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arm64: kgdb: Fix single-step exception handling oops
[linux/fpc-iii.git] / fs / ecryptfs / keystore.c
blobb134315fb69d060974a252a1ccd2191a9be865c3
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 <crypto/hash.h>
29 #include <crypto/skcipher.h>
30 #include <linux/string.h>
31 #include <linux/pagemap.h>
32 #include <linux/key.h>
33 #include <linux/random.h>
34 #include <linux/scatterlist.h>
35 #include <linux/slab.h>
36 #include "ecryptfs_kernel.h"
37
38 /**
39 * request_key returned an error instead of a valid key address;
40 * determine the type of error, make appropriate log entries, and
41 * return an error code.
42 */
43 static int process_request_key_err(long err_code)
44 {
45 int rc = 0;
46
47 switch (err_code) {
48 case -ENOKEY:
49 ecryptfs_printk(KERN_WARNING, "No key\n");
50 rc = -ENOENT;
51 break;
52 case -EKEYEXPIRED:
53 ecryptfs_printk(KERN_WARNING, "Key expired\n");
54 rc = -ETIME;
55 break;
56 case -EKEYREVOKED:
57 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
58 rc = -EINVAL;
59 break;
60 default:
61 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
62 "[0x%.16lx]\n", err_code);
63 rc = -EINVAL;
64 }
65 return rc;
66 }
67
68 static int process_find_global_auth_tok_for_sig_err(int err_code)
69 {
70 int rc = err_code;
71
72 switch (err_code) {
73 case -ENOENT:
74 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
75 break;
76 case -EINVAL:
77 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
78 break;
79 default:
80 rc = process_request_key_err(err_code);
81 break;
82 }
83 return rc;
84 }
85
86 /**
87 * ecryptfs_parse_packet_length
88 * @data: Pointer to memory containing length at offset
89 * @size: This function writes the decoded size to this memory
90 * address; zero on error
91 * @length_size: The number of bytes occupied by the encoded length
92 *
93 * Returns zero on success; non-zero on error
94 */
95 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
96 size_t *length_size)
97 {
98 int rc = 0;
99
100 (*length_size) = 0;
101 (*size) = 0;
102 if (data[0] < 192) {
103 /* One-byte length */
104 (*size) = data[0];
105 (*length_size) = 1;
106 } else if (data[0] < 224) {
107 /* Two-byte length */
108 (*size) = (data[0] - 192) * 256;
109 (*size) += 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 }
122 out:
123 return rc;
124 }
125
126 /**
127 * ecryptfs_write_packet_length
128 * @dest: The byte array target into which to write the length. Must
129 * have at least 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 */
136 int ecryptfs_write_packet_length(char *dest, size_t size,
137 size_t *packet_size_length)
138 {
139 int rc = 0;
140
141 if (size < 192) {
142 dest[0] = size;
143 (*packet_size_length) = 1;
144 } else if (size < 65536) {
145 dest[0] = (((size - 192) / 256) + 192);
146 dest[1] = ((size - 192) % 256);
147 (*packet_size_length) = 2;
148 } else {
149 /* 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
157 static int
158 write_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;
208 out:
209 return rc;
210 }
211
212 static int
213 parse_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 }
293 out:
294 return rc;
295 }
296
297
298 static int
299 write_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;
355 out:
356 return rc;
357 }
358
359 static int
360 parse_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);
421 out:
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 */
431 static 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 }
453 out:
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 if the payload is invalid; or
463 * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
464 */
465 static int
466 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
467 struct ecryptfs_auth_tok **auth_tok)
468 {
469 int rc = 0;
470
471 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
472 if (IS_ERR(*auth_tok)) {
473 rc = PTR_ERR(*auth_tok);
474 *auth_tok = NULL;
475 goto out;
476 }
477
478 if (ecryptfs_verify_version((*auth_tok)->version)) {
479 printk(KERN_ERR "Data structure version mismatch. Userspace "
480 "tools must match eCryptfs kernel module with major "
481 "version [%d] and minor version [%d]\n",
482 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
483 rc = -EINVAL;
484 goto out;
485 }
486 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
487 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
488 printk(KERN_ERR "Invalid auth_tok structure "
489 "returned from key query\n");
490 rc = -EINVAL;
491 goto out;
492 }
493 out:
494 return rc;
495 }
496
497 static int
498 ecryptfs_find_global_auth_tok_for_sig(
499 struct key **auth_tok_key,
500 struct ecryptfs_auth_tok **auth_tok,
501 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
502 {
503 struct ecryptfs_global_auth_tok *walker;
504 int rc = 0;
505
506 (*auth_tok_key) = NULL;
507 (*auth_tok) = NULL;
508 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
509 list_for_each_entry(walker,
510 &mount_crypt_stat->global_auth_tok_list,
511 mount_crypt_stat_list) {
512 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
513 continue;
514
515 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
516 rc = -EINVAL;
517 goto out;
518 }
519
520 rc = key_validate(walker->global_auth_tok_key);
521 if (rc) {
522 if (rc == -EKEYEXPIRED)
523 goto out;
524 goto out_invalid_auth_tok;
525 }
526
527 down_write(&(walker->global_auth_tok_key->sem));
528 rc = ecryptfs_verify_auth_tok_from_key(
529 walker->global_auth_tok_key, auth_tok);
530 if (rc)
531 goto out_invalid_auth_tok_unlock;
532
533 (*auth_tok_key) = walker->global_auth_tok_key;
534 key_get(*auth_tok_key);
535 goto out;
536 }
537 rc = -ENOENT;
538 goto out;
539 out_invalid_auth_tok_unlock:
540 up_write(&(walker->global_auth_tok_key->sem));
541 out_invalid_auth_tok:
542 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
543 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
544 key_put(walker->global_auth_tok_key);
545 walker->global_auth_tok_key = NULL;
546 out:
547 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
548 return rc;
549 }
550
551 /**
552 * ecryptfs_find_auth_tok_for_sig
553 * @auth_tok: Set to the matching auth_tok; NULL if not found
554 * @crypt_stat: inode crypt_stat crypto context
555 * @sig: Sig of auth_tok to find
556 *
557 * For now, this function simply looks at the registered auth_tok's
558 * linked off the mount_crypt_stat, so all the auth_toks that can be
559 * used must be registered at mount time. This function could
560 * potentially try a lot harder to find auth_tok's (e.g., by calling
561 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
562 * that static registration of auth_tok's will no longer be necessary.
