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HID: hiddev: Fix slab-out-of-bounds write in hiddev_ioctl_usage()
[linux/fpc-iii.git] / fs / ecryptfs / keystore.c
blob37920394c64cfb88f895408d4d4de0d39c3ee846
1 /**
2 * eCryptfs: Linux filesystem encryption layer
3 * In-kernel key management code. Includes functions to parse and
4 * write authentication token-related packets with the underlying
5 * file.
6 *
7 * Copyright (C) 2004-2006 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
9 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * Trevor S. Highland <trevor.highland@gmail.com>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
25 * 02111-1307, USA.
26 */
27
28 #include <linux/string.h>
29 #include <linux/pagemap.h>
30 #include <linux/key.h>
31 #include <linux/random.h>
32 #include <linux/crypto.h>
33 #include <linux/scatterlist.h>
34 #include <linux/slab.h>
35 #include "ecryptfs_kernel.h"
36
37 /**
38 * request_key returned an error instead of a valid key address;
39 * determine the type of error, make appropriate log entries, and
40 * return an error code.
41 */
42 static int process_request_key_err(long err_code)
43 {
44 int rc = 0;
45
46 switch (err_code) {
47 case -ENOKEY:
48 ecryptfs_printk(KERN_WARNING, "No key\n");
49 rc = -ENOENT;
50 break;
51 case -EKEYEXPIRED:
52 ecryptfs_printk(KERN_WARNING, "Key expired\n");
53 rc = -ETIME;
54 break;
55 case -EKEYREVOKED:
56 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
57 rc = -EINVAL;
58 break;
59 default:
60 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
61 "[0x%.16lx]\n", err_code);
62 rc = -EINVAL;
63 }
64 return rc;
65 }
66
67 static int process_find_global_auth_tok_for_sig_err(int err_code)
68 {
69 int rc = err_code;
70
71 switch (err_code) {
72 case -ENOENT:
73 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
74 break;
75 case -EINVAL:
76 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
77 break;
78 default:
79 rc = process_request_key_err(err_code);
80 break;
81 }
82 return rc;
83 }
84
85 /**
86 * ecryptfs_parse_packet_length
87 * @data: Pointer to memory containing length at offset
88 * @size: This function writes the decoded size to this memory
89 * address; zero on error
90 * @length_size: The number of bytes occupied by the encoded length
91 *
92 * Returns zero on success; non-zero on error
93 */
94 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
95 size_t *length_size)
96 {
97 int rc = 0;
98
99 (*length_size) = 0;
100 (*size) = 0;
101 if (data[0] < 192) {
102 /* One-byte length */
103 (*size) = data[0];
104 (*length_size) = 1;
105 } else if (data[0] < 224) {
106 /* Two-byte length */
107 (*size) = (data[0] - 192) * 256;
108 (*size) += data[1] + 192;
109 (*length_size) = 2;
110 } else if (data[0] == 255) {
111 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
112 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
113 "supported\n");
114 rc = -EINVAL;
115 goto out;
116 } else {
117 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
118 rc = -EINVAL;
119 goto out;
120 }
121 out:
122 return rc;
123 }
124
125 /**
126 * ecryptfs_write_packet_length
127 * @dest: The byte array target into which to write the length. Must
128 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
129 * @size: The length to write.
130 * @packet_size_length: The number of bytes used to encode the packet
131 * length is written to this address.
132 *
133 * Returns zero on success; non-zero on error.
134 */
135 int ecryptfs_write_packet_length(char *dest, size_t size,
136 size_t *packet_size_length)
137 {
138 int rc = 0;
139
140 if (size < 192) {
141 dest[0] = size;
142 (*packet_size_length) = 1;
143 } else if (size < 65536) {
144 dest[0] = (((size - 192) / 256) + 192);
145 dest[1] = ((size - 192) % 256);
146 (*packet_size_length) = 2;
147 } else {
148 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
149 rc = -EINVAL;
150 ecryptfs_printk(KERN_WARNING,
151 "Unsupported packet size: [%zd]\n", size);
152 }
153 return rc;
154 }
155
156 static int
157 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
158 char **packet, size_t *packet_len)
159 {
160 size_t i = 0;
161 size_t data_len;
162 size_t packet_size_len;
163 char *message;
164 int rc;
165
166 /*
167 * ***** TAG 64 Packet Format *****
168 * | Content Type | 1 byte |
169 * | Key Identifier Size | 1 or 2 bytes |
170 * | Key Identifier | arbitrary |
171 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
172 * | Encrypted File Encryption Key | arbitrary |
173 */
174 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
175 + session_key->encrypted_key_size);
176 *packet = kmalloc(data_len, GFP_KERNEL);
177 message = *packet;
178 if (!message) {
179 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
180 rc = -ENOMEM;
181 goto out;
182 }
183 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
184 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
185 &packet_size_len);
186 if (rc) {
187 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
188 "header; cannot generate packet length\n");
189 goto out;
190 }
191 i += packet_size_len;
192 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
193 i += ECRYPTFS_SIG_SIZE_HEX;
194 rc = ecryptfs_write_packet_length(&message[i],
195 session_key->encrypted_key_size,
196 &packet_size_len);
197 if (rc) {
198 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
199 "header; cannot generate packet length\n");
200 goto out;
201 }
202 i += packet_size_len;
203 memcpy(&message[i], session_key->encrypted_key,
204 session_key->encrypted_key_size);
205 i += session_key->encrypted_key_size;
206 *packet_len = i;
207 out:
208 return rc;
209 }
210
211 static int
212 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
213 struct ecryptfs_message *msg)
214 {
215 size_t i = 0;
216 char *data;
217 size_t data_len;
218 size_t m_size;
219 size_t message_len;
220 u16 checksum = 0;
221 u16 expected_checksum = 0;
222 int rc;
223
224 /*
225 * ***** TAG 65 Packet Format *****
226 * | Content Type | 1 byte |
227 * | Status Indicator | 1 byte |
228 * | File Encryption Key Size | 1 or 2 bytes |
229 * | File Encryption Key | arbitrary |
230 */
231 message_len = msg->data_len;
232 data = msg->data;
233 if (message_len < 4) {
234 rc = -EIO;
235 goto out;
236 }
237 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
238 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
239 rc = -EIO;
240 goto out;
241 }
242 if (data[i++]) {
243 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
244 "[%d]\n", data[i-1]);
245 rc = -EIO;
246 goto out;
247 }
248 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
249 if (rc) {
250 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
251 "rc = [%d]\n", rc);
252 goto out;
253 }
254 i += data_len;
255 if (message_len < (i + m_size)) {
256 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
257 "is shorter than expected\n");
258 rc = -EIO;
259 goto out;
260 }
261 if (m_size < 3) {
262 ecryptfs_printk(KERN_ERR,
263 "The decrypted key is not long enough to "
264 "include a cipher code and checksum\n");
265 rc = -EIO;
266 goto out;
267 }
268 *cipher_code = data[i++];
269 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
270 session_key->decrypted_key_size = m_size - 3;
271 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
272 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
273 "the maximum key size [%d]\n",
274 session_key->decrypted_key_size,
275 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
276 rc = -EIO;
277 goto out;
278 }
279 memcpy(session_key->decrypted_key, &data[i],
280 session_key->decrypted_key_size);
281 i += session_key->decrypted_key_size;
282 expected_checksum += (unsigned char)(data[i++]) << 8;
283 expected_checksum += (unsigned char)(data[i++]);
284 for (i = 0; i < session_key->decrypted_key_size; i++)
285 checksum += session_key->decrypted_key[i];
286 if (expected_checksum != checksum) {
287 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
288 "encryption key; expected [%x]; calculated "
289 "[%x]\n", expected_checksum, checksum);
290 rc = -EIO;
291 }
292 out:
293 return rc;
294 }
295
296
297 static int
298 write_tag_66_packet(char *signature, u8 cipher_code,
299 struct ecryptfs_crypt_stat *crypt_stat, char **packet,
300 size_t *packet_len)
301 {
302 size_t i = 0;
303 size_t j;
304 size_t data_len;
305 size_t checksum = 0;
306 size_t packet_size_len;
307 char *message;
308 int rc;
309
310 /*
311 * ***** TAG 66 Packet Format *****
312 * | Content Type | 1 byte |
313 * | Key Identifier Size | 1 or 2 bytes |
314 * | Key Identifier | arbitrary |
315 * | File Encryption Key Size | 1 or 2 bytes |
316 * | File Encryption Key | arbitrary |
317 */
318 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
319 *packet = kmalloc(data_len, GFP_KERNEL);
320 message = *packet;
321 if (!message) {
322 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
323 rc = -ENOMEM;
324 goto out;
325 }
326 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
327 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
328 &packet_size_len);
329 if (rc) {
330 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
331 "header; cannot generate packet length\n");
332 goto out;
333 }
334 i += packet_size_len;
335 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
336 i += ECRYPTFS_SIG_SIZE_HEX;
337 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
338 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
339 &packet_size_len);
340 if (rc) {
341 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
342 "header; cannot generate packet length\n");
343 goto out;
344 }
345 i += packet_size_len;
346 message[i++] = cipher_code;
347 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
348 i += crypt_stat->key_size;
349 for (j = 0; j < crypt_stat->key_size; j++)
350 checksum += crypt_stat->key[j];
351 message[i++] = (checksum / 256) % 256;
352 message[i++] = (checksum % 256);
353 *packet_len = i;
354 out:
355 return rc;
356 }
357
358 static int
359 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
360 struct ecryptfs_message *msg)
361 {
362 size_t i = 0;
363 char *data;
364 size_t data_len;
365 size_t message_len;
366 int rc;
367
368 /*
369 * ***** TAG 65 Packet Format *****
370 * | Content Type | 1 byte |
371 * | Status Indicator | 1 byte |
372 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
373 * | Encrypted File Encryption Key | arbitrary |
374 */
375 message_len = msg->data_len;
376 data = msg->data;
377 /* verify that everything through the encrypted FEK size is present */
378 if (message_len < 4) {
379 rc = -EIO;
380 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
381 "message length is [%d]\n", __func__, message_len, 4);
382 goto out;
383 }
384 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
385 rc = -EIO;
386 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
387 __func__);
388 goto out;
389 }
390 if (data[i++]) {
391 rc = -EIO;
392 printk(KERN_ERR "%s: Status indicator has non zero "
