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[linux/fpc-iii.git] / fs / ecryptfs / keystore.c
blob917bd5c9776aabcff5b482f59bd8d316193ead35
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/pagemap.h>
30 #include <linux/key.h>
31 #include <linux/random.h>
32 #include <linux/crypto.h>
33 #include <linux/scatterlist.h>
34 #include <linux/slab.h>
35 #include "ecryptfs_kernel.h"
36
37 /**
38 * request_key returned an error instead of a valid key address;
39 * determine the type of error, make appropriate log entries, and
40 * return an error code.
41 */
42 static int process_request_key_err(long err_code)
43 {
44 int rc = 0;
45
46 switch (err_code) {
47 case -ENOKEY:
48 ecryptfs_printk(KERN_WARNING, "No key\n");
49 rc = -ENOENT;
50 break;
51 case -EKEYEXPIRED:
52 ecryptfs_printk(KERN_WARNING, "Key expired\n");
53 rc = -ETIME;
54 break;
55 case -EKEYREVOKED:
56 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
57 rc = -EINVAL;
58 break;
59 default:
60 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
61 "[0x%.16lx]\n", err_code);
62 rc = -EINVAL;
63 }
64 return rc;
65 }
66
67 static int process_find_global_auth_tok_for_sig_err(int err_code)
68 {
69 int rc = err_code;
70
71 switch (err_code) {
72 case -ENOENT:
73 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
74 break;
75 case -EINVAL:
76 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
77 break;
78 default:
79 rc = process_request_key_err(err_code);
80 break;
81 }
82 return rc;
83 }
84
85 /**
86 * ecryptfs_parse_packet_length
87 * @data: Pointer to memory containing length at offset
88 * @size: This function writes the decoded size to this memory
89 * address; zero on error
90 * @length_size: The number of bytes occupied by the encoded length
91 *
92 * Returns zero on success; non-zero on error
93 */
94 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
95 size_t *length_size)
96 {
97 int rc = 0;
98
99 (*length_size) = 0;
100 (*size) = 0;
101 if (data[0] < 192) {
102 /* One-byte length */
103 (*size) = data[0];
104 (*length_size) = 1;
105 } else if (data[0] < 224) {
106 /* Two-byte length */
107 (*size) = (data[0] - 192) * 256;
108 (*size) += data[1] + 192;
109 (*length_size) = 2;
110 } else if (data[0] == 255) {
111 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
112 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
113 "supported\n");
114 rc = -EINVAL;
115 goto out;
116 } else {
117 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
118 rc = -EINVAL;
119 goto out;
120 }
121 out:
122 return rc;
123 }
124
125 /**
126 * ecryptfs_write_packet_length
127 * @dest: The byte array target into which to write the length. Must
128 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
129 * @size: The length to write.
130 * @packet_size_length: The number of bytes used to encode the packet
131 * length is written to this address.
132 *
133 * Returns zero on success; non-zero on error.
134 */
135 int ecryptfs_write_packet_length(char *dest, size_t size,
136 size_t *packet_size_length)
137 {
138 int rc = 0;
139
140 if (size < 192) {
141 dest[0] = size;
142 (*packet_size_length) = 1;
143 } else if (size < 65536) {
144 dest[0] = (((size - 192) / 256) + 192);
145 dest[1] = ((size - 192) % 256);
146 (*packet_size_length) = 2;
147 } else {
148 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
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[2];
603 struct scatterlist dst_sg[2];
604 struct blkcipher_desc desc;
605 char iv[ECRYPTFS_MAX_IV_BYTES];
606 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
607 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
608 struct hash_desc hash_desc;
609 struct scatterlist hash_sg;
610 };
611
612 /**
613 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
614 * @filename: NULL-terminated filename string
615 *
616 * This is the simplest mechanism for achieving filename encryption in
617 * eCryptfs. It encrypts the given filename with the mount-wide
618 * filename encryption key (FNEK) and stores it in a packet to @dest,
619 * which the callee will encode and write directly into the dentry
620 * name.
621 */
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 = (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 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
695 GFP_KERNEL);
696 if (!s->block_aligned_filename) {
697 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
698 "kzalloc [%zd] bytes\n", __func__,
699 s->block_aligned_filename_size);
700 rc = -ENOMEM;
701 goto out_unlock;
702 }
703 s->i = 0;
704 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
705 rc = ecryptfs_write_packet_length(&dest[s->i],
706 (ECRYPTFS_SIG_SIZE
707 + 1 /* Cipher code */
708 + s->block_aligned_filename_size),
709 &s->packet_size_len);
710 if (rc) {
711 printk(KERN_ERR "%s: Error generating tag 70 packet "
712 "header; cannot generate packet length; rc = [%d]\n",
713 __func__, rc);
714 goto out_free_unlock;
715 }
716 s->i += s->packet_size_len;
717 ecryptfs_from_hex(&dest[s->i],
718 mount_crypt_stat->global_default_fnek_sig,
719 ECRYPTFS_SIG_SIZE);
720 s->i += ECRYPTFS_SIG_SIZE;
721 s->cipher_code = ecryptfs_code_for_cipher_string(
722 mount_crypt_stat->global_default_fn_cipher_name,
723 mount_crypt_stat->global_default_fn_cipher_key_bytes);
724 if (s->cipher_code == 0) {
725 printk(KERN_WARNING "%s: Unable to generate code for "
726 "cipher [%s] with key bytes [%zd]\n", __func__,
727 mount_crypt_stat->global_default_fn_cipher_name,
728 mount_crypt_stat->global_default_fn_cipher_key_bytes);
729 rc = -EINVAL;
730 goto out_free_unlock;
731 }
732 dest[s->i++] = s->cipher_code;
733 /* TODO: Support other key modules than passphrase for
734 * filename encryption */
735 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
736 rc = -EOPNOTSUPP;
737 printk(KERN_INFO "%s: Filename encryption only supports "
738 "password tokens\n", __func__);
739 goto out_free_unlock;
740 }
741 sg_init_one(
742 &s->hash_sg,
743 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
744 s->auth_tok->token.password.session_key_encryption_key_bytes);
745 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
746 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
747 CRYPTO_ALG_ASYNC);
748 if (IS_ERR(s->hash_desc.tfm)) {
749 rc = PTR_ERR(s->hash_desc.tfm);
750 printk(KERN_ERR "%s: Error attempting to "
751 "allocate hash crypto context; rc = [%d]\n",
752 __func__, rc);
753 goto out_free_unlock;
754 }
755 rc = crypto_hash_init(&s->hash_desc);
756 if (rc) {
757 printk(KERN_ERR
758 "%s: Error initializing crypto hash; rc = [%d]\n",
759 __func__, rc);
760 goto out_release_free_unlock;
761 }
762 rc = crypto_hash_update(
763 &s->hash_desc, &s->hash_sg,
764 s->auth_tok->token.password.session_key_encryption_key_bytes);
765 if (rc) {
766 printk(KERN_ERR
767 "%s: Error updating crypto hash; rc = [%d]\n",
768 __func__, rc);
769 goto out_release_free_unlock;
770 }
771 rc = crypto_hash_final(&s->hash_desc, s->hash);
772 if (rc) {
773 printk(KERN_ERR
774 "%s: Error finalizing crypto hash; rc = [%d]\n",
775 __func__, rc);
776 goto out_release_free_unlock;
777 }
778 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
779 s->block_aligned_filename[s->j] =
780 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
781 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
782 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
783 sg_init_one(&s->hash_sg, (u8 *)s->hash,
784 ECRYPTFS_TAG_70_DIGEST_SIZE);
785 rc = crypto_hash_init(&s->hash_desc);
786 if (rc) {
787 printk(KERN_ERR
788 "%s: Error initializing crypto hash; "
789 "rc = [%d]\n", __func__, rc);
790 goto out_release_free_unlock;
791 }
792 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
793 ECRYPTFS_TAG_70_DIGEST_SIZE);
794 if (rc) {
795 printk(KERN_ERR
796 "%s: Error updating crypto hash; "
797 "rc = [%d]\n", __func__, rc);
798 goto out_release_free_unlock;
799 }
800 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
801 if (rc) {
802 printk(KERN_ERR
803 "%s: Error finalizing crypto hash; "
804 "rc = [%d]\n", __func__, rc);
805 goto out_release_free_unlock;
806 }
807 memcpy(s->hash, s->tmp_hash,
808 ECRYPTFS_TAG_70_DIGEST_SIZE);
809 }
810 if (s->block_aligned_filename[s->j] == '\0')
811 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
812 }
813 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
814 filename_size);
815 rc = virt_to_scatterlist(s->block_aligned_filename,
816 s->block_aligned_filename_size, s->src_sg, 2);
817 if (rc < 1) {
818 printk(KERN_ERR "%s: Internal error whilst attempting to "
819 "convert filename memory to scatterlist; rc = [%d]. "
820 "block_aligned_filename_size = [%zd]\n", __func__, rc,
821 s->block_aligned_filename_size);
822 goto out_release_free_unlock;
823 }
824 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
825 s->dst_sg, 2);
826 if (rc < 1) {
827 printk(KERN_ERR "%s: Internal error whilst attempting to "
828 "convert encrypted filename memory to scatterlist; "
829 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
830 __func__, rc, s->block_aligned_filename_size);
831 goto out_release_free_unlock;