563 *
564 * Returns zero on no error; non-zero on error
565 */
566 static int
567 ecryptfs_find_auth_tok_for_sig(
568 struct key **auth_tok_key,
569 struct ecryptfs_auth_tok **auth_tok,
570 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
571 char *sig)
572 {
573 int rc = 0;
574
575 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
576 mount_crypt_stat, sig);
577 if (rc == -ENOENT) {
578 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
579 * mount_crypt_stat structure, we prevent to use auth toks that
580 * are not inserted through the ecryptfs_add_global_auth_tok
581 * function.
582 */
583 if (mount_crypt_stat->flags
584 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
585 return -EINVAL;
586
587 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
588 sig);
589 }
590 return rc;
591 }
592
593 /**
594 * write_tag_70_packet can gobble a lot of stack space. We stuff most
595 * of the function's parameters in a kmalloc'd struct to help reduce
596 * eCryptfs' overall stack usage.
597 */
598 struct ecryptfs_write_tag_70_packet_silly_stack {
599 u8 cipher_code;
600 size_t max_packet_size;
601 size_t packet_size_len;
602 size_t block_aligned_filename_size;
603 size_t block_size;
604 size_t i;
605 size_t j;
606 size_t num_rand_bytes;
607 struct mutex *tfm_mutex;
608 char *block_aligned_filename;
609 struct ecryptfs_auth_tok *auth_tok;
610 struct scatterlist src_sg[2];
611 struct scatterlist dst_sg[2];
612 struct crypto_skcipher *skcipher_tfm;
613 struct skcipher_request *skcipher_req;
614 char iv[ECRYPTFS_MAX_IV_BYTES];
615 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
616 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
617 struct crypto_shash *hash_tfm;
618 struct shash_desc *hash_desc;
619 };
620
621 /**
622 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
623 * @filename: NULL-terminated filename string
624 *
625 * This is the simplest mechanism for achieving filename encryption in
626 * eCryptfs. It encrypts the given filename with the mount-wide
627 * filename encryption key (FNEK) and stores it in a packet to @dest,
628 * which the callee will encode and write directly into the dentry
629 * name.
630 */
631 int
632 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
633 size_t *packet_size,
634 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
635 char *filename, size_t filename_size)
636 {
637 struct ecryptfs_write_tag_70_packet_silly_stack *s;
638 struct key *auth_tok_key = NULL;
639 int rc = 0;
640
641 s = kzalloc(sizeof(*s), GFP_KERNEL);
642 if (!s) {
643 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
644 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
645 return -ENOMEM;
646 }
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->skcipher_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_skcipher_blocksize(s->skcipher_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
702 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
703 if (!s->skcipher_req) {
704 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
705 "skcipher_request_alloc for %s\n", __func__,
706 crypto_skcipher_driver_name(s->skcipher_tfm));
707 rc = -ENOMEM;
708 goto out_unlock;
709 }
710
711 skcipher_request_set_callback(s->skcipher_req,
712 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
713
714 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
715 GFP_KERNEL);
716 if (!s->block_aligned_filename) {
717 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
718 "kzalloc [%zd] bytes\n", __func__,
719 s->block_aligned_filename_size);
720 rc = -ENOMEM;
721 goto out_unlock;
722 }
723 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
724 rc = ecryptfs_write_packet_length(&dest[s->i],
725 (ECRYPTFS_SIG_SIZE
726 + 1 /* Cipher code */
727 + s->block_aligned_filename_size),
728 &s->packet_size_len);
729 if (rc) {
730 printk(KERN_ERR "%s: Error generating tag 70 packet "
731 "header; cannot generate packet length; rc = [%d]\n",
732 __func__, rc);
733 goto out_free_unlock;
734 }
735 s->i += s->packet_size_len;
736 ecryptfs_from_hex(&dest[s->i],
737 mount_crypt_stat->global_default_fnek_sig,
738 ECRYPTFS_SIG_SIZE);
739 s->i += ECRYPTFS_SIG_SIZE;
740 s->cipher_code = ecryptfs_code_for_cipher_string(
741 mount_crypt_stat->global_default_fn_cipher_name,
742 mount_crypt_stat->global_default_fn_cipher_key_bytes);
743 if (s->cipher_code == 0) {
744 printk(KERN_WARNING "%s: Unable to generate code for "
745 "cipher [%s] with key bytes [%zd]\n", __func__,
746 mount_crypt_stat->global_default_fn_cipher_name,
747 mount_crypt_stat->global_default_fn_cipher_key_bytes);
748 rc = -EINVAL;
749 goto out_free_unlock;
750 }
751 dest[s->i++] = s->cipher_code;
752 /* TODO: Support other key modules than passphrase for
753 * filename encryption */
754 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
755 rc = -EOPNOTSUPP;
756 printk(KERN_INFO "%s: Filename encryption only supports "
757 "password tokens\n", __func__);
758 goto out_free_unlock;
759 }
760 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
761 if (IS_ERR(s->hash_tfm)) {
762 rc = PTR_ERR(s->hash_tfm);
763 printk(KERN_ERR "%s: Error attempting to "
764 "allocate hash crypto context; rc = [%d]\n",
765 __func__, rc);
766 goto out_free_unlock;
767 }
768
769 s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
770 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
771 if (!s->hash_desc) {
772 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
773 "kmalloc [%zd] bytes\n", __func__,
774 sizeof(*s->hash_desc) +
775 crypto_shash_descsize(s->hash_tfm));
776 rc = -ENOMEM;
777 goto out_release_free_unlock;
778 }
779
780 s->hash_desc->tfm = s->hash_tfm;
781 s->hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
782
783 rc = crypto_shash_digest(s->hash_desc,
784 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
785 s->auth_tok->token.password.session_key_encryption_key_bytes,
786 s->hash);
787 if (rc) {
788 printk(KERN_ERR
789 "%s: Error computing crypto hash; rc = [%d]\n",
790 __func__, rc);
791 goto out_release_free_unlock;
792 }
793 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
794 s->block_aligned_filename[s->j] =
795 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
796 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
797 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
798 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
799 ECRYPTFS_TAG_70_DIGEST_SIZE,
800 s->tmp_hash);
801 if (rc) {
802 printk(KERN_ERR
803 "%s: Error computing crypto hash; "
804 "rc = [%d]\n", __func__, rc);
805 goto out_release_free_unlock;
806 }
807 memcpy(s->hash, s->tmp_hash,
808 ECRYPTFS_TAG_70_DIGEST_SIZE);
809 }
810 if (s->block_aligned_filename[s->j] == '\0')
811 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
812 }
813 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
814 filename_size);
815 rc = virt_to_scatterlist(s->block_aligned_filename,
816 s->block_aligned_filename_size, s->src_sg, 2);
817 if (rc < 1) {
818 printk(KERN_ERR "%s: Internal error whilst attempting to "
