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