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ALSA: hda - Constify fixup and other array data in patch_via.c
[linux/fpc-iii.git] / fs / ecryptfs / keystore.c
blob03e609c450120674673a5a6e07460b2014751ed0
1 /**
2 * eCryptfs: Linux filesystem encryption layer
3 * In-kernel key management code. Includes functions to parse and
4 * write authentication token-related packets with the underlying
5 * file.
6 *
7 * Copyright (C) 2004-2006 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
9 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * Trevor S. Highland <trevor.highland@gmail.com>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
25 * 02111-1307, USA.
26 */
27
28 #include <linux/string.h>
29 #include <linux/syscalls.h>
30 #include <linux/pagemap.h>
31 #include <linux/key.h>
32 #include <linux/random.h>
33 #include <linux/crypto.h>
34 #include <linux/scatterlist.h>
35 #include <linux/slab.h>
36 #include "ecryptfs_kernel.h"
37
38 /**
39 * request_key returned an error instead of a valid key address;
40 * determine the type of error, make appropriate log entries, and
41 * return an error code.
42 */
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) = (unsigned char)data[0];
105 (*length_size) = 1;
106 } else if (data[0] < 224) {
107 /* Two-byte length */
108 (*size) = (((unsigned char)(data[0]) - 192) * 256);
109 (*size) += ((unsigned char)(data[1]) + 192);
110 (*length_size) = 2;
111 } else if (data[0] == 255) {
112 /* Five-byte length; we're not supposed to see this */
113 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
114 "supported\n");
115 rc = -EINVAL;
116 goto out;
117 } else {
118 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
119 rc = -EINVAL;
120 goto out;
121 }
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 5 bytes allocated.
130 * @size: The length to write.
131 * @packet_size_length: The number of bytes used to encode the packet
132 * length is written to this address.
133 *
134 * Returns zero on success; non-zero on error.
135 */
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 rc = -EINVAL;
150 ecryptfs_printk(KERN_WARNING,
151 "Unsupported packet size: [%zd]\n", size);
152 }
153 return rc;
154 }
155
156 static int
157 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
158 char **packet, size_t *packet_len)
159 {
160 size_t i = 0;
161 size_t data_len;
162 size_t packet_size_len;
163 char *message;
164 int rc;
165
166 /*
167 * ***** TAG 64 Packet Format *****
168 * | Content Type | 1 byte |
169 * | Key Identifier Size | 1 or 2 bytes |
170 * | Key Identifier | arbitrary |
171 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
172 * | Encrypted File Encryption Key | arbitrary |
173 */
174 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
175 + session_key->encrypted_key_size);
176 *packet = kmalloc(data_len, GFP_KERNEL);
177 message = *packet;
178 if (!message) {
179 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
180 rc = -ENOMEM;
181 goto out;
182 }
183 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
184 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
185 &packet_size_len);
186 if (rc) {
187 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
188 "header; cannot generate packet length\n");
189 goto out;
190 }
191 i += packet_size_len;
192 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
193 i += ECRYPTFS_SIG_SIZE_HEX;
194 rc = ecryptfs_write_packet_length(&message[i],
195 session_key->encrypted_key_size,
196 &packet_size_len);
197 if (rc) {
198 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
199 "header; cannot generate packet length\n");
200 goto out;
201 }
202 i += packet_size_len;
203 memcpy(&message[i], session_key->encrypted_key,
204 session_key->encrypted_key_size);
205 i += session_key->encrypted_key_size;
206 *packet_len = i;
207 out:
208 return rc;
209 }
210
211 static int
212 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
213 struct ecryptfs_message *msg)
214 {
215 size_t i = 0;
216 char *data;
217 size_t data_len;
218 size_t m_size;
219 size_t message_len;
220 u16 checksum = 0;
221 u16 expected_checksum = 0;
222 int rc;
223
224 /*
225 * ***** TAG 65 Packet Format *****
226 * | Content Type | 1 byte |
227 * | Status Indicator | 1 byte |
228 * | File Encryption Key Size | 1 or 2 bytes |
229 * | File Encryption Key | arbitrary |
230 */
231 message_len = msg->data_len;
232 data = msg->data;
233 if (message_len < 4) {
234 rc = -EIO;
235 goto out;
236 }
237 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
238 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
239 rc = -EIO;
240 goto out;
241 }
242 if (data[i++]) {
243 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
244 "[%d]\n", data[i-1]);
245 rc = -EIO;
246 goto out;
247 }
248 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
249 if (rc) {
250 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
251 "rc = [%d]\n", rc);
252 goto out;
253 }
254 i += data_len;
255 if (message_len < (i + m_size)) {
256 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
257 "is shorter than expected\n");
258 rc = -EIO;
259 goto out;
260 }
261 if (m_size < 3) {
262 ecryptfs_printk(KERN_ERR,
263 "The decrypted key is not long enough to "
264 "include a cipher code and checksum\n");
265 rc = -EIO;
266 goto out;
267 }
268 *cipher_code = data[i++];
269 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
270 session_key->decrypted_key_size = m_size - 3;
271 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
272 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
273 "the maximum key size [%d]\n",
274 session_key->decrypted_key_size,
275 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
276 rc = -EIO;
277 goto out;
278 }
279 memcpy(session_key->decrypted_key, &data[i],
280 session_key->decrypted_key_size);
281 i += session_key->decrypted_key_size;
282 expected_checksum += (unsigned char)(data[i++]) << 8;
283 expected_checksum += (unsigned char)(data[i++]);
284 for (i = 0; i < session_key->decrypted_key_size; i++)
285 checksum += session_key->decrypted_key[i];
286 if (expected_checksum != checksum) {
287 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
288 "encryption key; expected [%x]; calculated "
289 "[%x]\n", expected_checksum, checksum);
290 rc = -EIO;
291 }
292 out:
293 return rc;
294 }
295
296
297 static int
298 write_tag_66_packet(char *signature, u8 cipher_code,
299 struct ecryptfs_crypt_stat *crypt_stat, char **packet,
300 size_t *packet_len)
301 {
302 size_t i = 0;
303 size_t j;
304 size_t data_len;
305 size_t checksum = 0;
306 size_t packet_size_len;
307 char *message;
308 int rc;
309
310 /*
311 * ***** TAG 66 Packet Format *****
312 * | Content Type | 1 byte |
313 * | Key Identifier Size | 1 or 2 bytes |
314 * | Key Identifier | arbitrary |
315 * | File Encryption Key Size | 1 or 2 bytes |
316 * | File Encryption Key | arbitrary |
317 */
318 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
319 *packet = kmalloc(data_len, GFP_KERNEL);
320 message = *packet;
321 if (!message) {
322 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
323 rc = -ENOMEM;
324 goto out;
325 }
326 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
327 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
328 &packet_size_len);
329 if (rc) {
330 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
331 "header; cannot generate packet length\n");
332 goto out;
333 }
334 i += packet_size_len;
335 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
336 i += ECRYPTFS_SIG_SIZE_HEX;
337 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
338 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
339 &packet_size_len);
340 if (rc) {
341 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
342 "header; cannot generate packet length\n");
343 goto out;
344 }
345 i += packet_size_len;
346 message[i++] = cipher_code;
347 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
348 i += crypt_stat->key_size;
349 for (j = 0; j < crypt_stat->key_size; j++)
350 checksum += crypt_stat->key[j];
351 message[i++] = (checksum / 256) % 256;
352 message[i++] = (checksum % 256);
353 *packet_len = i;
354 out:
355 return rc;
356 }
357
358 static int
359 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
360 struct ecryptfs_message *msg)
361 {
362 size_t i = 0;
363 char *data;
364 size_t data_len;
365 size_t message_len;
366 int rc;
367
368 /*
369 * ***** TAG 65 Packet Format *****
370 * | Content Type | 1 byte |
371 * | Status Indicator | 1 byte |
372 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
373 * | Encrypted File Encryption Key | arbitrary |
374 */
375 message_len = msg->data_len;
376 data = msg->data;
377 /* verify that everything through the encrypted FEK size is present */
378 if (message_len < 4) {
379 rc = -EIO;
380 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
381 "message length is [%d]\n", __func__, message_len, 4);
382 goto out;
383 }
384 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
385 rc = -EIO;
386 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
387 __func__);
388 goto out;
389 }
390 if (data[i++]) {
391 rc = -EIO;
392 printk(KERN_ERR "%s: Status indicator has non zero "
393 "value [%d]\n", __func__, data[i-1]);
394
395 goto out;
396 }
397 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
398 &data_len);
399 if (rc) {
400 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
401 "rc = [%d]\n", rc);
402 goto out;
403 }
404 i += data_len;
405 if (message_len < (i + key_rec->enc_key_size)) {
406 rc = -EIO;
407 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
408 __func__, message_len, (i + key_rec->enc_key_size));
409 goto out;
410 }
411 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
412 rc = -EIO;
413 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
414 "the maximum key size [%d]\n", __func__,
415 key_rec->enc_key_size,
416 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
417 goto out;
418 }
419 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
420 out:
421 return rc;
422 }
423
424 /**
425 * ecryptfs_verify_version
426 * @version: The version number to confirm
427 *
428 * Returns zero on good version; non-zero otherwise
429 */
430 static int ecryptfs_verify_version(u16 version)
431 {
432 int rc = 0;
433 unsigned char major;
434 unsigned char minor;
435
436 major = ((version >> 8) & 0xFF);
437 minor = (version & 0xFF);
438 if (major != ECRYPTFS_VERSION_MAJOR) {
439 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
440 "Expected [%d]; got [%d]\n",
