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ehea: fix skb_frag_size typo
[linux-btrfs-devel.git] / fs / ecryptfs / keystore.c
blobac1ad48c2376df4b3061e55a973b27b42388f510
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[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 = (1 /* Tag 70 identifier */
682 + 3 /* Max Tag 70 packet size */
683 + ECRYPTFS_SIG_SIZE /* FNEK sig */
684 + 1 /* Cipher identifier */
685 + s->block_aligned_filename_size);
686 if (dest == NULL) {
687 (*packet_size) = s->max_packet_size;
688 goto out_unlock;
689 }
690 if (s->max_packet_size > (*remaining_bytes)) {
691 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
692 "[%zd] available\n", __func__, s->max_packet_size,
693 (*remaining_bytes));
694 rc = -EINVAL;
695 goto out_unlock;
696 }
697 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
698 GFP_KERNEL);
699 if (!s->block_aligned_filename) {
700 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
701 "kzalloc [%zd] bytes\n", __func__,
702 s->block_aligned_filename_size);
703 rc = -ENOMEM;
704 goto out_unlock;
705 }
706 s->i = 0;
707 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
708 rc = ecryptfs_write_packet_length(&dest[s->i],
709 (ECRYPTFS_SIG_SIZE
710 + 1 /* Cipher code */
711 + s->block_aligned_filename_size),
712 &s->packet_size_len);
713 if (rc) {
714 printk(KERN_ERR "%s: Error generating tag 70 packet "
715 "header; cannot generate packet length; rc = [%d]\n",
716 __func__, rc);
717 goto out_free_unlock;
718 }
719 s->i += s->packet_size_len;
720 ecryptfs_from_hex(&dest[s->i],
721 mount_crypt_stat->global_default_fnek_sig,
722 ECRYPTFS_SIG_SIZE);
723 s->i += ECRYPTFS_SIG_SIZE;
724 s->cipher_code = ecryptfs_code_for_cipher_string(
725 mount_crypt_stat->global_default_fn_cipher_name,
726 mount_crypt_stat->global_default_fn_cipher_key_bytes);
727 if (s->cipher_code == 0) {
728 printk(KERN_WARNING "%s: Unable to generate code for "
729 "cipher [%s] with key bytes [%zd]\n", __func__,
730 mount_crypt_stat->global_default_fn_cipher_name,
731 mount_crypt_stat->global_default_fn_cipher_key_bytes);
732 rc = -EINVAL;
733 goto out_free_unlock;
734 }
735 dest[s->i++] = s->cipher_code;
736 /* TODO: Support other key modules than passphrase for
737 * filename encryption */
738 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
739 rc = -EOPNOTSUPP;
740 printk(KERN_INFO "%s: Filename encryption only supports "
741 "password tokens\n", __func__);
742 goto out_free_unlock;
743 }
744 sg_init_one(
745 &s->hash_sg,
746 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
747 s->auth_tok->token.password.session_key_encryption_key_bytes);
748 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
749 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
750 CRYPTO_ALG_ASYNC);
751 if (IS_ERR(s->hash_desc.tfm)) {
752 rc = PTR_ERR(s->hash_desc.tfm);
753 printk(KERN_ERR "%s: Error attempting to "
754 "allocate hash crypto context; rc = [%d]\n",
755 __func__, rc);
756 goto out_free_unlock;
757 }
758 rc = crypto_hash_init(&s->hash_desc);
759 if (rc) {
760 printk(KERN_ERR
761 "%s: Error initializing crypto hash; rc = [%d]\n",
762 __func__, rc);
763 goto out_release_free_unlock;
764 }
765 rc = crypto_hash_update(
766 &s->hash_desc, &s->hash_sg,
767 s->auth_tok->token.password.session_key_encryption_key_bytes);
768 if (rc) {
769 printk(KERN_ERR
770 "%s: Error updating crypto hash; rc = [%d]\n",
771 __func__, rc);
772 goto out_release_free_unlock;
773 }
774 rc = crypto_hash_final(&s->hash_desc, s->hash);
775 if (rc) {
776 printk(KERN_ERR
777 "%s: Error finalizing crypto hash; rc = [%d]\n",
778 __func__, rc);
779 goto out_release_free_unlock;
780 }
781 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
782 s->block_aligned_filename[s->j] =
783 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
784 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
785 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
786 sg_init_one(&s->hash_sg, (u8 *)s->hash,
787 ECRYPTFS_TAG_70_DIGEST_SIZE);
788 rc = crypto_hash_init(&s->hash_desc);
789 if (rc) {
790 printk(KERN_ERR
791 "%s: Error initializing crypto hash; "
792 "rc = [%d]\n", __func__, rc);
793 goto out_release_free_unlock;
794 }
795 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
796 ECRYPTFS_TAG_70_DIGEST_SIZE);
797 if (rc) {
798 printk(KERN_ERR
799 "%s: Error updating crypto hash; "
800 "rc = [%d]\n", __func__, rc);
801 goto out_release_free_unlock;
802 }
803 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
804 if (rc) {
805 printk(KERN_ERR
806 "%s: Error finalizing crypto hash; "
807 "rc = [%d]\n", __func__, rc);
808 goto out_release_free_unlock;
809 }
810 memcpy(s->hash, s->tmp_hash,
811 ECRYPTFS_TAG_70_DIGEST_SIZE);
812 }
813 if (s->block_aligned_filename[s->j] == '\0')
814 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
815 }
816 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
817 filename_size);
818 rc = virt_to_scatterlist(s->block_aligned_filename,
819 s->block_aligned_filename_size, s->src_sg, 2);
820 if (rc < 1) {
821 printk(KERN_ERR "%s: Internal error whilst attempting to "
822 "convert filename memory to scatterlist; rc = [%d]. "
823 "block_aligned_filename_size = [%zd]\n", __func__, rc,
824 s->block_aligned_filename_size);
825 goto out_release_free_unlock;
826 }
827 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
828 s->dst_sg, 2);
829 if (rc < 1) {
830 printk(KERN_ERR "%s: Internal error whilst attempting to "
831 "convert encrypted filename memory to scatterlist; "
832 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
833 __func__, rc, s->block_aligned_filename_size);
834 goto out_release_free_unlock;
835 }
836 /* The characters in the first block effectively do the job
837 * of the IV here, so we just use 0's for the IV. Note the
838 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
839 * >= ECRYPTFS_MAX_IV_BYTES. */
840 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
841 s->desc.info = s->iv;
842 rc = crypto_blkcipher_setkey(
843 s->desc.tfm,
844 s->auth_tok->token.password.session_key_encryption_key,
845 mount_crypt_stat->global_default_fn_cipher_key_bytes);
846 if (rc < 0) {
847 printk(KERN_ERR "%s: Error setting key for crypto context; "
848 "rc = [%d]. s->auth_tok->token.password.session_key_"
849 "encryption_key = [0x%p]; mount_crypt_stat->"
850 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
851 rc,
852 s->auth_tok->token.password.session_key_encryption_key,
853 mount_crypt_stat->global_default_fn_cipher_key_bytes);
854 goto out_release_free_unlock;
855 }
856 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
857 s->block_aligned_filename_size);
858 if (rc) {
859 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
860 "rc = [%d]\n", __func__, rc);
861 goto out_release_free_unlock;
862 }
863 s->i += s->block_aligned_filename_size;
864 (*packet_size) = s->i;
865 (*remaining_bytes) -= (*packet_size);
866 out_release_free_unlock:
867 crypto_free_hash(s->hash_desc.tfm);
868 out_free_unlock:
869 kzfree(s->block_aligned_filename);
870 out_unlock:
871 mutex_unlock(s->tfm_mutex);
872 out:
873 if (auth_tok_key) {
874 up_write(&(auth_tok_key->sem));
875 key_put(auth_tok_key);
876 }
877 kfree(s);
878 return rc;
879 }
880
881 struct ecryptfs_parse_tag_70_packet_silly_stack {
882 u8 cipher_code;
883 size_t max_packet_size;
884 size_t packet_size_len;
885 size_t parsed_tag_70_packet_size;
886 size_t block_aligned_filename_size;
887 size_t block_size;
888 size_t i;
889 struct mutex *tfm_mutex;
890 char *decrypted_filename;
891 struct ecryptfs_auth_tok *auth_tok;
892 struct scatterlist src_sg[2];
893 struct scatterlist dst_sg[2];
894 struct blkcipher_desc desc;
895 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
896 char iv[ECRYPTFS_MAX_IV_BYTES];
897 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
898 };
899
900 /**
901 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
902 * @filename: This function kmalloc's the memory for the filename
903 * @filename_size: This function sets this to the amount of memory
904 * kmalloc'd for the filename
905 * @packet_size: This function sets this to the the number of octets
906 * in the packet parsed
907 * @mount_crypt_stat: The mount-wide cryptographic context