393 "value [%d]\n", __func__, data[i-1]);
394
395 goto out;
396 }
397 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
398 &data_len);
399 if (rc) {
400 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
401 "rc = [%d]\n", rc);
402 goto out;
403 }
404 i += data_len;
405 if (message_len < (i + key_rec->enc_key_size)) {
406 rc = -EIO;
407 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
408 __func__, message_len, (i + key_rec->enc_key_size));
409 goto out;
410 }
411 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
412 rc = -EIO;
413 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
414 "the maximum key size [%d]\n", __func__,
415 key_rec->enc_key_size,
416 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
417 goto out;
418 }
419 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
420 out:
421 return rc;
422 }
423
424 /**
425 * ecryptfs_verify_version
426 * @version: The version number to confirm
427 *
428 * Returns zero on good version; non-zero otherwise
429 */
430 static int ecryptfs_verify_version(u16 version)
431 {
432 int rc = 0;
433 unsigned char major;
434 unsigned char minor;
435
436 major = ((version >> 8) & 0xFF);
437 minor = (version & 0xFF);
438 if (major != ECRYPTFS_VERSION_MAJOR) {
439 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
440 "Expected [%d]; got [%d]\n",
441 ECRYPTFS_VERSION_MAJOR, major);
442 rc = -EINVAL;
443 goto out;
444 }
445 if (minor != ECRYPTFS_VERSION_MINOR) {
446 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
447 "Expected [%d]; got [%d]\n",
448 ECRYPTFS_VERSION_MINOR, minor);
449 rc = -EINVAL;
450 goto out;
451 }
452 out:
453 return rc;
454 }
455
456 /**
457 * ecryptfs_verify_auth_tok_from_key
458 * @auth_tok_key: key containing the authentication token
459 * @auth_tok: authentication token
460 *
461 * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
462 * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
463 */
464 static int
465 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
466 struct ecryptfs_auth_tok **auth_tok)
467 {
468 int rc = 0;
469
470 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
471 if (IS_ERR(*auth_tok)) {
472 rc = PTR_ERR(*auth_tok);
473 *auth_tok = NULL;
474 goto out;
475 }
476
477 if (ecryptfs_verify_version((*auth_tok)->version)) {
478 printk(KERN_ERR "Data structure version mismatch. Userspace "
479 "tools must match eCryptfs kernel module with major "
480 "version [%d] and minor version [%d]\n",
481 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
482 rc = -EINVAL;
483 goto out;
484 }
485 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
486 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
487 printk(KERN_ERR "Invalid auth_tok structure "
488 "returned from key query\n");
489 rc = -EINVAL;
490 goto out;
491 }
492 out:
493 return rc;
494 }
495
496 static int
497 ecryptfs_find_global_auth_tok_for_sig(
498 struct key **auth_tok_key,
499 struct ecryptfs_auth_tok **auth_tok,
500 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
501 {
502 struct ecryptfs_global_auth_tok *walker;
503 int rc = 0;
504
505 (*auth_tok_key) = NULL;
506 (*auth_tok) = NULL;
507 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
508 list_for_each_entry(walker,
509 &mount_crypt_stat->global_auth_tok_list,
510 mount_crypt_stat_list) {
511 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
512 continue;
513
514 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
515 rc = -EINVAL;
516 goto out;
517 }
518
519 rc = key_validate(walker->global_auth_tok_key);
520 if (rc) {
521 if (rc == -EKEYEXPIRED)
522 goto out;
523 goto out_invalid_auth_tok;
524 }
525
526 down_write(&(walker->global_auth_tok_key->sem));
527 rc = ecryptfs_verify_auth_tok_from_key(
528 walker->global_auth_tok_key, auth_tok);
529 if (rc)
530 goto out_invalid_auth_tok_unlock;
531
532 (*auth_tok_key) = walker->global_auth_tok_key;
533 key_get(*auth_tok_key);
534 goto out;
535 }
536 rc = -ENOENT;
537 goto out;
538 out_invalid_auth_tok_unlock:
539 up_write(&(walker->global_auth_tok_key->sem));
540 out_invalid_auth_tok:
541 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
542 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
543 key_put(walker->global_auth_tok_key);
544 walker->global_auth_tok_key = NULL;
545 out:
546 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
547 return rc;
548 }
549
550 /**
551 * ecryptfs_find_auth_tok_for_sig
552 * @auth_tok: Set to the matching auth_tok; NULL if not found
553 * @crypt_stat: inode crypt_stat crypto context
554 * @sig: Sig of auth_tok to find
555 *
556 * For now, this function simply looks at the registered auth_tok's
557 * linked off the mount_crypt_stat, so all the auth_toks that can be
558 * used must be registered at mount time. This function could
559 * potentially try a lot harder to find auth_tok's (e.g., by calling
560 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
561 * that static registration of auth_tok's will no longer be necessary.
562 *
563 * Returns zero on no error; non-zero on error
564 */
565 static int
566 ecryptfs_find_auth_tok_for_sig(
567 struct key **auth_tok_key,
568 struct ecryptfs_auth_tok **auth_tok,
569 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
570 char *sig)
571 {
572 int rc = 0;
573
574 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
575 mount_crypt_stat, sig);
576 if (rc == -ENOENT) {
577 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
578 * mount_crypt_stat structure, we prevent to use auth toks that
579 * are not inserted through the ecryptfs_add_global_auth_tok
580 * function.
581 */
582 if (mount_crypt_stat->flags
583 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
584 return -EINVAL;
585
586 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
587 sig);
588 }
589 return rc;
590 }
591
592 /**
593 * write_tag_70_packet can gobble a lot of stack space. We stuff most
594 * of the function's parameters in a kmalloc'd struct to help reduce
595 * eCryptfs' overall stack usage.
596 */
597 struct ecryptfs_write_tag_70_packet_silly_stack {
598 u8 cipher_code;
599 size_t max_packet_size;
600 size_t packet_size_len;
601 size_t block_aligned_filename_size;
602 size_t block_size;
603 size_t i;
604 size_t j;
605 size_t num_rand_bytes;
606 struct mutex *tfm_mutex;
607 char *block_aligned_filename;
608 struct ecryptfs_auth_tok *auth_tok;
609 struct scatterlist src_sg[2];
610 struct scatterlist dst_sg[2];
611 struct blkcipher_desc desc;
612 char iv[ECRYPTFS_MAX_IV_BYTES];
613 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
614 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
615 struct hash_desc hash_desc;
616 struct scatterlist hash_sg;
617 };
618
619 /**
620 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
621 * @filename: NULL-terminated filename string
622 *
623 * This is the simplest mechanism for achieving filename encryption in
624 * eCryptfs. It encrypts the given filename with the mount-wide
625 * filename encryption key (FNEK) and stores it in a packet to @dest,
626 * which the callee will encode and write directly into the dentry
627 * name.
628 */
629 int
630 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
631 size_t *packet_size,
632 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
633 char *filename, size_t filename_size)
634 {
635 struct ecryptfs_write_tag_70_packet_silly_stack *s;
636 struct key *auth_tok_key = NULL;
637 int rc = 0;
638
639 s = kmalloc(sizeof(*s), GFP_KERNEL);
640 if (!s) {
641 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
642 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
643 rc = -ENOMEM;
644 goto out;
645 }
646 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
647 (*packet_size) = 0;
648 rc = ecryptfs_find_auth_tok_for_sig(
649 &auth_tok_key,
650 &s->auth_tok, mount_crypt_stat,
651 mount_crypt_stat->global_default_fnek_sig);
652 if (rc) {
653 printk(KERN_ERR "%s: Error attempting to find auth tok for "
654 "fnek sig [%s]; rc = [%d]\n", __func__,
655 mount_crypt_stat->global_default_fnek_sig, rc);
656 goto out;
657 }
658 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
659 &s->desc.tfm,
660 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
661 if (unlikely(rc)) {
662 printk(KERN_ERR "Internal error whilst attempting to get "
663 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
664 mount_crypt_stat->global_default_fn_cipher_name, rc);
665 goto out;
666 }
667 mutex_lock(s->tfm_mutex);
668 s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
669 /* Plus one for the \0 separator between the random prefix
670 * and the plaintext filename */
671 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
672 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
673 if ((s->block_aligned_filename_size % s->block_size) != 0) {
674 s->num_rand_bytes += (s->block_size
675 - (s->block_aligned_filename_size
676 % s->block_size));
677 s->block_aligned_filename_size = (s->num_rand_bytes
678 + filename_size);
679 }
680 /* Octet 0: Tag 70 identifier
681 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
682 * and block-aligned encrypted filename size)
683 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
684 * Octet N2-N3: Cipher identifier (1 octet)
685 * Octets N3-N4: Block-aligned encrypted filename
686 * - Consists of a minimum number of random characters, a \0
687 * separator, and then the filename */
688 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
689 + s->block_aligned_filename_size);
690 if (dest == NULL) {
691 (*packet_size) = s->max_packet_size;
692 goto out_unlock;
693 }
694 if (s->max_packet_size > (*remaining_bytes)) {
695 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
696 "[%zd] available\n", __func__, s->max_packet_size,
697 (*remaining_bytes));
698 rc = -EINVAL;
699 goto out_unlock;
700 }
701 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
702 GFP_KERNEL);
703 if (!s->block_aligned_filename) {
704 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
705 "kzalloc [%zd] bytes\n", __func__,
706 s->block_aligned_filename_size);
707 rc = -ENOMEM;
708 goto out_unlock;
709 }
710 s->i = 0;
711 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
712 rc = ecryptfs_write_packet_length(&dest[s->i],
713 (ECRYPTFS_SIG_SIZE
714 + 1 /* Cipher code */
715 + s->block_aligned_filename_size),
716 &s->packet_size_len);
717 if (rc) {
718 printk(KERN_ERR "%s: Error generating tag 70 packet "
719 "header; cannot generate packet length; rc = [%d]\n",
720 __func__, rc);
721 goto out_free_unlock;
722 }
723 s->i += s->packet_size_len;
724 ecryptfs_from_hex(&dest[s->i],
725 mount_crypt_stat->global_default_fnek_sig,
726 ECRYPTFS_SIG_SIZE);
727 s->i += ECRYPTFS_SIG_SIZE;
728 s->cipher_code = ecryptfs_code_for_cipher_string(
729 mount_crypt_stat->global_default_fn_cipher_name,
730 mount_crypt_stat->global_default_fn_cipher_key_bytes);
731 if (s->cipher_code == 0) {
732 printk(KERN_WARNING "%s: Unable to generate code for "
