;
1160 goto out;
1161 }
1162 rc = parse_tag_65_packet(&(auth_tok->session_key),
1163 &cipher_code, msg);
1164 if (rc) {
1165 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1166 rc);
1167 goto out;
1168 }
1169 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1170 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1171 auth_tok->session_key.decrypted_key_size);
1172 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1173 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1174 if (rc) {
1175 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1176 cipher_code);
1177 goto out;
1178 }
1179 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1180 if (ecryptfs_verbosity > 0) {
1181 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1182 ecryptfs_dump_hex(crypt_stat->key,
1183 crypt_stat->key_size);
1184 }
1185out:
1186 kfree(msg);
1187 kfree(payload);
1188 return rc;
1189}
1190
1191static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1192{
1193 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1194 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1195
1196 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1197 auth_tok_list_head, list) {
1198 list_del(&auth_tok_list_item->list);
1199 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1200 auth_tok_list_item);
1201 }
1202}
1203
1204struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1205
1206/**
1207 * parse_tag_1_packet
1208 * @crypt_stat: The cryptographic context to modify based on packet contents
1209 * @data: The raw bytes of the packet.
1210 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1211 * a new authentication token will be placed at the
1212 * end of this list for this packet.
1213 * @new_auth_tok: Pointer to a pointer to memory that this function
1214 * allocates; sets the memory address of the pointer to
1215 * NULL on error. This object is added to the
1216 * auth_tok_list.
1217 * @packet_size: This function writes the size of the parsed packet
1218 * into this memory location; zero on error.
1219 * @max_packet_size: The maximum allowable packet size
1220 *
1221 * Returns zero on success; non-zero on error.
1222 */
1223static int
1224parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1225 unsigned char *data, struct list_head *auth_tok_list,
1226 struct ecryptfs_auth_tok **new_auth_tok,
1227 size_t *packet_size, size_t max_packet_size)
1228{
1229 size_t body_size;
1230 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1231 size_t length_size;
1232 int rc = 0;
1233
1234 (*packet_size) = 0;
1235 (*new_auth_tok) = NULL;
1236 /**
1237 * This format is inspired by OpenPGP; see RFC 2440
1238 * packet tag 1
1239 *
1240 * Tag 1 identifier (1 byte)
1241 * Max Tag 1 packet size (max 3 bytes)
1242 * Version (1 byte)
1243 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1244 * Cipher identifier (1 byte)
1245 * Encrypted key size (arbitrary)
1246 *
1247 * 12 bytes minimum packet size
1248 */
1249 if (unlikely(max_packet_size < 12)) {
1250 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1251 rc = -EINVAL;
1252 goto out;
1253 }
1254 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1255 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1256 ECRYPTFS_TAG_1_PACKET_TYPE);
1257 rc = -EINVAL;
1258 goto out;
1259 }
1260 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1261 * at end of function upon failure */
1262 auth_tok_list_item =
1263 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1264 GFP_KERNEL);
1265 if (!auth_tok_list_item) {
1266 printk(KERN_ERR "Unable to allocate memory\n");
1267 rc = -ENOMEM;
1268 goto out;
1269 }
1270 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1271 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1272 &length_size);
1273 if (rc) {
1274 printk(KERN_WARNING "Error parsing packet length; "
1275 "rc = [%d]\n", rc);
1276 goto out_free;
1277 }
1278 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1279 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1280 rc = -EINVAL;
1281 goto out_free;
1282 }
1283 (*packet_size) += length_size;
1284 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1285 printk(KERN_WARNING "Packet size exceeds max\n");
1286 rc = -EINVAL;
1287 goto out_free;
1288 }
1289 if (unlikely(data[(*packet_size)++] != 0x03)) {
1290 printk(KERN_WARNING "Unknown version number [%d]\n",
1291 data[(*packet_size) - 1]);
1292 rc = -EINVAL;
1293 goto out_free;
1294 }
1295 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1296 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1297 *packet_size += ECRYPTFS_SIG_SIZE;
1298 /* This byte is skipped because the kernel does not need to
1299 * know which public key encryption algorithm was used */
1300 (*packet_size)++;
1301 (*new_auth_tok)->session_key.encrypted_key_size =
1302 body_size - (ECRYPTFS_SIG_SIZE + 2);
1303 if ((*new_auth_tok)->session_key.encrypted_key_size
1304 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1305 printk(KERN_WARNING "Tag 1 packet contains key larger "
1306 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1307 rc = -EINVAL;
1308 goto out_free;
1309 }
1310 memcpy((*new_auth_tok)->session_key.encrypted_key,
1311 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1312 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1313 (*new_auth_tok)->session_key.flags &=
1314 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1315 (*new_auth_tok)->session_key.flags |=
1316 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1317 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1318 (*new_auth_tok)->flags = 0;
1319 (*new_auth_tok)->session_key.flags &=
1320 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1321 (*new_auth_tok)->session_key.flags &=
1322 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1323 list_add(&auth_tok_list_item->list, auth_tok_list);
1324 goto out;
1325out_free:
1326 (*new_auth_tok) = NULL;
1327 memset(auth_tok_list_item, 0,
1328 sizeof(struct ecryptfs_auth_tok_list_item));
1329 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1330 auth_tok_list_item);
1331out:
1332 if (rc)
1333 (*packet_size) = 0;
1334 return rc;
1335}
1336
1337/**
1338 * parse_tag_3_packet
1339 * @crypt_stat: The cryptographic context to modify based on packet
1340 * contents.
1341 * @data: The raw bytes of the packet.
1342 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1343 * a new authentication token will be placed at the end
1344 * of this list for this packet.
1345 * @new_auth_tok: Pointer to a pointer to memory that this function
1346 * allocates; sets the memory address of the pointer to
1347 * NULL on error. This object is added to the
1348 * auth_tok_list.
1349 * @packet_size: This function writes the size of the parsed packet
1350 * into this memory location; zero on error.