832 }
833 /* The characters in the first block effectively do the job
834 * of the IV here, so we just use 0's for the IV. Note the
835 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
836 * >= ECRYPTFS_MAX_IV_BYTES. */
837 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
838 s->desc.info = s->iv;
839 rc = crypto_blkcipher_setkey(
840 s->desc.tfm,
841 s->auth_tok->token.password.session_key_encryption_key,
842 mount_crypt_stat->global_default_fn_cipher_key_bytes);
843 if (rc < 0) {
844 printk(KERN_ERR "%s: Error setting key for crypto context; "
845 "rc = [%d]. s->auth_tok->token.password.session_key_"
846 "encryption_key = [0x%p]; mount_crypt_stat->"
847 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
848 rc,
849 s->auth_tok->token.password.session_key_encryption_key,
850 mount_crypt_stat->global_default_fn_cipher_key_bytes);
851 goto out_release_free_unlock;
852 }
853 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
854 s->block_aligned_filename_size);
855 if (rc) {
856 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
857 "rc = [%d]\n", __func__, rc);
858 goto out_release_free_unlock;
859 }
860 s->i += s->block_aligned_filename_size;
861 (*packet_size) = s->i;
862 (*remaining_bytes) -= (*packet_size);
863 out_release_free_unlock:
864 crypto_free_hash(s->hash_desc.tfm);
865 out_free_unlock:
866 kzfree(s->block_aligned_filename);
867 out_unlock:
868 mutex_unlock(s->tfm_mutex);
869 out:
870 if (auth_tok_key) {
871 up_write(&(auth_tok_key->sem));
872 key_put(auth_tok_key);
873 }
874 kfree(s);
875 return rc;
876 }
877
878 struct ecryptfs_parse_tag_70_packet_silly_stack {
879 u8 cipher_code;
880 size_t max_packet_size;
881 size_t packet_size_len;
882 size_t parsed_tag_70_packet_size;
883 size_t block_aligned_filename_size;
884 size_t block_size;
885 size_t i;
886 struct mutex *tfm_mutex;
887 char *decrypted_filename;
888 struct ecryptfs_auth_tok *auth_tok;
889 struct scatterlist src_sg[2];
890 struct scatterlist dst_sg[2];
891 struct blkcipher_desc desc;
892 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
893 char iv[ECRYPTFS_MAX_IV_BYTES];
894 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
895 };
896
897 /**
898 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
899 * @filename: This function kmalloc's the memory for the filename
900 * @filename_size: This function sets this to the amount of memory
901 * kmalloc'd for the filename
902 * @packet_size: This function sets this to the the number of octets
903 * in the packet parsed
904 * @mount_crypt_stat: The mount-wide cryptographic context
905 * @data: The memory location containing the start of the tag 70
906 * packet
907 * @max_packet_size: The maximum legal size of the packet to be parsed
908 * from @data
909 *
910 * Returns zero on success; non-zero otherwise
911 */
912 int
913 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
914 size_t *packet_size,
915 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
916 char *data, size_t max_packet_size)
917 {
918 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
919 struct key *auth_tok_key = NULL;
920 int rc = 0;
921
922 (*packet_size) = 0;
923 (*filename_size) = 0;
924 (*filename) = NULL;
925 s = kmalloc(sizeof(*s), GFP_KERNEL);
926 if (!s) {
927 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
928 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
929 rc = -ENOMEM;
930 goto out;
931 }
932 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
933 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
934 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
935 "at least [%d]\n", __func__, max_packet_size,
936 ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
937 rc = -EINVAL;
938 goto out;
939 }
940 /* Octet 0: Tag 70 identifier
941 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
942 * and block-aligned encrypted filename size)
943 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
944 * Octet N2-N3: Cipher identifier (1 octet)
945 * Octets N3-N4: Block-aligned encrypted filename
946 * - Consists of a minimum number of random numbers, a \0
947 * separator, and then the filename */
948 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
949 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
950 "tag [0x%.2x]\n", __func__,
951 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
952 rc = -EINVAL;
953 goto out;
954 }
955 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
956 &s->parsed_tag_70_packet_size,
957 &s->packet_size_len);
958 if (rc) {
959 printk(KERN_WARNING "%s: Error parsing packet length; "
960 "rc = [%d]\n", __func__, rc);
961 goto out;
962 }
963 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
964 - ECRYPTFS_SIG_SIZE - 1);
965 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
966 > max_packet_size) {
967 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
968 "size is [%zd]\n", __func__, max_packet_size,
969 (1 + s->packet_size_len + 1
970 + s->block_aligned_filename_size));
971 rc = -EINVAL;
972 goto out;
973 }
974 (*packet_size) += s->packet_size_len;
975 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
976 ECRYPTFS_SIG_SIZE);
977 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
978 (*packet_size) += ECRYPTFS_SIG_SIZE;
979 s->cipher_code = data[(*packet_size)++];
980 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
981 if (rc) {
982 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
983 __func__, s->cipher_code);
984 goto out;
985 }
986 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
987 &s->auth_tok, mount_crypt_stat,
988 s->fnek_sig_hex);
989 if (rc) {
990 printk(KERN_ERR "%s: Error attempting to find auth tok for "
991 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
992 rc);
993 goto out;
994 }
995 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
996 &s->tfm_mutex,
997 s->cipher_string);
998 if (unlikely(rc)) {
999 printk(KERN_ERR "Internal error whilst attempting to get "
1000 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1001 s->cipher_string, rc);
1002 goto out;
1003 }
1004 mutex_lock(s->tfm_mutex);
1005 rc = virt_to_scatterlist(&data[(*packet_size)],
1006 s->block_aligned_filename_size, s->src_sg, 2);
1007 if (rc < 1) {
1008 printk(KERN_ERR "%s: Internal error whilst attempting to "
1009 "convert encrypted filename memory to scatterlist; "
1010 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1011 __func__, rc, s->block_aligned_filename_size);
1012 goto out_unlock;
1013 }
1014 (*packet_size) += s->block_aligned_filename_size;
1015 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1016 GFP_KERNEL);
1017 if (!s->decrypted_filename) {
1018 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1019 "kmalloc [%zd] bytes\n", __func__,
1020 s->block_aligned_filename_size);
1021 rc = -ENOMEM;
1022 goto out_unlock;
1023 }
1024 rc = virt_to_scatterlist(s->decrypted_filename,
1025 s->block_aligned_filename_size, s->dst_sg, 2);
1026 if (rc < 1) {
1027 printk(KERN_ERR "%s: Internal error whilst attempting to "
1028 "convert decrypted filename memory to scatterlist; "
1029 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1030 __func__, rc, s->block_aligned_filename_size);
1031 goto out_free_unlock;
1032 }
1033 /* The characters in the first block effectively do the job of
1034 * the IV here, so we just use 0's for the IV. Note the
1035 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1036 * >= ECRYPTFS_MAX_IV_BYTES. */
1037 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1038 s->desc.info = s->iv;
1039 /* TODO: Support other key modules than passphrase for
1040 * filename encryption */
1041 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1042 rc = -EOPNOTSUPP;
1043 printk(KERN_INFO "%s: Filename encryption only supports "
1044 "password tokens\n", __func__);
1045 goto out_free_unlock;
1046 }
1047 rc = crypto_blkcipher_setkey(
1048 s->desc.tfm,
1049 s->auth_tok->token.password.session_key_encryption_key,
1050 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1051 if (rc < 0) {
1052 printk(KERN_ERR "%s: Error setting key for crypto context; "
1053 "rc = [%d]. s->auth_tok->token.password.session_key_"
1054 "encryption_key = [0x%p]; mount_crypt_stat->"
1055 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1056 rc,
1057 s->auth_tok->token.password.session_key_encryption_key,
1058 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1059 goto out_free_unlock;
1060 }
1061 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
1062 s->block_aligned_filename_size);
1063 if (rc) {
1064 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1065 "rc = [%d]\n", __func__, rc);
1066 goto out_free_unlock;
1067 }
1068 s->i = 0;
1069 while (s->decrypted_filename[s->i] != '\0'
1070 && s->i < s->block_aligned_filename_size)
1071 s->i++;
1072 if (s->i == s->block_aligned_filename_size) {
1073 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1074 "find valid separator between random characters and "
1075 "the filename\n", __func__);
1076 rc = -EINVAL;
1077 goto out_free_unlock;
1078 }
1079 s->i++;