908 * @data: The memory location containing the start of the tag 70
909 * packet
910 * @max_packet_size: The maximum legal size of the packet to be parsed
911 * from @data
912 *
913 * Returns zero on success; non-zero otherwise
914 */
915 int
916 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
917 size_t *packet_size,
918 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
919 char *data, size_t max_packet_size)
920 {
921 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
922 struct key *auth_tok_key = NULL;
923 int rc = 0;
924
925 (*packet_size) = 0;
926 (*filename_size) = 0;
927 (*filename) = NULL;
928 s = kmalloc(sizeof(*s), GFP_KERNEL);
929 if (!s) {
930 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
931 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
932 rc = -ENOMEM;
933 goto out;
934 }
935 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
936 if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
937 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
938 "at least [%d]\n", __func__, max_packet_size,
939 (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
940 rc = -EINVAL;
941 goto out;
942 }
943 /* Octet 0: Tag 70 identifier
944 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
945 * and block-aligned encrypted filename size)
946 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
947 * Octet N2-N3: Cipher identifier (1 octet)
948 * Octets N3-N4: Block-aligned encrypted filename
949 * - Consists of a minimum number of random numbers, a \0
950 * separator, and then the filename */
951 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
952 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
953 "tag [0x%.2x]\n", __func__,
954 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
955 rc = -EINVAL;
956 goto out;
957 }
958 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
959 &s->parsed_tag_70_packet_size,
960 &s->packet_size_len);
961 if (rc) {
962 printk(KERN_WARNING "%s: Error parsing packet length; "
963 "rc = [%d]\n", __func__, rc);
964 goto out;
965 }
966 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
967 - ECRYPTFS_SIG_SIZE - 1);
968 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
969 > max_packet_size) {
970 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
971 "size is [%zd]\n", __func__, max_packet_size,
972 (1 + s->packet_size_len + 1
973 + s->block_aligned_filename_size));
974 rc = -EINVAL;
975 goto out;
976 }
977 (*packet_size) += s->packet_size_len;
978 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
979 ECRYPTFS_SIG_SIZE);
980 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
981 (*packet_size) += ECRYPTFS_SIG_SIZE;
982 s->cipher_code = data[(*packet_size)++];
983 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
984 if (rc) {
985 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
986 __func__, s->cipher_code);
987 goto out;
988 }
989 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
990 &s->auth_tok, mount_crypt_stat,
991 s->fnek_sig_hex);
992 if (rc) {
993 printk(KERN_ERR "%s: Error attempting to find auth tok for "
994 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
995 rc);
996 goto out;
997 }
998 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
999 &s->tfm_mutex,
1000 s->cipher_string);
1001 if (unlikely(rc)) {
1002 printk(KERN_ERR "Internal error whilst attempting to get "
1003 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1004 s->cipher_string, rc);
1005 goto out;
1006 }
1007 mutex_lock(s->tfm_mutex);
1008 rc = virt_to_scatterlist(&data[(*packet_size)],
1009 s->block_aligned_filename_size, s->src_sg, 2);
1010 if (rc < 1) {
1011 printk(KERN_ERR "%s: Internal error whilst attempting to "
1012 "convert encrypted filename memory to scatterlist; "
1013 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1014 __func__, rc, s->block_aligned_filename_size);
1015 goto out_unlock;
1016 }
1017 (*packet_size) += s->block_aligned_filename_size;
1018 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1019 GFP_KERNEL);
1020 if (!s->decrypted_filename) {
1021 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1022 "kmalloc [%zd] bytes\n", __func__,
1023 s->block_aligned_filename_size);
1024 rc = -ENOMEM;
1025 goto out_unlock;
1026 }
1027 rc = virt_to_scatterlist(s->decrypted_filename,
1028 s->block_aligned_filename_size, s->dst_sg, 2);
1029 if (rc < 1) {
1030 printk(KERN_ERR "%s: Internal error whilst attempting to "
1031 "convert decrypted filename memory to scatterlist; "
1032 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1033 __func__, rc, s->block_aligned_filename_size);
1034 goto out_free_unlock;
1035 }
1036 /* The characters in the first block effectively do the job of
1037 * the IV here, so we just use 0's for the IV. Note the
1038 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1039 * >= ECRYPTFS_MAX_IV_BYTES. */
1040 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1041 s->desc.info = s->iv;
1042 /* TODO: Support other key modules than passphrase for
1043 * filename encryption */
1044 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1045 rc = -EOPNOTSUPP;
1046 printk(KERN_INFO "%s: Filename encryption only supports "
1047 "password tokens\n", __func__);
1048 goto out_free_unlock;
1049 }
1050 rc = crypto_blkcipher_setkey(
1051 s->desc.tfm,
1052 s->auth_tok->token.password.session_key_encryption_key,
1053 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1054 if (rc < 0) {
1055 printk(KERN_ERR "%s: Error setting key for crypto context; "
1056 "rc = [%d]. s->auth_tok->token.password.session_key_"
1057 "encryption_key = [0x%p]; mount_crypt_stat->"
1058 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1059 rc,
1060 s->auth_tok->token.password.session_key_encryption_key,
1061 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1062 goto out_free_unlock;
1063 }
1064 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
1065 s->block_aligned_filename_size);
1066 if (rc) {
1067 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1068 "rc = [%d]\n", __func__, rc);
1069 goto out_free_unlock;
1070 }
1071 s->i = 0;
1072 while (s->decrypted_filename[s->i] != '\0'
1073 && s->i < s->block_aligned_filename_size)
1074 s->i++;
1075 if (s->i == s->block_aligned_filename_size) {
1076 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1077 "find valid separator between random characters and "
1078 "the filename\n", __func__);
1079 rc = -EINVAL;
1080 goto out_free_unlock;
1081 }
1082 s->i++;
1083 (*filename_size) = (s->block_aligned_filename_size - s->i);
1084 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1085 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1086 "invalid\n", __func__, (*filename_size));
1087 rc = -EINVAL;
1088 goto out_free_unlock;
1089 }
1090 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1091 if (!(*filename)) {
1092 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1093 "kmalloc [%zd] bytes\n", __func__,
1094 ((*filename_size) + 1));
1095 rc = -ENOMEM;
1096 goto out_free_unlock;
1097 }
1098 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1099 (*filename)[(*filename_size)] = '\0';
1100 out_free_unlock:
1101 kfree(s->decrypted_filename);
1102 out_unlock:
1103 mutex_unlock(s->tfm_mutex);
1104 out:
1105 if (rc) {
1106 (*packet_size) = 0;
1107 (*filename_size) = 0;
1108 (*filename) = NULL;
1109 }
1110 if (auth_tok_key) {
1111 up_write(&(auth_tok_key->sem));
1112 key_put(auth_tok_key);
1113 }
1114 kfree(s);
1115 return rc;
1116 }
1117
1118 static int
1119 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1120 {
1121 int rc = 0;
1122
1123 (*sig) = NULL;
1124 switch (auth_tok->token_type) {
1125 case ECRYPTFS_PASSWORD:
1126 (*sig) = auth_tok->token.password.signature;
1127 break;
1128 case ECRYPTFS_PRIVATE_KEY:
1129 (*sig) = auth_tok->token.private_key.signature;
1130 break;
1131 default:
1132 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1133 auth_tok->token_type);
1134 rc = -EINVAL;
1135 }
1136 return rc;
1137 }
1138
1139 /**
1140 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1141 * @auth_tok: The key authentication token used to decrypt the session key
1142 * @crypt_stat: The cryptographic context
1143 *
1144 * Returns zero on success; non-zero error otherwise.