1351 * @max_packet_size: maximum number of bytes to parse
1352 *
1353 * Returns zero on success; non-zero on error.
1354 */
1355static int
1356parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1357 unsigned char *data, struct list_head *auth_tok_list,
1358 struct ecryptfs_auth_tok **new_auth_tok,
1359 size_t *packet_size, size_t max_packet_size)
1360{
1361 size_t body_size;
1362 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1363 size_t length_size;
1364 int rc = 0;
1365
1366 (*packet_size) = 0;
1367 (*new_auth_tok) = NULL;
1368 /**
1369 *This format is inspired by OpenPGP; see RFC 2440
1370 * packet tag 3
1371 *
1372 * Tag 3 identifier (1 byte)
1373 * Max Tag 3 packet size (max 3 bytes)
1374 * Version (1 byte)
1375 * Cipher code (1 byte)
1376 * S2K specifier (1 byte)
1377 * Hash identifier (1 byte)
1378 * Salt (ECRYPTFS_SALT_SIZE)
1379 * Hash iterations (1 byte)
1380 * Encrypted key (arbitrary)
1381 *
1382 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1383 */
1384 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1385 printk(KERN_ERR "Max packet size too large\n");
1386 rc = -EINVAL;
1387 goto out;
1388 }
1389 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1390 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1391 ECRYPTFS_TAG_3_PACKET_TYPE);
1392 rc = -EINVAL;
1393 goto out;
1394 }
1395 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1396 * at end of function upon failure */
1397 auth_tok_list_item =
1398 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1399 if (!auth_tok_list_item) {
1400 printk(KERN_ERR "Unable to allocate memory\n");
1401 rc = -ENOMEM;
1402 goto out;
1403 }
1404 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1405 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1406 &length_size);
1407 if (rc) {
1408 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1409 rc);
1410 goto out_free;
1411 }
1412 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1413 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1414 rc = -EINVAL;
1415 goto out_free;
1416 }
1417 (*packet_size) += length_size;
1418 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1419 printk(KERN_ERR "Packet size exceeds max\n");
1420 rc = -EINVAL;
1421 goto out_free;
1422 }
1423 (*new_auth_tok)->session_key.encrypted_key_size =
1424 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1425 if ((*new_auth_tok)->session_key.encrypted_key_size
1426 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1427 printk(KERN_WARNING "Tag 3 packet contains key larger "
1428 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1429 rc = -EINVAL;
1430 goto out_free;
1431 }
1432 if (unlikely(data[(*packet_size)++] != 0x04)) {
1433 printk(KERN_WARNING "Unknown version number [%d]\n",
1434 data[(*packet_size) - 1]);
1435 rc = -EINVAL;
1436 goto out_free;
1437 }
1438 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1439 (u16)data[(*packet_size)]);
1440 if (rc)
1441 goto out_free;
1442 /* A little extra work to differentiate among the AES key
1443 * sizes; see RFC2440 */
1444 switch(data[(*packet_size)++]) {
1445 case RFC2440_CIPHER_AES_192:
1446 crypt_stat->key_size = 24;
1447 break;
1448 default:
1449 crypt_stat->key_size =
1450 (*new_auth_tok)->session_key.encrypted_key_size;
1451 }
1452 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1453 if (rc)
1454 goto out_free;
1455 if (unlikely(data[(*packet_size)++] != 0x03)) {
1456 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1457 rc = -ENOSYS;
1458 goto out_free;
1459 }
1460 /* TODO: finish the hash mapping */
1461 switch (data[(*packet_size)++]) {
1462 case 0x01: /* See RFC2440 for these numbers and their mappings */
1463 /* Choose MD5 */
1464 memcpy((*new_auth_tok)->token.password.salt,
1465 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1466 (*packet_size) += ECRYPTFS_SALT_SIZE;
1467 /* This conversion was taken straight from RFC2440 */
1468 (*new_auth_tok)->token.password.hash_iterations =
1469 ((u32) 16 + (data[(*packet_size)] & 15))
1470 << ((data[(*packet_size)] >> 4) + 6);
1471 (*packet_size)++;
1472 /* Friendly reminder:
1473 * (*new_auth_tok)->session_key.encrypted_key_size =
1474 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1475 memcpy((*new_auth_tok)->session_key.encrypted_key,
1476 &data[(*packet_size)],
1477 (*new_auth_tok)->session_key.encrypted_key_size);
1478 (*packet_size) +=
1479 (*new_auth_tok)->session_key.encrypted_key_size;
1480 (*new_auth_tok)->session_key.flags &=
1481 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1482 (*new_auth_tok)->session_key.flags |=
1483 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1484 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1485 break;
1486 default:
1487 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1488 "[%d]\n", data[(*packet_size) - 1]);
1489 rc = -ENOSYS;
1490 goto out_free;
1491 }
1492 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1493 /* TODO: Parametarize; we might actually want userspace to
1494 * decrypt the session key. */
1495 (*new_auth_tok)->session_key.flags &=
1496 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1497 (*new_auth_tok)->session_key.flags &=
1498 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1499 list_add(&auth_tok_list_item->list, auth_tok_list);
1500 goto out;
1501out_free:
1502 (*new_auth_tok) = NULL;
1503 memset(auth_tok_list_item, 0,
1504 sizeof(struct ecryptfs_auth_tok_list_item));
1505 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1506 auth_tok_list_item);
1507out:
1508 if (rc)
1509 (*packet_size) = 0;
1510 return rc;
1511}
1512
1513/**
1514 * parse_tag_11_packet
1515 * @data: The raw bytes of the packet
1516 * @contents: This function writes the data contents of the literal
1517 * packet into this memory location
1518 * @max_contents_bytes: The maximum number of bytes that this function
1519 * is allowed to write into contents
1520 * @tag_11_contents_size: This function writes the size of the parsed
1521 * contents into this memory location; zero on
1522 * error
1523 * @packet_size: This function writes the size of the parsed packet
1524 * into this memory location; zero on error
1525 * @max_packet_size: maximum number of bytes to parse
1526 *
1527 * Returns zero on success; non-zero on error.