1080 (*filename_size) = (s->block_aligned_filename_size - s->i);
1081 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1082 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1083 "invalid\n", __func__, (*filename_size));
1084 rc = -EINVAL;
1085 goto out_free_unlock;
1086 }
1087 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1088 if (!(*filename)) {
1089 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1090 "kmalloc [%zd] bytes\n", __func__,
1091 ((*filename_size) + 1));
1092 rc = -ENOMEM;
1093 goto out_free_unlock;
1094 }
1095 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1096 (*filename)[(*filename_size)] = '\0';
1097 out_free_unlock:
1098 kfree(s->decrypted_filename);
1099 out_unlock:
1100 mutex_unlock(s->tfm_mutex);
1101 out:
1102 if (rc) {
1103 (*packet_size) = 0;
1104 (*filename_size) = 0;
1105 (*filename) = NULL;
1106 }
1107 if (auth_tok_key) {
1108 up_write(&(auth_tok_key->sem));
1109 key_put(auth_tok_key);
1110 }
1111 kfree(s);
1112 return rc;
1113 }
1114
1115 static int
1116 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1117 {
1118 int rc = 0;
1119
1120 (*sig) = NULL;
1121 switch (auth_tok->token_type) {
1122 case ECRYPTFS_PASSWORD:
1123 (*sig) = auth_tok->token.password.signature;
1124 break;
1125 case ECRYPTFS_PRIVATE_KEY:
1126 (*sig) = auth_tok->token.private_key.signature;
1127 break;
1128 default:
1129 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1130 auth_tok->token_type);
1131 rc = -EINVAL;
1132 }
1133 return rc;
1134 }
1135
1136 /**
1137 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1138 * @auth_tok: The key authentication token used to decrypt the session key
1139 * @crypt_stat: The cryptographic context
1140 *
1141 * Returns zero on success; non-zero error otherwise.
1142 */
1143 static int
1144 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1145 struct ecryptfs_crypt_stat *crypt_stat)
1146 {
1147 u8 cipher_code = 0;
1148 struct ecryptfs_msg_ctx *msg_ctx;
1149 struct ecryptfs_message *msg = NULL;
1150 char *auth_tok_sig;
1151 char *payload = NULL;
1152 size_t payload_len = 0;
1153 int rc;
1154
1155 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1156 if (rc) {
1157 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1158 auth_tok->token_type);
1159 goto out;
1160 }
1161 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1162 &payload, &payload_len);
1163 if (rc) {
1164 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1165 goto out;
1166 }
1167 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1168 if (rc) {
1169 ecryptfs_printk(KERN_ERR, "Error sending message to "
1170 "ecryptfsd: %d\n", rc);
1171 goto out;
1172 }
1173 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1174 if (rc) {
1175 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1176 "from the user space daemon\n");
1177 rc = -EIO;
1178 goto out;
1179 }
1180 rc = parse_tag_65_packet(&(auth_tok->session_key),
1181 &cipher_code, msg);
1182 if (rc) {
1183 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1184 rc);
1185 goto out;
1186 }
1187 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1188 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1189 auth_tok->session_key.decrypted_key_size);
1190 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1191 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1192 if (rc) {
1193 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1194 cipher_code)
1195 goto out;
1196 }
1197 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1198 if (ecryptfs_verbosity > 0) {
1199 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1200 ecryptfs_dump_hex(crypt_stat->key,
1201 crypt_stat->key_size);
1202 }
1203 out:
1204 kfree(msg);
1205 kfree(payload);
1206 return rc;
1207 }
1208
1209 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1210 {
1211 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1212 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1213
1214 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1215 auth_tok_list_head, list) {
1216 list_del(&auth_tok_list_item->list);
1217 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1218 auth_tok_list_item);
1219 }
1220 }
1221
1222 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1223
1224 /**
1225 * parse_tag_1_packet
1226 * @crypt_stat: The cryptographic context to modify based on packet contents
1227 * @data: The raw bytes of the packet.
1228 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1229 * a new authentication token will be placed at the
1230 * end of this list for this packet.
1231 * @new_auth_tok: Pointer to a pointer to memory that this function
1232 * allocates; sets the memory address of the pointer to
1233 * NULL on error. This object is added to the
1234 * auth_tok_list.
1235 * @packet_size: This function writes the size of the parsed packet
1236 * into this memory location; zero on error.
1237 * @max_packet_size: The maximum allowable packet size
1238 *
1239 * Returns zero on success; non-zero on error.
1240 */
1241 static int
1242 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1243 unsigned char *data, struct list_head *auth_tok_list,
1244 struct ecryptfs_auth_tok **new_auth_tok,
1245 size_t *packet_size, size_t max_packet_size)
1246 {
1247 size_t body_size;
1248 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1249 size_t length_size;
1250 int rc = 0;
1251
1252 (*packet_size) = 0;
1253 (*new_auth_tok) = NULL;
1254 /**
1255 * This format is inspired by OpenPGP; see RFC 2440
1256 * packet tag 1
1257 *
1258 * Tag 1 identifier (1 byte)
1259 * Max Tag 1 packet size (max 3 bytes)
1260 * Version (1 byte)
1261 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1262 * Cipher identifier (1 byte)
1263 * Encrypted key size (arbitrary)
1264 *
1265 * 12 bytes minimum packet size
1266 */
1267 if (unlikely(max_packet_size < 12)) {
1268 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1269 rc = -EINVAL;
1270 goto out;
1271 }
1272 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1273 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1274 ECRYPTFS_TAG_1_PACKET_TYPE);
1275 rc = -EINVAL;
1276 goto out;
1277 }
1278 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1279 * at end of function upon failure */
1280 auth_tok_list_item =
1281 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1282 GFP_KERNEL);
1283 if (!auth_tok_list_item) {
1284 printk(KERN_ERR "Unable to allocate memory\n");
1285 rc = -ENOMEM;
1286 goto out;
1287 }
1288 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1289 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1290 &length_size);
1291 if (rc) {
1292 printk(KERN_WARNING "Error parsing packet length; "
1293 "rc = [%d]\n", rc);
1294 goto out_free;
1295 }
1296 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1297 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1298 rc = -EINVAL;
1299 goto out_free;
1300 }
1301 (*packet_size) += length_size;
1302 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1303 printk(KERN_WARNING "Packet size exceeds max\n");
1304 rc = -EINVAL;
1305 goto out_free;
1306 }
1307 if (unlikely(data[(*packet_size)++] != 0x03)) {
1308 printk(KERN_WARNING "Unknown version number [%d]\n",
1309 data[(*packet_size) - 1]);
1310 rc = -EINVAL;
1311 goto out_free;
1312 }
1313 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1314 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1315 *packet_size += ECRYPTFS_SIG_SIZE;
1316 /* This byte is skipped because the kernel does not need to
1317 * know which public key encryption algorithm was used */
1318 (*packet_size)++;
1319 (*new_auth_tok)->session_key.encrypted_key_size =
1320 body_size - (ECRYPTFS_SIG_SIZE + 2);
1321 if ((*new_auth_tok)->session_key.encrypted_key_size
1322 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1323 printk(KERN_WARNING "Tag 1 packet contains key larger "
1324 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1325 rc = -EINVAL;
1326 goto out;
1327 }
1328 memcpy((*new_auth_tok)->session_key.encrypted_key,
1329 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1330 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1331 (*new_auth_tok)->session_key.flags &=
1332 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1333 (*new_auth_tok)->session_key.flags |=
1334 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1335 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1336 (*new_auth_tok)->flags = 0;
1337 (*new_auth_tok)->session_key.flags &=
1338 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1339 (*new_auth_tok)->session_key.flags &=
1340 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1341 list_add(&auth_tok_list_item->list, auth_tok_list);
1342 goto out;
1343 out_free:
1344 (*new_auth_tok) = NULL;
1345 memset(auth_tok_list_item, 0,
1346 sizeof(struct ecryptfs_auth_tok_list_item));
1347 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1348 auth_tok_list_item);
1349 out:
1350 if (rc)
1351 (*packet_size) = 0;
1352 return rc;
1353 }
1354
1355 /**
1356 * parse_tag_3_packet
1357 * @crypt_stat: The cryptographic context to modify based on packet
1358 * contents.