733 "cipher [%s] with key bytes [%zd]\n", __func__,
734 mount_crypt_stat->global_default_fn_cipher_name,
735 mount_crypt_stat->global_default_fn_cipher_key_bytes);
736 rc = -EINVAL;
737 goto out_free_unlock;
738 }
739 dest[s->i++] = s->cipher_code;
740 /* TODO: Support other key modules than passphrase for
741 * filename encryption */
742 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
743 rc = -EOPNOTSUPP;
744 printk(KERN_INFO "%s: Filename encryption only supports "
745 "password tokens\n", __func__);
746 goto out_free_unlock;
747 }
748 sg_init_one(
749 &s->hash_sg,
750 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
751 s->auth_tok->token.password.session_key_encryption_key_bytes);
752 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
753 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
754 CRYPTO_ALG_ASYNC);
755 if (IS_ERR(s->hash_desc.tfm)) {
756 rc = PTR_ERR(s->hash_desc.tfm);
757 printk(KERN_ERR "%s: Error attempting to "
758 "allocate hash crypto context; rc = [%d]\n",
759 __func__, rc);
760 goto out_free_unlock;
761 }
762 rc = crypto_hash_init(&s->hash_desc);
763 if (rc) {
764 printk(KERN_ERR
765 "%s: Error initializing crypto hash; rc = [%d]\n",
766 __func__, rc);
767 goto out_release_free_unlock;
768 }
769 rc = crypto_hash_update(
770 &s->hash_desc, &s->hash_sg,
771 s->auth_tok->token.password.session_key_encryption_key_bytes);
772 if (rc) {
773 printk(KERN_ERR
774 "%s: Error updating crypto hash; rc = [%d]\n",
775 __func__, rc);
776 goto out_release_free_unlock;
777 }
778 rc = crypto_hash_final(&s->hash_desc, s->hash);
779 if (rc) {
780 printk(KERN_ERR
781 "%s: Error finalizing crypto hash; rc = [%d]\n",
782 __func__, rc);
783 goto out_release_free_unlock;
784 }
785 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
786 s->block_aligned_filename[s->j] =
787 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
788 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
789 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
790 sg_init_one(&s->hash_sg, (u8 *)s->hash,
791 ECRYPTFS_TAG_70_DIGEST_SIZE);
792 rc = crypto_hash_init(&s->hash_desc);
793 if (rc) {
794 printk(KERN_ERR
795 "%s: Error initializing crypto hash; "
796 "rc = [%d]\n", __func__, rc);
797 goto out_release_free_unlock;
798 }
799 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
800 ECRYPTFS_TAG_70_DIGEST_SIZE);
801 if (rc) {
802 printk(KERN_ERR
803 "%s: Error updating crypto hash; "
804 "rc = [%d]\n", __func__, rc);
805 goto out_release_free_unlock;
806 }
807 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
808 if (rc) {
809 printk(KERN_ERR
810 "%s: Error finalizing crypto hash; "
811 "rc = [%d]\n", __func__, rc);
812 goto out_release_free_unlock;
813 }
814 memcpy(s->hash, s->tmp_hash,
815 ECRYPTFS_TAG_70_DIGEST_SIZE);
816 }
817 if (s->block_aligned_filename[s->j] == '\0')
818 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
819 }
820 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
821 filename_size);
822 rc = virt_to_scatterlist(s->block_aligned_filename,
823 s->block_aligned_filename_size, s->src_sg, 2);
824 if (rc < 1) {
825 printk(KERN_ERR "%s: Internal error whilst attempting to "
826 "convert filename memory to scatterlist; rc = [%d]. "
827 "block_aligned_filename_size = [%zd]\n", __func__, rc,
828 s->block_aligned_filename_size);
829 goto out_release_free_unlock;
830 }
831 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
832 s->dst_sg, 2);
833 if (rc < 1) {
834 printk(KERN_ERR "%s: Internal error whilst attempting to "
835 "convert encrypted filename memory to scatterlist; "
836 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
837 __func__, rc, s->block_aligned_filename_size);
838 goto out_release_free_unlock;
839 }
840 /* The characters in the first block effectively do the job
841 * of the IV here, so we just use 0's for the IV. Note the
842 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
843 * >= ECRYPTFS_MAX_IV_BYTES. */
844 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
845 s->desc.info = s->iv;
846 rc = crypto_blkcipher_setkey(
847 s->desc.tfm,
848 s->auth_tok->token.password.session_key_encryption_key,
849 mount_crypt_stat->global_default_fn_cipher_key_bytes);
850 if (rc < 0) {
851 printk(KERN_ERR "%s: Error setting key for crypto context; "
852 "rc = [%d]. s->auth_tok->token.password.session_key_"
853 "encryption_key = [0x%p]; mount_crypt_stat->"
854 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
855 rc,
856 s->auth_tok->token.password.session_key_encryption_key,
857 mount_crypt_stat->global_default_fn_cipher_key_bytes);
858 goto out_release_free_unlock;
859 }
860 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
861 s->block_aligned_filename_size);
862 if (rc) {
863 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
864 "rc = [%d]\n", __func__, rc);
865 goto out_release_free_unlock;
866 }
867 s->i += s->block_aligned_filename_size;
868 (*packet_size) = s->i;
869 (*remaining_bytes) -= (*packet_size);
870 out_release_free_unlock:
871 crypto_free_hash(s->hash_desc.tfm);
872 out_free_unlock:
873 kzfree(s->block_aligned_filename);
874 out_unlock:
875 mutex_unlock(s->tfm_mutex);
876 out:
877 if (auth_tok_key) {
878 up_write(&(auth_tok_key->sem));
879 key_put(auth_tok_key);
880 }
881 kfree(s);
882 return rc;
883 }
884
885 struct ecryptfs_parse_tag_70_packet_silly_stack {
886 u8 cipher_code;
887 size_t max_packet_size;
888 size_t packet_size_len;
889 size_t parsed_tag_70_packet_size;
890 size_t block_aligned_filename_size;
891 size_t block_size;
892 size_t i;
893 struct mutex *tfm_mutex;
894 char *decrypted_filename;
895 struct ecryptfs_auth_tok *auth_tok;
896 struct scatterlist src_sg[2];
897 struct scatterlist dst_sg[2];
898 struct blkcipher_desc desc;
899 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
900 char iv[ECRYPTFS_MAX_IV_BYTES];
901 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
902 };
903
904 /**
905 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
906 * @filename: This function kmalloc's the memory for the filename
907 * @filename_size: This function sets this to the amount of memory
908 * kmalloc'd for the filename
909 * @packet_size: This function sets this to the the number of octets
910 * in the packet parsed
911 * @mount_crypt_stat: The mount-wide cryptographic context
912 * @data: The memory location containing the start of the tag 70
913 * packet
914 * @max_packet_size: The maximum legal size of the packet to be parsed
915 * from @data
916 *
917 * Returns zero on success; non-zero otherwise
918 */
919 int
920 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
921 size_t *packet_size,
922 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
923 char *data, size_t max_packet_size)
924 {
925 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
926 struct key *auth_tok_key = NULL;
927 int rc = 0;
928
929 (*packet_size) = 0;
930 (*filename_size) = 0;
931 (*filename) = NULL;
932 s = kmalloc(sizeof(*s), GFP_KERNEL);
933 if (!s) {
934 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
935 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
936 rc = -ENOMEM;
937 goto out;
938 }
939 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
940 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
941 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
942 "at least [%d]\n", __func__, max_packet_size,
943 ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
944 rc = -EINVAL;
945 goto out;
946 }
947 /* Octet 0: Tag 70 identifier
948 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
949 * and block-aligned encrypted filename size)
950 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
951 * Octet N2-N3: Cipher identifier (1 octet)
952 * Octets N3-N4: Block-aligned encrypted filename
953 * - Consists of a minimum number of random numbers, a \0
954 * separator, and then the filename */
955 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
956 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
957 "tag [0x%.2x]\n", __func__,
958 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
959 rc = -EINVAL;
960 goto out;
961 }
962 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
963 &s->parsed_tag_70_packet_size,
964 &s->packet_size_len);
965 if (rc) {
966 printk(KERN_WARNING "%s: Error parsing packet length; "
967 "rc = [%d]\n", __func__, rc);
968 goto out;
969 }
970 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
971 - ECRYPTFS_SIG_SIZE - 1);
972 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
973 > max_packet_size) {
974 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
975 "size is [%zd]\n", __func__, max_packet_size,
976 (1 + s->packet_size_len + 1
977 + s->block_aligned_filename_size));
978 rc = -EINVAL;
979 goto out;
980 }
981 (*packet_size) += s->packet_size_len;
982 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
983 ECRYPTFS_SIG_SIZE);
984 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
985 (*packet_size) += ECRYPTFS_SIG_SIZE;
986 s->cipher_code = data[(*packet_size)++];
987 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
988 if (rc) {
989 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
990 __func__, s->cipher_code);
991 goto out;
992 }
993 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
994 &s->auth_tok, mount_crypt_stat,
995 s->fnek_sig_hex);
996 if (rc) {
997 printk(KERN_ERR "%s: Error attempting to find auth tok for "
998 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
999 rc);
1000 goto out;
1001 }
1002 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
1003 &s->tfm_mutex,
1004 s->cipher_string);
1005 if (unlikely(rc)) {
1006 printk(KERN_ERR "Internal error whilst attempting to get "
1007 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1008 s->cipher_string, rc);
1009 goto out;
1010 }
1011 mutex_lock(s->tfm_mutex);
1012 rc = virt_to_scatterlist(&data[(*packet_size)],
1013 s->block_aligned_filename_size, s->src_sg, 2);
1014 if (rc < 1) {
1015 printk(KERN_ERR "%s: Internal error whilst attempting to "
1016 "convert encrypted filename memory to scatterlist; "
1017 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1018 __func__, rc, s->block_aligned_filename_size);
1019 goto out_unlock;
1020 }
1021 (*packet_size) += s->block_aligned_filename_size;
1022 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1023 GFP_KERNEL);
1024 if (!s->decrypted_filename) {
1025 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1026 "kmalloc [%zd] bytes\n", __func__,
1027 s->block_aligned_filename_size);
1028 rc = -ENOMEM;
1029 goto out_unlock;
1030 }
1031 rc = virt_to_scatterlist(s->decrypted_filename,
1032 s->block_aligned_filename_size, s->dst_sg, 2);
1033 if (rc < 1) {
1034 printk(KERN_ERR "%s: Internal error whilst attempting to "
1035 "convert decrypted filename memory to scatterlist; "
1036 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1037 __func__, rc, s->block_aligned_filename_size);
1038 goto out_free_unlock;