1528 */
1529static int
1530parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1531 size_t max_contents_bytes, size_t *tag_11_contents_size,
1532 size_t *packet_size, size_t max_packet_size)
1533{
1534 size_t body_size;
1535 size_t length_size;
1536 int rc = 0;
1537
1538 (*packet_size) = 0;
1539 (*tag_11_contents_size) = 0;
1540 /* This format is inspired by OpenPGP; see RFC 2440
1541 * packet tag 11
1542 *
1543 * Tag 11 identifier (1 byte)
1544 * Max Tag 11 packet size (max 3 bytes)
1545 * Binary format specifier (1 byte)
1546 * Filename length (1 byte)
1547 * Filename ("_CONSOLE") (8 bytes)
1548 * Modification date (4 bytes)
1549 * Literal data (arbitrary)
1550 *
1551 * We need at least 16 bytes of data for the packet to even be
1552 * valid.
1553 */
1554 if (max_packet_size < 16) {
1555 printk(KERN_ERR "Maximum packet size too small\n");
1556 rc = -EINVAL;
1557 goto out;
1558 }
1559 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1560 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1561 rc = -EINVAL;
1562 goto out;
1563 }
1564 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1565 &length_size);
1566 if (rc) {
1567 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1568 goto out;
1569 }
1570 if (body_size < 14) {
1571 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1572 rc = -EINVAL;
1573 goto out;
1574 }
1575 (*packet_size) += length_size;
1576 (*tag_11_contents_size) = (body_size - 14);
1577 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1578 printk(KERN_ERR "Packet size exceeds max\n");
1579 rc = -EINVAL;
1580 goto out;
1581 }
1582 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1583 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1584 "expected size\n");
1585 rc = -EINVAL;
1586 goto out;
1587 }
1588 if (data[(*packet_size)++] != 0x62) {
1589 printk(KERN_WARNING "Unrecognizable packet\n");
1590 rc = -EINVAL;
1591 goto out;
1592 }
1593 if (data[(*packet_size)++] != 0x08) {
1594 printk(KERN_WARNING "Unrecognizable packet\n");
1595 rc = -EINVAL;
1596 goto out;
1597 }
1598 (*packet_size) += 12; /* Ignore filename and modification date */
1599 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1600 (*packet_size) += (*tag_11_contents_size);
1601out:
1602 if (rc) {
1603 (*packet_size) = 0;
1604 (*tag_11_contents_size) = 0;
1605 }
1606 return rc;
1607}
1608
1609int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1610 struct ecryptfs_auth_tok **auth_tok,
1611 char *sig)
1612{
1613 int rc = 0;
1614
1615 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1616 if (IS_ERR(*auth_tok_key)) {
1617 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1618 if (IS_ERR(*auth_tok_key)) {
1619 printk(KERN_ERR "Could not find key with description: [%s]\n",
1620 sig);
1621 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1622 (*auth_tok_key) = NULL;
1623 goto out;
1624 }
1625 }
1626 down_write(&(*auth_tok_key)->sem);
1627 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1628 if (rc) {
1629 up_write(&(*auth_tok_key)->sem);
1630 key_put(*auth_tok_key);
1631 (*auth_tok_key) = NULL;
1632 goto out;
1633 }
1634out:
1635 return rc;
1636}
1637
1638/**
1639 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1640 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1641 * @crypt_stat: The cryptographic context
1642 *
1643 * Returns zero on success; non-zero error otherwise
1644 */
1645static int
1646decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1647 struct ecryptfs_crypt_stat *crypt_stat)
1648{
1649 struct scatterlist dst_sg[2];
1650 struct scatterlist src_sg[2];
1651 struct mutex *tfm_mutex;
1652 struct crypto_skcipher *tfm;
1653 struct skcipher_request *req = NULL;
1654 int rc = 0;
1655
1656 if (unlikely(ecryptfs_verbosity > 0)) {
1657 ecryptfs_printk(
1658 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1659 auth_tok->token.password.session_key_encryption_key_bytes);
1660 ecryptfs_dump_hex(
1661 auth_tok->token.password.session_key_encryption_key,
1662 auth_tok->token.password.session_key_encryption_key_bytes);
1663 }
1664 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
1665 crypt_stat->cipher);
1666 if (unlikely(rc)) {
1667 printk(KERN_ERR "Internal error whilst attempting to get "
1668 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1669 crypt_stat->cipher, rc);
1670 goto out;
1671 }
1672 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1673 auth_tok->session_key.encrypted_key_size,
1674 src_sg, 2);
1675 if (rc < 1 || rc > 2) {
1676 printk(KERN_ERR "Internal error whilst attempting to convert "
1677 "auth_tok->session_key.encrypted_key to scatterlist; "
1678 "expected rc = 1; got rc = [%d]. "
1679 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1680 auth_tok->session_key.encrypted_key_size);
1681 goto out;
1682 }
1683 auth_tok->session_key.decrypted_key_size =
1684 auth_tok->session_key.encrypted_key_size;
1685 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1686 auth_tok->session_key.decrypted_key_size,
1687 dst_sg, 2);
1688 if (rc < 1 || rc > 2) {
1689 printk(KERN_ERR "Internal error whilst attempting to convert "
1690 "auth_tok->session_key.decrypted_key to scatterlist; "
1691 "expected rc = 1; got rc = [%d]\n", rc);
1692 goto out;
1693 }
1694 mutex_lock(tfm_mutex);
1695 req = skcipher_request_alloc(tfm, GFP_KERNEL);
1696 if (!req) {
1697 mutex_unlock(tfm_mutex);
1698 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1699 "skcipher_request_alloc for %s\n", __func__,
1700 crypto_skcipher_driver_name(tfm));
1701 rc = -ENOMEM;
1702 goto out;
1703 }
1704
1705 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
1706 NULL, NULL);
1707 rc = crypto_skcipher_setkey(
1708 tfm, auth_tok->token.password.session_key_encryption_key,
1709 crypt_stat->key_size);
1710 if (unlikely(rc < 0)) {
1711 mutex_unlock(tfm_mutex);
1712 printk(KERN_ERR "Error setting key for crypto context\n");
1713 rc = -EINVAL;
1714 goto out;
1715 }
1716 skcipher_request_set_crypt(req, src_sg, dst_sg,
1717 auth_tok->session_key.encrypted_key_size,
1718 NULL);
1719 rc = crypto_skcipher_decrypt(req);
1720 mutex_unlock(tfm_mutex);
1721 if (unlikely(rc)) {
1722 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1723 goto out;
1724 }
1725 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1726 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1727 auth_tok->session_key.decrypted_key_size);
1728 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1729 if (unlikely(ecryptfs_verbosity > 0)) {
1730 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1731 crypt_stat->key_size);
1732 ecryptfs_dump_hex(crypt_stat->key,
1733 crypt_stat->key_size);
1734 }
1735out:
1736 skcipher_request_free(req);
1737 return rc;
1738}
1739
1740/**
1741 * ecryptfs_parse_packet_set
1742 * @crypt_stat: The cryptographic context
1743 * @src: Virtual address of region of memory containing the packets
1744 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1745 *
1746 * Get crypt_stat to have the file's session key if the requisite key
1747 * is available to decrypt the session key.