441 ECRYPTFS_VERSION_MAJOR, major);
442 rc = -EINVAL;
443 goto out;
444 }
445 if (minor != ECRYPTFS_VERSION_MINOR) {
446 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
447 "Expected [%d]; got [%d]\n",
448 ECRYPTFS_VERSION_MINOR, minor);
449 rc = -EINVAL;
450 goto out;
451 }
452 out:
453 return rc;
454 }
455
456 /**
457 * ecryptfs_verify_auth_tok_from_key
458 * @auth_tok_key: key containing the authentication token
459 * @auth_tok: authentication token
460 *
461 * Returns zero on valid auth tok; -EINVAL otherwise
462 */
463 static int
464 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
465 struct ecryptfs_auth_tok **auth_tok)
466 {
467 int rc = 0;
468
469 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
470 if (ecryptfs_verify_version((*auth_tok)->version)) {
471 printk(KERN_ERR "Data structure version mismatch. Userspace "
472 "tools must match eCryptfs kernel module with major "
473 "version [%d] and minor version [%d]\n",
474 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
475 rc = -EINVAL;
476 goto out;
477 }
478 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
479 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
480 printk(KERN_ERR "Invalid auth_tok structure "
481 "returned from key query\n");
482 rc = -EINVAL;
483 goto out;
484 }
485 out:
486 return rc;
487 }
488
489 static int
490 ecryptfs_find_global_auth_tok_for_sig(
491 struct key **auth_tok_key,
492 struct ecryptfs_auth_tok **auth_tok,
493 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
494 {
495 struct ecryptfs_global_auth_tok *walker;
496 int rc = 0;
497
498 (*auth_tok_key) = NULL;
499 (*auth_tok) = NULL;
500 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
501 list_for_each_entry(walker,
502 &mount_crypt_stat->global_auth_tok_list,
503 mount_crypt_stat_list) {
504 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
505 continue;
506
507 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
508 rc = -EINVAL;
509 goto out;
510 }
511
512 rc = key_validate(walker->global_auth_tok_key);
513 if (rc) {
514 if (rc == -EKEYEXPIRED)
515 goto out;
516 goto out_invalid_auth_tok;
517 }
518
519 down_write(&(walker->global_auth_tok_key->sem));
520 rc = ecryptfs_verify_auth_tok_from_key(
521 walker->global_auth_tok_key, auth_tok);
522 if (rc)
523 goto out_invalid_auth_tok_unlock;
524
525 (*auth_tok_key) = walker->global_auth_tok_key;
526 key_get(*auth_tok_key);
527 goto out;
528 }
529 rc = -ENOENT;
530 goto out;
531 out_invalid_auth_tok_unlock:
532 up_write(&(walker->global_auth_tok_key->sem));
533 out_invalid_auth_tok:
534 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
535 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
536 key_put(walker->global_auth_tok_key);
537 walker->global_auth_tok_key = NULL;
538 out:
539 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
540 return rc;
541 }
542
543 /**
544 * ecryptfs_find_auth_tok_for_sig
545 * @auth_tok: Set to the matching auth_tok; NULL if not found
546 * @crypt_stat: inode crypt_stat crypto context
547 * @sig: Sig of auth_tok to find
548 *
549 * For now, this function simply looks at the registered auth_tok's
550 * linked off the mount_crypt_stat, so all the auth_toks that can be
551 * used must be registered at mount time. This function could
552 * potentially try a lot harder to find auth_tok's (e.g., by calling
553 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
554 * that static registration of auth_tok's will no longer be necessary.
555 *
556 * Returns zero on no error; non-zero on error
557 */
558 static int
559 ecryptfs_find_auth_tok_for_sig(
560 struct key **auth_tok_key,
561 struct ecryptfs_auth_tok **auth_tok,
562 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
563 char *sig)
564 {
565 int rc = 0;
566
567 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
568 mount_crypt_stat, sig);
569 if (rc == -ENOENT) {
570 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
571 * mount_crypt_stat structure, we prevent to use auth toks that
572 * are not inserted through the ecryptfs_add_global_auth_tok
573 * function.
574 */
575 if (mount_crypt_stat->flags
576 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
577 return -EINVAL;
578
579 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
580 sig);
581 }
582 return rc;
583 }
584
585 /**
586 * write_tag_70_packet can gobble a lot of stack space. We stuff most
587 * of the function's parameters in a kmalloc'd struct to help reduce
588 * eCryptfs' overall stack usage.
589 */
590 struct ecryptfs_write_tag_70_packet_silly_stack {
591 u8 cipher_code;
592 size_t max_packet_size;
593 size_t packet_size_len;
594 size_t block_aligned_filename_size;
595 size_t block_size;
596 size_t i;
597 size_t j;
598 size_t num_rand_bytes;
599 struct mutex *tfm_mutex;
600 char *block_aligned_filename;
601 struct ecryptfs_auth_tok *auth_tok;
602 struct scatterlist src_sg;
603 struct scatterlist dst_sg;
604 struct blkcipher_desc desc;
605 char iv[ECRYPTFS_MAX_IV_BYTES];
606 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
607 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
608 struct hash_desc hash_desc;
609 struct scatterlist hash_sg;
610 };
611
612 /**
613 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
614 * @filename: NULL-terminated filename string
615 *
616 * This is the simplest mechanism for achieving filename encryption in
617 * eCryptfs. It encrypts the given filename with the mount-wide
618 * filename encryption key (FNEK) and stores it in a packet to @dest,
619 * which the callee will encode and write directly into the dentry
620 * name.
621 */
622 int
623 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
624 size_t *packet_size,
625 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
626 char *filename, size_t filename_size)
627 {
628 struct ecryptfs_write_tag_70_packet_silly_stack *s;
629 struct key *auth_tok_key = NULL;
630 int rc = 0;
631
632 s = kmalloc(sizeof(*s), GFP_KERNEL);
633 if (!s) {
634 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
635 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
636 rc = -ENOMEM;
637 goto out;
638 }
639 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
640 (*packet_size) = 0;
641 rc = ecryptfs_find_auth_tok_for_sig(
642 &auth_tok_key,
643 &s->auth_tok, mount_crypt_stat,
644 mount_crypt_stat->global_default_fnek_sig);
645 if (rc) {
646 printk(KERN_ERR "%s: Error attempting to find auth tok for "
647 "fnek sig [%s]; rc = [%d]\n", __func__,
648 mount_crypt_stat->global_default_fnek_sig, rc);
649 goto out;
650 }
651 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
652 &s->desc.tfm,
653 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
654 if (unlikely(rc)) {
655 printk(KERN_ERR "Internal error whilst attempting to get "
656 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
657 mount_crypt_stat->global_default_fn_cipher_name, rc);
658 goto out;
659 }
660 mutex_lock(s->tfm_mutex);
661 s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
662 /* Plus one for the \0 separator between the random prefix
663 * and the plaintext filename */
664 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
665 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
666 if ((s->block_aligned_filename_size % s->block_size) != 0) {
667 s->num_rand_bytes += (s->block_size
668 - (s->block_aligned_filename_size
669 % s->block_size));
670 s->block_aligned_filename_size = (s->num_rand_bytes
671 + filename_size);
672 }
673 /* Octet 0: Tag 70 identifier
674 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
675 * and block-aligned encrypted filename size)
676 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
677 * Octet N2-N3: Cipher identifier (1 octet)
678 * Octets N3-N4: Block-aligned encrypted filename
679 * - Consists of a minimum number of random characters, a \0
680 * separator, and then the filename */
681 s->max_packet_size = (1 /* Tag 70 identifier */
682 + 3 /* Max Tag 70 packet size */
683 + ECRYPTFS_SIG_SIZE /* FNEK sig */
684 + 1 /* Cipher identifier */
685 + s->block_aligned_filename_size);
686 if (dest == NULL) {
687 (*packet_size) = s->max_packet_size;
688 goto out_unlock;
689 }
690 if (s->max_packet_size > (*remaining_bytes)) {
691 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
692 "[%zd] available\n", __func__, s->max_packet_size,
693 (*remaining_bytes));
694 rc = -EINVAL;
695 goto out_unlock;
696 }
697 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
698 GFP_KERNEL);
699 if (!s->block_aligned_filename) {
700 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
701 "kzalloc [%zd] bytes\n", __func__,
702 s->block_aligned_filename_size);
703 rc = -ENOMEM;
704 goto out_unlock;
705 }
706 s->i = 0;
707 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
708 rc = ecryptfs_write_packet_length(&dest[s->i],
709 (ECRYPTFS_SIG_SIZE
710 + 1 /* Cipher code */
711 + s->block_aligned_filename_size),
712 &s->packet_size_len);
713 if (rc) {
714 printk(KERN_ERR "%s: Error generating tag 70 packet "
715 "header; cannot generate packet length; rc = [%d]\n",
716 __func__, rc);
717 goto out_free_unlock;
718 }
719 s->i += s->packet_size_len;
720 ecryptfs_from_hex(&dest[s->i],
721 mount_crypt_stat->global_default_fnek_sig,
722 ECRYPTFS_SIG_SIZE);
723 s->i += ECRYPTFS_SIG_SIZE;
724 s->cipher_code = ecryptfs_code_for_cipher_string(
725 mount_crypt_stat->global_default_fn_cipher_name,
726 mount_crypt_stat->global_default_fn_cipher_key_bytes);
727 if (s->cipher_code == 0) {
728 printk(KERN_WARNING "%s: Unable to generate code for "
729 "cipher [%s] with key bytes [%zd]\n", __func__,
730 mount_crypt_stat->global_default_fn_cipher_name,
731 mount_crypt_stat->global_default_fn_cipher_key_bytes);
732 rc = -EINVAL;
733 goto out_free_unlock;
734 }
735 dest[s->i++] = s->cipher_code;
736 /* TODO: Support other key modules than passphrase for
737 * filename encryption */
738 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
739 rc = -EOPNOTSUPP;
740 printk(KERN_INFO "%s: Filename encryption only supports "
741 "password tokens\n", __func__);
742 goto out_free_unlock;
743 }
744 sg_init_one(
745 &s->hash_sg,
746 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
747 s->auth_tok->token.password.session_key_encryption_key_bytes);
748 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
749 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
750 CRYPTO_ALG_ASYNC);
751 if (IS_ERR(s->hash_desc.tfm)) {
752 rc = PTR_ERR(s->hash_desc.tfm);
753 printk(KERN_ERR "%s: Error attempting to "
754 "allocate hash crypto context; rc = [%d]\n",