819 "convert filename memory to scatterlist; rc = [%d]. "
820 "block_aligned_filename_size = [%zd]\n", __func__, rc,
821 s->block_aligned_filename_size);
822 goto out_release_free_unlock;
823 }
824 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
825 s->dst_sg, 2);
826 if (rc < 1) {
827 printk(KERN_ERR "%s: Internal error whilst attempting to "
828 "convert encrypted filename memory to scatterlist; "
829 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
830 __func__, rc, s->block_aligned_filename_size);
831 goto out_release_free_unlock;
832 }
833 /* The characters in the first block effectively do the job
834 * of the IV here, so we just use 0's for the IV. Note the
835 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
836 * >= ECRYPTFS_MAX_IV_BYTES. */
837 rc = crypto_skcipher_setkey(
838 s->skcipher_tfm,
839 s->auth_tok->token.password.session_key_encryption_key,
840 mount_crypt_stat->global_default_fn_cipher_key_bytes);
841 if (rc < 0) {
842 printk(KERN_ERR "%s: Error setting key for crypto context; "
843 "rc = [%d]. s->auth_tok->token.password.session_key_"
844 "encryption_key = [0x%p]; mount_crypt_stat->"
845 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
846 rc,
847 s->auth_tok->token.password.session_key_encryption_key,
848 mount_crypt_stat->global_default_fn_cipher_key_bytes);
849 goto out_release_free_unlock;
850 }
851 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
852 s->block_aligned_filename_size, s->iv);
853 rc = crypto_skcipher_encrypt(s->skcipher_req);
854 if (rc) {
855 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
856 "rc = [%d]\n", __func__, rc);
857 goto out_release_free_unlock;
858 }
859 s->i += s->block_aligned_filename_size;
860 (*packet_size) = s->i;
861 (*remaining_bytes) -= (*packet_size);
862 out_release_free_unlock:
863 crypto_free_shash(s->hash_tfm);
864 out_free_unlock:
865 kzfree(s->block_aligned_filename);
866 out_unlock:
867 mutex_unlock(s->tfm_mutex);
868 out:
869 if (auth_tok_key) {
870 up_write(&(auth_tok_key->sem));
871 key_put(auth_tok_key);
872 }
873 skcipher_request_free(s->skcipher_req);
874 kzfree(s->hash_desc);
875 kfree(s);
876 return rc;
877 }
878
879 struct 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 crypto_skcipher *skcipher_tfm;
893 struct skcipher_request *skcipher_req;
894 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
895 char iv[ECRYPTFS_MAX_IV_BYTES];
896 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
897 };
898
899 /**
900 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
901 * @filename: This function kmalloc's the memory for the filename
902 * @filename_size: This function sets this to the amount of memory
903 * kmalloc'd for the filename
904 * @packet_size: This function sets this to the the number of octets
905 * in the packet parsed
906 * @mount_crypt_stat: The mount-wide cryptographic context
907 * @data: The memory location containing the start of the tag 70
908 * packet
909 * @max_packet_size: The maximum legal size of the packet to be parsed
910 * from @data
911 *
912 * Returns zero on success; non-zero otherwise
913 */
914 int
915 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
916 size_t *packet_size,
917 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
918 char *data, size_t max_packet_size)
919 {
920 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
921 struct key *auth_tok_key = NULL;
922 int rc = 0;
923
924 (*packet_size) = 0;
925 (*filename_size) = 0;
926 (*filename) = NULL;
927 s = kzalloc(sizeof(*s), GFP_KERNEL);
928 if (!s) {
929 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
930 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
931 return -ENOMEM;
932 }
933 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
934 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
935 "at least [%d]\n", __func__, max_packet_size,
936 ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
937 rc = -EINVAL;
938 goto out;
939 }
940 /* Octet 0: Tag 70 identifier
941 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
942 * and block-aligned encrypted filename size)
943 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
944 * Octet N2-N3: Cipher identifier (1 octet)
945 * Octets N3-N4: Block-aligned encrypted filename
946 * - Consists of a minimum number of random numbers, a \0
947 * separator, and then the filename */
948 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
949 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
950 "tag [0x%.2x]\n", __func__,
951 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
952 rc = -EINVAL;
953 goto out;
954 }
955 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
956 &s->parsed_tag_70_packet_size,
957 &s->packet_size_len);
958 if (rc) {
959 printk(KERN_WARNING "%s: Error parsing packet length; "
960 "rc = [%d]\n", __func__, rc);
961 goto out;
962 }
963 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
964 - ECRYPTFS_SIG_SIZE - 1);
965 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
966 > max_packet_size) {
967 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
968 "size is [%zd]\n", __func__, max_packet_size,
969 (1 + s->packet_size_len + 1
970 + s->block_aligned_filename_size));
971 rc = -EINVAL;
972 goto out;
973 }
974 (*packet_size) += s->packet_size_len;
975 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
976 ECRYPTFS_SIG_SIZE);
977 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
978 (*packet_size) += ECRYPTFS_SIG_SIZE;
979 s->cipher_code = data[(*packet_size)++];
980 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
981 if (rc) {
982 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
983 __func__, s->cipher_code);
984 goto out;
985 }
986 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
987 &s->auth_tok, mount_crypt_stat,
988 s->fnek_sig_hex);
989 if (rc) {
990 printk(KERN_ERR "%s: Error attempting to find auth tok for "
991 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
992 rc);
993 goto out;
994 }
995 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
996 &s->tfm_mutex,
997 s->cipher_string);
998 if (unlikely(rc)) {
999 printk(KERN_ERR "Internal error whilst attempting to get "
1000 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1001 s->cipher_string, rc);
1002 goto out;
1003 }
1004 mutex_lock(s->tfm_mutex);
1005 rc = virt_to_scatterlist(&data[(*packet_size)],
1006 s->block_aligned_filename_size, s->src_sg, 2);
1007 if (rc < 1) {
1008 printk(KERN_ERR "%s: Internal error whilst attempting to "
1009 "convert encrypted filename memory to scatterlist; "
1010 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1011 __func__, rc, s->block_aligned_filename_size);
1012 goto out_unlock;
1013 }
1014 (*packet_size) += s->block_aligned_filename_size;
1015 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1016 GFP_KERNEL);
1017 if (!s->decrypted_filename) {
1018 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1019 "kmalloc [%zd] bytes\n", __func__,
1020 s->block_aligned_filename_size);
1021 rc = -ENOMEM;
1022 goto out_unlock;
1023 }