1748 *
1749 * Returns Zero if a valid authentication token was retrieved and
1750 * processed; negative value for file not encrypted or for error
1751 * conditions.
1752 */
1753int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1754 unsigned char *src,
1755 struct dentry *ecryptfs_dentry)
1756{
1757 size_t i = 0;
1758 size_t found_auth_tok;
1759 size_t next_packet_is_auth_tok_packet;
1760 struct list_head auth_tok_list;
1761 struct ecryptfs_auth_tok *matching_auth_tok;
1762 struct ecryptfs_auth_tok *candidate_auth_tok;
1763 char *candidate_auth_tok_sig;
1764 size_t packet_size;
1765 struct ecryptfs_auth_tok *new_auth_tok;
1766 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1767 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1768 size_t tag_11_contents_size;
1769 size_t tag_11_packet_size;
1770 struct key *auth_tok_key = NULL;
1771 int rc = 0;
1772
1773 INIT_LIST_HEAD(&auth_tok_list);
1774 /* Parse the header to find as many packets as we can; these will be
1775 * added the our &auth_tok_list */
1776 next_packet_is_auth_tok_packet = 1;
1777 while (next_packet_is_auth_tok_packet) {
1778 size_t max_packet_size = ((PAGE_SIZE - 8) - i);
1779
1780 switch (src[i]) {
1781 case ECRYPTFS_TAG_3_PACKET_TYPE:
1782 rc = parse_tag_3_packet(crypt_stat,
1783 (unsigned char *)&src[i],
1784 &auth_tok_list, &new_auth_tok,
1785 &packet_size, max_packet_size);
1786 if (rc) {
1787 ecryptfs_printk(KERN_ERR, "Error parsing "
1788 "tag 3 packet\n");
1789 rc = -EIO;
1790 goto out_wipe_list;
1791 }
1792 i += packet_size;
1793 rc = parse_tag_11_packet((unsigned char *)&src[i],
1794 sig_tmp_space,
1795 ECRYPTFS_SIG_SIZE,
1796 &tag_11_contents_size,
1797 &tag_11_packet_size,
1798 max_packet_size);
1799 if (rc) {
1800 ecryptfs_printk(KERN_ERR, "No valid "
1801 "(ecryptfs-specific) literal "
1802 "packet containing "
1803 "authentication token "
1804 "signature found after "
1805 "tag 3 packet\n");
1806 rc = -EIO;
1807 goto out_wipe_list;
1808 }
1809 i += tag_11_packet_size;
1810 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1811 ecryptfs_printk(KERN_ERR, "Expected "
1812 "signature of size [%d]; "
1813 "read size [%zd]\n",
1814 ECRYPTFS_SIG_SIZE,
1815 tag_11_contents_size);
1816 rc = -EIO;
1817 goto out_wipe_list;
1818 }
1819 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1820 sig_tmp_space, tag_11_contents_size);
1821 new_auth_tok->token.password.signature[
1822 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1823 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1824 break;
1825 case ECRYPTFS_TAG_1_PACKET_TYPE:
1826 rc = parse_tag_1_packet(crypt_stat,
1827 (unsigned char *)&src[i],
1828 &auth_tok_list, &new_auth_tok,
1829 &packet_size, max_packet_size);
1830 if (rc) {
1831 ecryptfs_printk(KERN_ERR, "Error parsing "
1832 "tag 1 packet\n");
1833 rc = -EIO;
1834 goto out_wipe_list;
1835 }
1836 i += packet_size;
1837 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1838 break;
1839 case ECRYPTFS_TAG_11_PACKET_TYPE:
1840 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1841 "(Tag 11 not allowed by itself)\n");
1842 rc = -EIO;
1843 goto out_wipe_list;
1844 default:
1845 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1846 "of the file header; hex value of "
1847 "character is [0x%.2x]\n", i, src[i]);
1848 next_packet_is_auth_tok_packet = 0;
1849 }
1850 }
1851 if (list_empty(&auth_tok_list)) {
1852 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1853 "eCryptfs file; this is not supported in this version "
1854 "of the eCryptfs kernel module\n");
1855 rc = -EINVAL;
1856 goto out;
1857 }
1858 /* auth_tok_list contains the set of authentication tokens
1859 * parsed from the metadata. We need to find a matching
1860 * authentication token that has the secret component(s)
1861 * necessary to decrypt the EFEK in the auth_tok parsed from
1862 * the metadata. There may be several potential matches, but
1863 * just one will be sufficient to decrypt to get the FEK. */
1864find_next_matching_auth_tok:
1865 found_auth_tok = 0;
1866 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1867 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1868 if (unlikely(ecryptfs_verbosity > 0)) {
1869 ecryptfs_printk(KERN_DEBUG,
1870 "Considering candidate auth tok:\n");
1871 ecryptfs_dump_auth_tok(candidate_auth_tok);
1872 }
1873 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1874 candidate_auth_tok);
1875 if (rc) {
1876 printk(KERN_ERR
1877 "Unrecognized candidate auth tok type: [%d]\n",