1145 */
1146 static int
1147 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1148 struct ecryptfs_crypt_stat *crypt_stat)
1149 {
1150 u8 cipher_code = 0;
1151 struct ecryptfs_msg_ctx *msg_ctx;
1152 struct ecryptfs_message *msg = NULL;
1153 char *auth_tok_sig;
1154 char *payload;
1155 size_t payload_len;
1156 int rc;
1157
1158 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1159 if (rc) {
1160 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1161 auth_tok->token_type);
1162 goto out;
1163 }
1164 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1165 &payload, &payload_len);
1166 if (rc) {
1167 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1168 goto out;
1169 }
1170 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1171 if (rc) {
1172 ecryptfs_printk(KERN_ERR, "Error sending message to "
1173 "ecryptfsd\n");
1174 goto out;
1175 }
1176 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1177 if (rc) {
1178 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1179 "from the user space daemon\n");
1180 rc = -EIO;
1181 goto out;
1182 }
1183 rc = parse_tag_65_packet(&(auth_tok->session_key),
1184 &cipher_code, msg);
1185 if (rc) {
1186 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1187 rc);
1188 goto out;
1189 }
1190 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1191 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1192 auth_tok->session_key.decrypted_key_size);
1193 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1194 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1195 if (rc) {
1196 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1197 cipher_code)
1198 goto out;
1199 }
1200 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1201 if (ecryptfs_verbosity > 0) {
1202 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1203 ecryptfs_dump_hex(crypt_stat->key,
1204 crypt_stat->key_size);
1205 }
1206 out:
1207 if (msg)
1208 kfree(msg);
1209 return rc;
1210 }
1211
1212 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1213 {
1214 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1215 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1216
1217 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1218 auth_tok_list_head, list) {
1219 list_del(&auth_tok_list_item->list);
1220 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1221 auth_tok_list_item);
1222 }
1223 }
1224
1225 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1226
1227 /**
1228 * parse_tag_1_packet
1229 * @crypt_stat: The cryptographic context to modify based on packet contents
1230 * @data: The raw bytes of the packet.
1231 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1232 * a new authentication token will be placed at the
1233 * end of this list for this packet.
1234 * @new_auth_tok: Pointer to a pointer to memory that this function
1235 * allocates; sets the memory address of the pointer to
1236 * NULL on error. This object is added to the
1237 * auth_tok_list.
1238 * @packet_size: This function writes the size of the parsed packet
1239 * into this memory location; zero on error.
1240 * @max_packet_size: The maximum allowable packet size
1241 *
1242 * Returns zero on success; non-zero on error.
1243 */
1244 static int
1245 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1246 unsigned char *data, struct list_head *auth_tok_list,
1247 struct ecryptfs_auth_tok **new_auth_tok,
1248 size_t *packet_size, size_t max_packet_size)
1249 {
1250 size_t body_size;
1251 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1252 size_t length_size;
1253 int rc = 0;
1254
1255 (*packet_size) = 0;
1256 (*new_auth_tok) = NULL;
1257 /**
1258 * This format is inspired by OpenPGP; see RFC 2440
1259 * packet tag 1
1260 *
1261 * Tag 1 identifier (1 byte)
1262 * Max Tag 1 packet size (max 3 bytes)
1263 * Version (1 byte)
1264 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1265 * Cipher identifier (1 byte)
1266 * Encrypted key size (arbitrary)
1267 *
1268 * 12 bytes minimum packet size
1269 */
1270 if (unlikely(max_packet_size < 12)) {
1271 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1272 rc = -EINVAL;
1273 goto out;
1274 }
1275 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1276 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1277 ECRYPTFS_TAG_1_PACKET_TYPE);
1278 rc = -EINVAL;
1279 goto out;
1280 }
1281 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1282 * at end of function upon failure */
1283 auth_tok_list_item =
1284 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1285 GFP_KERNEL);
1286 if (!auth_tok_list_item) {
1287 printk(KERN_ERR "Unable to allocate memory\n");
1288 rc = -ENOMEM;
1289 goto out;
1290 }
1291 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1292 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1293 &length_size);
1294 if (rc) {
1295 printk(KERN_WARNING "Error parsing packet length; "
1296 "rc = [%d]\n", rc);
1297 goto out_free;
1298 }
1299 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1300 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1301 rc = -EINVAL;
1302 goto out_free;
1303 }
1304 (*packet_size) += length_size;
1305 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1306 printk(KERN_WARNING "Packet size exceeds max\n");
1307 rc = -EINVAL;
1308 goto out_free;
1309 }
1310 if (unlikely(data[(*packet_size)++] != 0x03)) {
1311 printk(KERN_WARNING "Unknown version number [%d]\n",
1312 data[(*packet_size) - 1]);
1313 rc = -EINVAL;
1314 goto out_free;
1315 }
1316 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1317 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1318 *packet_size += ECRYPTFS_SIG_SIZE;
1319 /* This byte is skipped because the kernel does not need to
1320 * know which public key encryption algorithm was used */
1321 (*packet_size)++;
1322 (*new_auth_tok)->session_key.encrypted_key_size =
1323 body_size - (ECRYPTFS_SIG_SIZE + 2);
1324 if ((*new_auth_tok)->session_key.encrypted_key_size
1325 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1326 printk(KERN_WARNING "Tag 1 packet contains key larger "
1327 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1328 rc = -EINVAL;
1329 goto out;
1330 }
1331 memcpy((*new_auth_tok)->session_key.encrypted_key,
1332 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1333 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1334 (*new_auth_tok)->session_key.flags &=
1335 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1336 (*new_auth_tok)->session_key.flags |=
1337 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1338 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1339 (*new_auth_tok)->flags = 0;
1340 (*new_auth_tok)->session_key.flags &=
1341 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1342 (*new_auth_tok)->session_key.flags &=
1343 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1344 list_add(&auth_tok_list_item->list, auth_tok_list);
1345 goto out;
1346 out_free:
1347 (*new_auth_tok) = NULL;
1348 memset(auth_tok_list_item, 0,
1349 sizeof(struct ecryptfs_auth_tok_list_item));
1350 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1351 auth_tok_list_item);
1352 out:
1353 if (rc)
1354 (*packet_size) = 0;
1355 return rc;
1356 }
1357
1358 /**
1359 * parse_tag_3_packet
1360 * @crypt_stat: The cryptographic context to modify based on packet
1361 * contents.
1362 * @data: The raw bytes of the packet.
1363 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1364 * a new authentication token will be placed at the end
1365 * of this list for this packet.
1366 * @new_auth_tok: Pointer to a pointer to memory that this function
1367 * allocates; sets the memory address of the pointer to
1368 * NULL on error. This object is added to the
1369 * auth_tok_list.
1370 * @packet_size: This function writes the size of the parsed packet
1371 * into this memory location; zero on error.
1372 * @max_packet_size: maximum number of bytes to parse
1373 *
1374 * Returns zero on success; non-zero on error.