755 __func__, rc);
756 goto out_free_unlock;
757 }
758 rc = crypto_hash_init(&s->hash_desc);
759 if (rc) {
760 printk(KERN_ERR
761 "%s: Error initializing crypto hash; rc = [%d]\n",
762 __func__, rc);
763 goto out_release_free_unlock;
764 }
765 rc = crypto_hash_update(
766 &s->hash_desc, &s->hash_sg,
767 s->auth_tok->token.password.session_key_encryption_key_bytes);
768 if (rc) {
769 printk(KERN_ERR
770 "%s: Error updating crypto hash; rc = [%d]\n",
771 __func__, rc);
772 goto out_release_free_unlock;
773 }
774 rc = crypto_hash_final(&s->hash_desc, s->hash);
775 if (rc) {
776 printk(KERN_ERR
777 "%s: Error finalizing crypto hash; rc = [%d]\n",
778 __func__, rc);
779 goto out_release_free_unlock;
780 }
781 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
782 s->block_aligned_filename[s->j] =
783 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
784 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
785 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
786 sg_init_one(&s->hash_sg, (u8 *)s->hash,
787 ECRYPTFS_TAG_70_DIGEST_SIZE);
788 rc = crypto_hash_init(&s->hash_desc);
789 if (rc) {
790 printk(KERN_ERR
791 "%s: Error initializing crypto hash; "
792 "rc = [%d]\n", __func__, rc);
793 goto out_release_free_unlock;
794 }
795 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
796 ECRYPTFS_TAG_70_DIGEST_SIZE);
797 if (rc) {
798 printk(KERN_ERR
799 "%s: Error updating crypto hash; "
800 "rc = [%d]\n", __func__, rc);
801 goto out_release_free_unlock;
802 }
803 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
804 if (rc) {
805 printk(KERN_ERR
806 "%s: Error finalizing crypto hash; "
807 "rc = [%d]\n", __func__, rc);
808 goto out_release_free_unlock;
809 }
810 memcpy(s->hash, s->tmp_hash,
811 ECRYPTFS_TAG_70_DIGEST_SIZE);
812 }
813 if (s->block_aligned_filename[s->j] == '\0')
814 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
815 }
816 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
817 filename_size);
818 rc = virt_to_scatterlist(s->block_aligned_filename,
819 s->block_aligned_filename_size, &s->src_sg, 1);
820 if (rc != 1) {
821 printk(KERN_ERR "%s: Internal error whilst attempting to "
822 "convert filename memory to scatterlist; "
823 "expected rc = 1; got rc = [%d]. "
824 "block_aligned_filename_size = [%zd]\n", __func__, rc,
825 s->block_aligned_filename_size);
826 goto out_release_free_unlock;
827 }
828 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
829 &s->dst_sg, 1);
830 if (rc != 1) {
831 printk(KERN_ERR "%s: Internal error whilst attempting to "
832 "convert encrypted filename memory to scatterlist; "
833 "expected rc = 1; got rc = [%d]. "
834 "block_aligned_filename_size = [%zd]\n", __func__, rc,
835 s->block_aligned_filename_size);
836 goto out_release_free_unlock;
837 }
838 /* The characters in the first block effectively do the job
839 * of the IV here, so we just use 0's for the IV. Note the
840 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
841 * >= ECRYPTFS_MAX_IV_BYTES. */
842 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
843 s->desc.info = s->iv;
844 rc = crypto_blkcipher_setkey(
845 s->desc.tfm,
846 s->auth_tok->token.password.session_key_encryption_key,
847 mount_crypt_stat->global_default_fn_cipher_key_bytes);
848 if (rc < 0) {
849 printk(KERN_ERR "%s: Error setting key for crypto context; "
850 "rc = [%d]. s->auth_tok->token.password.session_key_"
851 "encryption_key = [0x%p]; mount_crypt_stat->"
852 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
853 rc,
854 s->auth_tok->token.password.session_key_encryption_key,
855 mount_crypt_stat->global_default_fn_cipher_key_bytes);
856 goto out_release_free_unlock;
857 }
858 rc = crypto_blkcipher_encrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
859 s->block_aligned_filename_size);
860 if (rc) {
861 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
862 "rc = [%d]\n", __func__, rc);
863 goto out_release_free_unlock;
864 }
865 s->i += s->block_aligned_filename_size;
866 (*packet_size) = s->i;
867 (*remaining_bytes) -= (*packet_size);
868 out_release_free_unlock:
869 crypto_free_hash(s->hash_desc.tfm);
870 out_free_unlock:
871 kzfree(s->block_aligned_filename);
872 out_unlock:
873 mutex_unlock(s->tfm_mutex);
874 out:
875 if (auth_tok_key) {
876 up_write(&(auth_tok_key->sem));
877 key_put(auth_tok_key);
878 }
879 kfree(s);
880 return rc;
881 }
882
883 struct ecryptfs_parse_tag_70_packet_silly_stack {
884 u8 cipher_code;
885 size_t max_packet_size;
886 size_t packet_size_len;
887 size_t parsed_tag_70_packet_size;
888 size_t block_aligned_filename_size;
889 size_t block_size;
890 size_t i;
891 struct mutex *tfm_mutex;
892 char *decrypted_filename;
893 struct ecryptfs_auth_tok *auth_tok;
894 struct scatterlist src_sg;
895 struct scatterlist dst_sg;
896 struct blkcipher_desc desc;
897 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
898 char iv[ECRYPTFS_MAX_IV_BYTES];
899 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
900 };
901
902 /**
903 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
904 * @filename: This function kmalloc's the memory for the filename
905 * @filename_size: This function sets this to the amount of memory
906 * kmalloc'd for the filename
907 * @packet_size: This function sets this to the the number of octets
908 * in the packet parsed
909 * @mount_crypt_stat: The mount-wide cryptographic context
910 * @data: The memory location containing the start of the tag 70
911 * packet
912 * @max_packet_size: The maximum legal size of the packet to be parsed
913 * from @data
914 *
915 * Returns zero on success; non-zero otherwise
916 */
917 int
918 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
919 size_t *packet_size,
920 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
921 char *data, size_t max_packet_size)
922 {
923 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
924 struct key *auth_tok_key = NULL;
925 int rc = 0;
926
927 (*packet_size) = 0;
928 (*filename_size) = 0;
929 (*filename) = NULL;
930 s = kmalloc(sizeof(*s), GFP_KERNEL);
931 if (!s) {
932 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
933 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
934 rc = -ENOMEM;
935 goto out;
936 }
937 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
938 if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
939 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
940 "at least [%d]\n", __func__, max_packet_size,
941 (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
942 rc = -EINVAL;
943 goto out;
944 }
945 /* Octet 0: Tag 70 identifier
946 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
947 * and block-aligned encrypted filename size)
948 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
949 * Octet N2-N3: Cipher identifier (1 octet)
950 * Octets N3-N4: Block-aligned encrypted filename
951 * - Consists of a minimum number of random numbers, a \0
952 * separator, and then the filename */
953 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
954 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
955 "tag [0x%.2x]\n", __func__,
956 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
957 rc = -EINVAL;
958 goto out;
959 }
960 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
961 &s->parsed_tag_70_packet_size,
962 &s->packet_size_len);
963 if (rc) {
964 printk(KERN_WARNING "%s: Error parsing packet length; "
965 "rc = [%d]\n", __func__, rc);
966 goto out;
967 }
968 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
969 - ECRYPTFS_SIG_SIZE - 1);
970 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
971 > max_packet_size) {
972 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
973 "size is [%zd]\n", __func__, max_packet_size,
974 (1 + s->packet_size_len + 1
975 + s->block_aligned_filename_size));
976 rc = -EINVAL;
977 goto out;
978 }
979 (*packet_size) += s->packet_size_len;
980 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
981 ECRYPTFS_SIG_SIZE);
982 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
983 (*packet_size) += ECRYPTFS_SIG_SIZE;
984 s->cipher_code = data[(*packet_size)++];
985 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
986 if (rc) {
987 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
988 __func__, s->cipher_code);
989 goto out;
990 }
991 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
992 &s->auth_tok, mount_crypt_stat,
993 s->fnek_sig_hex);
994 if (rc) {
995 printk(KERN_ERR "%s: Error attempting to find auth tok for "
996 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
997 rc);
998 goto out;
999 }
1000 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
1001 &s->tfm_mutex,
1002 s->cipher_string);
1003 if (unlikely(rc)) {
1004 printk(KERN_ERR "Internal error whilst attempting to get "
1005 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1006 s->cipher_string, rc);
1007 goto out;
1008 }
1009 mutex_lock(s->tfm_mutex);
1010 rc = virt_to_scatterlist(&data[(*packet_size)],
1011 s->block_aligned_filename_size, &s->src_sg, 1);
1012 if (rc != 1) {
1013 printk(KERN_ERR "%s: Internal error whilst attempting to "
1014 "convert encrypted filename memory to scatterlist; "
1015 "expected rc = 1; got rc = [%d]. "
1016 "block_aligned_filename_size = [%zd]\n", __func__, rc,
1017 s->block_aligned_filename_size);
1018 goto out_unlock;
1019 }
1020 (*packet_size) += s->block_aligned_filename_size;
1021 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1022 GFP_KERNEL);
1023 if (!s->decrypted_filename) {
1024 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1025 "kmalloc [%zd] bytes\n", __func__,
1026 s->block_aligned_filename_size);
1027 rc = -ENOMEM;
1028 goto out_unlock;
1029 }
1030 rc = virt_to_scatterlist(s->decrypted_filename,
1031 s->block_aligned_filename_size, &s->dst_sg, 1);
1032 if (rc != 1) {
1033 printk(KERN_ERR "%s: Internal error whilst attempting to "
1034 "convert decrypted filename memory to scatterlist; "
1035 "expected rc = 1; got rc = [%d]. "
1036 "block_aligned_filename_size = [%zd]\n", __func__, rc,
1037 s->block_aligned_filename_size);
1038 goto out_free_unlock;
1039 }
1040 /* The characters in the first block effectively do the job of
1041 * the IV here, so we just use 0's for the IV. Note the
1042 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1043 * >= ECRYPTFS_MAX_IV_BYTES. */
1044 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1045 s->desc.info = s->iv;
1046 /* TODO: Support other key modules than passphrase for
1047 * filename encryption */