1878 candidate_auth_tok->token_type);
1879 rc = -EINVAL;
1880 goto out_wipe_list;
1881 }
1882 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1883 &matching_auth_tok,
1884 crypt_stat->mount_crypt_stat,
1885 candidate_auth_tok_sig);
1886 if (!rc) {
1887 found_auth_tok = 1;
1888 goto found_matching_auth_tok;
1889 }
1890 }
1891 if (!found_auth_tok) {
1892 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1893 "authentication token\n");
1894 rc = -EIO;
1895 goto out_wipe_list;
1896 }
1897found_matching_auth_tok:
1898 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1899 memcpy(&(candidate_auth_tok->token.private_key),
1900 &(matching_auth_tok->token.private_key),
1901 sizeof(struct ecryptfs_private_key));
1902 up_write(&(auth_tok_key->sem));
1903 key_put(auth_tok_key);
1904 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1905 crypt_stat);
1906 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1907 memcpy(&(candidate_auth_tok->token.password),
1908 &(matching_auth_tok->token.password),
1909 sizeof(struct ecryptfs_password));
1910 up_write(&(auth_tok_key->sem));
1911 key_put(auth_tok_key);
1912 rc = decrypt_passphrase_encrypted_session_key(
1913 candidate_auth_tok, crypt_stat);
1914 } else {
1915 up_write(&(auth_tok_key->sem));
1916 key_put(auth_tok_key);
1917 rc = -EINVAL;
1918 }
1919 if (rc) {
1920 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1921
1922 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1923 "session key for authentication token with sig "
1924 "[%.*s]; rc = [%d]. Removing auth tok "
1925 "candidate from the list and searching for "
1926 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1927 candidate_auth_tok_sig, rc);
1928 list_for_each_entry_safe(auth_tok_list_item,
1929 auth_tok_list_item_tmp,
1930 &auth_tok_list, list) {
1931 if (candidate_auth_tok
1932 == &auth_tok_list_item->auth_tok) {
1933 list_del(&auth_tok_list_item->list);
1934 kmem_cache_free(
1935 ecryptfs_auth_tok_list_item_cache,
1936 auth_tok_list_item);
1937 goto find_next_matching_auth_tok;
1938 }
1939 }
1940 BUG();
1941 }
1942 rc = ecryptfs_compute_root_iv(crypt_stat);
1943 if (rc) {
1944 ecryptfs_printk(KERN_ERR, "Error computing "
1945 "the root IV\n");
1946 goto out_wipe_list;
1947 }
1948 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1949 if (rc) {
1950 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1951 "context for cipher [%s]; rc = [%d]\n",
1952 crypt_stat->cipher, rc);
1953 }
1954out_wipe_list:
1955 wipe_auth_tok_list(&auth_tok_list);
1956out:
1957 return rc;
1958}
1959
1960static int
1961pki_encrypt_session_key(struct key *auth_tok_key,
1962 struct ecryptfs_auth_tok *auth_tok,
1963 struct ecryptfs_crypt_stat *crypt_stat,
1964 struct ecryptfs_key_record *key_rec)
1965{
1966 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1967 char *payload = NULL;
1968 size_t payload_len = 0;
1969 struct ecryptfs_message *msg;
1970 int rc;
1971
1972 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1973 ecryptfs_code_for_cipher_string(
1974 crypt_stat->cipher,
1975 crypt_stat->key_size),
1976 crypt_stat, &payload, &payload_len);
1977 up_write(&(auth_tok_key->sem));
1978 key_put(auth_tok_key);
1979 if (rc) {
1980 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1981 goto out;
1982 }
1983 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1984 if (rc) {
1985 ecryptfs_printk(KERN_ERR, "Error sending message to "
1986 "ecryptfsd: %d\n", rc);
1987 goto out;
1988 }
1989 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1990 if (rc) {
1991 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1992 "from the user space daemon\n");
1993 rc = -EIO;
1994 goto out;
1995 }
1996 rc = parse_tag_67_packet(key_rec, msg);
1997 if (rc)
1998 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
1999 kfree(msg);
2000out:
2001 kfree(payload);
2002 return rc;
2003}
2004/**
2005 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2006 * @dest: Buffer into which to write the packet
2007 * @remaining_bytes: Maximum number of bytes that can be writtn
2008 * @auth_tok_key: The authentication token key to unlock and put when done with
2009 * @auth_tok
2010 * @auth_tok: The authentication token used for generating the tag 1 packet
2011 * @crypt_stat: The cryptographic context
2012 * @key_rec: The key record struct for the tag 1 packet
2013 * @packet_size: This function will write the number of bytes that end
2014 * up constituting the packet; set to zero on error
2015 *
2016 * Returns zero on success; non-zero on error.