1024 rc = virt_to_scatterlist(s->decrypted_filename,
1025 s->block_aligned_filename_size, s->dst_sg, 2);
1026 if (rc < 1) {
1027 printk(KERN_ERR "%s: Internal error whilst attempting to "
1028 "convert decrypted filename memory to scatterlist; "
1029 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1030 __func__, rc, s->block_aligned_filename_size);
1031 goto out_free_unlock;
1032 }
1033
1034 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
1035 if (!s->skcipher_req) {
1036 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1037 "skcipher_request_alloc for %s\n", __func__,
1038 crypto_skcipher_driver_name(s->skcipher_tfm));
1039 rc = -ENOMEM;
1040 goto out_free_unlock;
1041 }
1042
1043 skcipher_request_set_callback(s->skcipher_req,
1044 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
1045
1046 /* The characters in the first block effectively do the job of
1047 * the IV here, so we just use 0's for the IV. Note the
1048 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1049 * >= ECRYPTFS_MAX_IV_BYTES. */
1050 /* TODO: Support other key modules than passphrase for
1051 * filename encryption */
1052 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1053 rc = -EOPNOTSUPP;
1054 printk(KERN_INFO "%s: Filename encryption only supports "
1055 "password tokens\n", __func__);
1056 goto out_free_unlock;
1057 }
1058 rc = crypto_skcipher_setkey(
1059 s->skcipher_tfm,
1060 s->auth_tok->token.password.session_key_encryption_key,
1061 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1062 if (rc < 0) {
1063 printk(KERN_ERR "%s: Error setting key for crypto context; "
1064 "rc = [%d]. s->auth_tok->token.password.session_key_"
1065 "encryption_key = [0x%p]; mount_crypt_stat->"
1066 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1067 rc,
1068 s->auth_tok->token.password.session_key_encryption_key,
1069 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1070 goto out_free_unlock;
1071 }
1072 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
1073 s->block_aligned_filename_size, s->iv);
1074 rc = crypto_skcipher_decrypt(s->skcipher_req);
1075 if (rc) {
1076 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1077 "rc = [%d]\n", __func__, rc);
1078 goto out_free_unlock;
1079 }
1080 while (s->decrypted_filename[s->i] != '\0'
1081 && s->i < s->block_aligned_filename_size)
1082 s->i++;
1083 if (s->i == s->block_aligned_filename_size) {
1084 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1085 "find valid separator between random characters and "
1086 "the filename\n", __func__);
1087 rc = -EINVAL;
1088 goto out_free_unlock;
1089 }
1090 s->i++;
1091 (*filename_size) = (s->block_aligned_filename_size - s->i);
1092 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1093 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1094 "invalid\n", __func__, (*filename_size));
1095 rc = -EINVAL;
1096 goto out_free_unlock;
1097 }
1098 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1099 if (!(*filename)) {
1100 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1101 "kmalloc [%zd] bytes\n", __func__,
1102 ((*filename_size) + 1));
1103 rc = -ENOMEM;
1104 goto out_free_unlock;
1105 }
1106 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1107 (*filename)[(*filename_size)] = '\0';
1108 out_free_unlock:
1109 kfree(s->decrypted_filename);
1110 out_unlock:
1111 mutex_unlock(s->tfm_mutex);
1112 out:
1113 if (rc) {
1114 (*packet_size) = 0;
1115 (*filename_size) = 0;
1116 (*filename) = NULL;
1117 }
1118 if (auth_tok_key) {
1119 up_write(&(auth_tok_key->sem));
1120 key_put(auth_tok_key);
1121 }
1122 skcipher_request_free(s->skcipher_req);
1123 kfree(s);
1124 return rc;
1125 }
1126
1127 static int
1128 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1129 {
1130 int rc = 0;
1131
1132 (*sig) = NULL;
1133 switch (auth_tok->token_type) {
1134 case ECRYPTFS_PASSWORD:
1135 (*sig) = auth_tok->token.password.signature;
1136 break;
1137 case ECRYPTFS_PRIVATE_KEY:
1138 (*sig) = auth_tok->token.private_key.signature;
1139 break;
1140 default:
1141 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1142 auth_tok->token_type);
1143 rc = -EINVAL;
1144 }
1145 return rc;
1146 }
1147
1148 /**
1149 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1150 * @auth_tok: The key authentication token used to decrypt the session key
1151 * @crypt_stat: The cryptographic context
1152 *
1153 * Returns zero on success; non-zero error otherwise.
1154 */
1155 static int
1156 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1157 struct ecryptfs_crypt_stat *crypt_stat)
1158 {
1159 u8 cipher_code = 0;
1160 struct ecryptfs_msg_ctx *msg_ctx;
1161 struct ecryptfs_message *msg = NULL;
1162 char *auth_tok_sig;
1163 char *payload = NULL;
1164 size_t payload_len = 0;
1165 int rc;
1166
1167 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1168 if (rc) {
1169 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1170 auth_tok->token_type);
1171 goto out;
1172 }
1173 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1174 &payload, &payload_len);
1175 if (rc) {
1176 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1177 goto out;
1178 }
1179 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1180 if (rc) {
1181 ecryptfs_printk(KERN_ERR, "Error sending message to "
1182 "ecryptfsd: %d\n", rc);
1183 goto out;
1184 }
1185 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1186 if (rc) {
1187 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1188 "from the user space daemon\n");
1189 rc = -EIO;
1190 goto out;
1191 }
1192 rc = parse_tag_65_packet(&(auth_tok->session_key),
1193 &cipher_code, msg);
1194 if (rc) {
1195 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1196 rc);
1197 goto out;
1198 }
1199 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1200 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1201 auth_tok->session_key.decrypted_key_size);
1202 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1203 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1204 if (rc) {
1205 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1206 cipher_code)
1207 goto out;
1208 }
1209 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1210 if (ecryptfs_verbosity > 0) {
1211 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1212 ecryptfs_dump_hex(crypt_stat->key,
1213 crypt_stat->key_size);
1214 }
1215 out:
1216 kfree(msg);
1217 kfree(payload);
1218 return rc;
1219 }
1220
1221 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1222 {
1223 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1224 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1225
1226 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1227 auth_tok_list_head, list) {
1228 list_del(&auth_tok_list_item->list);
1229 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1230 auth_tok_list_item);
1231 }
1232 }
1233
1234 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1235
1236 /**
1237 * parse_tag_1_packet
1238 * @crypt_stat: The cryptographic context to modify based on packet contents
1239 * @data: The raw bytes of the packet.