1375 */
1376 static int
1377 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1378 unsigned char *data, struct list_head *auth_tok_list,
1379 struct ecryptfs_auth_tok **new_auth_tok,
1380 size_t *packet_size, size_t max_packet_size)
1381 {
1382 size_t body_size;
1383 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1384 size_t length_size;
1385 int rc = 0;
1386
1387 (*packet_size) = 0;
1388 (*new_auth_tok) = NULL;
1389 /**
1390 *This format is inspired by OpenPGP; see RFC 2440
1391 * packet tag 3
1392 *
1393 * Tag 3 identifier (1 byte)
1394 * Max Tag 3 packet size (max 3 bytes)
1395 * Version (1 byte)
1396 * Cipher code (1 byte)
1397 * S2K specifier (1 byte)
1398 * Hash identifier (1 byte)
1399 * Salt (ECRYPTFS_SALT_SIZE)
1400 * Hash iterations (1 byte)
1401 * Encrypted key (arbitrary)
1402 *
1403 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1404 */
1405 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1406 printk(KERN_ERR "Max packet size too large\n");
1407 rc = -EINVAL;
1408 goto out;
1409 }
1410 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1411 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1412 ECRYPTFS_TAG_3_PACKET_TYPE);
1413 rc = -EINVAL;
1414 goto out;
1415 }
1416 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1417 * at end of function upon failure */
1418 auth_tok_list_item =
1419 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1420 if (!auth_tok_list_item) {
1421 printk(KERN_ERR "Unable to allocate memory\n");
1422 rc = -ENOMEM;
1423 goto out;
1424 }
1425 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1426 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1427 &length_size);
1428 if (rc) {
1429 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1430 rc);
1431 goto out_free;
1432 }
1433 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1434 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1435 rc = -EINVAL;
1436 goto out_free;
1437 }
1438 (*packet_size) += length_size;
1439 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1440 printk(KERN_ERR "Packet size exceeds max\n");
1441 rc = -EINVAL;
1442 goto out_free;
1443 }
1444 (*new_auth_tok)->session_key.encrypted_key_size =
1445 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1446 if ((*new_auth_tok)->session_key.encrypted_key_size
1447 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1448 printk(KERN_WARNING "Tag 3 packet contains key larger "
1449 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1450 rc = -EINVAL;
1451 goto out_free;
1452 }
1453 if (unlikely(data[(*packet_size)++] != 0x04)) {
1454 printk(KERN_WARNING "Unknown version number [%d]\n",
1455 data[(*packet_size) - 1]);
1456 rc = -EINVAL;
1457 goto out_free;
1458 }
1459 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1460 (u16)data[(*packet_size)]);
1461 if (rc)
1462 goto out_free;
1463 /* A little extra work to differentiate among the AES key
1464 * sizes; see RFC2440 */
1465 switch(data[(*packet_size)++]) {
1466 case RFC2440_CIPHER_AES_192:
1467 crypt_stat->key_size = 24;
1468 break;
1469 default:
1470 crypt_stat->key_size =
1471 (*new_auth_tok)->session_key.encrypted_key_size;
1472 }
1473 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1474 if (rc)
1475 goto out_free;
1476 if (unlikely(data[(*packet_size)++] != 0x03)) {
1477 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1478 rc = -ENOSYS;
1479 goto out_free;
1480 }
1481 /* TODO: finish the hash mapping */
1482 switch (data[(*packet_size)++]) {
1483 case 0x01: /* See RFC2440 for these numbers and their mappings */
1484 /* Choose MD5 */
1485 memcpy((*new_auth_tok)->token.password.salt,
1486 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1487 (*packet_size) += ECRYPTFS_SALT_SIZE;
1488 /* This conversion was taken straight from RFC2440 */
1489 (*new_auth_tok)->token.password.hash_iterations =
1490 ((u32) 16 + (data[(*packet_size)] & 15))
1491 << ((data[(*packet_size)] >> 4) + 6);
1492 (*packet_size)++;
1493 /* Friendly reminder:
1494 * (*new_auth_tok)->session_key.encrypted_key_size =
1495 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1496 memcpy((*new_auth_tok)->session_key.encrypted_key,
1497 &data[(*packet_size)],
1498 (*new_auth_tok)->session_key.encrypted_key_size);
1499 (*packet_size) +=
1500 (*new_auth_tok)->session_key.encrypted_key_size;
1501 (*new_auth_tok)->session_key.flags &=
1502 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1503 (*new_auth_tok)->session_key.flags |=
1504 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1505 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1506 break;
1507 default:
1508 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1509 "[%d]\n", data[(*packet_size) - 1]);
1510 rc = -ENOSYS;
1511 goto out_free;
1512 }
1513 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1514 /* TODO: Parametarize; we might actually want userspace to
1515 * decrypt the session key. */
1516 (*new_auth_tok)->session_key.flags &=
1517 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1518 (*new_auth_tok)->session_key.flags &=
1519 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1520 list_add(&auth_tok_list_item->list, auth_tok_list);
1521 goto out;
1522 out_free:
1523 (*new_auth_tok) = NULL;
1524 memset(auth_tok_list_item, 0,
1525 sizeof(struct ecryptfs_auth_tok_list_item));
1526 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1527 auth_tok_list_item);
1528 out:
1529 if (rc)
1530 (*packet_size) = 0;
1531 return rc;
1532 }
1533
1534 /**
1535 * parse_tag_11_packet
1536 * @data: The raw bytes of the packet
1537 * @contents: This function writes the data contents of the literal
1538 * packet into this memory location
1539 * @max_contents_bytes: The maximum number of bytes that this function
1540 * is allowed to write into contents
1541 * @tag_11_contents_size: This function writes the size of the parsed
1542 * contents into this memory location; zero on
1543 * error
1544 * @packet_size: This function writes the size of the parsed packet
1545 * into this memory location; zero on error
1546 * @max_packet_size: maximum number of bytes to parse
1547 *
1548 * Returns zero on success; non-zero on error.
1549 */
1550 static int
1551 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1552 size_t max_contents_bytes, size_t *tag_11_contents_size,
1553 size_t *packet_size, size_t max_packet_size)
1554 {
1555 size_t body_size;
1556 size_t length_size;
1557 int rc = 0;
1558
1559 (*packet_size) = 0;
1560 (*tag_11_contents_size) = 0;
1561 /* This format is inspired by OpenPGP; see RFC 2440
1562 * packet tag 11
1563 *
1564 * Tag 11 identifier (1 byte)
1565 * Max Tag 11 packet size (max 3 bytes)
1566 * Binary format specifier (1 byte)
1567 * Filename length (1 byte)
1568 * Filename ("_CONSOLE") (8 bytes)
1569 * Modification date (4 bytes)
1570 * Literal data (arbitrary)
1571 *
1572 * We need at least 16 bytes of data for the packet to even be
1573 * valid.