2017 */
2018static int
2019write_tag_1_packet(char *dest, size_t *remaining_bytes,
2020 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2021 struct ecryptfs_crypt_stat *crypt_stat,
2022 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2023{
2024 size_t i;
2025 size_t encrypted_session_key_valid = 0;
2026 size_t packet_size_length;
2027 size_t max_packet_size;
2028 int rc = 0;
2029
2030 (*packet_size) = 0;
2031 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2032 ECRYPTFS_SIG_SIZE);
2033 encrypted_session_key_valid = 0;
2034 for (i = 0; i < crypt_stat->key_size; i++)
2035 encrypted_session_key_valid |=
2036 auth_tok->session_key.encrypted_key[i];
2037 if (encrypted_session_key_valid) {
2038 memcpy(key_rec->enc_key,
2039 auth_tok->session_key.encrypted_key,
2040 auth_tok->session_key.encrypted_key_size);
2041 up_write(&(auth_tok_key->sem));
2042 key_put(auth_tok_key);
2043 goto encrypted_session_key_set;
2044 }
2045 if (auth_tok->session_key.encrypted_key_size == 0)
2046 auth_tok->session_key.encrypted_key_size =
2047 auth_tok->token.private_key.key_size;
2048 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2049 key_rec);
2050 if (rc) {
2051 printk(KERN_ERR "Failed to encrypt session key via a key "
2052 "module; rc = [%d]\n", rc);
2053 goto out;
2054 }
2055 if (ecryptfs_verbosity > 0) {
2056 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2057 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2058 }
2059encrypted_session_key_set:
2060 /* This format is inspired by OpenPGP; see RFC 2440
2061 * packet tag 1 */
2062 max_packet_size = (1 /* Tag 1 identifier */
2063 + 3 /* Max Tag 1 packet size */
2064 + 1 /* Version */
2065 + ECRYPTFS_SIG_SIZE /* Key identifier */
2066 + 1 /* Cipher identifier */
2067 + key_rec->enc_key_size); /* Encrypted key size */
2068 if (max_packet_size > (*remaining_bytes)) {
2069 printk(KERN_ERR "Packet length larger than maximum allowable; "
2070 "need up to [%td] bytes, but there are only [%td] "
2071 "available\n", max_packet_size, (*remaining_bytes));
2072 rc = -EINVAL;
2073 goto out;
2074 }
2075 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2076 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2077 (max_packet_size - 4),
2078 &packet_size_length);
2079 if (rc) {
2080 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2081 "header; cannot generate packet length\n");
2082 goto out;
2083 }
2084 (*packet_size) += packet_size_length;
2085 dest[(*packet_size)++] = 0x03; /* version 3 */
2086 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2087 (*packet_size) += ECRYPTFS_SIG_SIZE;
2088 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2089 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2090 key_rec->enc_key_size);
2091 (*packet_size) += key_rec->enc_key_size;
2092out:
2093 if (rc)
2094 (*packet_size) = 0;
2095 else
2096 (*remaining_bytes) -= (*packet_size);
2097 return rc;
2098}
2099
2100/**
2101 * write_tag_11_packet
2102 * @dest: Target into which Tag 11 packet is to be written
2103 * @remaining_bytes: Maximum packet length
2104 * @contents: Byte array of contents to copy in
2105 * @contents_length: Number of bytes in contents
2106 * @packet_length: Length of the Tag 11 packet written; zero on error
2107 *
2108 * Returns zero on success; non-zero on error.
2109 */
2110static int
2111write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2112 size_t contents_length, size_t *packet_length)
2113{
2114 size_t packet_size_length;
2115 size_t max_packet_size;
2116 int rc = 0;
2117
2118 (*packet_length) = 0;
2119 /* This format is inspired by OpenPGP; see RFC 2440
2120 * packet tag 11 */
2121 max_packet_size = (1 /* Tag 11 identifier */
2122 + 3 /* Max Tag 11 packet size */
2123 + 1 /* Binary format specifier */
2124 + 1 /* Filename length */
2125 + 8 /* Filename ("_CONSOLE") */
2126 + 4 /* Modification date */
2127 + contents_length); /* Literal data */
2128 if (max_packet_size > (*remaining_bytes)) {
2129 printk(KERN_ERR "Packet length larger than maximum allowable; "
2130 "need up to [%td] bytes, but there are only [%td] "
2131 "available\n", max_packet_size, (*remaining_bytes));
2132 rc = -EINVAL;
2133 goto out;
2134 }
2135 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2136 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2137 (max_packet_size - 4),
2138 &packet_size_length);
2139 if (rc) {
2140 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2141 "generate packet length. rc = [%d]\n", rc);
2142 goto out;
2143 }
2144 (*packet_length) += packet_size_length;
2145 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2146 dest[(*packet_length)++] = 8;
2147 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2148 (*packet_length) += 8;
2149 memset(&dest[(*packet_length)], 0x00, 4);
2150 (*packet_length) += 4;
2151 memcpy(&dest[(*packet_length)], contents, contents_length);
2152 (*packet_length) += contents_length;
2153 out:
2154 if (rc)
2155 (*packet_length) = 0;
2156 else
2157 (*remaining_bytes) -= (*packet_length);
2158 return rc;
2159}
2160
2161/**
2162 * write_tag_3_packet
2163 * @dest: Buffer into which to write the packet
2164 * @remaining_bytes: Maximum number of bytes that can be written
2165 * @auth_tok: Authentication token
2166 * @crypt_stat: The cryptographic context
2167 * @key_rec: encrypted key
2168 * @packet_size: This function will write the number of bytes that end
2169 * up constituting the packet; set to zero on error
2170 *
2171 * Returns zero on success; non-zero on error.