1048 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1049 rc = -EOPNOTSUPP;
1050 printk(KERN_INFO "%s: Filename encryption only supports "
1051 "password tokens\n", __func__);
1052 goto out_free_unlock;
1053 }
1054 rc = crypto_blkcipher_setkey(
1055 s->desc.tfm,
1056 s->auth_tok->token.password.session_key_encryption_key,
1057 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1058 if (rc < 0) {
1059 printk(KERN_ERR "%s: Error setting key for crypto context; "
1060 "rc = [%d]. s->auth_tok->token.password.session_key_"
1061 "encryption_key = [0x%p]; mount_crypt_stat->"
1062 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1063 rc,
1064 s->auth_tok->token.password.session_key_encryption_key,
1065 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1066 goto out_free_unlock;
1067 }
1068 rc = crypto_blkcipher_decrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
1069 s->block_aligned_filename_size);
1070 if (rc) {
1071 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1072 "rc = [%d]\n", __func__, rc);
1073 goto out_free_unlock;
1074 }
1075 s->i = 0;
1076 while (s->decrypted_filename[s->i] != '\0'
1077 && s->i < s->block_aligned_filename_size)
1078 s->i++;
1079 if (s->i == s->block_aligned_filename_size) {
1080 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1081 "find valid separator between random characters and "
1082 "the filename\n", __func__);
1083 rc = -EINVAL;
1084 goto out_free_unlock;
1085 }
1086 s->i++;
1087 (*filename_size) = (s->block_aligned_filename_size - s->i);
1088 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1089 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1090 "invalid\n", __func__, (*filename_size));
1091 rc = -EINVAL;
1092 goto out_free_unlock;
1093 }
1094 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1095 if (!(*filename)) {
1096 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1097 "kmalloc [%zd] bytes\n", __func__,
1098 ((*filename_size) + 1));
1099 rc = -ENOMEM;
1100 goto out_free_unlock;
1101 }
1102 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1103 (*filename)[(*filename_size)] = '\0';
1104 out_free_unlock:
1105 kfree(s->decrypted_filename);
1106 out_unlock:
1107 mutex_unlock(s->tfm_mutex);
1108 out:
1109 if (rc) {
1110 (*packet_size) = 0;
1111 (*filename_size) = 0;
1112 (*filename) = NULL;
1113 }
1114 if (auth_tok_key) {
1115 up_write(&(auth_tok_key->sem));
1116 key_put(auth_tok_key);
1117 }
1118 kfree(s);
1119 return rc;
1120 }
1121
1122 static int
1123 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1124 {
1125 int rc = 0;
1126
1127 (*sig) = NULL;
1128 switch (auth_tok->token_type) {
1129 case ECRYPTFS_PASSWORD:
1130 (*sig) = auth_tok->token.password.signature;
1131 break;
1132 case ECRYPTFS_PRIVATE_KEY:
1133 (*sig) = auth_tok->token.private_key.signature;
1134 break;
1135 default:
1136 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1137 auth_tok->token_type);
1138 rc = -EINVAL;
1139 }
1140 return rc;
1141 }
1142
1143 /**
1144 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1145 * @auth_tok: The key authentication token used to decrypt the session key
1146 * @crypt_stat: The cryptographic context
1147 *
1148 * Returns zero on success; non-zero error otherwise.
1149 */
1150 static int
1151 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1152 struct ecryptfs_crypt_stat *crypt_stat)
1153 {
1154 u8 cipher_code = 0;
1155 struct ecryptfs_msg_ctx *msg_ctx;
1156 struct ecryptfs_message *msg = NULL;
1157 char *auth_tok_sig;
1158 char *payload;
1159 size_t payload_len;
1160 int rc;
1161
1162 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1163 if (rc) {
1164 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1165 auth_tok->token_type);
1166 goto out;
1167 }
1168 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1169 &payload, &payload_len);
1170 if (rc) {
1171 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1172 goto out;
1173 }
1174 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1175 if (rc) {
1176 ecryptfs_printk(KERN_ERR, "Error sending message to "
1177 "ecryptfsd\n");
1178 goto out;
1179 }
1180 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1181 if (rc) {
1182 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1183 "from the user space daemon\n");
1184 rc = -EIO;
1185 goto out;
1186 }
1187 rc = parse_tag_65_packet(&(auth_tok->session_key),
1188 &cipher_code, msg);
1189 if (rc) {
1190 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1191 rc);
1192 goto out;
1193 }
1194 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1195 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1196 auth_tok->session_key.decrypted_key_size);
1197 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1198 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1199 if (rc) {
1200 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1201 cipher_code)
1202 goto out;
1203 }
1204 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1205 if (ecryptfs_verbosity > 0) {
1206 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1207 ecryptfs_dump_hex(crypt_stat->key,
1208 crypt_stat->key_size);
1209 }
1210 out:
1211 if (msg)
1212 kfree(msg);
1213 return rc;
1214 }
1215
1216 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1217 {
1218 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1219 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1220
1221 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1222 auth_tok_list_head, list) {
1223 list_del(&auth_tok_list_item->list);
1224 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1225 auth_tok_list_item);
1226 }
1227 }
1228
1229 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1230
1231 /**
1232 * parse_tag_1_packet
1233 * @crypt_stat: The cryptographic context to modify based on packet contents
1234 * @data: The raw bytes of the packet.
1235 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1236 * a new authentication token will be placed at the
1237 * end of this list for this packet.
1238 * @new_auth_tok: Pointer to a pointer to memory that this function
1239 * allocates; sets the memory address of the pointer to
1240 * NULL on error. This object is added to the
1241 * auth_tok_list.
1242 * @packet_size: This function writes the size of the parsed packet
1243 * into this memory location; zero on error.
1244 * @max_packet_size: The maximum allowable packet size
1245 *
1246 * Returns zero on success; non-zero on error.
1247 */
1248 static int
1249 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1250 unsigned char *data, struct list_head *auth_tok_list,
1251 struct ecryptfs_auth_tok **new_auth_tok,
1252 size_t *packet_size, size_t max_packet_size)
1253 {
1254 size_t body_size;
1255 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1256 size_t length_size;
1257 int rc = 0;
1258
1259 (*packet_size) = 0;
1260 (*new_auth_tok) = NULL;
1261 /**
1262 * This format is inspired by OpenPGP; see RFC 2440
1263 * packet tag 1
1264 *
1265 * Tag 1 identifier (1 byte)
1266 * Max Tag 1 packet size (max 3 bytes)
1267 * Version (1 byte)
1268 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1269 * Cipher identifier (1 byte)
1270 * Encrypted key size (arbitrary)
1271 *
1272 * 12 bytes minimum packet size
1273 */
1274 if (unlikely(max_packet_size < 12)) {
1275 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1276 rc = -EINVAL;
1277 goto out;
1278 }
1279 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1280 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1281 ECRYPTFS_TAG_1_PACKET_TYPE);
1282 rc = -EINVAL;
1283 goto out;
1284 }
1285 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1286 * at end of function upon failure */
1287 auth_tok_list_item =
1288 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1289 GFP_KERNEL);
1290 if (!auth_tok_list_item) {
1291 printk(KERN_ERR "Unable to allocate memory\n");
1292 rc = -ENOMEM;
1293 goto out;
1294 }
1295 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1296 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1297 &length_size);
1298 if (rc) {
1299 printk(KERN_WARNING "Error parsing packet length; "
1300 "rc = [%d]\n", rc);
1301 goto out_free;
1302 }
1303 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1304 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1305 rc = -EINVAL;
1306 goto out_free;
1307 }
1308 (*packet_size) += length_size;
1309 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1310 printk(KERN_WARNING "Packet size exceeds max\n");
1311 rc = -EINVAL;
1312 goto out_free;
1313 }
1314 if (unlikely(data[(*packet_size)++] != 0x03)) {
1315 printk(KERN_WARNING "Unknown version number [%d]\n",
1316 data[(*packet_size) - 1]);
1317 rc = -EINVAL;
1318 goto out_free;
1319 }
1320 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1321 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1322 *packet_size += ECRYPTFS_SIG_SIZE;
1323 /* This byte is skipped because the kernel does not need to
1324 * know which public key encryption algorithm was used */
1325 (*packet_size)++;
1326 (*new_auth_tok)->session_key.encrypted_key_size =
1327 body_size - (ECRYPTFS_SIG_SIZE + 2);
1328 if ((*new_auth_tok)->session_key.encrypted_key_size
1329 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1330 printk(KERN_WARNING "Tag 1 packet contains key larger "
1331 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1332 rc = -EINVAL;
1333 goto out;
1334 }
1335 memcpy((*new_auth_tok)->session_key.encrypted_key,
1336 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1337 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1338 (*new_auth_tok)->session_key.flags &=
1339 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1340 (*new_auth_tok)->session_key.flags |=
1341 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1342 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1343 (*new_auth_tok)->flags = 0;
1344 (*new_auth_tok)->session_key.flags &=
1345 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1346 (*new_auth_tok)->session_key.flags &=
1347 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1348 list_add(&auth_tok_list_item->list, auth_tok_list);
1349 goto out;
1350 out_free:
1351 (*new_auth_tok) = NULL;
1352 memset(auth_tok_list_item, 0,
1353 sizeof(struct ecryptfs_auth_tok_list_item));
1354 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1355 auth_tok_list_item);
1356 out:
1357 if (rc)
1358 (*packet_size) = 0;
1359 return rc;
1360 }
1361
1362 /**
1363 * parse_tag_3_packet
1364 * @crypt_stat: The cryptographic context to modify based on packet
1365 * contents.