1359 * @data: The raw bytes of the packet.
1360 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1361 * a new authentication token will be placed at the end
1362 * of this list for this packet.
1363 * @new_auth_tok: Pointer to a pointer to memory that this function
1364 * allocates; sets the memory address of the pointer to
1365 * NULL on error. This object is added to the
1366 * auth_tok_list.
1367 * @packet_size: This function writes the size of the parsed packet
1368 * into this memory location; zero on error.
1369 * @max_packet_size: maximum number of bytes to parse
1370 *
1371 * Returns zero on success; non-zero on error.
1372 */
1373 static int
1374 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1375 unsigned char *data, struct list_head *auth_tok_list,
1376 struct ecryptfs_auth_tok **new_auth_tok,
1377 size_t *packet_size, size_t max_packet_size)
1378 {
1379 size_t body_size;
1380 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1381 size_t length_size;
1382 int rc = 0;
1383
1384 (*packet_size) = 0;
1385 (*new_auth_tok) = NULL;
1386 /**
1387 *This format is inspired by OpenPGP; see RFC 2440
1388 * packet tag 3
1389 *
1390 * Tag 3 identifier (1 byte)
1391 * Max Tag 3 packet size (max 3 bytes)
1392 * Version (1 byte)
1393 * Cipher code (1 byte)
1394 * S2K specifier (1 byte)
1395 * Hash identifier (1 byte)
1396 * Salt (ECRYPTFS_SALT_SIZE)
1397 * Hash iterations (1 byte)
1398 * Encrypted key (arbitrary)
1399 *
1400 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1401 */
1402 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1403 printk(KERN_ERR "Max packet size too large\n");
1404 rc = -EINVAL;
1405 goto out;
1406 }
1407 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1408 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1409 ECRYPTFS_TAG_3_PACKET_TYPE);
1410 rc = -EINVAL;
1411 goto out;
1412 }
1413 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1414 * at end of function upon failure */
1415 auth_tok_list_item =
1416 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1417 if (!auth_tok_list_item) {
1418 printk(KERN_ERR "Unable to allocate memory\n");
1419 rc = -ENOMEM;
1420 goto out;
1421 }
1422 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1423 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1424 &length_size);
1425 if (rc) {
1426 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1427 rc);
1428 goto out_free;
1429 }
1430 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1431 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1432 rc = -EINVAL;
1433 goto out_free;
1434 }
1435 (*packet_size) += length_size;
1436 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1437 printk(KERN_ERR "Packet size exceeds max\n");
1438 rc = -EINVAL;
1439 goto out_free;
1440 }
1441 (*new_auth_tok)->session_key.encrypted_key_size =
1442 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1443 if ((*new_auth_tok)->session_key.encrypted_key_size
1444 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1445 printk(KERN_WARNING "Tag 3 packet contains key larger "
1446 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1447 rc = -EINVAL;
1448 goto out_free;
1449 }
1450 if (unlikely(data[(*packet_size)++] != 0x04)) {
1451 printk(KERN_WARNING "Unknown version number [%d]\n",
1452 data[(*packet_size) - 1]);
1453 rc = -EINVAL;
1454 goto out_free;
1455 }
1456 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1457 (u16)data[(*packet_size)]);
1458 if (rc)
1459 goto out_free;
1460 /* A little extra work to differentiate among the AES key
1461 * sizes; see RFC2440 */
1462 switch(data[(*packet_size)++]) {
1463 case RFC2440_CIPHER_AES_192:
1464 crypt_stat->key_size = 24;
1465 break;
1466 default:
1467 crypt_stat->key_size =
1468 (*new_auth_tok)->session_key.encrypted_key_size;
1469 }
1470 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1471 if (rc)
1472 goto out_free;
1473 if (unlikely(data[(*packet_size)++] != 0x03)) {
1474 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1475 rc = -ENOSYS;
1476 goto out_free;
1477 }
1478 /* TODO: finish the hash mapping */
1479 switch (data[(*packet_size)++]) {
1480 case 0x01: /* See RFC2440 for these numbers and their mappings */
1481 /* Choose MD5 */
1482 memcpy((*new_auth_tok)->token.password.salt,
1483 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1484 (*packet_size) += ECRYPTFS_SALT_SIZE;
1485 /* This conversion was taken straight from RFC2440 */
1486 (*new_auth_tok)->token.password.hash_iterations =
1487 ((u32) 16 + (data[(*packet_size)] & 15))
1488 << ((data[(*packet_size)] >> 4) + 6);
1489 (*packet_size)++;
1490 /* Friendly reminder:
1491 * (*new_auth_tok)->session_key.encrypted_key_size =
1492 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1493 memcpy((*new_auth_tok)->session_key.encrypted_key,
1494 &data[(*packet_size)],
1495 (*new_auth_tok)->session_key.encrypted_key_size);
1496 (*packet_size) +=
1497 (*new_auth_tok)->session_key.encrypted_key_size;
1498 (*new_auth_tok)->session_key.flags &=
1499 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1500 (*new_auth_tok)->session_key.flags |=
1501 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1502 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1503 break;
1504 default:
1505 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1506 "[%d]\n", data[(*packet_size) - 1]);
1507 rc = -ENOSYS;
1508 goto out_free;
1509 }
1510 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1511 /* TODO: Parametarize; we might actually want userspace to
1512 * decrypt the session key. */
1513 (*new_auth_tok)->session_key.flags &=
1514 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1515 (*new_auth_tok)->session_key.flags &=
1516 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1517 list_add(&auth_tok_list_item->list, auth_tok_list);
1518 goto out;
1519 out_free:
1520 (*new_auth_tok) = NULL;
1521 memset(auth_tok_list_item, 0,
1522 sizeof(struct ecryptfs_auth_tok_list_item));
1523 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1524 auth_tok_list_item);
1525 out:
1526 if (rc)
1527 (*packet_size) = 0;
1528 return rc;
1529 }
1530
1531 /**
1532 * parse_tag_11_packet
1533 * @data: The raw bytes of the packet
1534 * @contents: This function writes the data contents of the literal
1535 * packet into this memory location
1536 * @max_contents_bytes: The maximum number of bytes that this function
1537 * is allowed to write into contents
1538 * @tag_11_contents_size: This function writes the size of the parsed
1539 * contents into this memory location; zero on
1540 * error
1541 * @packet_size: This function writes the size of the parsed packet
1542 * into this memory location; zero on error
1543 * @max_packet_size: maximum number of bytes to parse
1544 *
1545 * Returns zero on success; non-zero on error.
1546 */
1547 static int
1548 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1549 size_t max_contents_bytes, size_t *tag_11_contents_size,
1550 size_t *packet_size, size_t max_packet_size)
1551 {
1552 size_t body_size;
1553 size_t length_size;
1554 int rc = 0;
1555
1556 (*packet_size) = 0;
1557 (*tag_11_contents_size) = 0;
1558 /* This format is inspired by OpenPGP; see RFC 2440
1559 * packet tag 11
1560 *
1561 * Tag 11 identifier (1 byte)
1562 * Max Tag 11 packet size (max 3 bytes)
1563 * Binary format specifier (1 byte)
1564 * Filename length (1 byte)
1565 * Filename ("_CONSOLE") (8 bytes)
1566 * Modification date (4 bytes)
1567 * Literal data (arbitrary)
1568 *
1569 * We need at least 16 bytes of data for the packet to even be
1570 * valid.