2172 */
2173static int
2174write_tag_3_packet(char *dest, size_t *remaining_bytes,
2175 struct ecryptfs_auth_tok *auth_tok,
2176 struct ecryptfs_crypt_stat *crypt_stat,
2177 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2178{
2179 size_t i;
2180 size_t encrypted_session_key_valid = 0;
2181 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2182 struct scatterlist dst_sg[2];
2183 struct scatterlist src_sg[2];
2184 struct mutex *tfm_mutex = NULL;
2185 u8 cipher_code;
2186 size_t packet_size_length;
2187 size_t max_packet_size;
2188 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2189 crypt_stat->mount_crypt_stat;
2190 struct crypto_skcipher *tfm;
2191 struct skcipher_request *req;
2192 int rc = 0;
2193
2194 (*packet_size) = 0;
2195 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2196 ECRYPTFS_SIG_SIZE);
2197 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
2198 crypt_stat->cipher);
2199 if (unlikely(rc)) {
2200 printk(KERN_ERR "Internal error whilst attempting to get "
2201 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2202 crypt_stat->cipher, rc);
2203 goto out;
2204 }
2205 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2206 printk(KERN_WARNING "No key size specified at mount; "
2207 "defaulting to [%d]\n",
2208 crypto_skcipher_max_keysize(tfm));
2209 mount_crypt_stat->global_default_cipher_key_size =
2210 crypto_skcipher_max_keysize(tfm);
2211 }
2212 if (crypt_stat->key_size == 0)
2213 crypt_stat->key_size =
2214 mount_crypt_stat->global_default_cipher_key_size;
2215 if (auth_tok->session_key.encrypted_key_size == 0)
2216 auth_tok->session_key.encrypted_key_size =
2217 crypt_stat->key_size;
2218 if (crypt_stat->key_size == 24
2219 && strcmp("aes", crypt_stat->cipher) == 0) {
2220 memset((crypt_stat->key + 24), 0, 8);
2221 auth_tok->session_key.encrypted_key_size = 32;
2222 } else
2223 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2224 key_rec->enc_key_size =
2225 auth_tok->session_key.encrypted_key_size;
2226 encrypted_session_key_valid = 0;
2227 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2228 encrypted_session_key_valid |=
2229 auth_tok->session_key.encrypted_key[i];
2230 if (encrypted_session_key_valid) {
2231 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2232 "using auth_tok->session_key.encrypted_key, "
2233 "where key_rec->enc_key_size = [%zd]\n",
2234 key_rec->enc_key_size);
2235 memcpy(key_rec->enc_key,
2236 auth_tok->session_key.encrypted_key,
2237 key_rec->enc_key_size);
2238 goto encrypted_session_key_set;
2239 }
2240 if (auth_tok->token.password.flags &
2241 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2242 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2243 "session key encryption key of size [%d]\n",
2244 auth_tok->token.password.
2245 session_key_encryption_key_bytes);
2246 memcpy(session_key_encryption_key,
2247 auth_tok->token.password.session_key_encryption_key,
2248 crypt_stat->key_size);
2249 ecryptfs_printk(KERN_DEBUG,
2250 "Cached session key encryption key:\n");
2251 if (ecryptfs_verbosity > 0)
2252 ecryptfs_dump_hex(session_key_encryption_key, 16);
2253 }
2254 if (unlikely(ecryptfs_verbosity > 0)) {
2255 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2256 ecryptfs_dump_hex(session_key_encryption_key, 16);
2257 }
2258 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2259 src_sg, 2);
2260 if (rc < 1 || rc > 2) {
2261 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2262 "for crypt_stat session key; expected rc = 1; "
2263 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2264 rc, key_rec->enc_key_size);
2265 rc = -ENOMEM;
2266 goto out;
2267 }
2268 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2269 dst_sg, 2);
2270 if (rc < 1 || rc > 2) {
2271 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2272 "for crypt_stat encrypted session key; "
2273 "expected rc = 1; got rc = [%d]. "
2274 "key_rec->enc_key_size = [%zd]\n", rc,
2275 key_rec->enc_key_size);
2276 rc = -ENOMEM;
2277 goto out;
2278 }
2279 mutex_lock(tfm_mutex);
2280 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
2281 crypt_stat->key_size);
2282 if (rc < 0) {
2283 mutex_unlock(tfm_mutex);
2284 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2285 "context; rc = [%d]\n", rc);
2286 goto out;
2287 }
2288
2289 req = skcipher_request_alloc(tfm, GFP_KERNEL);
2290 if (!req) {
2291 mutex_unlock(tfm_mutex);
2292 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
2293 "attempting to skcipher_request_alloc for "
2294 "%s\n", crypto_skcipher_driver_name(tfm));
2295 rc = -ENOMEM;
2296 goto out;
2297 }
2298
2299 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
2300 NULL, NULL);
2301
2302 rc = 0;
2303 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2304 crypt_stat->key_size);
2305 skcipher_request_set_crypt(req, src_sg, dst_sg,
2306 (*key_rec).enc_key_size, NULL);
2307 rc = crypto_skcipher_encrypt(req);
2308 mutex_unlock(tfm_mutex);
2309 skcipher_request_free(req);
2310 if (rc) {
2311 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2312 goto out;
2313 }
2314 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2315 if (ecryptfs_verbosity > 0) {
2316 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2317 key_rec->enc_key_size);
2318 ecryptfs_dump_hex(key_rec->enc_key,
2319 key_rec->enc_key_size);
2320 }
2321encrypted_session_key_set:
2322 /* This format is inspired by OpenPGP; see RFC 2440
2323 * packet tag 3 */
2324 max_packet_size = (1 /* Tag 3 identifier */
2325 + 3 /* Max Tag 3 packet size */
2326 + 1 /* Version */
2327 + 1 /* Cipher code */
2328 + 1 /* S2K specifier */
2329 + 1 /* Hash identifier */
2330 + ECRYPTFS_SALT_SIZE /* Salt */
2331 + 1 /* Hash iterations */
2332 + key_rec->enc_key_size); /* Encrypted key size */
2333 if (max_packet_size > (*remaining_bytes)) {
2334 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2335 "there are only [%td] available\n", max_packet_size,
2336 (*remaining_bytes));
2337 rc = -EINVAL;
2338 goto out;
2339 }
2340 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2341 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2342 * to get the number of octets in the actual Tag 3 packet */
2343 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2344 (max_packet_size - 4),
2345 &packet_size_length);
2346 if (rc) {
2347 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2348 "generate packet length. rc = [%d]\n", rc);
2349 goto out;
2350 }
2351 (*packet_size) += packet_size_length;
2352 dest[(*packet_size)++] = 0x04; /* version 4 */
2353 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2354 * specified with strings */
2355 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2356 crypt_stat->key_size);
2357 if (cipher_code == 0) {
2358 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2359 "cipher [%s]\n", crypt_stat->cipher);
2360 rc = -EINVAL;
2361 goto out;
2362 }
2363 dest[(*packet_size)++] = cipher_code;
2364 dest[(*packet_size)++] = 0x03; /* S2K */
2365 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2366 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2367 ECRYPTFS_SALT_SIZE);
2368 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2369 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2370 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2371 key_rec->enc_key_size);
2372 (*packet_size) += key_rec->enc_key_size;
2373out:
2374 if (rc)
2375 (*packet_size) = 0;
2376 else
2377 (*remaining_bytes) -= (*packet_size);
2378 return rc;
2379}
2380
2381struct kmem_cache *ecryptfs_key_record_cache;
2382
2383/**
2384 * ecryptfs_generate_key_packet_set
2385 * @dest_base: Virtual address from which to write the key record set
2386 * @crypt_stat: The cryptographic context from which the
2387 * authentication tokens will be retrieved
2388 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2389 * for the global parameters
2390 * @len: The amount written
2391 * @max: The maximum amount of data allowed to be written
2392 *
2393 * Generates a key packet set and writes it to the virtual address
2394 * passed in.
