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Merge tag 'regmap-fix-v4.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux/fpc-iii.git] / fs / ecryptfs / keystore.c
blob3cf1546dca8257677572db866f86e3f2190a918e
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 */
43 static 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
68 static 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 */
95 int 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 }
122 out:
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 */
136 int 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
157 static int
158 write_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;
208 out:
209 return rc;
210 }
211
212 static int
213 parse_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 }
293 out:
294 return rc;
295 }
296
297
298 static int
299 write_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;
355 out:
356 return rc;
357 }
358
359 static int
360 parse_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);
421 out:
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 */
431 static 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 }
453 out:
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 */
464 static int
465 ecryptfs_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 }
486 out:
487 return rc;
488 }
489
490 static int
491 ecryptfs_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;
532 out_invalid_auth_tok_unlock:
533 up_write(&(walker->global_auth_tok_key->sem));
534 out_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;
539 out:
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 */
559 static int
560 ecryptfs_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 */
591 struct 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 */
624 int
625 ecryptfs_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);
855 out_release_free_unlock:
856 crypto_free_shash(s->hash_tfm);
857 out_free_unlock:
858 kzfree(s->block_aligned_filename);
859 out_unlock:
860 mutex_unlock(s->tfm_mutex);
861 out:
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
872 struct 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 */
907 int
908 ecryptfs_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';
1101 out_free_unlock:
1102 kfree(s->decrypted_filename);
1103 out_unlock:
1104 mutex_unlock(s->tfm_mutex);
1105 out:
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
1120 static int
1121 ecryptfs_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 */
1148 static int
1149 decrypt_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 }
1208 out:
1209 kfree(msg);
1210 kfree(payload);
1211 return rc;
1212 }
1213
1214 static 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
1227 struct 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 */
1246 static int
1247 parse_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;
1348 out_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);
1354 out:
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 */
1378 static int
1379 parse_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;
1524 out_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);
1530 out:
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 */
1552 static int
1553 parse_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);
1624 out:
1625 if (rc) {
1626 (*packet_size) = 0;
1627 (*tag_11_contents_size) = 0;
1628 }
1629 return rc;
1630 }
1631
1632 int 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 }
1657 out:
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 */
1668 static int
1669 decrypt_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 }
1758 out:
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 */
1776 int 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. */
1887 find_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 }
1920 found_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 }
1977 out_wipe_list:
1978 wipe_auth_tok_list(&auth_tok_list);
1979 out:
1980 return rc;
1981 }
1982
1983 static int
1984 pki_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);
2023 out:
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 */
2041 static int
2042 write_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 }
2082 encrypted_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;
2115 out:
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 */
2133 static int
2134 write_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 */
2196 static int
2197 write_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 }
2344 encrypted_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;
2396 out:
2397 if (rc)
2398 (*packet_size) = 0;
2399 else
2400 (*remaining_bytes) -= (*packet_size);
2401 return rc;
2402 }
2403
2404 struct 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 */
2421 int
2422 ecryptfs_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 }
2505 out_free:
2506 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2507 out:
2508 if (rc)
2509 (*len) = 0;
2510 mutex_unlock(&crypt_stat->keysig_list_mutex);
2511 return rc;
2512 }
2513
2514 struct kmem_cache *ecryptfs_key_sig_cache;
2515
2516 int 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
2534 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2535
2536 int
2537 ecryptfs_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);
2558 out:
2559 return rc;
2560 }
2561
Linux with added FPC-III support