1571 */
1572 if (max_packet_size < 16) {
1573 printk(KERN_ERR "Maximum packet size too small\n");
1574 rc = -EINVAL;
1575 goto out;
1576 }
1577 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1578 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1579 rc = -EINVAL;
1580 goto out;
1581 }
1582 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1583 &length_size);
1584 if (rc) {
1585 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1586 goto out;
1587 }
1588 if (body_size < 14) {
1589 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1590 rc = -EINVAL;
1591 goto out;
1592 }
1593 (*packet_size) += length_size;
1594 (*tag_11_contents_size) = (body_size - 14);
1595 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1596 printk(KERN_ERR "Packet size exceeds max\n");
1597 rc = -EINVAL;
1598 goto out;
1599 }
1600 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1601 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1602 "expected size\n");
1603 rc = -EINVAL;
1604 goto out;
1605 }
1606 if (data[(*packet_size)++] != 0x62) {
1607 printk(KERN_WARNING "Unrecognizable packet\n");
1608 rc = -EINVAL;
1609 goto out;
1610 }
1611 if (data[(*packet_size)++] != 0x08) {
1612 printk(KERN_WARNING "Unrecognizable packet\n");
1613 rc = -EINVAL;
1614 goto out;
1615 }
1616 (*packet_size) += 12; /* Ignore filename and modification date */
1617 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1618 (*packet_size) += (*tag_11_contents_size);
1619 out:
1620 if (rc) {
1621 (*packet_size) = 0;
1622 (*tag_11_contents_size) = 0;
1623 }
1624 return rc;
1625 }
1626
1627 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1628 struct ecryptfs_auth_tok **auth_tok,
1629 char *sig)
1630 {
1631 int rc = 0;
1632
1633 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1634 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1635 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1636 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1637 printk(KERN_ERR "Could not find key with description: [%s]\n",
1638 sig);
1639 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1640 (*auth_tok_key) = NULL;
1641 goto out;
1642 }
1643 }
1644 down_write(&(*auth_tok_key)->sem);
1645 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1646 if (rc) {
1647 up_write(&(*auth_tok_key)->sem);
1648 key_put(*auth_tok_key);
1649 (*auth_tok_key) = NULL;
1650 goto out;
1651 }
1652 out:
1653 return rc;
1654 }
1655
1656 /**
1657 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1658 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1659 * @crypt_stat: The cryptographic context
1660 *
1661 * Returns zero on success; non-zero error otherwise
1662 */
1663 static int
1664 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1665 struct ecryptfs_crypt_stat *crypt_stat)
1666 {
1667 struct scatterlist dst_sg[2];
1668 struct scatterlist src_sg[2];
1669 struct mutex *tfm_mutex;
1670 struct blkcipher_desc desc = {
1671 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1672 };
1673 int rc = 0;
1674
1675 if (unlikely(ecryptfs_verbosity > 0)) {
1676 ecryptfs_printk(
1677 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1678 auth_tok->token.password.session_key_encryption_key_bytes);
1679 ecryptfs_dump_hex(
1680 auth_tok->token.password.session_key_encryption_key,
1681 auth_tok->token.password.session_key_encryption_key_bytes);
1682 }
1683 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1684 crypt_stat->cipher);
1685 if (unlikely(rc)) {
1686 printk(KERN_ERR "Internal error whilst attempting to get "
1687 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1688 crypt_stat->cipher, rc);
1689 goto out;
1690 }
1691 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1692 auth_tok->session_key.encrypted_key_size,
1693 src_sg, 2);
1694 if (rc < 1 || rc > 2) {
1695 printk(KERN_ERR "Internal error whilst attempting to convert "
1696 "auth_tok->session_key.encrypted_key to scatterlist; "
1697 "expected rc = 1; got rc = [%d]. "
1698 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1699 auth_tok->session_key.encrypted_key_size);
1700 goto out;
1701 }
1702 auth_tok->session_key.decrypted_key_size =
1703 auth_tok->session_key.encrypted_key_size;
1704 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1705 auth_tok->session_key.decrypted_key_size,
1706 dst_sg, 2);
1707 if (rc < 1 || rc > 2) {
1708 printk(KERN_ERR "Internal error whilst attempting to convert "
1709 "auth_tok->session_key.decrypted_key to scatterlist; "
1710 "expected rc = 1; got rc = [%d]\n", rc);
1711 goto out;
1712 }
1713 mutex_lock(tfm_mutex);
1714 rc = crypto_blkcipher_setkey(
1715 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1716 crypt_stat->key_size);
1717 if (unlikely(rc < 0)) {
1718 mutex_unlock(tfm_mutex);
1719 printk(KERN_ERR "Error setting key for crypto context\n");
1720 rc = -EINVAL;
1721 goto out;
1722 }
1723 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1724 auth_tok->session_key.encrypted_key_size);
1725 mutex_unlock(tfm_mutex);
1726 if (unlikely(rc)) {
1727 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1728 goto out;
1729 }
1730 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1731 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1732 auth_tok->session_key.decrypted_key_size);
1733 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1734 if (unlikely(ecryptfs_verbosity > 0)) {
1735 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1736 crypt_stat->key_size);
1737 ecryptfs_dump_hex(crypt_stat->key,
1738 crypt_stat->key_size);
1739 }
1740 out:
1741 return rc;
1742 }
1743
1744 /**
1745 * ecryptfs_parse_packet_set
1746 * @crypt_stat: The cryptographic context
1747 * @src: Virtual address of region of memory containing the packets
1748 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1749 *
1750 * Get crypt_stat to have the file's session key if the requisite key
1751 * is available to decrypt the session key.
1752 *
1753 * Returns Zero if a valid authentication token was retrieved and
1754 * processed; negative value for file not encrypted or for error
1755 * conditions.