2395 *
2396 * Returns zero on success; non-zero on error.
2397 */
2398int
2399ecryptfs_generate_key_packet_set(char *dest_base,
2400 struct ecryptfs_crypt_stat *crypt_stat,
2401 struct dentry *ecryptfs_dentry, size_t *len,
2402 size_t max)
2403{
2404 struct ecryptfs_auth_tok *auth_tok;
2405 struct key *auth_tok_key = NULL;
2406 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2407 &ecryptfs_superblock_to_private(
2408 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2409 size_t written;
2410 struct ecryptfs_key_record *key_rec;
2411 struct ecryptfs_key_sig *key_sig;
2412 int rc = 0;
2413
2414 (*len) = 0;
2415 mutex_lock(&crypt_stat->keysig_list_mutex);
2416 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2417 if (!key_rec) {
2418 rc = -ENOMEM;
2419 goto out;
2420 }
2421 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2422 crypt_stat_list) {
2423 memset(key_rec, 0, sizeof(*key_rec));
2424 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2425 &auth_tok,
2426 mount_crypt_stat,
2427 key_sig->keysig);
2428 if (rc) {
2429 printk(KERN_WARNING "Unable to retrieve auth tok with "
2430 "sig = [%s]\n", key_sig->keysig);
2431 rc = process_find_global_auth_tok_for_sig_err(rc);
2432 goto out_free;
2433 }
2434 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2435 rc = write_tag_3_packet((dest_base + (*len)),
2436 &max, auth_tok,
2437 crypt_stat, key_rec,
2438 &written);
2439 up_write(&(auth_tok_key->sem));
2440 key_put(auth_tok_key);
2441 if (rc) {
2442 ecryptfs_printk(KERN_WARNING, "Error "
2443 "writing tag 3 packet\n");
2444 goto out_free;
2445 }
2446 (*len) += written;
2447 /* Write auth tok signature packet */
2448 rc = write_tag_11_packet((dest_base + (*len)), &max,
2449 key_rec->sig,
2450 ECRYPTFS_SIG_SIZE, &written);
2451 if (rc) {
2452 ecryptfs_printk(KERN_ERR, "Error writing "
2453 "auth tok signature packet\n");
2454 goto out_free;
2455 }
2456 (*len) += written;
2457 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2458 rc = write_tag_1_packet(dest_base + (*len), &max,
2459 auth_tok_key, auth_tok,
2460 crypt_stat, key_rec, &written);
2461 if (rc) {
2462 ecryptfs_printk(KERN_WARNING, "Error "
2463 "writing tag 1 packet\n");
2464 goto out_free;
2465 }
2466 (*len) += written;
2467 } else {
2468 up_write(&(auth_tok_key->sem));
2469 key_put(auth_tok_key);
2470 ecryptfs_printk(KERN_WARNING, "Unsupported "
2471 "authentication token type\n");
2472 rc = -EINVAL;
2473 goto out_free;
2474 }
2475 }
2476 if (likely(max > 0)) {
2477 dest_base[(*len)] = 0x00;
2478 } else {
2479 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2480 rc = -EIO;
2481 }
2482out_free:
2483 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2484out:
2485 if (rc)
2486 (*len) = 0;
2487 mutex_unlock(&crypt_stat->keysig_list_mutex);
2488 return rc;
2489}
2490
2491struct kmem_cache *ecryptfs_key_sig_cache;
2492
2493int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2494{
2495 struct ecryptfs_key_sig *new_key_sig;
2496
2497 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2498 if (!new_key_sig)
2499 return -ENOMEM;
2500
2501 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2502 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2503 /* Caller must hold keysig_list_mutex */
2504 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2505
2506 return 0;
2507}
2508
2509struct kmem_cache *ecryptfs_global_auth_tok_cache;
2510
2511int
2512ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2513 char *sig, u32 global_auth_tok_flags)
2514{
2515 struct ecryptfs_global_auth_tok *new_auth_tok;
2516
2517 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2518 GFP_KERNEL);
2519 if (!new_auth_tok)
2520 return -ENOMEM;
2521
2522 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2523 new_auth_tok->flags = global_auth_tok_flags;
2524 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2525 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2526 list_add(&new_auth_tok->mount_crypt_stat_list,
2527 &mount_crypt_stat->global_auth_tok_list);
2528 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2529 return 0;
2530}
2531