1240 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1241 * a new authentication token will be placed at the
1242 * end of this list for this packet.
1243 * @new_auth_tok: Pointer to a pointer to memory that this function
1244 * allocates; sets the memory address of the pointer to
1245 * NULL on error. This object is added to the
1246 * auth_tok_list.
1247 * @packet_size: This function writes the size of the parsed packet
1248 * into this memory location; zero on error.
1249 * @max_packet_size: The maximum allowable packet size
1250 *
1251 * Returns zero on success; non-zero on error.
1252 */
1253 static int
1254 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1255 unsigned char *data, struct list_head *auth_tok_list,
1256 struct ecryptfs_auth_tok **new_auth_tok,
1257 size_t *packet_size, size_t max_packet_size)
1258 {
1259 size_t body_size;
1260 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1261 size_t length_size;
1262 int rc = 0;
1263
1264 (*packet_size) = 0;
1265 (*new_auth_tok) = NULL;
1266 /**
1267 * This format is inspired by OpenPGP; see RFC 2440
1268 * packet tag 1
1269 *
1270 * Tag 1 identifier (1 byte)
1271 * Max Tag 1 packet size (max 3 bytes)
1272 * Version (1 byte)
1273 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1274 * Cipher identifier (1 byte)
1275 * Encrypted key size (arbitrary)
1276 *
1277 * 12 bytes minimum packet size
1278 */
1279 if (unlikely(max_packet_size < 12)) {
1280 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1281 rc = -EINVAL;
1282 goto out;
1283 }
1284 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1285 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1286 ECRYPTFS_TAG_1_PACKET_TYPE);
1287 rc = -EINVAL;
1288 goto out;
1289 }
1290 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1291 * at end of function upon failure */
1292 auth_tok_list_item =
1293 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1294 GFP_KERNEL);
1295 if (!auth_tok_list_item) {
1296 printk(KERN_ERR "Unable to allocate memory\n");
1297 rc = -ENOMEM;
1298 goto out;
1299 }
1300 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1301 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1302 &length_size);
1303 if (rc) {
1304 printk(KERN_WARNING "Error parsing packet length; "
1305 "rc = [%d]\n", rc);
1306 goto out_free;
1307 }
1308 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1309 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1310 rc = -EINVAL;
1311 goto out_free;
1312 }
1313 (*packet_size) += length_size;
1314 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1315 printk(KERN_WARNING "Packet size exceeds max\n");
1316 rc = -EINVAL;
1317 goto out_free;
1318 }
1319 if (unlikely(data[(*packet_size)++] != 0x03)) {
1320 printk(KERN_WARNING "Unknown version number [%d]\n",
1321 data[(*packet_size) - 1]);
1322 rc = -EINVAL;
1323 goto out_free;
1324 }
1325 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1326 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1327 *packet_size += ECRYPTFS_SIG_SIZE;
1328 /* This byte is skipped because the kernel does not need to
1329 * know which public key encryption algorithm was used */
1330 (*packet_size)++;
1331 (*new_auth_tok)->session_key.encrypted_key_size =
1332 body_size - (ECRYPTFS_SIG_SIZE + 2);
1333 if ((*new_auth_tok)->session_key.encrypted_key_size
1334 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1335 printk(KERN_WARNING "Tag 1 packet contains key larger "
1336 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1337 rc = -EINVAL;
1338 goto out_free;
1339 }
1340 memcpy((*new_auth_tok)->session_key.encrypted_key,
1341 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1342 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1343 (*new_auth_tok)->session_key.flags &=
1344 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1345 (*new_auth_tok)->session_key.flags |=
1346 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1347 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1348 (*new_auth_tok)->flags = 0;
1349 (*new_auth_tok)->session_key.flags &=
1350 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1351 (*new_auth_tok)->session_key.flags &=
1352 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1353 list_add(&auth_tok_list_item->list, auth_tok_list);
1354 goto out;
1355 out_free:
1356 (*new_auth_tok) = NULL;
1357 memset(auth_tok_list_item, 0,
1358 sizeof(struct ecryptfs_auth_tok_list_item));
1359 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1360 auth_tok_list_item);
1361 out:
1362 if (rc)
1363 (*packet_size) = 0;
1364 return rc;
1365 }
1366
1367 /**
1368 * parse_tag_3_packet
1369 * @crypt_stat: The cryptographic context to modify based on packet
1370 * contents.
1371 * @data: The raw bytes of the packet.
1372 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1373 * a new authentication token will be placed at the end
1374 * of this list for this packet.
1375 * @new_auth_tok: Pointer to a pointer to memory that this function
1376 * allocates; sets the memory address of the pointer to
1377 * NULL on error. This object is added to the
1378 * auth_tok_list.
1379 * @packet_size: This function writes the size of the parsed packet
1380 * into this memory location; zero on error.
1381 * @max_packet_size: maximum number of bytes to parse
1382 *
1383 * Returns zero on success; non-zero on error.