1756 */
1757 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1758 unsigned char *src,
1759 struct dentry *ecryptfs_dentry)
1760 {
1761 size_t i = 0;
1762 size_t found_auth_tok;
1763 size_t next_packet_is_auth_tok_packet;
1764 struct list_head auth_tok_list;
1765 struct ecryptfs_auth_tok *matching_auth_tok;
1766 struct ecryptfs_auth_tok *candidate_auth_tok;
1767 char *candidate_auth_tok_sig;
1768 size_t packet_size;
1769 struct ecryptfs_auth_tok *new_auth_tok;
1770 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1771 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1772 size_t tag_11_contents_size;
1773 size_t tag_11_packet_size;
1774 struct key *auth_tok_key = NULL;
1775 int rc = 0;
1776
1777 INIT_LIST_HEAD(&auth_tok_list);
1778 /* Parse the header to find as many packets as we can; these will be
1779 * added the our &auth_tok_list */
1780 next_packet_is_auth_tok_packet = 1;
1781 while (next_packet_is_auth_tok_packet) {
1782 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1783
1784 switch (src[i]) {
1785 case ECRYPTFS_TAG_3_PACKET_TYPE:
1786 rc = parse_tag_3_packet(crypt_stat,
1787 (unsigned char *)&src[i],
1788 &auth_tok_list, &new_auth_tok,
1789 &packet_size, max_packet_size);
1790 if (rc) {
1791 ecryptfs_printk(KERN_ERR, "Error parsing "
1792 "tag 3 packet\n");
1793 rc = -EIO;
1794 goto out_wipe_list;
1795 }
1796 i += packet_size;
1797 rc = parse_tag_11_packet((unsigned char *)&src[i],
1798 sig_tmp_space,
1799 ECRYPTFS_SIG_SIZE,
1800 &tag_11_contents_size,
1801 &tag_11_packet_size,
1802 max_packet_size);
1803 if (rc) {
1804 ecryptfs_printk(KERN_ERR, "No valid "
1805 "(ecryptfs-specific) literal "
1806 "packet containing "
1807 "authentication token "
1808 "signature found after "
1809 "tag 3 packet\n");
1810 rc = -EIO;
1811 goto out_wipe_list;
1812 }
1813 i += tag_11_packet_size;
1814 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1815 ecryptfs_printk(KERN_ERR, "Expected "
1816 "signature of size [%d]; "
1817 "read size [%zd]\n",
1818 ECRYPTFS_SIG_SIZE,
1819 tag_11_contents_size);
1820 rc = -EIO;
1821 goto out_wipe_list;
1822 }
1823 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1824 sig_tmp_space, tag_11_contents_size);
1825 new_auth_tok->token.password.signature[
1826 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1827 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1828 break;
1829 case ECRYPTFS_TAG_1_PACKET_TYPE:
1830 rc = parse_tag_1_packet(crypt_stat,
1831 (unsigned char *)&src[i],
1832 &auth_tok_list, &new_auth_tok,
1833 &packet_size, max_packet_size);
1834 if (rc) {
1835 ecryptfs_printk(KERN_ERR, "Error parsing "
1836 "tag 1 packet\n");
1837 rc = -EIO;
1838 goto out_wipe_list;
1839 }
1840 i += packet_size;
1841 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1842 break;
1843 case ECRYPTFS_TAG_11_PACKET_TYPE:
1844 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1845 "(Tag 11 not allowed by itself)\n");
1846 rc = -EIO;
1847 goto out_wipe_list;
1848 default:
1849 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1850 "of the file header; hex value of "
1851 "character is [0x%.2x]\n", i, src[i]);
1852 next_packet_is_auth_tok_packet = 0;
1853 }
1854 }
1855 if (list_empty(&auth_tok_list)) {
1856 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1857 "eCryptfs file; this is not supported in this version "
1858 "of the eCryptfs kernel module\n");
1859 rc = -EINVAL;
1860 goto out;
1861 }
1862 /* auth_tok_list contains the set of authentication tokens
1863 * parsed from the metadata. We need to find a matching
1864 * authentication token that has the secret component(s)
1865 * necessary to decrypt the EFEK in the auth_tok parsed from
1866 * the metadata. There may be several potential matches, but
1867 * just one will be sufficient to decrypt to get the FEK. */
1868 find_next_matching_auth_tok:
1869 found_auth_tok = 0;
1870 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1871 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1872 if (unlikely(ecryptfs_verbosity > 0)) {
1873 ecryptfs_printk(KERN_DEBUG,
1874 "Considering cadidate auth tok:\n");
1875 ecryptfs_dump_auth_tok(candidate_auth_tok);
1876 }
1877 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1878 candidate_auth_tok);
1879 if (rc) {
1880 printk(KERN_ERR
1881 "Unrecognized candidate auth tok type: [%d]\n",
1882 candidate_auth_tok->token_type);
1883 rc = -EINVAL;
1884 goto out_wipe_list;
1885 }
1886 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1887 &matching_auth_tok,
1888 crypt_stat->mount_crypt_stat,
1889 candidate_auth_tok_sig);
1890 if (!rc) {
1891 found_auth_tok = 1;
1892 goto found_matching_auth_tok;
1893 }
1894 }
1895 if (!found_auth_tok) {
1896 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1897 "authentication token\n");
1898 rc = -EIO;
1899 goto out_wipe_list;
1900 }
1901 found_matching_auth_tok:
1902 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1903 memcpy(&(candidate_auth_tok->token.private_key),
1904 &(matching_auth_tok->token.private_key),
1905 sizeof(struct ecryptfs_private_key));
1906 up_write(&(auth_tok_key->sem));
1907 key_put(auth_tok_key);
1908 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1909 crypt_stat);
1910 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1911 memcpy(&(candidate_auth_tok->token.password),
1912 &(matching_auth_tok->token.password),
1913 sizeof(struct ecryptfs_password));
1914 up_write(&(auth_tok_key->sem));
1915 key_put(auth_tok_key);
1916 rc = decrypt_passphrase_encrypted_session_key(
1917 candidate_auth_tok, crypt_stat);
1918 } else {
1919 up_write(&(auth_tok_key->sem));
1920 key_put(auth_tok_key);
1921 rc = -EINVAL;
1922 }
1923 if (rc) {
1924 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1925
1926 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1927 "session key for authentication token with sig "
1928 "[%.*s]; rc = [%d]. Removing auth tok "
1929 "candidate from the list and searching for "
1930 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1931 candidate_auth_tok_sig, rc);
1932 list_for_each_entry_safe(auth_tok_list_item,
1933 auth_tok_list_item_tmp,
1934 &auth_tok_list, list) {
1935 if (candidate_auth_tok
1936 == &auth_tok_list_item->auth_tok) {
1937 list_del(&auth_tok_list_item->list);
1938 kmem_cache_free(
1939 ecryptfs_auth_tok_list_item_cache,
1940 auth_tok_list_item);
1941 goto find_next_matching_auth_tok;
1942 }
1943 }
1944 BUG();
1945 }
1946 rc = ecryptfs_compute_root_iv(crypt_stat);
1947 if (rc) {
1948 ecryptfs_printk(KERN_ERR, "Error computing "
1949 "the root IV\n");
1950 goto out_wipe_list;
1951 }
1952 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1953 if (rc) {
1954 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1955 "context for cipher [%s]; rc = [%d]\n",
1956 crypt_stat->cipher, rc);
1957 }
1958 out_wipe_list:
1959 wipe_auth_tok_list(&auth_tok_list);
1960 out:
1961 return rc;
1962 }
1963
1964 static int
1965 pki_encrypt_session_key(struct key *auth_tok_key,
1966 struct ecryptfs_auth_tok *auth_tok,
1967 struct ecryptfs_crypt_stat *crypt_stat,
1968 struct ecryptfs_key_record *key_rec)
1969 {
1970 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1971 char *payload = NULL;
1972 size_t payload_len = 0;
1973 struct ecryptfs_message *msg;
1974 int rc;
1975
1976 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1977 ecryptfs_code_for_cipher_string(
1978 crypt_stat->cipher,
1979 crypt_stat->key_size),
1980 crypt_stat, &payload, &payload_len);
1981 up_write(&(auth_tok_key->sem));
1982 key_put(auth_tok_key);
1983 if (rc) {
1984 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1985 goto out;
1986 }
1987 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1988 if (rc) {
1989 ecryptfs_printk(KERN_ERR, "Error sending message to "
1990 "ecryptfsd: %d\n", rc);
1991 goto out;
1992 }
1993 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1994 if (rc) {
1995 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1996 "from the user space daemon\n");
1997 rc = -EIO;
1998 goto out;
1999 }
2000 rc = parse_tag_67_packet(key_rec, msg);
2001 if (rc)
2002 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2003 kfree(msg);
2004 out:
2005 kfree(payload);
2006 return rc;
2007 }
2008 /**
2009 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2010 * @dest: Buffer into which to write the packet
2011 * @remaining_bytes: Maximum number of bytes that can be writtn
2012 * @auth_tok_key: The authentication token key to unlock and put when done with
2013 * @auth_tok
2014 * @auth_tok: The authentication token used for generating the tag 1 packet
2015 * @crypt_stat: The cryptographic context
2016 * @key_rec: The key record struct for the tag 1 packet
2017 * @packet_size: This function will write the number of bytes that end
2018 * up constituting the packet; set to zero on error
2019 *
2020 * Returns zero on success; non-zero on error.
