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