1366 * @data: The raw bytes of the packet.
1367 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1368 * a new authentication token will be placed at the end
1369 * of this list for this packet.
1370 * @new_auth_tok: Pointer to a pointer to memory that this function
1371 * allocates; sets the memory address of the pointer to
1372 * NULL on error. This object is added to the
1373 * auth_tok_list.
1374 * @packet_size: This function writes the size of the parsed packet
1375 * into this memory location; zero on error.
1376 * @max_packet_size: maximum number of bytes to parse
1377 *
1378 * Returns zero on success; non-zero on error.
1379 */
1380 static int
1381 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1382 unsigned char *data, struct list_head *auth_tok_list,
1383 struct ecryptfs_auth_tok **new_auth_tok,
1384 size_t *packet_size, size_t max_packet_size)
1385 {
1386 size_t body_size;
1387 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1388 size_t length_size;
1389 int rc = 0;
1390
1391 (*packet_size) = 0;
1392 (*new_auth_tok) = NULL;
1393 /**
1394 *This format is inspired by OpenPGP; see RFC 2440
1395 * packet tag 3
1396 *
1397 * Tag 3 identifier (1 byte)
1398 * Max Tag 3 packet size (max 3 bytes)
1399 * Version (1 byte)
1400 * Cipher code (1 byte)
1401 * S2K specifier (1 byte)
1402 * Hash identifier (1 byte)
1403 * Salt (ECRYPTFS_SALT_SIZE)
1404 * Hash iterations (1 byte)
1405 * Encrypted key (arbitrary)
1406 *
1407 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1408 */
1409 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1410 printk(KERN_ERR "Max packet size too large\n");
1411 rc = -EINVAL;
1412 goto out;
1413 }
1414 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1415 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1416 ECRYPTFS_TAG_3_PACKET_TYPE);
1417 rc = -EINVAL;
1418 goto out;
1419 }
1420 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1421 * at end of function upon failure */
1422 auth_tok_list_item =
1423 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1424 if (!auth_tok_list_item) {
1425 printk(KERN_ERR "Unable to allocate memory\n");
1426 rc = -ENOMEM;
1427 goto out;
1428 }
1429 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1430 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1431 &length_size);
1432 if (rc) {
1433 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1434 rc);
1435 goto out_free;
1436 }
1437 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1438 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1439 rc = -EINVAL;
1440 goto out_free;
1441 }
1442 (*packet_size) += length_size;
1443 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1444 printk(KERN_ERR "Packet size exceeds max\n");
1445 rc = -EINVAL;
1446 goto out_free;
1447 }
1448 (*new_auth_tok)->session_key.encrypted_key_size =
1449 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1450 if ((*new_auth_tok)->session_key.encrypted_key_size
1451 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1452 printk(KERN_WARNING "Tag 3 packet contains key larger "
1453 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1454 rc = -EINVAL;
1455 goto out_free;
1456 }
1457 if (unlikely(data[(*packet_size)++] != 0x04)) {
1458 printk(KERN_WARNING "Unknown version number [%d]\n",
1459 data[(*packet_size) - 1]);
1460 rc = -EINVAL;
1461 goto out_free;
1462 }
1463 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1464 (u16)data[(*packet_size)]);
1465 if (rc)
1466 goto out_free;
1467 /* A little extra work to differentiate among the AES key
1468 * sizes; see RFC2440 */
1469 switch(data[(*packet_size)++]) {
1470 case RFC2440_CIPHER_AES_192:
1471 crypt_stat->key_size = 24;
1472 break;
1473 default:
1474 crypt_stat->key_size =
1475 (*new_auth_tok)->session_key.encrypted_key_size;
1476 }
1477 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1478 if (rc)
1479 goto out_free;
1480 if (unlikely(data[(*packet_size)++] != 0x03)) {
1481 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1482 rc = -ENOSYS;
1483 goto out_free;
1484 }
1485 /* TODO: finish the hash mapping */
1486 switch (data[(*packet_size)++]) {
1487 case 0x01: /* See RFC2440 for these numbers and their mappings */
1488 /* Choose MD5 */
1489 memcpy((*new_auth_tok)->token.password.salt,
1490 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1491 (*packet_size) += ECRYPTFS_SALT_SIZE;
1492 /* This conversion was taken straight from RFC2440 */
1493 (*new_auth_tok)->token.password.hash_iterations =
1494 ((u32) 16 + (data[(*packet_size)] & 15))
1495 << ((data[(*packet_size)] >> 4) + 6);
1496 (*packet_size)++;
1497 /* Friendly reminder:
1498 * (*new_auth_tok)->session_key.encrypted_key_size =
1499 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1500 memcpy((*new_auth_tok)->session_key.encrypted_key,
1501 &data[(*packet_size)],
1502 (*new_auth_tok)->session_key.encrypted_key_size);
1503 (*packet_size) +=
1504 (*new_auth_tok)->session_key.encrypted_key_size;
1505 (*new_auth_tok)->session_key.flags &=
1506 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1507 (*new_auth_tok)->session_key.flags |=
1508 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1509 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1510 break;
1511 default:
1512 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1513 "[%d]\n", data[(*packet_size) - 1]);
1514 rc = -ENOSYS;
1515 goto out_free;
1516 }
1517 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1518 /* TODO: Parametarize; we might actually want userspace to
1519 * decrypt the session key. */
1520 (*new_auth_tok)->session_key.flags &=
1521 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1522 (*new_auth_tok)->session_key.flags &=
1523 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1524 list_add(&auth_tok_list_item->list, auth_tok_list);
1525 goto out;
1526 out_free:
1527 (*new_auth_tok) = NULL;
1528 memset(auth_tok_list_item, 0,
1529 sizeof(struct ecryptfs_auth_tok_list_item));
1530 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1531 auth_tok_list_item);
1532 out:
1533 if (rc)
1534 (*packet_size) = 0;
1535 return rc;
1536 }
1537
1538 /**
1539 * parse_tag_11_packet
1540 * @data: The raw bytes of the packet
1541 * @contents: This function writes the data contents of the literal
1542 * packet into this memory location
1543 * @max_contents_bytes: The maximum number of bytes that this function
1544 * is allowed to write into contents
1545 * @tag_11_contents_size: This function writes the size of the parsed
1546 * contents into this memory location; zero on
1547 * error
1548 * @packet_size: This function writes the size of the parsed packet
1549 * into this memory location; zero on error
1550 * @max_packet_size: maximum number of bytes to parse
1551 *
1552 * Returns zero on success; non-zero on error.
1553 */
1554 static int
1555 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1556 size_t max_contents_bytes, size_t *tag_11_contents_size,
1557 size_t *packet_size, size_t max_packet_size)
1558 {
1559 size_t body_size;
1560 size_t length_size;
1561 int rc = 0;
1562
1563 (*packet_size) = 0;
1564 (*tag_11_contents_size) = 0;
1565 /* This format is inspired by OpenPGP; see RFC 2440
1566 * packet tag 11
1567 *
1568 * Tag 11 identifier (1 byte)
1569 * Max Tag 11 packet size (max 3 bytes)
1570 * Binary format specifier (1 byte)
1571 * Filename length (1 byte)
1572 * Filename ("_CONSOLE") (8 bytes)
1573 * Modification date (4 bytes)
1574 * Literal data (arbitrary)
1575 *
1576 * We need at least 16 bytes of data for the packet to even be
1577 * valid.