2021 */
2022 static int
2023 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2024 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2025 struct ecryptfs_crypt_stat *crypt_stat,
2026 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2027 {
2028 size_t i;
2029 size_t encrypted_session_key_valid = 0;
2030 size_t packet_size_length;
2031 size_t max_packet_size;
2032 int rc = 0;
2033
2034 (*packet_size) = 0;
2035 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2036 ECRYPTFS_SIG_SIZE);
2037 encrypted_session_key_valid = 0;
2038 for (i = 0; i < crypt_stat->key_size; i++)
2039 encrypted_session_key_valid |=
2040 auth_tok->session_key.encrypted_key[i];
2041 if (encrypted_session_key_valid) {
2042 memcpy(key_rec->enc_key,
2043 auth_tok->session_key.encrypted_key,
2044 auth_tok->session_key.encrypted_key_size);
2045 up_write(&(auth_tok_key->sem));
2046 key_put(auth_tok_key);
2047 goto encrypted_session_key_set;
2048 }
2049 if (auth_tok->session_key.encrypted_key_size == 0)
2050 auth_tok->session_key.encrypted_key_size =
2051 auth_tok->token.private_key.key_size;
2052 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2053 key_rec);
2054 if (rc) {
2055 printk(KERN_ERR "Failed to encrypt session key via a key "
2056 "module; rc = [%d]\n", rc);
2057 goto out;
2058 }
2059 if (ecryptfs_verbosity > 0) {
2060 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2061 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2062 }
2063 encrypted_session_key_set:
2064 /* This format is inspired by OpenPGP; see RFC 2440
2065 * packet tag 1 */
2066 max_packet_size = (1 /* Tag 1 identifier */
2067 + 3 /* Max Tag 1 packet size */
2068 + 1 /* Version */
2069 + ECRYPTFS_SIG_SIZE /* Key identifier */
2070 + 1 /* Cipher identifier */
2071 + key_rec->enc_key_size); /* Encrypted key size */
2072 if (max_packet_size > (*remaining_bytes)) {
2073 printk(KERN_ERR "Packet length larger than maximum allowable; "
2074 "need up to [%td] bytes, but there are only [%td] "
2075 "available\n", max_packet_size, (*remaining_bytes));
2076 rc = -EINVAL;
2077 goto out;
2078 }
2079 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2080 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2081 (max_packet_size - 4),
2082 &packet_size_length);
2083 if (rc) {
2084 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2085 "header; cannot generate packet length\n");
2086 goto out;
2087 }
2088 (*packet_size) += packet_size_length;
2089 dest[(*packet_size)++] = 0x03; /* version 3 */
2090 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2091 (*packet_size) += ECRYPTFS_SIG_SIZE;
2092 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2093 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2094 key_rec->enc_key_size);
2095 (*packet_size) += key_rec->enc_key_size;
2096 out:
2097 if (rc)
2098 (*packet_size) = 0;
2099 else
2100 (*remaining_bytes) -= (*packet_size);
2101 return rc;
2102 }
2103
2104 /**
2105 * write_tag_11_packet
2106 * @dest: Target into which Tag 11 packet is to be written
2107 * @remaining_bytes: Maximum packet length
2108 * @contents: Byte array of contents to copy in
2109 * @contents_length: Number of bytes in contents
2110 * @packet_length: Length of the Tag 11 packet written; zero on error
2111 *
2112 * Returns zero on success; non-zero on error.
2113 */
2114 static int
2115 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2116 size_t contents_length, size_t *packet_length)
2117 {
2118 size_t packet_size_length;
2119 size_t max_packet_size;
2120 int rc = 0;
2121
2122 (*packet_length) = 0;
2123 /* This format is inspired by OpenPGP; see RFC 2440
2124 * packet tag 11 */
2125 max_packet_size = (1 /* Tag 11 identifier */
2126 + 3 /* Max Tag 11 packet size */
2127 + 1 /* Binary format specifier */
2128 + 1 /* Filename length */
2129 + 8 /* Filename ("_CONSOLE") */
2130 + 4 /* Modification date */
2131 + contents_length); /* Literal data */
2132 if (max_packet_size > (*remaining_bytes)) {
2133 printk(KERN_ERR "Packet length larger than maximum allowable; "
2134 "need up to [%td] bytes, but there are only [%td] "
2135 "available\n", max_packet_size, (*remaining_bytes));
2136 rc = -EINVAL;
2137 goto out;
2138 }
2139 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2140 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2141 (max_packet_size - 4),
2142 &packet_size_length);
2143 if (rc) {
2144 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2145 "generate packet length. rc = [%d]\n", rc);
2146 goto out;
2147 }
2148 (*packet_length) += packet_size_length;
2149 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2150 dest[(*packet_length)++] = 8;
2151 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2152 (*packet_length) += 8;
2153 memset(&dest[(*packet_length)], 0x00, 4);
2154 (*packet_length) += 4;
2155 memcpy(&dest[(*packet_length)], contents, contents_length);
2156 (*packet_length) += contents_length;
2157 out:
2158 if (rc)
2159 (*packet_length) = 0;
2160 else
2161 (*remaining_bytes) -= (*packet_length);
2162 return rc;
2163 }
2164
2165 /**
2166 * write_tag_3_packet
2167 * @dest: Buffer into which to write the packet
2168 * @remaining_bytes: Maximum number of bytes that can be written
2169 * @auth_tok: Authentication token
2170 * @crypt_stat: The cryptographic context
2171 * @key_rec: encrypted key
2172 * @packet_size: This function will write the number of bytes that end
2173 * up constituting the packet; set to zero on error
2174 *
2175 * Returns zero on success; non-zero on error.
2176 */
2177 static int
2178 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2179 struct ecryptfs_auth_tok *auth_tok,
2180 struct ecryptfs_crypt_stat *crypt_stat,
2181 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2182 {
2183 size_t i;
2184 size_t encrypted_session_key_valid = 0;
2185 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2186 struct scatterlist dst_sg[2];
2187 struct scatterlist src_sg[2];
2188 struct mutex *tfm_mutex = NULL;
2189 u8 cipher_code;
2190 size_t packet_size_length;
2191 size_t max_packet_size;
2192 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2193 crypt_stat->mount_crypt_stat;
2194 struct blkcipher_desc desc = {
2195 .tfm = NULL,
2196 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2197 };
2198 int rc = 0;
2199
2200 (*packet_size) = 0;
2201 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2202 ECRYPTFS_SIG_SIZE);
2203 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2204 crypt_stat->cipher);
2205 if (unlikely(rc)) {
2206 printk(KERN_ERR "Internal error whilst attempting to get "
2207 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2208 crypt_stat->cipher, rc);
2209 goto out;
2210 }
2211 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2212 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2213
2214 printk(KERN_WARNING "No key size specified at mount; "
2215 "defaulting to [%d]\n", alg->max_keysize);
2216 mount_crypt_stat->global_default_cipher_key_size =
2217 alg->max_keysize;
2218 }
2219 if (crypt_stat->key_size == 0)
2220 crypt_stat->key_size =
2221 mount_crypt_stat->global_default_cipher_key_size;
2222 if (auth_tok->session_key.encrypted_key_size == 0)
2223 auth_tok->session_key.encrypted_key_size =
2224 crypt_stat->key_size;
2225 if (crypt_stat->key_size == 24
2226 && strcmp("aes", crypt_stat->cipher) == 0) {
2227 memset((crypt_stat->key + 24), 0, 8);
2228 auth_tok->session_key.encrypted_key_size = 32;
2229 } else
2230 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2231 key_rec->enc_key_size =
2232 auth_tok->session_key.encrypted_key_size;
2233 encrypted_session_key_valid = 0;
2234 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2235 encrypted_session_key_valid |=
2236 auth_tok->session_key.encrypted_key[i];
2237 if (encrypted_session_key_valid) {
2238 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2239 "using auth_tok->session_key.encrypted_key, "
2240 "where key_rec->enc_key_size = [%zd]\n",
2241 key_rec->enc_key_size);
2242 memcpy(key_rec->enc_key,
2243 auth_tok->session_key.encrypted_key,
2244 key_rec->enc_key_size);
2245 goto encrypted_session_key_set;
2246 }
2247 if (auth_tok->token.password.flags &
2248 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2249 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2250 "session key encryption key of size [%d]\n",
2251 auth_tok->token.password.