1039 }
1040 /* The characters in the first block effectively do the job of
1041 * the IV here, so we just use 0's for the IV. Note the
1042 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1043 * >= ECRYPTFS_MAX_IV_BYTES. */
1044 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1045 s->desc.info = s->iv;
1046 /* TODO: Support other key modules than passphrase for
1047 * filename encryption */
1048 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1049 rc = -EOPNOTSUPP;
1050 printk(KERN_INFO "%s: Filename encryption only supports "
1051 "password tokens\n", __func__);
1052 goto out_free_unlock;
1053 }
1054 rc = crypto_blkcipher_setkey(
1055 s->desc.tfm,
1056 s->auth_tok->token.password.session_key_encryption_key,
1057 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1058 if (rc < 0) {
1059 printk(KERN_ERR "%s: Error setting key for crypto context; "
1060 "rc = [%d]. s->auth_tok->token.password.session_key_"
1061 "encryption_key = [0x%p]; mount_crypt_stat->"
1062 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1063 rc,
1064 s->auth_tok->token.password.session_key_encryption_key,
1065 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1066 goto out_free_unlock;
1067 }
1068 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
1069 s->block_aligned_filename_size);
1070 if (rc) {
1071 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1072 "rc = [%d]\n", __func__, rc);
1073 goto out_free_unlock;
1074 }
1075 s->i = 0;
1076 while (s->decrypted_filename[s->i] != '\0'
1077 && s->i < s->block_aligned_filename_size)
1078 s->i++;
1079 if (s->i == s->block_aligned_filename_size) {
1080 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1081 "find valid separator between random characters and "
1082 "the filename\n", __func__);
1083 rc = -EINVAL;
1084 goto out_free_unlock;
1085 }
1086 s->i++;
1087 (*filename_size) = (s->block_aligned_filename_size - s->i);
1088 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1089 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1090 "invalid\n", __func__, (*filename_size));
1091 rc = -EINVAL;
1092 goto out_free_unlock;
1093 }
1094 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1095 if (!(*filename)) {
1096 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1097 "kmalloc [%zd] bytes\n", __func__,
1098 ((*filename_size) + 1));
1099 rc = -ENOMEM;
1100 goto out_free_unlock;
1101 }
1102 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1103 (*filename)[(*filename_size)] = '\0';
1104 out_free_unlock:
1105 kfree(s->decrypted_filename);
1106 out_unlock:
1107 mutex_unlock(s->tfm_mutex);
1108 out:
1109 if (rc) {
1110 (*packet_size) = 0;
1111 (*filename_size) = 0;
1112 (*filename) = NULL;
1113 }
1114 if (auth_tok_key) {
1115 up_write(&(auth_tok_key->sem));
1116 key_put(auth_tok_key);
1117 }
1118 kfree(s);
1119 return rc;
1120 }
1121
1122 static int
1123 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1124 {
1125 int rc = 0;
1126
1127 (*sig) = NULL;
1128 switch (auth_tok->token_type) {
1129 case ECRYPTFS_PASSWORD:
1130 (*sig) = auth_tok->token.password.signature;
1131 break;
1132 case ECRYPTFS_PRIVATE_KEY:
1133 (*sig) = auth_tok->token.private_key.signature;
1134 break;
1135 default:
1136 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1137 auth_tok->token_type);
1138 rc = -EINVAL;
1139 }
1140 return rc;
1141 }
1142
1143 /**
1144 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1145 * @auth_tok: The key authentication token used to decrypt the session key
1146 * @crypt_stat: The cryptographic context
1147 *
1148 * Returns zero on success; non-zero error otherwise.
1149 */
1150 static int
1151 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1152 struct ecryptfs_crypt_stat *crypt_stat)
1153 {
1154 u8 cipher_code = 0;
1155 struct ecryptfs_msg_ctx *msg_ctx;
1156 struct ecryptfs_message *msg = NULL;
1157 char *auth_tok_sig;
1158 char *payload = NULL;
1159 size_t payload_len = 0;
1160 int rc;
1161
1162 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1163 if (rc) {
1164 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1165 auth_tok->token_type);
1166 goto out;
1167 }
1168 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1169 &payload, &payload_len);
1170 if (rc) {
1171 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1172 goto out;
1173 }
1174 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1175 if (rc) {
1176 ecryptfs_printk(KERN_ERR, "Error sending message to "
1177 "ecryptfsd: %d\n", rc);
1178 goto out;
1179 }
1180 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1181 if (rc) {
1182 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1183 "from the user space daemon\n");
1184 rc = -EIO;
1185 goto out;
1186 }
1187 rc = parse_tag_65_packet(&(auth_tok->session_key),
1188 &cipher_code, msg);
1189 if (rc) {
1190 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1191 rc);
1192 goto out;
1193 }
1194 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1195 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1196 auth_tok->session_key.decrypted_key_size);
1197 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1198 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1199 if (rc) {
1200 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1201 cipher_code)
1202 goto out;
1203 }
1204 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1205 if (ecryptfs_verbosity > 0) {
1206 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1207 ecryptfs_dump_hex(crypt_stat->key,
1208 crypt_stat->key_size);
1209 }
1210 out:
1211 kfree(msg);
1212 kfree(payload);
1213 return rc;
1214 }
1215
1216 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1217 {
1218 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1219 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1220
1221 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1222 auth_tok_list_head, list) {
1223 list_del(&auth_tok_list_item->list);
1224 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1225 auth_tok_list_item);
1226 }
1227 }
1228
1229 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1230
1231 /**
1232 * parse_tag_1_packet
1233 * @crypt_stat: The cryptographic context to modify based on packet contents
1234 * @data: The raw bytes of the packet.
1235 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1236 * a new authentication token will be placed at the
1237 * end of this list for this packet.
1238 * @new_auth_tok: Pointer to a pointer to memory that this function
1239 * allocates; sets the memory address of the pointer to
1240 * NULL on error. This object is added to the
1241 * auth_tok_list.
1242 * @packet_size: This function writes the size of the parsed packet
1243 * into this memory location; zero on error.
1244 * @max_packet_size: The maximum allowable packet size
1245 *
1246 * Returns zero on success; non-zero on error.
1247 */
1248 static int
1249 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1250 unsigned char *data, struct list_head *auth_tok_list,
1251 struct ecryptfs_auth_tok **new_auth_tok,
1252 size_t *packet_size, size_t max_packet_size)
1253 {
1254 size_t body_size;
1255 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1256 size_t length_size;
1257 int rc = 0;
1258
1259 (*packet_size) = 0;
1260 (*new_auth_tok) = NULL;
1261 /**
1262 * This format is inspired by OpenPGP; see RFC 2440
1263 * packet tag 1
1264 *
1265 * Tag 1 identifier (1 byte)
1266 * Max Tag 1 packet size (max 3 bytes)
1267 * Version (1 byte)
1268 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1269 * Cipher identifier (1 byte)
1270 * Encrypted key size (arbitrary)
1271 *
1272 * 12 bytes minimum packet size
1273 */
1274 if (unlikely(max_packet_size < 12)) {
1275 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1276 rc = -EINVAL;
1277 goto out;
1278 }
1279 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1280 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1281 ECRYPTFS_TAG_1_PACKET_TYPE);
1282 rc = -EINVAL;
1283 goto out;
1284 }
1285 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1286 * at end of function upon failure */
1287 auth_tok_list_item =
1288 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1289 GFP_KERNEL);
1290 if (!auth_tok_list_item) {
1291 printk(KERN_ERR "Unable to allocate memory\n");
1292 rc = -ENOMEM;
1293 goto out;
1294 }
1295 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1296 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1297 &length_size);
1298 if (rc) {
1299 printk(KERN_WARNING "Error parsing packet length; "
1300 "rc = [%d]\n", rc);
1301 goto out_free;
1302 }
1303 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1304 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1305 rc = -EINVAL;
1306 goto out_free;
1307 }
1308 (*packet_size) += length_size;
1309 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1310 printk(KERN_WARNING "Packet size exceeds max\n");
1311 rc = -EINVAL;
1312 goto out_free;
1313 }
1314 if (unlikely(data[(*packet_size)++] != 0x03)) {
1315 printk(KERN_WARNING "Unknown version number [%d]\n",
1316 data[(*packet_size) - 1]);
1317 rc = -EINVAL;
1318 goto out_free;
1319 }
1320 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1321 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1322 *packet_size += ECRYPTFS_SIG_SIZE;
1323 /* This byte is skipped because the kernel does not need to
1324 * know which public key encryption algorithm was used */
1325 (*packet_size)++;
1326 (*new_auth_tok)->session_key.encrypted_key_size =
1327 body_size - (ECRYPTFS_SIG_SIZE + 2);
1328 if ((*new_auth_tok)->session_key.encrypted_key_size
1329 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1330 printk(KERN_WARNING "Tag 1 packet contains key larger "
1331 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1332 rc = -EINVAL;
1333 goto out_free;
1334 }
1335 memcpy((*new_auth_tok)->session_key.encrypted_key,
1336 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1337 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1338 (*new_auth_tok)->session_key.flags &=
1339 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1340 (*new_auth_tok)->session_key.flags |=
1341 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1342 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1343 (*new_auth_tok)->flags = 0;
1344 (*new_auth_tok)->session_key.flags &=
1345 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1346 (*new_auth_tok)->session_key.flags &=
1347 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1348 list_add(&auth_tok_list_item->list, auth_tok_list);
1349 goto out;
1350 out_free:
1351 (*new_auth_tok) = NULL;
1352 memset(auth_tok_list_item, 0,
1353 sizeof(struct ecryptfs_auth_tok_list_item));
1354 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1355 auth_tok_list_item);
1356 out:
1357 if (rc)
1358 (*packet_size) = 0;
1359 return rc;
1360 }
1361
1362 /**
1363 * parse_tag_3_packet
1364 * @crypt_stat: The cryptographic context to modify based on packet
1365 * contents.