1384 */
1385 static int
1386 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1387 unsigned char *data, struct list_head *auth_tok_list,
1388 struct ecryptfs_auth_tok **new_auth_tok,
1389 size_t *packet_size, size_t max_packet_size)
1390 {
1391 size_t body_size;
1392 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1393 size_t length_size;
1394 int rc = 0;
1395
1396 (*packet_size) = 0;
1397 (*new_auth_tok) = NULL;
1398 /**
1399 *This format is inspired by OpenPGP; see RFC 2440
1400 * packet tag 3
1401 *
1402 * Tag 3 identifier (1 byte)
1403 * Max Tag 3 packet size (max 3 bytes)
1404 * Version (1 byte)
1405 * Cipher code (1 byte)
1406 * S2K specifier (1 byte)
1407 * Hash identifier (1 byte)
1408 * Salt (ECRYPTFS_SALT_SIZE)
1409 * Hash iterations (1 byte)
1410 * Encrypted key (arbitrary)
1411 *
1412 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1413 */
1414 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1415 printk(KERN_ERR "Max packet size too large\n");
1416 rc = -EINVAL;
1417 goto out;
1418 }
1419 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1420 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1421 ECRYPTFS_TAG_3_PACKET_TYPE);
1422 rc = -EINVAL;
1423 goto out;
1424 }
1425 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1426 * at end of function upon failure */
1427 auth_tok_list_item =
1428 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1429 if (!auth_tok_list_item) {
1430 printk(KERN_ERR "Unable to allocate memory\n");
1431 rc = -ENOMEM;
1432 goto out;
1433 }
1434 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1435 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1436 &length_size);
1437 if (rc) {
1438 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1439 rc);
1440 goto out_free;
1441 }
1442 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1443 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1444 rc = -EINVAL;
1445 goto out_free;
1446 }
1447 (*packet_size) += length_size;
1448 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1449 printk(KERN_ERR "Packet size exceeds max\n");
1450 rc = -EINVAL;
1451 goto out_free;
1452 }
1453 (*new_auth_tok)->session_key.encrypted_key_size =
1454 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1455 if ((*new_auth_tok)->session_key.encrypted_key_size
1456 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1457 printk(KERN_WARNING "Tag 3 packet contains key larger "
1458 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1459 rc = -EINVAL;
1460 goto out_free;
1461 }
1462 if (unlikely(data[(*packet_size)++] != 0x04)) {
1463 printk(KERN_WARNING "Unknown version number [%d]\n",
1464 data[(*packet_size) - 1]);
1465 rc = -EINVAL;
1466 goto out_free;
1467 }
1468 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1469 (u16)data[(*packet_size)]);
1470 if (rc)
1471 goto out_free;
1472 /* A little extra work to differentiate among the AES key
1473 * sizes; see RFC2440 */
1474 switch(data[(*packet_size)++]) {
1475 case RFC2440_CIPHER_AES_192:
1476 crypt_stat->key_size = 24;
1477 break;
1478 default:
1479 crypt_stat->key_size =
1480 (*new_auth_tok)->session_key.encrypted_key_size;
1481 }
1482 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1483 if (rc)
1484 goto out_free;
1485 if (unlikely(data[(*packet_size)++] != 0x03)) {
1486 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1487 rc = -ENOSYS;
1488 goto out_free;
1489 }
1490 /* TODO: finish the hash mapping */
1491 switch (data[(*packet_size)++]) {
1492 case 0x01: /* See RFC2440 for these numbers and their mappings */
1493 /* Choose MD5 */
1494 memcpy((*new_auth_tok)->token.password.salt,
1495 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1496 (*packet_size) += ECRYPTFS_SALT_SIZE;
1497 /* This conversion was taken straight from RFC2440 */
1498 (*new_auth_tok)->token.password.hash_iterations =
1499 ((u32) 16 + (data[(*packet_size)] & 15))
1500 << ((data[(*packet_size)] >> 4) + 6);
1501 (*packet_size)++;
1502 /* Friendly reminder:
1503 * (*new_auth_tok)->session_key.encrypted_key_size =
1504 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1505 memcpy((*new_auth_tok)->session_key.encrypted_key,
1506 &data[(*packet_size)],
1507 (*new_auth_tok)->session_key.encrypted_key_size);
1508 (*packet_size) +=
1509 (*new_auth_tok)->session_key.encrypted_key_size;
1510 (*new_auth_tok)->session_key.flags &=
1511 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1512 (*new_auth_tok)->session_key.flags |=
1513 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1514 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1515 break;
1516 default:
1517 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1518 "[%d]\n", data[(*packet_size) - 1]);
1519 rc = -ENOSYS;
1520 goto out_free;
1521 }
1522 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1523 /* TODO: Parametarize; we might actually want userspace to
1524 * decrypt the session key. */
1525 (*new_auth_tok)->session_key.flags &=
1526 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1527 (*new_auth_tok)->session_key.flags &=
1528 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1529 list_add(&auth_tok_list_item->list, auth_tok_list);
1530 goto out;
1531 out_free:
1532 (*new_auth_tok) = NULL;
1533 memset(auth_tok_list_item, 0,
1534 sizeof(struct ecryptfs_auth_tok_list_item));
1535 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1536 auth_tok_list_item);
1537 out:
1538 if (rc)
1539 (*packet_size) = 0;
1540 return rc;
1541 }
1542
1543 /**
1544 * parse_tag_11_packet
1545 * @data: The raw bytes of the packet
1546 * @contents: This function writes the data contents of the literal
1547 * packet into this memory location
1548 * @max_contents_bytes: The maximum number of bytes that this function
1549 * is allowed to write into contents
1550 * @tag_11_contents_size: This function writes the size of the parsed
1551 * contents into this memory location; zero on
1552 * error
1553 * @packet_size: This function writes the size of the parsed packet
1554 * into this memory location; zero on error
1555 * @max_packet_size: maximum number of bytes to parse
1556 *
1557 * Returns zero on success; non-zero on error.
1558 */
1559 static int
1560 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1561 size_t max_contents_bytes, size_t *tag_11_contents_size,
1562 size_t *packet_size, size_t max_packet_size)
1563 {
1564 size_t body_size;
1565 size_t length_size;
1566 int rc = 0;
1567
1568 (*packet_size) = 0;
1569 (*tag_11_contents_size) = 0;
1570 /* This format is inspired by OpenPGP; see RFC 2440
1571 * packet tag 11
1572 *
1573 * Tag 11 identifier (1 byte)
1574 * Max Tag 11 packet size (max 3 bytes)
1575 * Binary format specifier (1 byte)
1576 * Filename length (1 byte)
1577 * Filename ("_CONSOLE") (8 bytes)
1578 * Modification date (4 bytes)
1579 * Literal data (arbitrary)
1580 *
1581 * We need at least 16 bytes of data for the packet to even be
1582 * valid.