2252 session_key_encryption_key_bytes);
2253 memcpy(session_key_encryption_key,
2254 auth_tok->token.password.session_key_encryption_key,
2255 crypt_stat->key_size);
2256 ecryptfs_printk(KERN_DEBUG,
2257 "Cached session key encryption key:\n");
2258 if (ecryptfs_verbosity > 0)
2259 ecryptfs_dump_hex(session_key_encryption_key, 16);
2260 }
2261 if (unlikely(ecryptfs_verbosity > 0)) {
2262 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2263 ecryptfs_dump_hex(session_key_encryption_key, 16);
2264 }
2265 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2266 src_sg, 2);
2267 if (rc < 1 || rc > 2) {
2268 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2269 "for crypt_stat session key; expected rc = 1; "
2270 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2271 rc, key_rec->enc_key_size);
2272 rc = -ENOMEM;
2273 goto out;
2274 }
2275 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2276 dst_sg, 2);
2277 if (rc < 1 || rc > 2) {
2278 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2279 "for crypt_stat encrypted session key; "
2280 "expected rc = 1; got rc = [%d]. "
2281 "key_rec->enc_key_size = [%zd]\n", rc,
2282 key_rec->enc_key_size);
2283 rc = -ENOMEM;
2284 goto out;
2285 }
2286 mutex_lock(tfm_mutex);
2287 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2288 crypt_stat->key_size);
2289 if (rc < 0) {
2290 mutex_unlock(tfm_mutex);
2291 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2292 "context; rc = [%d]\n", rc);
2293 goto out;
2294 }
2295 rc = 0;
2296 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2297 crypt_stat->key_size);
2298 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2299 (*key_rec).enc_key_size);
2300 mutex_unlock(tfm_mutex);
2301 if (rc) {
2302 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2303 goto out;
2304 }
2305 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2306 if (ecryptfs_verbosity > 0) {
2307 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2308 key_rec->enc_key_size);
2309 ecryptfs_dump_hex(key_rec->enc_key,
2310 key_rec->enc_key_size);
2311 }
2312 encrypted_session_key_set:
2313 /* This format is inspired by OpenPGP; see RFC 2440
2314 * packet tag 3 */
2315 max_packet_size = (1 /* Tag 3 identifier */
2316 + 3 /* Max Tag 3 packet size */
2317 + 1 /* Version */
2318 + 1 /* Cipher code */
2319 + 1 /* S2K specifier */
2320 + 1 /* Hash identifier */
2321 + ECRYPTFS_SALT_SIZE /* Salt */
2322 + 1 /* Hash iterations */
2323 + key_rec->enc_key_size); /* Encrypted key size */
2324 if (max_packet_size > (*remaining_bytes)) {
2325 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2326 "there are only [%td] available\n", max_packet_size,
2327 (*remaining_bytes));
2328 rc = -EINVAL;
2329 goto out;
2330 }
2331 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2332 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2333 * to get the number of octets in the actual Tag 3 packet */
2334 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2335 (max_packet_size - 4),
2336 &packet_size_length);
2337 if (rc) {
2338 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2339 "generate packet length. rc = [%d]\n", rc);
2340 goto out;
2341 }
2342 (*packet_size) += packet_size_length;
2343 dest[(*packet_size)++] = 0x04; /* version 4 */
2344 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2345 * specified with strings */
2346 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2347 crypt_stat->key_size);
2348 if (cipher_code == 0) {
2349 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2350 "cipher [%s]\n", crypt_stat->cipher);
2351 rc = -EINVAL;
2352 goto out;
2353 }
2354 dest[(*packet_size)++] = cipher_code;
2355 dest[(*packet_size)++] = 0x03; /* S2K */
2356 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2357 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2358 ECRYPTFS_SALT_SIZE);
2359 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2360 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2361 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2362 key_rec->enc_key_size);
2363 (*packet_size) += key_rec->enc_key_size;
2364 out:
2365 if (rc)
2366 (*packet_size) = 0;
2367 else
2368 (*remaining_bytes) -= (*packet_size);
2369 return rc;
2370 }
2371
2372 struct kmem_cache *ecryptfs_key_record_cache;
2373
2374 /**
2375 * ecryptfs_generate_key_packet_set
2376 * @dest_base: Virtual address from which to write the key record set
2377 * @crypt_stat: The cryptographic context from which the
2378 * authentication tokens will be retrieved
2379 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2380 * for the global parameters
2381 * @len: The amount written
2382 * @max: The maximum amount of data allowed to be written
2383 *
2384 * Generates a key packet set and writes it to the virtual address
2385 * passed in.
2386 *
2387 * Returns zero on success; non-zero on error.
2388 */
2389 int
2390 ecryptfs_generate_key_packet_set(char *dest_base,
2391 struct ecryptfs_crypt_stat *crypt_stat,
2392 struct dentry *ecryptfs_dentry, size_t *len,
2393 size_t max)
2394 {
2395 struct ecryptfs_auth_tok *auth_tok;
2396 struct key *auth_tok_key = NULL;
2397 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2398 &ecryptfs_superblock_to_private(
2399 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2400 size_t written;
2401 struct ecryptfs_key_record *key_rec;
2402 struct ecryptfs_key_sig *key_sig;
2403 int rc = 0;
2404
2405 (*len) = 0;
2406 mutex_lock(&crypt_stat->keysig_list_mutex);
2407 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2408 if (!key_rec) {
2409 rc = -ENOMEM;
2410 goto out;
2411 }
2412 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2413 crypt_stat_list) {
2414 memset(key_rec, 0, sizeof(*key_rec));
2415 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2416 &auth_tok,
2417 mount_crypt_stat,
2418 key_sig->keysig);
2419 if (rc) {
2420 printk(KERN_WARNING "Unable to retrieve auth tok with "
2421 "sig = [%s]\n", key_sig->keysig);
2422 rc = process_find_global_auth_tok_for_sig_err(rc);
2423 goto out_free;
2424 }
2425 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2426 rc = write_tag_3_packet((dest_base + (*len)),
2427 &max, auth_tok,
2428 crypt_stat, key_rec,
2429 &written);
2430 up_write(&(auth_tok_key->sem));
2431 key_put(auth_tok_key);
2432 if (rc) {
2433 ecryptfs_printk(KERN_WARNING, "Error "
2434 "writing tag 3 packet\n");
2435 goto out_free;
2436 }
2437 (*len) += written;
2438 /* Write auth tok signature packet */
2439 rc = write_tag_11_packet((dest_base + (*len)), &max,
2440 key_rec->sig,
2441 ECRYPTFS_SIG_SIZE, &written);
2442 if (rc) {
2443 ecryptfs_printk(KERN_ERR, "Error writing "
2444 "auth tok signature packet\n");
2445 goto out_free;
2446 }
2447 (*len) += written;
2448 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2449 rc = write_tag_1_packet(dest_base + (*len), &max,
2450 auth_tok_key, auth_tok,
2451 crypt_stat, key_rec, &written);
2452 if (rc) {
2453 ecryptfs_printk(KERN_WARNING, "Error "
2454 "writing tag 1 packet\n");
2455 goto out_free;
2456 }
2457 (*len) += written;
2458 } else {
2459 up_write(&(auth_tok_key->sem));
2460 key_put(auth_tok_key);
2461 ecryptfs_printk(KERN_WARNING, "Unsupported "
2462 "authentication token type\n");
2463 rc = -EINVAL;
2464 goto out_free;
2465 }
2466 }
2467 if (likely(max > 0)) {
2468 dest_base[(*len)] = 0x00;
2469 } else {
2470 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2471 rc = -EIO;
2472 }
2473 out_free:
2474 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2475 out:
2476 if (rc)
2477 (*len) = 0;
2478 mutex_unlock(&crypt_stat->keysig_list_mutex);
2479 return rc;
2480 }
2481
2482 struct kmem_cache *ecryptfs_key_sig_cache;
2483
2484 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2485 {
2486 struct ecryptfs_key_sig *new_key_sig;
2487
2488 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2489 if (!new_key_sig) {
2490 printk(KERN_ERR
2491 "Error allocating from ecryptfs_key_sig_cache\n");
2492 return -ENOMEM;
2493 }
2494 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2495 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2496 /* Caller must hold keysig_list_mutex */
2497 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2498
2499 return 0;
2500 }
2501
2502 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2503
2504 int
2505 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2506 char *sig, u32 global_auth_tok_flags)
2507 {
2508 struct ecryptfs_global_auth_tok *new_auth_tok;
2509 int rc = 0;
2510
2511 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2512 GFP_KERNEL);
2513 if (!new_auth_tok) {
2514 rc = -ENOMEM;
2515 printk(KERN_ERR "Error allocating from "
2516 "ecryptfs_global_auth_tok_cache\n");
2517 goto out;
2518 }
2519 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2520 new_auth_tok->flags = global_auth_tok_flags;
2521 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2522 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2523 list_add(&new_auth_tok->mount_crypt_stat_list,
2524 &mount_crypt_stat->global_auth_tok_list);
2525 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2526 out:
2527 return rc;
2528 }
2529
Linux with added FPC-III support