1366 * @data: The raw bytes of the packet.
1367 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1368 * a new authentication token will be placed at the end
1369 * of this list for this packet.
1370 * @new_auth_tok: Pointer to a pointer to memory that this function
1371 * allocates; sets the memory address of the pointer to
1372 * NULL on error. This object is added to the
1373 * auth_tok_list.
1374 * @packet_size: This function writes the size of the parsed packet
1375 * into this memory location; zero on error.
1376 * @max_packet_size: maximum number of bytes to parse
1377 *
1378 * Returns zero on success; non-zero on error.
1379 */
1380 static int
1381 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1382 unsigned char *data, struct list_head *auth_tok_list,
1383 struct ecryptfs_auth_tok **new_auth_tok,
1384 size_t *packet_size, size_t max_packet_size)
1385 {
1386 size_t body_size;
1387 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1388 size_t length_size;
1389 int rc = 0;
1390
1391 (*packet_size) = 0;
1392 (*new_auth_tok) = NULL;
1393 /**
1394 *This format is inspired by OpenPGP; see RFC 2440
1395 * packet tag 3
1396 *
1397 * Tag 3 identifier (1 byte)
1398 * Max Tag 3 packet size (max 3 bytes)
1399 * Version (1 byte)
1400 * Cipher code (1 byte)
1401 * S2K specifier (1 byte)
1402 * Hash identifier (1 byte)
1403 * Salt (ECRYPTFS_SALT_SIZE)
1404 * Hash iterations (1 byte)
1405 * Encrypted key (arbitrary)
1406 *
1407 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1408 */
1409 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1410 printk(KERN_ERR "Max packet size too large\n");
1411 rc = -EINVAL;
1412 goto out;
1413 }
1414 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1415 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1416 ECRYPTFS_TAG_3_PACKET_TYPE);
1417 rc = -EINVAL;
1418 goto out;
1419 }
1420 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1421 * at end of function upon failure */
1422 auth_tok_list_item =
1423 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1424 if (!auth_tok_list_item) {
1425 printk(KERN_ERR "Unable to allocate memory\n");
1426 rc = -ENOMEM;
1427 goto out;
1428 }
1429 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1430 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1431 &length_size);
1432 if (rc) {
1433 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1434 rc);
1435 goto out_free;
1436 }
1437 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1438 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1439 rc = -EINVAL;
1440 goto out_free;
1441 }
1442 (*packet_size) += length_size;
1443 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1444 printk(KERN_ERR "Packet size exceeds max\n");
1445 rc = -EINVAL;
1446 goto out_free;
1447 }
1448 (*new_auth_tok)->session_key.encrypted_key_size =
1449 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1450 if ((*new_auth_tok)->session_key.encrypted_key_size
1451 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1452 printk(KERN_WARNING "Tag 3 packet contains key larger "
1453 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1454 rc = -EINVAL;
1455 goto out_free;
1456 }
1457 if (unlikely(data[(*packet_size)++] != 0x04)) {
1458 printk(KERN_WARNING "Unknown version number [%d]\n",
1459 data[(*packet_size) - 1]);
1460 rc = -EINVAL;
1461 goto out_free;
1462 }
1463 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1464 (u16)data[(*packet_size)]);
1465 if (rc)
1466 goto out_free;
1467 /* A little extra work to differentiate among the AES key
1468 * sizes; see RFC2440 */
1469 switch(data[(*packet_size)++]) {
1470 case RFC2440_CIPHER_AES_192:
1471 crypt_stat->key_size = 24;
1472 break;
1473 default:
1474 crypt_stat->key_size =
1475 (*new_auth_tok)->session_key.encrypted_key_size;
1476 }
1477 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1478 if (rc)
1479 goto out_free;
1480 if (unlikely(data[(*packet_size)++] != 0x03)) {
1481 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1482 rc = -ENOSYS;
1483 goto out_free;
1484 }
1485 /* TODO: finish the hash mapping */
1486 switch (data[(*packet_size)++]) {
1487 case 0x01: /* See RFC2440 for these numbers and their mappings */
1488 /* Choose MD5 */
1489 memcpy((*new_auth_tok)->token.password.salt,
1490 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1491 (*packet_size) += ECRYPTFS_SALT_SIZE;
1492 /* This conversion was taken straight from RFC2440 */
1493 (*new_auth_tok)->token.password.hash_iterations =
1494 ((u32) 16 + (data[(*packet_size)] & 15))
1495 << ((data[(*packet_size)] >> 4) + 6);
1496 (*packet_size)++;
1497 /* Friendly reminder:
1498 * (*new_auth_tok)->session_key.encrypted_key_size =
1499 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1500 memcpy((*new_auth_tok)->session_key.encrypted_key,
1501 &data[(*packet_size)],
1502 (*new_auth_tok)->session_key.encrypted_key_size);
1503 (*packet_size) +=
1504 (*new_auth_tok)->session_key.encrypted_key_size;
1505 (*new_auth_tok)->session_key.flags &=
1506 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1507 (*new_auth_tok)->session_key.flags |=
1508 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1509 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1510 break;
1511 default:
1512 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1513 "[%d]\n", data[(*packet_size) - 1]);
1514 rc = -ENOSYS;
1515 goto out_free;
1516 }
1517 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1518 /* TODO: Parametarize; we might actually want userspace to
1519 * decrypt the session key. */
1520 (*new_auth_tok)->session_key.flags &=
1521 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1522 (*new_auth_tok)->session_key.flags &=
1523 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1524 list_add(&auth_tok_list_item->list, auth_tok_list);
1525 goto out;
1526 out_free:
1527 (*new_auth_tok) = NULL;
1528 memset(auth_tok_list_item, 0,
1529 sizeof(struct ecryptfs_auth_tok_list_item));
1530 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1531 auth_tok_list_item);
1532 out:
1533 if (rc)
1534 (*packet_size) = 0;
1535 return rc;
1536 }
1537
1538 /**
1539 * parse_tag_11_packet
1540 * @data: The raw bytes of the packet
1541 * @contents: This function writes the data contents of the literal
1542 * packet into this memory location
1543 * @max_contents_bytes: The maximum number of bytes that this function
1544 * is allowed to write into contents
1545 * @tag_11_contents_size: This function writes the size of the parsed
1546 * contents into this memory location; zero on
1547 * error
1548 * @packet_size: This function writes the size of the parsed packet
1549 * into this memory location; zero on error
1550 * @max_packet_size: maximum number of bytes to parse
1551 *
1552 * Returns zero on success; non-zero on error.
1553 */
1554 static int
1555 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1556 size_t max_contents_bytes, size_t *tag_11_contents_size,
1557 size_t *packet_size, size_t max_packet_size)
1558 {
1559 size_t body_size;
1560 size_t length_size;
1561 int rc = 0;
1562
1563 (*packet_size) = 0;
1564 (*tag_11_contents_size) = 0;
1565 /* This format is inspired by OpenPGP; see RFC 2440
1566 * packet tag 11
1567 *
1568 * Tag 11 identifier (1 byte)
1569 * Max Tag 11 packet size (max 3 bytes)
1570 * Binary format specifier (1 byte)
1571 * Filename length (1 byte)
1572 * Filename ("_CONSOLE") (8 bytes)
1573 * Modification date (4 bytes)
1574 * Literal data (arbitrary)
1575 *
1576 * We need at least 16 bytes of data for the packet to even be
1577 * valid.