1578 */
1579 if (max_packet_size < 16) {
1580 printk(KERN_ERR "Maximum packet size too small\n");
1581 rc = -EINVAL;
1582 goto out;
1583 }
1584 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1585 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1586 rc = -EINVAL;
1587 goto out;
1588 }
1589 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1590 &length_size);
1591 if (rc) {
1592 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1593 goto out;
1594 }
1595 if (body_size < 14) {
1596 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1597 rc = -EINVAL;
1598 goto out;
1599 }
1600 (*packet_size) += length_size;
1601 (*tag_11_contents_size) = (body_size - 14);
1602 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1603 printk(KERN_ERR "Packet size exceeds max\n");
1604 rc = -EINVAL;
1605 goto out;
1606 }
1607 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1608 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1609 "expected size\n");
1610 rc = -EINVAL;
1611 goto out;
1612 }
1613 if (data[(*packet_size)++] != 0x62) {
1614 printk(KERN_WARNING "Unrecognizable packet\n");
1615 rc = -EINVAL;
1616 goto out;
1617 }
1618 if (data[(*packet_size)++] != 0x08) {
1619 printk(KERN_WARNING "Unrecognizable packet\n");
1620 rc = -EINVAL;
1621 goto out;
1622 }
1623 (*packet_size) += 12; /* Ignore filename and modification date */
1624 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1625 (*packet_size) += (*tag_11_contents_size);
1626 out:
1627 if (rc) {
1628 (*packet_size) = 0;
1629 (*tag_11_contents_size) = 0;
1630 }
1631 return rc;
1632 }
1633
1634 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1635 struct ecryptfs_auth_tok **auth_tok,
1636 char *sig)
1637 {
1638 int rc = 0;
1639
1640 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
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 down_write(&(*auth_tok_key)->sem);
1649 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1650 if (rc) {
1651 up_write(&(*auth_tok_key)->sem);
1652 key_put(*auth_tok_key);
1653 (*auth_tok_key) = NULL;
1654 goto out;
1655 }
1656 out:
1657 return rc;
1658 }
1659
1660 /**
1661 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1662 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1663 * @crypt_stat: The cryptographic context
1664 *
1665 * Returns zero on success; non-zero error otherwise
1666 */
1667 static int
1668 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1669 struct ecryptfs_crypt_stat *crypt_stat)
1670 {
1671 struct scatterlist dst_sg[2];
1672 struct scatterlist src_sg[2];
1673 struct mutex *tfm_mutex;
1674 struct blkcipher_desc desc = {
1675 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1676 };
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(&desc.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 rc = crypto_blkcipher_setkey(
1719 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1720 crypt_stat->key_size);
1721 if (unlikely(rc < 0)) {
1722 mutex_unlock(tfm_mutex);
1723 printk(KERN_ERR "Error setting key for crypto context\n");
1724 rc = -EINVAL;
1725 goto out;
1726 }
1727 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1728 auth_tok->session_key.encrypted_key_size);
1729 mutex_unlock(tfm_mutex);
1730 if (unlikely(rc)) {
1731 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1732 goto out;
1733 }
1734 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1735 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1736 auth_tok->session_key.decrypted_key_size);
1737 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1738 if (unlikely(ecryptfs_verbosity > 0)) {
1739 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1740 crypt_stat->key_size);
1741 ecryptfs_dump_hex(crypt_stat->key,
1742 crypt_stat->key_size);
1743 }
1744 out:
1745 return rc;
1746 }
1747
1748 /**
1749 * ecryptfs_parse_packet_set
1750 * @crypt_stat: The cryptographic context
1751 * @src: Virtual address of region of memory containing the packets
1752 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1753 *
1754 * Get crypt_stat to have the file's session key if the requisite key
1755 * is available to decrypt the session key.
1756 *
1757 * Returns Zero if a valid authentication token was retrieved and
1758 * processed; negative value for file not encrypted or for error
1759 * conditions.
1760 */
1761 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1762 unsigned char *src,
1763 struct dentry *ecryptfs_dentry)
1764 {
1765 size_t i = 0;
1766 size_t found_auth_tok;
1767 size_t next_packet_is_auth_tok_packet;
1768 struct list_head auth_tok_list;
1769 struct ecryptfs_auth_tok *matching_auth_tok;
1770 struct ecryptfs_auth_tok *candidate_auth_tok;
1771 char *candidate_auth_tok_sig;
1772 size_t packet_size;
1773 struct ecryptfs_auth_tok *new_auth_tok;
1774 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1775 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1776 size_t tag_11_contents_size;
1777 size_t tag_11_packet_size;
1778 struct key *auth_tok_key = NULL;
1779 int rc = 0;
1780
1781 INIT_LIST_HEAD(&auth_tok_list);
1782 /* Parse the header to find as many packets as we can; these will be
1783 * added the our &auth_tok_list */
1784 next_packet_is_auth_tok_packet = 1;
1785 while (next_packet_is_auth_tok_packet) {
1786 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1787
1788 switch (src[i]) {
1789 case ECRYPTFS_TAG_3_PACKET_TYPE:
1790 rc = parse_tag_3_packet(crypt_stat,
1791 (unsigned char *)&src[i],
1792 &auth_tok_list, &new_auth_tok,
1793 &packet_size, max_packet_size);
1794 if (rc) {
1795 ecryptfs_printk(KERN_ERR, "Error parsing "
1796 "tag 3 packet\n");
1797 rc = -EIO;
1798 goto out_wipe_list;
1799 }
1800 i += packet_size;
1801 rc = parse_tag_11_packet((unsigned char *)&src[i],
1802 sig_tmp_space,
1803 ECRYPTFS_SIG_SIZE,
1804 &tag_11_contents_size,
1805 &tag_11_packet_size,
1806 max_packet_size);
1807 if (rc) {
1808 ecryptfs_printk(KERN_ERR, "No valid "
1809 "(ecryptfs-specific) literal "
1810 "packet containing "
1811 "authentication token "
1812 "signature found after "
1813 "tag 3 packet\n");
1814 rc = -EIO;
1815 goto out_wipe_list;
1816 }
1817 i += tag_11_packet_size;
1818 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1819 ecryptfs_printk(KERN_ERR, "Expected "
1820 "signature of size [%d]; "
1821 "read size [%zd]\n",
1822 ECRYPTFS_SIG_SIZE,
1823 tag_11_contents_size);
1824 rc = -EIO;
1825 goto out_wipe_list;
1826 }
1827 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1828 sig_tmp_space, tag_11_contents_size);
1829 new_auth_tok->token.password.signature[
1830 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1831 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1832 break;
1833 case ECRYPTFS_TAG_1_PACKET_TYPE:
1834 rc = parse_tag_1_packet(crypt_stat,
1835 (unsigned char *)&src[i],
1836 &auth_tok_list, &new_auth_tok,
1837 &packet_size, max_packet_size);
1838 if (rc) {
1839 ecryptfs_printk(KERN_ERR, "Error parsing "
1840 "tag 1 packet\n");
1841 rc = -EIO;
1842 goto out_wipe_list;
1843 }
1844 i += packet_size;
1845 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1846 break;
1847 case ECRYPTFS_TAG_11_PACKET_TYPE:
1848 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1849 "(Tag 11 not allowed by itself)\n");
1850 rc = -EIO;
1851 goto out_wipe_list;
1852 break;
1853 default:
1854 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1855 "of the file header; hex value of "
1856 "character is [0x%.2x]\n", i, src[i]);
1857 next_packet_is_auth_tok_packet = 0;
1858 }
1859 }
1860 if (list_empty(&auth_tok_list)) {
1861 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1862 "eCryptfs file; this is not supported in this version "
1863 "of the eCryptfs kernel module\n");
1864 rc = -EINVAL;
1865 goto out;
1866 }
1867 /* auth_tok_list contains the set of authentication tokens
1868 * parsed from the metadata. We need to find a matching
1869 * authentication token that has the secret component(s)
1870 * necessary to decrypt the EFEK in the auth_tok parsed from
1871 * the metadata. There may be several potential matches, but
1872 * just one will be sufficient to decrypt to get the FEK. */
1873 find_next_matching_auth_tok:
1874 found_auth_tok = 0;
1875 if (auth_tok_key) {
1876 up_write(&(auth_tok_key->sem));
1877 key_put(auth_tok_key);
1878 auth_tok_key = NULL;
1879 }
1880 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1881 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1882 if (unlikely(ecryptfs_verbosity > 0)) {
1883 ecryptfs_printk(KERN_DEBUG,
1884 "Considering cadidate auth tok:\n");
1885 ecryptfs_dump_auth_tok(candidate_auth_tok);
1886 }
1887 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1888 candidate_auth_tok);
1889 if (rc) {
1890 printk(KERN_ERR
1891 "Unrecognized candidate auth tok type: [%d]\n",
1892 candidate_auth_tok->token_type);
1893 rc = -EINVAL;
1894 goto out_wipe_list;
1895 }
1896 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1897 &matching_auth_tok,
1898 crypt_stat->mount_crypt_stat,
1899 candidate_auth_tok_sig);
1900 if (!rc) {
1901 found_auth_tok = 1;
1902 goto found_matching_auth_tok;
1903 }
1904 }
1905 if (!found_auth_tok) {
1906 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1907 "authentication token\n");
1908 rc = -EIO;
1909 goto out_wipe_list;
1910 }
1911 found_matching_auth_tok:
1912 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1913 memcpy(&(candidate_auth_tok->token.private_key),
1914 &(matching_auth_tok->token.private_key),
1915 sizeof(struct ecryptfs_private_key));
1916 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1917 crypt_stat);
1918 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1919 memcpy(&(candidate_auth_tok->token.password),
1920 &(matching_auth_tok->token.password),
1921 sizeof(struct ecryptfs_password));
1922 rc = decrypt_passphrase_encrypted_session_key(
1923 candidate_auth_tok, crypt_stat);
1924 }
1925 if (rc) {
1926 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1927
1928 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1929 "session key for authentication token with sig "
1930 "[%.*s]; rc = [%d]. Removing auth tok "
1931 "candidate from the list and searching for "
1932 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1933 candidate_auth_tok_sig, rc);
1934 list_for_each_entry_safe(auth_tok_list_item,
1935 auth_tok_list_item_tmp,
1936 &auth_tok_list, list) {
1937 if (candidate_auth_tok
1938 == &auth_tok_list_item->auth_tok) {
1939 list_del(&auth_tok_list_item->list);
1940 kmem_cache_free(
1941 ecryptfs_auth_tok_list_item_cache,
1942 auth_tok_list_item);
1943 goto find_next_matching_auth_tok;
1944 }
1945 }
1946 BUG();
1947 }
1948 rc = ecryptfs_compute_root_iv(crypt_stat);
1949 if (rc) {
1950 ecryptfs_printk(KERN_ERR, "Error computing "
1951 "the root IV\n");
1952 goto out_wipe_list;
1953 }
1954 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1955 if (rc) {
1956 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1957 "context for cipher [%s]; rc = [%d]\n",
1958 crypt_stat->cipher, rc);
1959 }
1960 out_wipe_list:
1961 wipe_auth_tok_list(&auth_tok_list);
1962 out:
1963 if (auth_tok_key) {
1964 up_write(&(auth_tok_key->sem));
1965 key_put(auth_tok_key);
1966 }
1967 return rc;
1968 }
1969
1970 static int
1971 pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
1972 struct ecryptfs_crypt_stat *crypt_stat,
1973 struct ecryptfs_key_record *key_rec)
1974 {
1975 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1976 char *payload = NULL;
1977 size_t payload_len;
1978 struct ecryptfs_message *msg;
1979 int rc;
1980
1981 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1982 ecryptfs_code_for_cipher_string(
1983 crypt_stat->cipher,
1984 crypt_stat->key_size),
1985 crypt_stat, &payload, &payload_len);
1986 if (rc) {
1987 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1988 goto out;
1989 }
1990 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1991 if (rc) {
1992 ecryptfs_printk(KERN_ERR, "Error sending message to "
1993 "ecryptfsd\n");
1994 goto out;
1995 }
1996 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1997 if (rc) {
1998 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1999 "from the user space daemon\n");
2000 rc = -EIO;
2001 goto out;
2002 }
2003 rc = parse_tag_67_packet(key_rec, msg);
2004 if (rc)
2005 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2006 kfree(msg);
2007 out:
2008 kfree(payload);
2009 return rc;
2010 }
2011 /**
2012 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2013 * @dest: Buffer into which to write the packet
2014 * @remaining_bytes: Maximum number of bytes that can be writtn
2015 * @auth_tok: The authentication token used for generating the tag 1 packet
2016 * @crypt_stat: The cryptographic context
2017 * @key_rec: The key record struct for the tag 1 packet
2018 * @packet_size: This function will write the number of bytes that end
2019 * up constituting the packet; set to zero on error
2020 *
2021 * Returns zero on success; non-zero on error.
