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