1578 */
1579 if (max_packet_size < 16) {
1580 printk(KERN_ERR "Maximum packet size too small\n");
1581 rc = -EINVAL;
1582 goto out;
1583 }
1584 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1585 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1586 rc = -EINVAL;
1587 goto out;
1588 }
1589 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1590 &length_size);
1591 if (rc) {
1592 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1593 goto out;
1594 }
1595 if (body_size < 14) {
1596 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1597 rc = -EINVAL;
1598 goto out;
1599 }
1600 (*packet_size) += length_size;
1601 (*tag_11_contents_size) = (body_size - 14);
1602 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1603 printk(KERN_ERR "Packet size exceeds max\n");
1604 rc = -EINVAL;
1605 goto out;
1606 }
1607 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1608 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1609 "expected size\n");
1610 rc = -EINVAL;
1611 goto out;
1612 }
1613 if (data[(*packet_size)++] != 0x62) {
1614 printk(KERN_WARNING "Unrecognizable packet\n");
1615 rc = -EINVAL;
1616 goto out;
1617 }
1618 if (data[(*packet_size)++] != 0x08) {
1619 printk(KERN_WARNING "Unrecognizable packet\n");
1620 rc = -EINVAL;
1621 goto out;
1622 }
1623 (*packet_size) += 12; /* Ignore filename and modification date */
1624 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1625 (*packet_size) += (*tag_11_contents_size);
1626 out:
1627 if (rc) {
1628 (*packet_size) = 0;
1629 (*tag_11_contents_size) = 0;
1630 }
1631 return rc;
1632 }
1633
1634 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1635 struct ecryptfs_auth_tok **auth_tok,
1636 char *sig)
1637 {
1638 int rc = 0;
1639
1640 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1641 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1642 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1643 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1644 printk(KERN_ERR "Could not find key with description: [%s]\n",
1645 sig);
1646 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1647 (*auth_tok_key) = NULL;
1648 goto out;
1649 }
1650 }
1651 down_write(&(*auth_tok_key)->sem);
1652 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1653 if (rc) {
1654 up_write(&(*auth_tok_key)->sem);
1655 key_put(*auth_tok_key);
1656 (*auth_tok_key) = NULL;
1657 goto out;
1658 }
1659 out:
1660 return rc;
1661 }
1662
1663 /**
1664 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1665 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1666 * @crypt_stat: The cryptographic context
1667 *
1668 * Returns zero on success; non-zero error otherwise
1669 */
1670 static int
1671 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1672 struct ecryptfs_crypt_stat *crypt_stat)
1673 {
1674 struct scatterlist dst_sg[2];
1675 struct scatterlist src_sg[2];
1676 struct mutex *tfm_mutex;
1677 struct blkcipher_desc desc = {
1678 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1679 };
1680 int rc = 0;
1681
1682 if (unlikely(ecryptfs_verbosity > 0)) {
1683 ecryptfs_printk(
1684 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1685 auth_tok->token.password.session_key_encryption_key_bytes);
1686 ecryptfs_dump_hex(
1687 auth_tok->token.password.session_key_encryption_key,
1688 auth_tok->token.password.session_key_encryption_key_bytes);
1689 }
1690 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1691 crypt_stat->cipher);
1692 if (unlikely(rc)) {
1693 printk(KERN_ERR "Internal error whilst attempting to get "
1694 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1695 crypt_stat->cipher, rc);
1696 goto out;
1697 }
1698 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1699 auth_tok->session_key.encrypted_key_size,
1700 src_sg, 2);
1701 if (rc < 1 || rc > 2) {
1702 printk(KERN_ERR "Internal error whilst attempting to convert "
1703 "auth_tok->session_key.encrypted_key to scatterlist; "
1704 "expected rc = 1; got rc = [%d]. "
1705 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1706 auth_tok->session_key.encrypted_key_size);
1707 goto out;
1708 }
1709 auth_tok->session_key.decrypted_key_size =
1710 auth_tok->session_key.encrypted_key_size;
1711 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1712 auth_tok->session_key.decrypted_key_size,
1713 dst_sg, 2);
1714 if (rc < 1 || rc > 2) {
1715 printk(KERN_ERR "Internal error whilst attempting to convert "
1716 "auth_tok->session_key.decrypted_key to scatterlist; "
1717 "expected rc = 1; got rc = [%d]\n", rc);
1718 goto out;
1719 }
1720 mutex_lock(tfm_mutex);
1721 rc = crypto_blkcipher_setkey(
1722 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1723 crypt_stat->key_size);
1724 if (unlikely(rc < 0)) {
1725 mutex_unlock(tfm_mutex);
1726 printk(KERN_ERR "Error setting key for crypto context\n");
1727 rc = -EINVAL;
1728 goto out;
1729 }
1730 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1731 auth_tok->session_key.encrypted_key_size);
1732 mutex_unlock(tfm_mutex);
1733 if (unlikely(rc)) {
1734 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1735 goto out;
1736 }
1737 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1738 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1739 auth_tok->session_key.decrypted_key_size);
1740 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1741 if (unlikely(ecryptfs_verbosity > 0)) {
1742 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1743 crypt_stat->key_size);
1744 ecryptfs_dump_hex(crypt_stat->key,
1745 crypt_stat->key_size);
1746 }
1747 out:
1748 return rc;
1749 }
1750
1751 /**
1752 * ecryptfs_parse_packet_set
1753 * @crypt_stat: The cryptographic context
1754 * @src: Virtual address of region of memory containing the packets
1755 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1756 *
1757 * Get crypt_stat to have the file's session key if the requisite key
1758 * is available to decrypt the session key.
1759 *
1760 * Returns Zero if a valid authentication token was retrieved and
1761 * processed; negative value for file not encrypted or for error
1762 * conditions.
1763 */
1764 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1765 unsigned char *src,
1766 struct dentry *ecryptfs_dentry)
1767 {
1768 size_t i = 0;
1769 size_t found_auth_tok;
1770 size_t next_packet_is_auth_tok_packet;
1771 struct list_head auth_tok_list;
1772 struct ecryptfs_auth_tok *matching_auth_tok;
1773 struct ecryptfs_auth_tok *candidate_auth_tok;
1774 char *candidate_auth_tok_sig;
1775 size_t packet_size;
1776 struct ecryptfs_auth_tok *new_auth_tok;
1777 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1778 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1779 size_t tag_11_contents_size;
1780 size_t tag_11_packet_size;
1781 struct key *auth_tok_key = NULL;
1782 int rc = 0;
1783
1784 INIT_LIST_HEAD(&auth_tok_list);
1785 /* Parse the header to find as many packets as we can; these will be
1786 * added the our &auth_tok_list */
1787 next_packet_is_auth_tok_packet = 1;
1788 while (next_packet_is_auth_tok_packet) {
1789 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1790
1791 switch (src[i]) {
1792 case ECRYPTFS_TAG_3_PACKET_TYPE:
1793 rc = parse_tag_3_packet(crypt_stat,
1794 (unsigned char *)&src[i],
1795 &auth_tok_list, &new_auth_tok,
1796 &packet_size, max_packet_size);
1797 if (rc) {
1798 ecryptfs_printk(KERN_ERR, "Error parsing "
1799 "tag 3 packet\n");
1800 rc = -EIO;
1801 goto out_wipe_list;
1802 }
1803 i += packet_size;
1804 rc = parse_tag_11_packet((unsigned char *)&src[i],
1805 sig_tmp_space,
1806 ECRYPTFS_SIG_SIZE,
1807 &tag_11_contents_size,
1808 &tag_11_packet_size,
1809 max_packet_size);
1810 if (rc) {
1811 ecryptfs_printk(KERN_ERR, "No valid "
1812 "(ecryptfs-specific) literal "
1813 "packet containing "
1814 "authentication token "
1815 "signature found after "
1816 "tag 3 packet\n");
1817 rc = -EIO;
1818 goto out_wipe_list;
1819 }
1820 i += tag_11_packet_size;
1821 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1822 ecryptfs_printk(KERN_ERR, "Expected "
1823 "signature of size [%d]; "
1824 "read size [%zd]\n",
1825 ECRYPTFS_SIG_SIZE,
1826 tag_11_contents_size);
1827 rc = -EIO;
1828 goto out_wipe_list;
1829 }
1830 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1831 sig_tmp_space, tag_11_contents_size);
1832 new_auth_tok->token.password.signature[
1833 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1834 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1835 break;
1836 case ECRYPTFS_TAG_1_PACKET_TYPE:
1837 rc = parse_tag_1_packet(crypt_stat,
1838 (unsigned char *)&src[i],
1839 &auth_tok_list, &new_auth_tok,
1840 &packet_size, max_packet_size);
1841 if (rc) {
1842 ecryptfs_printk(KERN_ERR, "Error parsing "
1843 "tag 1 packet\n");
1844 rc = -EIO;
1845 goto out_wipe_list;
1846 }
1847 i += packet_size;
1848 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1849 break;
1850 case ECRYPTFS_TAG_11_PACKET_TYPE:
1851 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1852 "(Tag 11 not allowed by itself)\n");
1853 rc = -EIO;
1854 goto out_wipe_list;
1855 default:
1856 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1857 "of the file header; hex value of "
1858 "character is [0x%.2x]\n", i, src[i]);
1859 next_packet_is_auth_tok_packet = 0;
1860 }
1861 }
1862 if (list_empty(&auth_tok_list)) {
1863 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1864 "eCryptfs file; this is not supported in this version "
1865 "of the eCryptfs kernel module\n");
1866 rc = -EINVAL;
1867 goto out;
1868 }
1869 /* auth_tok_list contains the set of authentication tokens
1870 * parsed from the metadata. We need to find a matching
1871 * authentication token that has the secret component(s)
1872 * necessary to decrypt the EFEK in the auth_tok parsed from
1873 * the metadata. There may be several potential matches, but
1874 * just one will be sufficient to decrypt to get the FEK. */
1875 find_next_matching_auth_tok:
1876 found_auth_tok = 0;
1877 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1878 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1879 if (unlikely(ecryptfs_verbosity > 0)) {
1880 ecryptfs_printk(KERN_DEBUG,
1881 "Considering cadidate auth tok:\n");
1882 ecryptfs_dump_auth_tok(candidate_auth_tok);
1883 }
1884 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1885 candidate_auth_tok);
1886 if (rc) {
1887 printk(KERN_ERR
1888 "Unrecognized candidate auth tok type: [%d]\n",
1889 candidate_auth_tok->token_type);
1890 rc = -EINVAL;
1891 goto out_wipe_list;
1892 }
1893 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1894 &matching_auth_tok,
1895 crypt_stat->mount_crypt_stat,
1896 candidate_auth_tok_sig);
1897 if (!rc) {
1898 found_auth_tok = 1;
1899 goto found_matching_auth_tok;
1900 }
1901 }
1902 if (!found_auth_tok) {
1903 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1904 "authentication token\n");
1905 rc = -EIO;
1906 goto out_wipe_list;
1907 }
1908 found_matching_auth_tok:
1909 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1910 memcpy(&(candidate_auth_tok->token.private_key),
1911 &(matching_auth_tok->token.private_key),
1912 sizeof(struct ecryptfs_private_key));
1913 up_write(&(auth_tok_key->sem));
1914 key_put(auth_tok_key);
1915 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1916 crypt_stat);
1917 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1918 memcpy(&(candidate_auth_tok->token.password),
1919 &(matching_auth_tok->token.password),
1920 sizeof(struct ecryptfs_password));
1921 up_write(&(auth_tok_key->sem));
1922 key_put(auth_tok_key);
1923 rc = decrypt_passphrase_encrypted_session_key(
1924 candidate_auth_tok, crypt_stat);
1925 } else {
1926 up_write(&(auth_tok_key->sem));
1927 key_put(auth_tok_key);
1928 rc = -EINVAL;
1929 }
1930 if (rc) {
1931 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1932
1933 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1934 "session key for authentication token with sig "
1935 "[%.*s]; rc = [%d]. Removing auth tok "
1936 "candidate from the list and searching for "
1937 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1938 candidate_auth_tok_sig, rc);
1939 list_for_each_entry_safe(auth_tok_list_item,
1940 auth_tok_list_item_tmp,
1941 &auth_tok_list, list) {
1942 if (candidate_auth_tok
1943 == &auth_tok_list_item->auth_tok) {
1944 list_del(&auth_tok_list_item->list);
1945 kmem_cache_free(
1946 ecryptfs_auth_tok_list_item_cache,
1947 auth_tok_list_item);
1948 goto find_next_matching_auth_tok;
1949 }
1950 }
1951 BUG();
1952 }
1953 rc = ecryptfs_compute_root_iv(crypt_stat);
1954 if (rc) {
1955 ecryptfs_printk(KERN_ERR, "Error computing "
1956 "the root IV\n");
1957 goto out_wipe_list;
1958 }
1959 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1960 if (rc) {
1961 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1962 "context for cipher [%s]; rc = [%d]\n",
1963 crypt_stat->cipher, rc);
1964 }
1965 out_wipe_list:
1966 wipe_auth_tok_list(&auth_tok_list);
1967 out:
1968 return rc;
1969 }
1970
1971 static int
1972 pki_encrypt_session_key(struct key *auth_tok_key,
1973 struct ecryptfs_auth_tok *auth_tok,
1974 struct ecryptfs_crypt_stat *crypt_stat,
1975 struct ecryptfs_key_record *key_rec)
1976 {
1977 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1978 char *payload = NULL;
1979 size_t payload_len = 0;
1980 struct ecryptfs_message *msg;
1981 int rc;
1982
1983 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1984 ecryptfs_code_for_cipher_string(
1985 crypt_stat->cipher,
1986 crypt_stat->key_size),
1987 crypt_stat, &payload, &payload_len);
1988 up_write(&(auth_tok_key->sem));
1989 key_put(auth_tok_key);
1990 if (rc) {
1991 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1992 goto out;
1993 }
1994 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1995 if (rc) {
1996 ecryptfs_printk(KERN_ERR, "Error sending message to "
1997 "ecryptfsd: %d\n", rc);
1998 goto out;
1999 }
2000 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
2001 if (rc) {
2002 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2003 "from the user space daemon\n");
2004 rc = -EIO;
2005 goto out;
2006 }
2007 rc = parse_tag_67_packet(key_rec, msg);
2008 if (rc)
2009 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2010 kfree(msg);
2011 out:
2012 kfree(payload);
2013 return rc;
2014 }
2015 /**
2016 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2017 * @dest: Buffer into which to write the packet
2018 * @remaining_bytes: Maximum number of bytes that can be writtn
2019 * @auth_tok_key: The authentication token key to unlock and put when done with
2020 * @auth_tok
2021 * @auth_tok: The authentication token used for generating the tag 1 packet
2022 * @crypt_stat: The cryptographic context
2023 * @key_rec: The key record struct for the tag 1 packet
2024 * @packet_size: This function will write the number of bytes that end
2025 * up constituting the packet; set to zero on error
2026 *
2027 * Returns zero on success; non-zero on error.