2022 */
2023 static int
2024 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2025 struct ecryptfs_auth_tok *auth_tok,
2026 struct ecryptfs_crypt_stat *crypt_stat,
2027 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2028 {
2029 size_t i;
2030 size_t encrypted_session_key_valid = 0;
2031 size_t packet_size_length;
2032 size_t max_packet_size;
2033 int rc = 0;
2034
2035 (*packet_size) = 0;
2036 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2037 ECRYPTFS_SIG_SIZE);
2038 encrypted_session_key_valid = 0;
2039 for (i = 0; i < crypt_stat->key_size; i++)
2040 encrypted_session_key_valid |=
2041 auth_tok->session_key.encrypted_key[i];
2042 if (encrypted_session_key_valid) {
2043 memcpy(key_rec->enc_key,
2044 auth_tok->session_key.encrypted_key,
2045 auth_tok->session_key.encrypted_key_size);
2046 goto encrypted_session_key_set;
2047 }
2048 if (auth_tok->session_key.encrypted_key_size == 0)
2049 auth_tok->session_key.encrypted_key_size =
2050 auth_tok->token.private_key.key_size;
2051 rc = pki_encrypt_session_key(auth_tok, crypt_stat, key_rec);
2052 if (rc) {
2053 printk(KERN_ERR "Failed to encrypt session key via a key "
2054 "module; rc = [%d]\n", rc);
2055 goto out;
2056 }
2057 if (ecryptfs_verbosity > 0) {
2058 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2059 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2060 }
2061 encrypted_session_key_set:
2062 /* This format is inspired by OpenPGP; see RFC 2440
2063 * packet tag 1 */
2064 max_packet_size = (1 /* Tag 1 identifier */
2065 + 3 /* Max Tag 1 packet size */
2066 + 1 /* Version */
2067 + ECRYPTFS_SIG_SIZE /* Key identifier */
2068 + 1 /* Cipher identifier */
2069 + key_rec->enc_key_size); /* Encrypted key size */
2070 if (max_packet_size > (*remaining_bytes)) {
2071 printk(KERN_ERR "Packet length larger than maximum allowable; "
2072 "need up to [%td] bytes, but there are only [%td] "
2073 "available\n", max_packet_size, (*remaining_bytes));
2074 rc = -EINVAL;
2075 goto out;
2076 }
2077 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2078 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2079 (max_packet_size - 4),
2080 &packet_size_length);
2081 if (rc) {
2082 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2083 "header; cannot generate packet length\n");
2084 goto out;
2085 }
2086 (*packet_size) += packet_size_length;
2087 dest[(*packet_size)++] = 0x03; /* version 3 */
2088 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2089 (*packet_size) += ECRYPTFS_SIG_SIZE;
2090 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2091 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2092 key_rec->enc_key_size);
2093 (*packet_size) += key_rec->enc_key_size;
2094 out:
2095 if (rc)
2096 (*packet_size) = 0;
2097 else
2098 (*remaining_bytes) -= (*packet_size);
2099 return rc;
2100 }
2101
2102 /**
2103 * write_tag_11_packet
2104 * @dest: Target into which Tag 11 packet is to be written
2105 * @remaining_bytes: Maximum packet length
2106 * @contents: Byte array of contents to copy in
2107 * @contents_length: Number of bytes in contents
2108 * @packet_length: Length of the Tag 11 packet written; zero on error
2109 *
2110 * Returns zero on success; non-zero on error.
2111 */
2112 static int
2113 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2114 size_t contents_length, size_t *packet_length)
2115 {
2116 size_t packet_size_length;
2117 size_t max_packet_size;
2118 int rc = 0;
2119
2120 (*packet_length) = 0;
2121 /* This format is inspired by OpenPGP; see RFC 2440
2122 * packet tag 11 */
2123 max_packet_size = (1 /* Tag 11 identifier */
2124 + 3 /* Max Tag 11 packet size */
2125 + 1 /* Binary format specifier */
2126 + 1 /* Filename length */
2127 + 8 /* Filename ("_CONSOLE") */
2128 + 4 /* Modification date */
2129 + contents_length); /* Literal data */
2130 if (max_packet_size > (*remaining_bytes)) {
2131 printk(KERN_ERR "Packet length larger than maximum allowable; "
2132 "need up to [%td] bytes, but there are only [%td] "
2133 "available\n", max_packet_size, (*remaining_bytes));
2134 rc = -EINVAL;
2135 goto out;
2136 }
2137 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2138 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2139 (max_packet_size - 4),
2140 &packet_size_length);
2141 if (rc) {
2142 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2143 "generate packet length. rc = [%d]\n", rc);
2144 goto out;
2145 }
2146 (*packet_length) += packet_size_length;
2147 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2148 dest[(*packet_length)++] = 8;
2149 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2150 (*packet_length) += 8;
2151 memset(&dest[(*packet_length)], 0x00, 4);
2152 (*packet_length) += 4;
2153 memcpy(&dest[(*packet_length)], contents, contents_length);
2154 (*packet_length) += contents_length;
2155 out:
2156 if (rc)
2157 (*packet_length) = 0;
2158 else
2159 (*remaining_bytes) -= (*packet_length);
2160 return rc;
2161 }
2162
2163 /**
2164 * write_tag_3_packet
2165 * @dest: Buffer into which to write the packet
2166 * @remaining_bytes: Maximum number of bytes that can be written
2167 * @auth_tok: Authentication token
2168 * @crypt_stat: The cryptographic context
2169 * @key_rec: encrypted key
2170 * @packet_size: This function will write the number of bytes that end
2171 * up constituting the packet; set to zero on error
2172 *
2173 * Returns zero on success; non-zero on error.
2174 */
2175 static int
2176 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2177 struct ecryptfs_auth_tok *auth_tok,
2178 struct ecryptfs_crypt_stat *crypt_stat,
2179 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2180 {
2181 size_t i;
2182 size_t encrypted_session_key_valid = 0;
2183 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2184 struct scatterlist dst_sg[2];
2185 struct scatterlist src_sg[2];
2186 struct mutex *tfm_mutex = NULL;
2187 u8 cipher_code;
2188 size_t packet_size_length;
2189 size_t max_packet_size;
2190 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2191 crypt_stat->mount_crypt_stat;
2192 struct blkcipher_desc desc = {
2193 .tfm = NULL,
2194 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2195 };
2196 int rc = 0;
2197
2198 (*packet_size) = 0;
2199 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2200 ECRYPTFS_SIG_SIZE);
2201 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2202 crypt_stat->cipher);
2203 if (unlikely(rc)) {
2204 printk(KERN_ERR "Internal error whilst attempting to get "
2205 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2206 crypt_stat->cipher, rc);
2207 goto out;
2208 }
2209 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2210 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2211
2212 printk(KERN_WARNING "No key size specified at mount; "
2213 "defaulting to [%d]\n", alg->max_keysize);
2214 mount_crypt_stat->global_default_cipher_key_size =
2215 alg->max_keysize;
2216 }
2217 if (crypt_stat->key_size == 0)
2218 crypt_stat->key_size =
2219 mount_crypt_stat->global_default_cipher_key_size;
2220 if (auth_tok->session_key.encrypted_key_size == 0)
2221 auth_tok->session_key.encrypted_key_size =
2222 crypt_stat->key_size;
2223 if (crypt_stat->key_size == 24
2224 && strcmp("aes", crypt_stat->cipher) == 0) {
2225 memset((crypt_stat->key + 24), 0, 8);
2226 auth_tok->session_key.encrypted_key_size = 32;
2227 } else
2228 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2229 key_rec->enc_key_size =
2230 auth_tok->session_key.encrypted_key_size;
2231 encrypted_session_key_valid = 0;
2232 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2233 encrypted_session_key_valid |=
2234 auth_tok->session_key.encrypted_key[i];
2235 if (encrypted_session_key_valid) {
2236 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2237 "using auth_tok->session_key.encrypted_key, "
2238 "where key_rec->enc_key_size = [%zd]\n",
2239 key_rec->enc_key_size);
2240 memcpy(key_rec->enc_key,
2241 auth_tok->session_key.encrypted_key,
2242 key_rec->enc_key_size);
2243 goto encrypted_session_key_set;
2244 }
2245 if (auth_tok->token.password.flags &
2246 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2247 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2248 "session key encryption key of size [%d]\n",
2249 auth_tok->token.password.