1583 */
1584 if (max_packet_size < 16) {
1585 printk(KERN_ERR "Maximum packet size too small\n");
1586 rc = -EINVAL;
1587 goto out;
1588 }
1589 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1590 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1591 rc = -EINVAL;
1592 goto out;
1593 }
1594 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1595 &length_size);
1596 if (rc) {
1597 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1598 goto out;
1599 }
1600 if (body_size < 14) {
1601 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1602 rc = -EINVAL;
1603 goto out;
1604 }
1605 (*packet_size) += length_size;
1606 (*tag_11_contents_size) = (body_size - 14);
1607 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1608 printk(KERN_ERR "Packet size exceeds max\n");
1609 rc = -EINVAL;
1610 goto out;
1611 }
1612 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1613 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1614 "expected size\n");
1615 rc = -EINVAL;
1616 goto out;
1617 }
1618 if (data[(*packet_size)++] != 0x62) {
1619 printk(KERN_WARNING "Unrecognizable packet\n");
1620 rc = -EINVAL;
1621 goto out;
1622 }
1623 if (data[(*packet_size)++] != 0x08) {
1624 printk(KERN_WARNING "Unrecognizable packet\n");
1625 rc = -EINVAL;
1626 goto out;
1627 }
1628 (*packet_size) += 12; /* Ignore filename and modification date */
1629 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1630 (*packet_size) += (*tag_11_contents_size);
1631 out:
1632 if (rc) {
1633 (*packet_size) = 0;
1634 (*tag_11_contents_size) = 0;
1635 }
1636 return rc;
1637 }
1638
1639 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1640 struct ecryptfs_auth_tok **auth_tok,
1641 char *sig)
1642 {
1643 int rc = 0;
1644
1645 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1646 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1647 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1648 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1649 printk(KERN_ERR "Could not find key with description: [%s]\n",
1650 sig);
1651 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1652 (*auth_tok_key) = NULL;
1653 goto out;
1654 }
1655 }
1656 down_write(&(*auth_tok_key)->sem);
1657 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1658 if (rc) {
1659 up_write(&(*auth_tok_key)->sem);
1660 key_put(*auth_tok_key);
1661 (*auth_tok_key) = NULL;
1662 goto out;
1663 }
1664 out:
1665 return rc;
1666 }
1667
1668 /**
1669 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1670 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1671 * @crypt_stat: The cryptographic context
1672 *
1673 * Returns zero on success; non-zero error otherwise
1674 */
1675 static int
1676 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1677 struct ecryptfs_crypt_stat *crypt_stat)
1678 {
1679 struct scatterlist dst_sg[2];
1680 struct scatterlist src_sg[2];
1681 struct mutex *tfm_mutex;
1682 struct crypto_skcipher *tfm;
1683 struct skcipher_request *req = NULL;
1684 int rc = 0;
1685
1686 if (unlikely(ecryptfs_verbosity > 0)) {
1687 ecryptfs_printk(
1688 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1689 auth_tok->token.password.session_key_encryption_key_bytes);
1690 ecryptfs_dump_hex(
1691 auth_tok->token.password.session_key_encryption_key,
1692 auth_tok->token.password.session_key_encryption_key_bytes);
1693 }
1694 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
1695 crypt_stat->cipher);
1696 if (unlikely(rc)) {
1697 printk(KERN_ERR "Internal error whilst attempting to get "
1698 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1699 crypt_stat->cipher, rc);
1700 goto out;
1701 }
1702 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1703 auth_tok->session_key.encrypted_key_size,
1704 src_sg, 2);
1705 if (rc < 1 || rc > 2) {
1706 printk(KERN_ERR "Internal error whilst attempting to convert "
1707 "auth_tok->session_key.encrypted_key to scatterlist; "
1708 "expected rc = 1; got rc = [%d]. "
1709 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1710 auth_tok->session_key.encrypted_key_size);
1711 goto out;
1712 }
1713 auth_tok->session_key.decrypted_key_size =
1714 auth_tok->session_key.encrypted_key_size;
1715 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1716 auth_tok->session_key.decrypted_key_size,
1717 dst_sg, 2);
1718 if (rc < 1 || rc > 2) {
1719 printk(KERN_ERR "Internal error whilst attempting to convert "
1720 "auth_tok->session_key.decrypted_key to scatterlist; "
1721 "expected rc = 1; got rc = [%d]\n", rc);
1722 goto out;
1723 }
1724 mutex_lock(tfm_mutex);
1725 req = skcipher_request_alloc(tfm, GFP_KERNEL);
1726 if (!req) {
1727 mutex_unlock(tfm_mutex);
1728 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1729 "skcipher_request_alloc for %s\n", __func__,
1730 crypto_skcipher_driver_name(tfm));
1731 rc = -ENOMEM;
1732 goto out;
1733 }
1734
1735 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
1736 NULL, NULL);
1737 rc = crypto_skcipher_setkey(
1738 tfm, auth_tok->token.password.session_key_encryption_key,
1739 crypt_stat->key_size);
1740 if (unlikely(rc < 0)) {
1741 mutex_unlock(tfm_mutex);
1742 printk(KERN_ERR "Error setting key for crypto context\n");
1743 rc = -EINVAL;
1744 goto out;
1745 }
1746 skcipher_request_set_crypt(req, src_sg, dst_sg,
1747 auth_tok->session_key.encrypted_key_size,
1748 NULL);
1749 rc = crypto_skcipher_decrypt(req);
1750 mutex_unlock(tfm_mutex);
1751 if (unlikely(rc)) {
1752 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1753 goto out;
1754 }
1755 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1756 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1757 auth_tok->session_key.decrypted_key_size);
1758 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1759 if (unlikely(ecryptfs_verbosity > 0)) {
1760 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1761 crypt_stat->key_size);
1762 ecryptfs_dump_hex(crypt_stat->key,
1763 crypt_stat->key_size);
1764 }
1765 out:
1766 skcipher_request_free(req);
1767 return rc;
1768 }
1769
1770 /**
1771 * ecryptfs_parse_packet_set
1772 * @crypt_stat: The cryptographic context
1773 * @src: Virtual address of region of memory containing the packets
1774 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1775 *
1776 * Get crypt_stat to have the file's session key if the requisite key
1777 * is available to decrypt the session key.
1778 *
1779 * Returns Zero if a valid authentication token was retrieved and
1780 * processed; negative value for file not encrypted or for error
1781 * conditions.