2028 */
2029 static int
2030 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2031 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2032 struct ecryptfs_crypt_stat *crypt_stat,
2033 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2034 {
2035 size_t i;
2036 size_t encrypted_session_key_valid = 0;
2037 size_t packet_size_length;
2038 size_t max_packet_size;
2039 int rc = 0;
2040
2041 (*packet_size) = 0;
2042 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2043 ECRYPTFS_SIG_SIZE);
2044 encrypted_session_key_valid = 0;
2045 for (i = 0; i < crypt_stat->key_size; i++)
2046 encrypted_session_key_valid |=
2047 auth_tok->session_key.encrypted_key[i];
2048 if (encrypted_session_key_valid) {
2049 memcpy(key_rec->enc_key,
2050 auth_tok->session_key.encrypted_key,
2051 auth_tok->session_key.encrypted_key_size);
2052 up_write(&(auth_tok_key->sem));
2053 key_put(auth_tok_key);
2054 goto encrypted_session_key_set;
2055 }
2056 if (auth_tok->session_key.encrypted_key_size == 0)
2057 auth_tok->session_key.encrypted_key_size =
2058 auth_tok->token.private_key.key_size;
2059 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2060 key_rec);
2061 if (rc) {
2062 printk(KERN_ERR "Failed to encrypt session key via a key "
2063 "module; rc = [%d]\n", rc);
2064 goto out;
2065 }
2066 if (ecryptfs_verbosity > 0) {
2067 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2068 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2069 }
2070 encrypted_session_key_set:
2071 /* This format is inspired by OpenPGP; see RFC 2440
2072 * packet tag 1 */
2073 max_packet_size = (1 /* Tag 1 identifier */
2074 + 3 /* Max Tag 1 packet size */
2075 + 1 /* Version */
2076 + ECRYPTFS_SIG_SIZE /* Key identifier */
2077 + 1 /* Cipher identifier */
2078 + key_rec->enc_key_size); /* Encrypted key size */
2079 if (max_packet_size > (*remaining_bytes)) {
2080 printk(KERN_ERR "Packet length larger than maximum allowable; "
2081 "need up to [%td] bytes, but there are only [%td] "
2082 "available\n", max_packet_size, (*remaining_bytes));
2083 rc = -EINVAL;
2084 goto out;
2085 }
2086 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2087 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2088 (max_packet_size - 4),
2089 &packet_size_length);
2090 if (rc) {
2091 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2092 "header; cannot generate packet length\n");
2093 goto out;
2094 }
2095 (*packet_size) += packet_size_length;
2096 dest[(*packet_size)++] = 0x03; /* version 3 */
2097 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2098 (*packet_size) += ECRYPTFS_SIG_SIZE;
2099 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2100 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2101 key_rec->enc_key_size);
2102 (*packet_size) += key_rec->enc_key_size;
2103 out:
2104 if (rc)
2105 (*packet_size) = 0;
2106 else
2107 (*remaining_bytes) -= (*packet_size);
2108 return rc;
2109 }
2110
2111 /**
2112 * write_tag_11_packet
2113 * @dest: Target into which Tag 11 packet is to be written
2114 * @remaining_bytes: Maximum packet length
2115 * @contents: Byte array of contents to copy in
2116 * @contents_length: Number of bytes in contents
2117 * @packet_length: Length of the Tag 11 packet written; zero on error
2118 *
2119 * Returns zero on success; non-zero on error.
2120 */
2121 static int
2122 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2123 size_t contents_length, size_t *packet_length)
2124 {
2125 size_t packet_size_length;
2126 size_t max_packet_size;
2127 int rc = 0;
2128
2129 (*packet_length) = 0;
2130 /* This format is inspired by OpenPGP; see RFC 2440
2131 * packet tag 11 */
2132 max_packet_size = (1 /* Tag 11 identifier */
2133 + 3 /* Max Tag 11 packet size */
2134 + 1 /* Binary format specifier */
2135 + 1 /* Filename length */
2136 + 8 /* Filename ("_CONSOLE") */
2137 + 4 /* Modification date */
2138 + contents_length); /* Literal data */
2139 if (max_packet_size > (*remaining_bytes)) {
2140 printk(KERN_ERR "Packet length larger than maximum allowable; "
2141 "need up to [%td] bytes, but there are only [%td] "
2142 "available\n", max_packet_size, (*remaining_bytes));
2143 rc = -EINVAL;
2144 goto out;
2145 }
2146 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2147 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2148 (max_packet_size - 4),
2149 &packet_size_length);
2150 if (rc) {
2151 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2152 "generate packet length. rc = [%d]\n", rc);
2153 goto out;
2154 }
2155 (*packet_length) += packet_size_length;
2156 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2157 dest[(*packet_length)++] = 8;
2158 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2159 (*packet_length) += 8;
2160 memset(&dest[(*packet_length)], 0x00, 4);
2161 (*packet_length) += 4;
2162 memcpy(&dest[(*packet_length)], contents, contents_length);
2163 (*packet_length) += contents_length;
2164 out:
2165 if (rc)
2166 (*packet_length) = 0;
2167 else
2168 (*remaining_bytes) -= (*packet_length);
2169 return rc;
2170 }
2171
2172 /**
2173 * write_tag_3_packet
2174 * @dest: Buffer into which to write the packet
2175 * @remaining_bytes: Maximum number of bytes that can be written
2176 * @auth_tok: Authentication token
2177 * @crypt_stat: The cryptographic context
2178 * @key_rec: encrypted key
2179 * @packet_size: This function will write the number of bytes that end
2180 * up constituting the packet; set to zero on error
2181 *
2182 * Returns zero on success; non-zero on error.
2183 */
2184 static int
2185 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2186 struct ecryptfs_auth_tok *auth_tok,
2187 struct ecryptfs_crypt_stat *crypt_stat,
2188 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2189 {
2190 size_t i;
2191 size_t encrypted_session_key_valid = 0;
2192 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2193 struct scatterlist dst_sg[2];
2194 struct scatterlist src_sg[2];
2195 struct mutex *tfm_mutex = NULL;
2196 u8 cipher_code;
2197 size_t packet_size_length;
2198 size_t max_packet_size;
2199 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2200 crypt_stat->mount_crypt_stat;
2201 struct blkcipher_desc desc = {
2202 .tfm = NULL,
2203 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2204 };
2205 int rc = 0;
2206
2207 (*packet_size) = 0;
2208 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2209 ECRYPTFS_SIG_SIZE);
2210 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2211 crypt_stat->cipher);
2212 if (unlikely(rc)) {
2213 printk(KERN_ERR "Internal error whilst attempting to get "
2214 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2215 crypt_stat->cipher, rc);
2216 goto out;
2217 }
2218 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2219 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2220
2221 printk(KERN_WARNING "No key size specified at mount; "
2222 "defaulting to [%d]\n", alg->max_keysize);
2223 mount_crypt_stat->global_default_cipher_key_size =
2224 alg->max_keysize;
2225 }
2226 if (crypt_stat->key_size == 0)
2227 crypt_stat->key_size =
2228 mount_crypt_stat->global_default_cipher_key_size;
2229 if (auth_tok->session_key.encrypted_key_size == 0)
2230 auth_tok->session_key.encrypted_key_size =
2231 crypt_stat->key_size;
2232 if (crypt_stat->key_size == 24
2233 && strcmp("aes", crypt_stat->cipher) == 0) {
2234 memset((crypt_stat->key + 24), 0, 8);
2235 auth_tok->session_key.encrypted_key_size = 32;
2236 } else
2237 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2238 key_rec->enc_key_size =
2239 auth_tok->session_key.encrypted_key_size;
2240 encrypted_session_key_valid = 0;
2241 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2242 encrypted_session_key_valid |=
2243 auth_tok->session_key.encrypted_key[i];
2244 if (encrypted_session_key_valid) {
2245 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2246 "using auth_tok->session_key.encrypted_key, "
2247 "where key_rec->enc_key_size = [%zd]\n",
2248 key_rec->enc_key_size);
2249 memcpy(key_rec->enc_key,
2250 auth_tok->session_key.encrypted_key,
2251 key_rec->enc_key_size);
2252 goto encrypted_session_key_set;
2253 }
2254 if (auth_tok->token.password.flags &
2255 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2256 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2257 "session key encryption key of size [%d]\n",
2258 auth_tok->token.password.