2250 session_key_encryption_key_bytes);
2251 memcpy(session_key_encryption_key,
2252 auth_tok->token.password.session_key_encryption_key,
2253 crypt_stat->key_size);
2254 ecryptfs_printk(KERN_DEBUG,
2255 "Cached session key " "encryption key: \n");
2256 if (ecryptfs_verbosity > 0)
2257 ecryptfs_dump_hex(session_key_encryption_key, 16);
2258 }
2259 if (unlikely(ecryptfs_verbosity > 0)) {
2260 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2261 ecryptfs_dump_hex(session_key_encryption_key, 16);
2262 }
2263 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2264 src_sg, 2);
2265 if (rc < 1 || rc > 2) {
2266 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2267 "for crypt_stat session key; expected rc = 1; "
2268 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2269 rc, key_rec->enc_key_size);
2270 rc = -ENOMEM;
2271 goto out;
2272 }
2273 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2274 dst_sg, 2);
2275 if (rc < 1 || rc > 2) {
2276 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2277 "for crypt_stat encrypted session key; "
2278 "expected rc = 1; got rc = [%d]. "
2279 "key_rec->enc_key_size = [%zd]\n", rc,
2280 key_rec->enc_key_size);
2281 rc = -ENOMEM;
2282 goto out;
2283 }
2284 mutex_lock(tfm_mutex);
2285 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2286 crypt_stat->key_size);
2287 if (rc < 0) {
2288 mutex_unlock(tfm_mutex);
2289 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2290 "context; rc = [%d]\n", rc);
2291 goto out;
2292 }
2293 rc = 0;
2294 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2295 crypt_stat->key_size);
2296 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2297 (*key_rec).enc_key_size);
2298 mutex_unlock(tfm_mutex);
2299 if (rc) {
2300 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2301 goto out;
2302 }
2303 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2304 if (ecryptfs_verbosity > 0) {
2305 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2306 key_rec->enc_key_size);
2307 ecryptfs_dump_hex(key_rec->enc_key,
2308 key_rec->enc_key_size);
2309 }
2310 encrypted_session_key_set:
2311 /* This format is inspired by OpenPGP; see RFC 2440
2312 * packet tag 3 */
2313 max_packet_size = (1 /* Tag 3 identifier */
2314 + 3 /* Max Tag 3 packet size */
2315 + 1 /* Version */
2316 + 1 /* Cipher code */
2317 + 1 /* S2K specifier */
2318 + 1 /* Hash identifier */
2319 + ECRYPTFS_SALT_SIZE /* Salt */
2320 + 1 /* Hash iterations */
2321 + key_rec->enc_key_size); /* Encrypted key size */
2322 if (max_packet_size > (*remaining_bytes)) {
2323 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2324 "there are only [%td] available\n", max_packet_size,
2325 (*remaining_bytes));
2326 rc = -EINVAL;
2327 goto out;
2328 }
2329 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2330 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2331 * to get the number of octets in the actual Tag 3 packet */
2332 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2333 (max_packet_size - 4),
2334 &packet_size_length);
2335 if (rc) {
2336 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2337 "generate packet length. rc = [%d]\n", rc);
2338 goto out;
2339 }
2340 (*packet_size) += packet_size_length;
2341 dest[(*packet_size)++] = 0x04; /* version 4 */
2342 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2343 * specified with strings */
2344 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2345 crypt_stat->key_size);
2346 if (cipher_code == 0) {
2347 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2348 "cipher [%s]\n", crypt_stat->cipher);
2349 rc = -EINVAL;
2350 goto out;
2351 }
2352 dest[(*packet_size)++] = cipher_code;
2353 dest[(*packet_size)++] = 0x03; /* S2K */
2354 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2355 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2356 ECRYPTFS_SALT_SIZE);
2357 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2358 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2359 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2360 key_rec->enc_key_size);
2361 (*packet_size) += key_rec->enc_key_size;
2362 out:
2363 if (rc)
2364 (*packet_size) = 0;
2365 else
2366 (*remaining_bytes) -= (*packet_size);
2367 return rc;
2368 }
2369
2370 struct kmem_cache *ecryptfs_key_record_cache;
2371
2372 /**
2373 * ecryptfs_generate_key_packet_set
2374 * @dest_base: Virtual address from which to write the key record set
2375 * @crypt_stat: The cryptographic context from which the
2376 * authentication tokens will be retrieved
2377 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2378 * for the global parameters
2379 * @len: The amount written
2380 * @max: The maximum amount of data allowed to be written
2381 *
2382 * Generates a key packet set and writes it to the virtual address
2383 * passed in.
2384 *
2385 * Returns zero on success; non-zero on error.
2386 */
2387 int
2388 ecryptfs_generate_key_packet_set(char *dest_base,
2389 struct ecryptfs_crypt_stat *crypt_stat,
2390 struct dentry *ecryptfs_dentry, size_t *len,
2391 size_t max)
2392 {
2393 struct ecryptfs_auth_tok *auth_tok;
2394 struct key *auth_tok_key = NULL;
2395 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2396 &ecryptfs_superblock_to_private(
2397 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2398 size_t written;
2399 struct ecryptfs_key_record *key_rec;
2400 struct ecryptfs_key_sig *key_sig;
2401 int rc = 0;
2402
2403 (*len) = 0;
2404 mutex_lock(&crypt_stat->keysig_list_mutex);
2405 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2406 if (!key_rec) {
2407 rc = -ENOMEM;
2408 goto out;
2409 }
2410 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2411 crypt_stat_list) {
2412 memset(key_rec, 0, sizeof(*key_rec));
2413 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2414 &auth_tok,
2415 mount_crypt_stat,
2416 key_sig->keysig);
2417 if (rc) {
2418 printk(KERN_WARNING "Unable to retrieve auth tok with "
2419 "sig = [%s]\n", key_sig->keysig);
2420 rc = process_find_global_auth_tok_for_sig_err(rc);
2421 goto out_free;
2422 }
2423 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2424 rc = write_tag_3_packet((dest_base + (*len)),
2425 &max, auth_tok,
2426 crypt_stat, key_rec,
2427 &written);
2428 if (rc) {
2429 ecryptfs_printk(KERN_WARNING, "Error "
2430 "writing tag 3 packet\n");
2431 goto out_free;
2432 }
2433 (*len) += written;
2434 /* Write auth tok signature packet */
2435 rc = write_tag_11_packet((dest_base + (*len)), &max,
2436 key_rec->sig,
2437 ECRYPTFS_SIG_SIZE, &written);
2438 if (rc) {
2439 ecryptfs_printk(KERN_ERR, "Error writing "
2440 "auth tok signature packet\n");
2441 goto out_free;
2442 }
2443 (*len) += written;
2444 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2445 rc = write_tag_1_packet(dest_base + (*len),
2446 &max, auth_tok,
2447 crypt_stat, key_rec, &written);
2448 if (rc) {
2449 ecryptfs_printk(KERN_WARNING, "Error "
2450 "writing tag 1 packet\n");
2451 goto out_free;
2452 }
2453 (*len) += written;
2454 } else {
2455 ecryptfs_printk(KERN_WARNING, "Unsupported "
2456 "authentication token type\n");
2457 rc = -EINVAL;
2458 goto out_free;
2459 }
2460 up_write(&(auth_tok_key->sem));
2461 key_put(auth_tok_key);
2462 auth_tok_key = NULL;
2463 }
2464 if (likely(max > 0)) {
2465 dest_base[(*len)] = 0x00;
2466 } else {
2467 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2468 rc = -EIO;
2469 }
2470 out_free:
2471 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2472 out:
2473 if (rc)
2474 (*len) = 0;
2475 if (auth_tok_key) {
2476 up_write(&(auth_tok_key->sem));
2477 key_put(auth_tok_key);
2478 }
2479
2480 mutex_unlock(&crypt_stat->keysig_list_mutex);
2481 return rc;
2482 }
2483
2484 struct kmem_cache *ecryptfs_key_sig_cache;
2485
2486 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2487 {
2488 struct ecryptfs_key_sig *new_key_sig;
2489
2490 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2491 if (!new_key_sig) {
2492 printk(KERN_ERR
2493 "Error allocating from ecryptfs_key_sig_cache\n");
2494 return -ENOMEM;
2495 }
2496 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2497 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2498 /* Caller must hold keysig_list_mutex */
2499 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2500
2501 return 0;
2502 }
2503
2504 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2505
2506 int
2507 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2508 char *sig, u32 global_auth_tok_flags)
2509 {
2510 struct ecryptfs_global_auth_tok *new_auth_tok;
2511 int rc = 0;
2512
2513 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2514 GFP_KERNEL);
2515 if (!new_auth_tok) {
2516 rc = -ENOMEM;
2517 printk(KERN_ERR "Error allocating from "
2518 "ecryptfs_global_auth_tok_cache\n");
2519 goto out;
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 out:
2529 return rc;
2530 }
2531
Linux with added FPC-III support