1574 */
1575 if (max_packet_size < 16) {
1576 printk(KERN_ERR "Maximum packet size too small\n");
1577 rc = -EINVAL;
1578 goto out;
1579 }
1580 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1581 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1582 rc = -EINVAL;
1583 goto out;
1584 }
1585 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1586 &length_size);
1587 if (rc) {
1588 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1589 goto out;
1590 }
1591 if (body_size < 14) {
1592 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1593 rc = -EINVAL;
1594 goto out;
1595 }
1596 (*packet_size) += length_size;
1597 (*tag_11_contents_size) = (body_size - 14);
1598 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1599 printk(KERN_ERR "Packet size exceeds max\n");
1600 rc = -EINVAL;
1601 goto out;
1602 }
1603 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1604 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1605 "expected size\n");
1606 rc = -EINVAL;
1607 goto out;
1608 }
1609 if (data[(*packet_size)++] != 0x62) {
1610 printk(KERN_WARNING "Unrecognizable packet\n");
1611 rc = -EINVAL;
1612 goto out;
1613 }
1614 if (data[(*packet_size)++] != 0x08) {
1615 printk(KERN_WARNING "Unrecognizable packet\n");
1616 rc = -EINVAL;
1617 goto out;
1618 }
1619 (*packet_size) += 12; /* Ignore filename and modification date */
1620 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1621 (*packet_size) += (*tag_11_contents_size);
1622 out:
1623 if (rc) {
1624 (*packet_size) = 0;
1625 (*tag_11_contents_size) = 0;
1626 }
1627 return rc;
1628 }
1629
1630 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1631 struct ecryptfs_auth_tok **auth_tok,
1632 char *sig)
1633 {
1634 int rc = 0;
1635
1636 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1637 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1638 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1639 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1640 printk(KERN_ERR "Could not find key with description: [%s]\n",
1641 sig);
1642 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1643 (*auth_tok_key) = NULL;
1644 goto out;
1645 }
1646 }
1647 down_write(&(*auth_tok_key)->sem);
1648 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1649 if (rc) {
1650 up_write(&(*auth_tok_key)->sem);
1651 key_put(*auth_tok_key);
1652 (*auth_tok_key) = NULL;
1653 goto out;
1654 }
1655 out:
1656 return rc;
1657 }
1658
1659 /**
1660 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1661 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1662 * @crypt_stat: The cryptographic context
1663 *
1664 * Returns zero on success; non-zero error otherwise
1665 */
1666 static int
1667 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1668 struct ecryptfs_crypt_stat *crypt_stat)
1669 {
1670 struct scatterlist dst_sg[2];
1671 struct scatterlist src_sg[2];
1672 struct mutex *tfm_mutex;
1673 struct blkcipher_desc desc = {
1674 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1675 };
1676 int rc = 0;
1677
1678 if (unlikely(ecryptfs_verbosity > 0)) {
1679 ecryptfs_printk(
1680 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1681 auth_tok->token.password.session_key_encryption_key_bytes);
1682 ecryptfs_dump_hex(
1683 auth_tok->token.password.session_key_encryption_key,
1684 auth_tok->token.password.session_key_encryption_key_bytes);
1685 }
1686 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1687 crypt_stat->cipher);
1688 if (unlikely(rc)) {
1689 printk(KERN_ERR "Internal error whilst attempting to get "
1690 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1691 crypt_stat->cipher, rc);
1692 goto out;
1693 }
1694 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1695 auth_tok->session_key.encrypted_key_size,
1696 src_sg, 2);
1697 if (rc < 1 || rc > 2) {
1698 printk(KERN_ERR "Internal error whilst attempting to convert "
1699 "auth_tok->session_key.encrypted_key to scatterlist; "
1700 "expected rc = 1; got rc = [%d]. "
1701 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1702 auth_tok->session_key.encrypted_key_size);
1703 goto out;
1704 }
1705 auth_tok->session_key.decrypted_key_size =
1706 auth_tok->session_key.encrypted_key_size;
1707 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1708 auth_tok->session_key.decrypted_key_size,
1709 dst_sg, 2);
1710 if (rc < 1 || rc > 2) {
1711 printk(KERN_ERR "Internal error whilst attempting to convert "
1712 "auth_tok->session_key.decrypted_key to scatterlist; "
1713 "expected rc = 1; got rc = [%d]\n", rc);
1714 goto out;
1715 }
1716 mutex_lock(tfm_mutex);
1717 rc = crypto_blkcipher_setkey(
1718 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1719 crypt_stat->key_size);
1720 if (unlikely(rc < 0)) {
1721 mutex_unlock(tfm_mutex);
1722 printk(KERN_ERR "Error setting key for crypto context\n");
1723 rc = -EINVAL;
1724 goto out;
1725 }
1726 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1727 auth_tok->session_key.encrypted_key_size);
1728 mutex_unlock(tfm_mutex);
1729 if (unlikely(rc)) {
1730 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1731 goto out;
1732 }
1733 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1734 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1735 auth_tok->session_key.decrypted_key_size);
1736 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1737 if (unlikely(ecryptfs_verbosity > 0)) {
1738 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1739 crypt_stat->key_size);
1740 ecryptfs_dump_hex(crypt_stat->key,
1741 crypt_stat->key_size);
1742 }
1743 out:
1744 return rc;
1745 }
1746
1747 /**
1748 * ecryptfs_parse_packet_set
1749 * @crypt_stat: The cryptographic context
1750 * @src: Virtual address of region of memory containing the packets
1751 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1752 *
1753 * Get crypt_stat to have the file's session key if the requisite key
1754 * is available to decrypt the session key.
1755 *
1756 * Returns Zero if a valid authentication token was retrieved and
1757 * processed; negative value for file not encrypted or for error
1758 * conditions.
1759 */
1760 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1761 unsigned char *src,
1762 struct dentry *ecryptfs_dentry)
1763 {
1764 size_t i = 0;
1765 size_t found_auth_tok;
1766 size_t next_packet_is_auth_tok_packet;
1767 struct list_head auth_tok_list;
1768 struct ecryptfs_auth_tok *matching_auth_tok;
1769 struct ecryptfs_auth_tok *candidate_auth_tok;
1770 char *candidate_auth_tok_sig;
1771 size_t packet_size;
1772 struct ecryptfs_auth_tok *new_auth_tok;
1773 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1774 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1775 size_t tag_11_contents_size;
1776 size_t tag_11_packet_size;
1777 struct key *auth_tok_key = NULL;
1778 int rc = 0;
1779
1780 INIT_LIST_HEAD(&auth_tok_list);
1781 /* Parse the header to find as many packets as we can; these will be
1782 * added the our &auth_tok_list */
1783 next_packet_is_auth_tok_packet = 1;
1784 while (next_packet_is_auth_tok_packet) {
1785 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1786
1787 switch (src[i]) {
1788 case ECRYPTFS_TAG_3_PACKET_TYPE:
1789 rc = parse_tag_3_packet(crypt_stat,
1790 (unsigned char *)&src[i],
1791 &auth_tok_list, &new_auth_tok,
1792 &packet_size, max_packet_size);
1793 if (rc) {
1794 ecryptfs_printk(KERN_ERR, "Error parsing "
1795 "tag 3 packet\n");
1796 rc = -EIO;
1797 goto out_wipe_list;
1798 }
1799 i += packet_size;
1800 rc = parse_tag_11_packet((unsigned char *)&src[i],
1801 sig_tmp_space,
1802 ECRYPTFS_SIG_SIZE,
1803 &tag_11_contents_size,
1804 &tag_11_packet_size,
1805 max_packet_size);
1806 if (rc) {
1807 ecryptfs_printk(KERN_ERR, "No valid "
1808 "(ecryptfs-specific) literal "
1809 "packet containing "
1810 "authentication token "
1811 "signature found after "
1812 "tag 3 packet\n");
1813 rc = -EIO;
1814 goto out_wipe_list;
1815 }
1816 i += tag_11_packet_size;
1817 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1818 ecryptfs_printk(KERN_ERR, "Expected "
1819 "signature of size [%d]; "
1820 "read size [%zd]\n",
1821 ECRYPTFS_SIG_SIZE,
1822 tag_11_contents_size);
1823 rc = -EIO;
1824 goto out_wipe_list;
1825 }
1826 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1827 sig_tmp_space, tag_11_contents_size);
1828 new_auth_tok->token.password.signature[
1829 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1830 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1831 break;
1832 case ECRYPTFS_TAG_1_PACKET_TYPE:
1833 rc = parse_tag_1_packet(crypt_stat,
1834 (unsigned char *)&src[i],
1835 &auth_tok_list, &new_auth_tok,
1836 &packet_size, max_packet_size);
1837 if (rc) {
1838 ecryptfs_printk(KERN_ERR, "Error parsing "
1839 "tag 1 packet\n");
1840 rc = -EIO;
1841 goto out_wipe_list;
1842 }
1843 i += packet_size;
1844 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1845 break;
1846 case ECRYPTFS_TAG_11_PACKET_TYPE:
1847 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1848 "(Tag 11 not allowed by itself)\n");
1849 rc = -EIO;
1850 goto out_wipe_list;
1851 break;
1852 default:
1853 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1854 "of the file header; hex value of "
1855 "character is [0x%.2x]\n", i, src[i]);
1856 next_packet_is_auth_tok_packet = 0;
1857 }
1858 }
1859 if (list_empty(&auth_tok_list)) {
1860 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1861 "eCryptfs file; this is not supported in this version "
1862 "of the eCryptfs kernel module\n");
1863 rc = -EINVAL;
1864 goto out;
1865 }
1866 /* auth_tok_list contains the set of authentication tokens
1867 * parsed from the metadata. We need to find a matching
1868 * authentication token that has the secret component(s)
1869 * necessary to decrypt the EFEK in the auth_tok parsed from
1870 * the metadata. There may be several potential matches, but
1871 * just one will be sufficient to decrypt to get the FEK. */
1872 find_next_matching_auth_tok:
1873 found_auth_tok = 0;
1874 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1875 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1876 if (unlikely(ecryptfs_verbosity > 0)) {
1877 ecryptfs_printk(KERN_DEBUG,
1878 "Considering cadidate auth tok:\n");
1879 ecryptfs_dump_auth_tok(candidate_auth_tok);
1880 }
1881 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1882 candidate_auth_tok);
1883 if (rc) {
1884 printk(KERN_ERR
1885 "Unrecognized candidate auth tok type: [%d]\n",
1886 candidate_auth_tok->token_type);
1887 rc = -EINVAL;
1888 goto out_wipe_list;
1889 }
1890 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1891 &matching_auth_tok,
1892 crypt_stat->mount_crypt_stat,
1893 candidate_auth_tok_sig);
1894 if (!rc) {
1895 found_auth_tok = 1;
1896 goto found_matching_auth_tok;
1897 }
1898 }
1899 if (!found_auth_tok) {
1900 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1901 "authentication token\n");
1902 rc = -EIO;
1903 goto out_wipe_list;
1904 }
1905 found_matching_auth_tok:
1906 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1907 memcpy(&(candidate_auth_tok->token.private_key),
1908 &(matching_auth_tok->token.private_key),
1909 sizeof(struct ecryptfs_private_key));
1910 up_write(&(auth_tok_key->sem));
1911 key_put(auth_tok_key);
1912 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1913 crypt_stat);
1914 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1915 memcpy(&(candidate_auth_tok->token.password),
1916 &(matching_auth_tok->token.password),
1917 sizeof(struct ecryptfs_password));
1918 up_write(&(auth_tok_key->sem));
1919 key_put(auth_tok_key);
1920 rc = decrypt_passphrase_encrypted_session_key(
1921 candidate_auth_tok, crypt_stat);
1922 } else {
1923 up_write(&(auth_tok_key->sem));
1924 key_put(auth_tok_key);
1925 rc = -EINVAL;
1926 }
1927 if (rc) {
1928 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1929
1930 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1931 "session key for authentication token with sig "
1932 "[%.*s]; rc = [%d]. Removing auth tok "
1933 "candidate from the list and searching for "
1934 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1935 candidate_auth_tok_sig, rc);
1936 list_for_each_entry_safe(auth_tok_list_item,
1937 auth_tok_list_item_tmp,
1938 &auth_tok_list, list) {
1939 if (candidate_auth_tok
1940 == &auth_tok_list_item->auth_tok) {
1941 list_del(&auth_tok_list_item->list);
1942 kmem_cache_free(
1943 ecryptfs_auth_tok_list_item_cache,
1944 auth_tok_list_item);
1945 goto find_next_matching_auth_tok;
1946 }
1947 }
1948 BUG();
1949 }
1950 rc = ecryptfs_compute_root_iv(crypt_stat);
1951 if (rc) {
1952 ecryptfs_printk(KERN_ERR, "Error computing "
1953 "the root IV\n");
1954 goto out_wipe_list;
1955 }
1956 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1957 if (rc) {
1958 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1959 "context for cipher [%s]; rc = [%d]\n",
1960 crypt_stat->cipher, rc);
1961 }
1962 out_wipe_list:
1963 wipe_auth_tok_list(&auth_tok_list);
1964 out:
1965 return rc;
1966 }
1967
1968 static int
1969 pki_encrypt_session_key(struct key *auth_tok_key,
1970 struct ecryptfs_auth_tok *auth_tok,
1971 struct ecryptfs_crypt_stat *crypt_stat,
1972 struct ecryptfs_key_record *key_rec)
1973 {
1974 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1975 char *payload = NULL;
1976 size_t payload_len = 0;
1977 struct ecryptfs_message *msg;
1978 int rc;
1979
1980 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1981 ecryptfs_code_for_cipher_string(
1982 crypt_stat->cipher,
1983 crypt_stat->key_size),
1984 crypt_stat, &payload, &payload_len);
1985 up_write(&(auth_tok_key->sem));
1986 key_put(auth_tok_key);
1987 if (rc) {
1988 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1989 goto out;
1990 }
1991 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1992 if (rc) {
1993 ecryptfs_printk(KERN_ERR, "Error sending message to "
1994 "ecryptfsd\n");
1995 goto out;
1996 }
1997 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1998 if (rc) {
1999 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2000 "from the user space daemon\n");
2001 rc = -EIO;
2002 goto out;
2003 }
2004 rc = parse_tag_67_packet(key_rec, msg);
2005 if (rc)
2006 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2007 kfree(msg);
2008 out:
2009 kfree(payload);
2010 return rc;
2011 }
2012 /**
2013 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2014 * @dest: Buffer into which to write the packet
2015 * @remaining_bytes: Maximum number of bytes that can be writtn
2016 * @auth_tok_key: The authentication token key to unlock and put when done with
2017 * @auth_tok
2018 * @auth_tok: The authentication token used for generating the tag 1 packet
2019 * @crypt_stat: The cryptographic context
2020 * @key_rec: The key record struct for the tag 1 packet
2021 * @packet_size: This function will write the number of bytes that end
2022 * up constituting the packet; set to zero on error
2023 *
2024 * Returns zero on success; non-zero on error.
2025 */
2026 static int
2027 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2028 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2029 struct ecryptfs_crypt_stat *crypt_stat,
2030 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2031 {
2032 size_t i;
2033 size_t encrypted_session_key_valid = 0;
2034 size_t packet_size_length;
2035 size_t max_packet_size;
2036 int rc = 0;
2037
2038 (*packet_size) = 0;
2039 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2040 ECRYPTFS_SIG_SIZE);
2041 encrypted_session_key_valid = 0;
2042 for (i = 0; i < crypt_stat->key_size; i++)
2043 encrypted_session_key_valid |=
2044 auth_tok->session_key.encrypted_key[i];
2045 if (encrypted_session_key_valid) {
2046 memcpy(key_rec->enc_key,
2047 auth_tok->session_key.encrypted_key,
2048 auth_tok->session_key.encrypted_key_size);
2049 up_write(&(auth_tok_key->sem));
2050 key_put(auth_tok_key);
2051 goto encrypted_session_key_set;
2052 }
2053 if (auth_tok->session_key.encrypted_key_size == 0)
2054 auth_tok->session_key.encrypted_key_size =
2055 auth_tok->token.private_key.key_size;
2056 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2057 key_rec);
2058 if (rc) {
2059 printk(KERN_ERR "Failed to encrypt session key via a key "
2060 "module; rc = [%d]\n", rc);
2061 goto out;
2062 }
2063 if (ecryptfs_verbosity > 0) {
2064 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2065 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2066 }
2067 encrypted_session_key_set:
2068 /* This format is inspired by OpenPGP; see RFC 2440
2069 * packet tag 1 */
2070 max_packet_size = (1 /* Tag 1 identifier */
2071 + 3 /* Max Tag 1 packet size */
2072 + 1 /* Version */
2073 + ECRYPTFS_SIG_SIZE /* Key identifier */
2074 + 1 /* Cipher identifier */
2075 + key_rec->enc_key_size); /* Encrypted key size */
2076 if (max_packet_size > (*remaining_bytes)) {
2077 printk(KERN_ERR "Packet length larger than maximum allowable; "
2078 "need up to [%td] bytes, but there are only [%td] "
2079 "available\n", max_packet_size, (*remaining_bytes));
2080 rc = -EINVAL;
2081 goto out;
2082 }
2083 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2084 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2085 (max_packet_size - 4),
2086 &packet_size_length);
2087 if (rc) {
2088 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2089 "header; cannot generate packet length\n");
2090 goto out;
2091 }
2092 (*packet_size) += packet_size_length;
2093 dest[(*packet_size)++] = 0x03; /* version 3 */
2094 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2095 (*packet_size) += ECRYPTFS_SIG_SIZE;
2096 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2097 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2098 key_rec->enc_key_size);
2099 (*packet_size) += key_rec->enc_key_size;
2100 out:
2101 if (rc)
2102 (*packet_size) = 0;
2103 else
2104 (*remaining_bytes) -= (*packet_size);
2105 return rc;
2106 }
2107
2108 /**
2109 * write_tag_11_packet
2110 * @dest: Target into which Tag 11 packet is to be written
2111 * @remaining_bytes: Maximum packet length
2112 * @contents: Byte array of contents to copy in
2113 * @contents_length: Number of bytes in contents
2114 * @packet_length: Length of the Tag 11 packet written; zero on error
2115 *
2116 * Returns zero on success; non-zero on error.