2259 session_key_encryption_key_bytes);
2260 memcpy(session_key_encryption_key,
2261 auth_tok->token.password.session_key_encryption_key,
2262 crypt_stat->key_size);
2263 ecryptfs_printk(KERN_DEBUG,
2264 "Cached session key encryption key:\n");
2265 if (ecryptfs_verbosity > 0)
2266 ecryptfs_dump_hex(session_key_encryption_key, 16);
2267 }
2268 if (unlikely(ecryptfs_verbosity > 0)) {
2269 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2270 ecryptfs_dump_hex(session_key_encryption_key, 16);
2271 }
2272 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2273 src_sg, 2);
2274 if (rc < 1 || rc > 2) {
2275 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2276 "for crypt_stat session key; expected rc = 1; "
2277 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2278 rc, key_rec->enc_key_size);
2279 rc = -ENOMEM;
2280 goto out;
2281 }
2282 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2283 dst_sg, 2);
2284 if (rc < 1 || rc > 2) {
2285 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2286 "for crypt_stat encrypted session key; "
2287 "expected rc = 1; got rc = [%d]. "
2288 "key_rec->enc_key_size = [%zd]\n", rc,
2289 key_rec->enc_key_size);
2290 rc = -ENOMEM;
2291 goto out;
2292 }
2293 mutex_lock(tfm_mutex);
2294 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2295 crypt_stat->key_size);
2296 if (rc < 0) {
2297 mutex_unlock(tfm_mutex);
2298 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2299 "context; rc = [%d]\n", rc);
2300 goto out;
2301 }
2302 rc = 0;
2303 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2304 crypt_stat->key_size);
2305 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2306 (*key_rec).enc_key_size);
2307 mutex_unlock(tfm_mutex);
2308 if (rc) {
2309 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2310 goto out;
2311 }
2312 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2313 if (ecryptfs_verbosity > 0) {
2314 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2315 key_rec->enc_key_size);
2316 ecryptfs_dump_hex(key_rec->enc_key,
2317 key_rec->enc_key_size);
2318 }
2319 encrypted_session_key_set:
2320 /* This format is inspired by OpenPGP; see RFC 2440
2321 * packet tag 3 */
2322 max_packet_size = (1 /* Tag 3 identifier */
2323 + 3 /* Max Tag 3 packet size */
2324 + 1 /* Version */
2325 + 1 /* Cipher code */
2326 + 1 /* S2K specifier */
2327 + 1 /* Hash identifier */
2328 + ECRYPTFS_SALT_SIZE /* Salt */
2329 + 1 /* Hash iterations */
2330 + key_rec->enc_key_size); /* Encrypted key size */
2331 if (max_packet_size > (*remaining_bytes)) {
2332 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2333 "there are only [%td] available\n", max_packet_size,
2334 (*remaining_bytes));
2335 rc = -EINVAL;
2336 goto out;
2337 }
2338 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2339 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2340 * to get the number of octets in the actual Tag 3 packet */
2341 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2342 (max_packet_size - 4),
2343 &packet_size_length);
2344 if (rc) {
2345 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2346 "generate packet length. rc = [%d]\n", rc);
2347 goto out;
2348 }
2349 (*packet_size) += packet_size_length;
2350 dest[(*packet_size)++] = 0x04; /* version 4 */
2351 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2352 * specified with strings */
2353 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2354 crypt_stat->key_size);
2355 if (cipher_code == 0) {
2356 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2357 "cipher [%s]\n", crypt_stat->cipher);
2358 rc = -EINVAL;
2359 goto out;
2360 }
2361 dest[(*packet_size)++] = cipher_code;
2362 dest[(*packet_size)++] = 0x03; /* S2K */
2363 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2364 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2365 ECRYPTFS_SALT_SIZE);
2366 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2367 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2368 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2369 key_rec->enc_key_size);
2370 (*packet_size) += key_rec->enc_key_size;
2371 out:
2372 if (rc)
2373 (*packet_size) = 0;
2374 else
2375 (*remaining_bytes) -= (*packet_size);
2376 return rc;
2377 }
2378
2379 struct kmem_cache *ecryptfs_key_record_cache;
2380
2381 /**
2382 * ecryptfs_generate_key_packet_set
2383 * @dest_base: Virtual address from which to write the key record set
2384 * @crypt_stat: The cryptographic context from which the
2385 * authentication tokens will be retrieved
2386 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2387 * for the global parameters
2388 * @len: The amount written
2389 * @max: The maximum amount of data allowed to be written
2390 *
2391 * Generates a key packet set and writes it to the virtual address
2392 * passed in.
2393 *
2394 * Returns zero on success; non-zero on error.
2395 */
2396 int
2397 ecryptfs_generate_key_packet_set(char *dest_base,
2398 struct ecryptfs_crypt_stat *crypt_stat,
2399 struct dentry *ecryptfs_dentry, size_t *len,
2400 size_t max)
2401 {
2402 struct ecryptfs_auth_tok *auth_tok;
2403 struct key *auth_tok_key = NULL;
2404 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2405 &ecryptfs_superblock_to_private(
2406 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2407 size_t written;
2408 struct ecryptfs_key_record *key_rec;
2409 struct ecryptfs_key_sig *key_sig;
2410 int rc = 0;
2411
2412 (*len) = 0;
2413 mutex_lock(&crypt_stat->keysig_list_mutex);
2414 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2415 if (!key_rec) {
2416 rc = -ENOMEM;
2417 goto out;
2418 }
2419 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2420 crypt_stat_list) {
2421 memset(key_rec, 0, sizeof(*key_rec));
2422 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2423 &auth_tok,
2424 mount_crypt_stat,
2425 key_sig->keysig);
2426 if (rc) {
2427 printk(KERN_WARNING "Unable to retrieve auth tok with "
2428 "sig = [%s]\n", key_sig->keysig);
2429 rc = process_find_global_auth_tok_for_sig_err(rc);
2430 goto out_free;
2431 }
2432 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2433 rc = write_tag_3_packet((dest_base + (*len)),
2434 &max, auth_tok,
2435 crypt_stat, key_rec,
2436 &written);
2437 up_write(&(auth_tok_key->sem));
2438 key_put(auth_tok_key);
2439 if (rc) {
2440 ecryptfs_printk(KERN_WARNING, "Error "
2441 "writing tag 3 packet\n");
2442 goto out_free;
2443 }
2444 (*len) += written;
2445 /* Write auth tok signature packet */
2446 rc = write_tag_11_packet((dest_base + (*len)), &max,
2447 key_rec->sig,
2448 ECRYPTFS_SIG_SIZE, &written);
2449 if (rc) {
2450 ecryptfs_printk(KERN_ERR, "Error writing "
2451 "auth tok signature packet\n");
2452 goto out_free;
2453 }
2454 (*len) += written;
2455 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2456 rc = write_tag_1_packet(dest_base + (*len), &max,
2457 auth_tok_key, auth_tok,
2458 crypt_stat, key_rec, &written);
2459 if (rc) {
2460 ecryptfs_printk(KERN_WARNING, "Error "
2461 "writing tag 1 packet\n");
2462 goto out_free;
2463 }
2464 (*len) += written;
2465 } else {
2466 up_write(&(auth_tok_key->sem));
2467 key_put(auth_tok_key);
2468 ecryptfs_printk(KERN_WARNING, "Unsupported "
2469 "authentication token type\n");
2470 rc = -EINVAL;
2471 goto out_free;
2472 }
2473 }
2474 if (likely(max > 0)) {
2475 dest_base[(*len)] = 0x00;
2476 } else {
2477 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2478 rc = -EIO;
2479 }
2480 out_free:
2481 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2482 out:
2483 if (rc)
2484 (*len) = 0;
2485 mutex_unlock(&crypt_stat->keysig_list_mutex);
2486 return rc;
2487 }
2488
2489 struct kmem_cache *ecryptfs_key_sig_cache;
2490
2491 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2492 {
2493 struct ecryptfs_key_sig *new_key_sig;
2494
2495 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2496 if (!new_key_sig) {
2497 printk(KERN_ERR
2498 "Error allocating from ecryptfs_key_sig_cache\n");
2499 return -ENOMEM;
2500 }
2501 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2502 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2503 /* Caller must hold keysig_list_mutex */
2504 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2505
2506 return 0;
2507 }
2508
2509 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2510
2511 int
2512 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2513 char *sig, u32 global_auth_tok_flags)
2514 {
2515 struct ecryptfs_global_auth_tok *new_auth_tok;
2516 int rc = 0;
2517
2518 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2519 GFP_KERNEL);
2520 if (!new_auth_tok) {
2521 rc = -ENOMEM;
2522 printk(KERN_ERR "Error allocating from "
2523 "ecryptfs_global_auth_tok_cache\n");
2524 goto out;
2525 }
2526 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2527 new_auth_tok->flags = global_auth_tok_flags;
2528 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2529 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2530 list_add(&new_auth_tok->mount_crypt_stat_list,
2531 &mount_crypt_stat->global_auth_tok_list);
2532 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2533 out:
2534 return rc;
2535 }
2536
Linux with added FPC-III support