2117 */
2118 static int
2119 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2120 size_t contents_length, size_t *packet_length)
2121 {
2122 size_t packet_size_length;
2123 size_t max_packet_size;
2124 int rc = 0;
2125
2126 (*packet_length) = 0;
2127 /* This format is inspired by OpenPGP; see RFC 2440
2128 * packet tag 11 */
2129 max_packet_size = (1 /* Tag 11 identifier */
2130 + 3 /* Max Tag 11 packet size */
2131 + 1 /* Binary format specifier */
2132 + 1 /* Filename length */
2133 + 8 /* Filename ("_CONSOLE") */
2134 + 4 /* Modification date */
2135 + contents_length); /* Literal data */
2136 if (max_packet_size > (*remaining_bytes)) {
2137 printk(KERN_ERR "Packet length larger than maximum allowable; "
2138 "need up to [%td] bytes, but there are only [%td] "
2139 "available\n", max_packet_size, (*remaining_bytes));
2140 rc = -EINVAL;
2141 goto out;
2142 }
2143 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2144 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2145 (max_packet_size - 4),
2146 &packet_size_length);
2147 if (rc) {
2148 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2149 "generate packet length. rc = [%d]\n", rc);
2150 goto out;
2151 }
2152 (*packet_length) += packet_size_length;
2153 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2154 dest[(*packet_length)++] = 8;
2155 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2156 (*packet_length) += 8;
2157 memset(&dest[(*packet_length)], 0x00, 4);
2158 (*packet_length) += 4;
2159 memcpy(&dest[(*packet_length)], contents, contents_length);
2160 (*packet_length) += contents_length;
2161 out:
2162 if (rc)
2163 (*packet_length) = 0;
2164 else
2165 (*remaining_bytes) -= (*packet_length);
2166 return rc;
2167 }
2168
2169 /**
2170 * write_tag_3_packet
2171 * @dest: Buffer into which to write the packet
2172 * @remaining_bytes: Maximum number of bytes that can be written
2173 * @auth_tok: Authentication token
2174 * @crypt_stat: The cryptographic context
2175 * @key_rec: encrypted key
2176 * @packet_size: This function will write the number of bytes that end
2177 * up constituting the packet; set to zero on error
2178 *
2179 * Returns zero on success; non-zero on error.
2180 */
2181 static int
2182 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2183 struct ecryptfs_auth_tok *auth_tok,
2184 struct ecryptfs_crypt_stat *crypt_stat,
2185 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2186 {
2187 size_t i;
2188 size_t encrypted_session_key_valid = 0;
2189 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2190 struct scatterlist dst_sg[2];
2191 struct scatterlist src_sg[2];
2192 struct mutex *tfm_mutex = NULL;
2193 u8 cipher_code;
2194 size_t packet_size_length;
2195 size_t max_packet_size;
2196 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2197 crypt_stat->mount_crypt_stat;
2198 struct blkcipher_desc desc = {
2199 .tfm = NULL,
2200 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2201 };
2202 int rc = 0;
2203
2204 (*packet_size) = 0;
2205 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2206 ECRYPTFS_SIG_SIZE);
2207 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2208 crypt_stat->cipher);
2209 if (unlikely(rc)) {
2210 printk(KERN_ERR "Internal error whilst attempting to get "
2211 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2212 crypt_stat->cipher, rc);
2213 goto out;
2214 }
2215 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2216 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2217
2218 printk(KERN_WARNING "No key size specified at mount; "
2219 "defaulting to [%d]\n", alg->max_keysize);
2220 mount_crypt_stat->global_default_cipher_key_size =
2221 alg->max_keysize;
2222 }
2223 if (crypt_stat->key_size == 0)
2224 crypt_stat->key_size =
2225 mount_crypt_stat->global_default_cipher_key_size;
2226 if (auth_tok->session_key.encrypted_key_size == 0)
2227 auth_tok->session_key.encrypted_key_size =
2228 crypt_stat->key_size;
2229 if (crypt_stat->key_size == 24
2230 && strcmp("aes", crypt_stat->cipher) == 0) {
2231 memset((crypt_stat->key + 24), 0, 8);
2232 auth_tok->session_key.encrypted_key_size = 32;
2233 } else
2234 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2235 key_rec->enc_key_size =
2236 auth_tok->session_key.encrypted_key_size;
2237 encrypted_session_key_valid = 0;
2238 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2239 encrypted_session_key_valid |=
2240 auth_tok->session_key.encrypted_key[i];
2241 if (encrypted_session_key_valid) {
2242 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2243 "using auth_tok->session_key.encrypted_key, "
2244 "where key_rec->enc_key_size = [%zd]\n",
2245 key_rec->enc_key_size);
2246 memcpy(key_rec->enc_key,
2247 auth_tok->session_key.encrypted_key,
2248 key_rec->enc_key_size);
2249 goto encrypted_session_key_set;
2250 }
2251 if (auth_tok->token.password.flags &
2252 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2253 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2254 "session key encryption key of size [%d]\n",
2255 auth_tok->token.password.
2256 session_key_encryption_key_bytes);
2257 memcpy(session_key_encryption_key,
2258 auth_tok->token.password.session_key_encryption_key,
2259 crypt_stat->key_size);
2260 ecryptfs_printk(KERN_DEBUG,
2261 "Cached session key encryption key:\n");
2262 if (ecryptfs_verbosity > 0)
2263 ecryptfs_dump_hex(session_key_encryption_key, 16);
2264 }
2265 if (unlikely(ecryptfs_verbosity > 0)) {
2266 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2267 ecryptfs_dump_hex(session_key_encryption_key, 16);
2268 }
2269 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2270 src_sg, 2);
2271 if (rc < 1 || rc > 2) {
2272 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2273 "for crypt_stat session key; expected rc = 1; "
2274 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2275 rc, key_rec->enc_key_size);
2276 rc = -ENOMEM;
2277 goto out;
2278 }
2279 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2280 dst_sg, 2);
2281 if (rc < 1 || rc > 2) {
2282 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2283 "for crypt_stat encrypted session key; "
2284 "expected rc = 1; got rc = [%d]. "
2285 "key_rec->enc_key_size = [%zd]\n", rc,
2286 key_rec->enc_key_size);
2287 rc = -ENOMEM;
2288 goto out;
2289 }
2290 mutex_lock(tfm_mutex);
2291 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2292 crypt_stat->key_size);
2293 if (rc < 0) {
2294 mutex_unlock(tfm_mutex);
2295 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2296 "context; rc = [%d]\n", rc);
2297 goto out;
2298 }
2299 rc = 0;
2300 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2301 crypt_stat->key_size);
2302 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2303 (*key_rec).enc_key_size);
2304 mutex_unlock(tfm_mutex);
2305 if (rc) {
2306 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2307 goto out;
2308 }
2309 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2310 if (ecryptfs_verbosity > 0) {
2311 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2312 key_rec->enc_key_size);
2313 ecryptfs_dump_hex(key_rec->enc_key,
2314 key_rec->enc_key_size);
2315 }
2316 encrypted_session_key_set:
2317 /* This format is inspired by OpenPGP; see RFC 2440
2318 * packet tag 3 */
2319 max_packet_size = (1 /* Tag 3 identifier */
2320 + 3 /* Max Tag 3 packet size */
2321 + 1 /* Version */
2322 + 1 /* Cipher code */
2323 + 1 /* S2K specifier */
2324 + 1 /* Hash identifier */
2325 + ECRYPTFS_SALT_SIZE /* Salt */
2326 + 1 /* Hash iterations */
2327 + key_rec->enc_key_size); /* Encrypted key size */
2328 if (max_packet_size > (*remaining_bytes)) {
2329 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2330 "there are only [%td] available\n", max_packet_size,
2331 (*remaining_bytes));
2332 rc = -EINVAL;
2333 goto out;
2334 }
2335 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2336 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2337 * to get the number of octets in the actual Tag 3 packet */
2338 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2339 (max_packet_size - 4),
2340 &packet_size_length);
2341 if (rc) {
2342 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2343 "generate packet length. rc = [%d]\n", rc);
2344 goto out;
2345 }
2346 (*packet_size) += packet_size_length;
2347 dest[(*packet_size)++] = 0x04; /* version 4 */
2348 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2349 * specified with strings */
2350 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2351 crypt_stat->key_size);
2352 if (cipher_code == 0) {
2353 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2354 "cipher [%s]\n", crypt_stat->cipher);
2355 rc = -EINVAL;
2356 goto out;
2357 }
2358 dest[(*packet_size)++] = cipher_code;
2359 dest[(*packet_size)++] = 0x03; /* S2K */
2360 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2361 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2362 ECRYPTFS_SALT_SIZE);
2363 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2364 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2365 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2366 key_rec->enc_key_size);
2367 (*packet_size) += key_rec->enc_key_size;
2368 out:
2369 if (rc)
2370 (*packet_size) = 0;
2371 else
2372 (*remaining_bytes) -= (*packet_size);
2373 return rc;
2374 }
2375
2376 struct kmem_cache *ecryptfs_key_record_cache;
2377
2378 /**
2379 * ecryptfs_generate_key_packet_set
2380 * @dest_base: Virtual address from which to write the key record set
2381 * @crypt_stat: The cryptographic context from which the
2382 * authentication tokens will be retrieved
2383 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2384 * for the global parameters
2385 * @len: The amount written
2386 * @max: The maximum amount of data allowed to be written
2387 *
2388 * Generates a key packet set and writes it to the virtual address
2389 * passed in.
2390 *
2391 * Returns zero on success; non-zero on error.
2392 */
2393 int
2394 ecryptfs_generate_key_packet_set(char *dest_base,
2395 struct ecryptfs_crypt_stat *crypt_stat,
2396 struct dentry *ecryptfs_dentry, size_t *len,
2397 size_t max)
2398 {
2399 struct ecryptfs_auth_tok *auth_tok;
2400 struct key *auth_tok_key = NULL;
2401 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2402 &ecryptfs_superblock_to_private(
2403 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2404 size_t written;
2405 struct ecryptfs_key_record *key_rec;
2406 struct ecryptfs_key_sig *key_sig;
2407 int rc = 0;
2408
2409 (*len) = 0;
2410 mutex_lock(&crypt_stat->keysig_list_mutex);
2411 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2412 if (!key_rec) {
2413 rc = -ENOMEM;
2414 goto out;
2415 }
2416 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2417 crypt_stat_list) {
2418 memset(key_rec, 0, sizeof(*key_rec));
2419 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2420 &auth_tok,
2421 mount_crypt_stat,
2422 key_sig->keysig);
2423 if (rc) {
2424 printk(KERN_WARNING "Unable to retrieve auth tok with "
2425 "sig = [%s]\n", key_sig->keysig);
2426 rc = process_find_global_auth_tok_for_sig_err(rc);
2427 goto out_free;
2428 }
2429 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2430 rc = write_tag_3_packet((dest_base + (*len)),
2431 &max, auth_tok,
2432 crypt_stat, key_rec,
2433 &written);
2434 up_write(&(auth_tok_key->sem));
2435 key_put(auth_tok_key);
2436 if (rc) {
2437 ecryptfs_printk(KERN_WARNING, "Error "
2438 "writing tag 3 packet\n");
2439 goto out_free;
2440 }
2441 (*len) += written;
2442 /* Write auth tok signature packet */
2443 rc = write_tag_11_packet((dest_base + (*len)), &max,
2444 key_rec->sig,
2445 ECRYPTFS_SIG_SIZE, &written);
2446 if (rc) {
2447 ecryptfs_printk(KERN_ERR, "Error writing "
2448 "auth tok signature packet\n");
2449 goto out_free;
2450 }
2451 (*len) += written;
2452 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2453 rc = write_tag_1_packet(dest_base + (*len), &max,
2454 auth_tok_key, auth_tok,
2455 crypt_stat, key_rec, &written);
2456 if (rc) {
2457 ecryptfs_printk(KERN_WARNING, "Error "
2458 "writing tag 1 packet\n");
2459 goto out_free;
2460 }
2461 (*len) += written;
2462 } else {
2463 up_write(&(auth_tok_key->sem));
2464 key_put(auth_tok_key);
2465 ecryptfs_printk(KERN_WARNING, "Unsupported "
2466 "authentication token type\n");
2467 rc = -EINVAL;
2468 goto out_free;
2469 }
2470 }
2471 if (likely(max > 0)) {
2472 dest_base[(*len)] = 0x00;
2473 } else {
2474 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2475 rc = -EIO;
2476 }
2477 out_free:
2478 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2479 out:
2480 if (rc)
2481 (*len) = 0;
2482 mutex_unlock(&crypt_stat->keysig_list_mutex);
2483 return rc;
2484 }
2485
2486 struct kmem_cache *ecryptfs_key_sig_cache;
2487
2488 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2489 {
2490 struct ecryptfs_key_sig *new_key_sig;
2491
2492 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2493 if (!new_key_sig) {
2494 printk(KERN_ERR
2495 "Error allocating from ecryptfs_key_sig_cache\n");
2496 return -ENOMEM;
2497 }
2498 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2499 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2500 /* Caller must hold keysig_list_mutex */
2501 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2502
2503 return 0;
2504 }
2505
2506 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2507
2508 int
2509 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2510 char *sig, u32 global_auth_tok_flags)
2511 {
2512 struct ecryptfs_global_auth_tok *new_auth_tok;
2513 int rc = 0;
2514
2515 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2516 GFP_KERNEL);
2517 if (!new_auth_tok) {
2518 rc = -ENOMEM;
2519 printk(KERN_ERR "Error allocating from "
2520 "ecryptfs_global_auth_tok_cache\n");
2521 goto out;
2522 }
2523 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2524 new_auth_tok->flags = global_auth_tok_flags;
2525 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2526 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2527 list_add(&new_auth_tok->mount_crypt_stat_list,
2528 &mount_crypt_stat->global_auth_tok_list);
2529 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2530 out:
2531 return rc;
2532 }
2533
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