1782 */
1783 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1784 unsigned char *src,
1785 struct dentry *ecryptfs_dentry)
1786 {
1787 size_t i = 0;
1788 size_t found_auth_tok;
1789 size_t next_packet_is_auth_tok_packet;
1790 struct list_head auth_tok_list;
1791 struct ecryptfs_auth_tok *matching_auth_tok;
1792 struct ecryptfs_auth_tok *candidate_auth_tok;
1793 char *candidate_auth_tok_sig;
1794 size_t packet_size;
1795 struct ecryptfs_auth_tok *new_auth_tok;
1796 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1797 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1798 size_t tag_11_contents_size;
1799 size_t tag_11_packet_size;
1800 struct key *auth_tok_key = NULL;
1801 int rc = 0;
1802
1803 INIT_LIST_HEAD(&auth_tok_list);
1804 /* Parse the header to find as many packets as we can; these will be
1805 * added the our &auth_tok_list */
1806 next_packet_is_auth_tok_packet = 1;
1807 while (next_packet_is_auth_tok_packet) {
1808 size_t max_packet_size = ((PAGE_SIZE - 8) - i);
1809
1810 switch (src[i]) {
1811 case ECRYPTFS_TAG_3_PACKET_TYPE:
1812 rc = parse_tag_3_packet(crypt_stat,
1813 (unsigned char *)&src[i],
1814 &auth_tok_list, &new_auth_tok,
1815 &packet_size, max_packet_size);
1816 if (rc) {
1817 ecryptfs_printk(KERN_ERR, "Error parsing "
1818 "tag 3 packet\n");
1819 rc = -EIO;
1820 goto out_wipe_list;
1821 }
1822 i += packet_size;
1823 rc = parse_tag_11_packet((unsigned char *)&src[i],
1824 sig_tmp_space,
1825 ECRYPTFS_SIG_SIZE,
1826 &tag_11_contents_size,
1827 &tag_11_packet_size,
1828 max_packet_size);
1829 if (rc) {
1830 ecryptfs_printk(KERN_ERR, "No valid "
1831 "(ecryptfs-specific) literal "
1832 "packet containing "
1833 "authentication token "
1834 "signature found after "
1835 "tag 3 packet\n");
1836 rc = -EIO;
1837 goto out_wipe_list;
1838 }
1839 i += tag_11_packet_size;
1840 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1841 ecryptfs_printk(KERN_ERR, "Expected "
1842 "signature of size [%d]; "
1843 "read size [%zd]\n",
1844 ECRYPTFS_SIG_SIZE,
1845 tag_11_contents_size);
1846 rc = -EIO;
1847 goto out_wipe_list;
1848 }
1849 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1850 sig_tmp_space, tag_11_contents_size);
1851 new_auth_tok->token.password.signature[
1852 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1853 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1854 break;
1855 case ECRYPTFS_TAG_1_PACKET_TYPE:
1856 rc = parse_tag_1_packet(crypt_stat,
1857 (unsigned char *)&src[i],
1858 &auth_tok_list, &new_auth_tok,
1859 &packet_size, max_packet_size);
1860 if (rc) {
1861 ecryptfs_printk(KERN_ERR, "Error parsing "
1862 "tag 1 packet\n");
1863 rc = -EIO;
1864 goto out_wipe_list;
1865 }
1866 i += packet_size;
1867 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1868 break;
1869 case ECRYPTFS_TAG_11_PACKET_TYPE:
1870 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1871 "(Tag 11 not allowed by itself)\n");
1872 rc = -EIO;
1873 goto out_wipe_list;
1874 default:
1875 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1876 "of the file header; hex value of "
1877 "character is [0x%.2x]\n", i, src[i]);
1878 next_packet_is_auth_tok_packet = 0;
1879 }
1880 }
1881 if (list_empty(&auth_tok_list)) {
1882 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1883 "eCryptfs file; this is not supported in this version "
1884 "of the eCryptfs kernel module\n");
1885 rc = -EINVAL;
1886 goto out;
1887 }
1888 /* auth_tok_list contains the set of authentication tokens
1889 * parsed from the metadata. We need to find a matching
1890 * authentication token that has the secret component(s)
1891 * necessary to decrypt the EFEK in the auth_tok parsed from
1892 * the metadata. There may be several potential matches, but
1893 * just one will be sufficient to decrypt to get the FEK. */
1894 find_next_matching_auth_tok:
1895 found_auth_tok = 0;
1896 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1897 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1898 if (unlikely(ecryptfs_verbosity > 0)) {
1899 ecryptfs_printk(KERN_DEBUG,
1900 "Considering cadidate auth tok:\n");
1901 ecryptfs_dump_auth_tok(candidate_auth_tok);
1902 }
1903 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1904 candidate_auth_tok);
1905 if (rc) {
1906 printk(KERN_ERR
1907 "Unrecognized candidate auth tok type: [%d]\n",
1908 candidate_auth_tok->token_type);
1909 rc = -EINVAL;
1910 goto out_wipe_list;
1911 }
1912 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1913 &matching_auth_tok,
1914 crypt_stat->mount_crypt_stat,
1915 candidate_auth_tok_sig);
1916 if (!rc) {
1917 found_auth_tok = 1;
1918 goto found_matching_auth_tok;
1919 }
1920 }
1921 if (!found_auth_tok) {
1922 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1923 "authentication token\n");
1924 rc = -EIO;
1925 goto out_wipe_list;
1926 }
1927 found_matching_auth_tok:
1928 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1929 memcpy(&(candidate_auth_tok->token.private_key),
1930 &(matching_auth_tok->token.private_key),
1931 sizeof(struct ecryptfs_private_key));
1932 up_write(&(auth_tok_key->sem));
1933 key_put(auth_tok_key);
1934 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1935 crypt_stat);
1936 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1937 memcpy(&(candidate_auth_tok->token.password),
1938 &(matching_auth_tok->token.password),
1939 sizeof(struct ecryptfs_password));
1940 up_write(&(auth_tok_key->sem));
1941 key_put(auth_tok_key);
1942 rc = decrypt_passphrase_encrypted_session_key(
1943 candidate_auth_tok, crypt_stat);
1944 } else {
1945 up_write(&(auth_tok_key->sem));
1946 key_put(auth_tok_key);
1947 rc = -EINVAL;
1948 }
1949 if (rc) {
1950 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1951
1952 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1953 "session key for authentication token with sig "
1954 "[%.*s]; rc = [%d]. Removing auth tok "
1955 "candidate from the list and searching for "
1956 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1957 candidate_auth_tok_sig, rc);
1958 list_for_each_entry_safe(auth_tok_list_item,
1959 auth_tok_list_item_tmp,
1960 &auth_tok_list, list) {
1961 if (candidate_auth_tok
1962 == &auth_tok_list_item->auth_tok) {
1963 list_del(&auth_tok_list_item->list);
1964 kmem_cache_free(
1965 ecryptfs_auth_tok_list_item_cache,
1966 auth_tok_list_item);
1967 goto find_next_matching_auth_tok;
1968 }
1969 }
1970 BUG();
1971 }
1972 rc = ecryptfs_compute_root_iv(crypt_stat);
1973 if (rc) {
1974 ecryptfs_printk(KERN_ERR, "Error computing "
1975 "the root IV\n");
1976 goto out_wipe_list;
1977 }
1978 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1979 if (rc) {
1980 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1981 "context for cipher [%s]; rc = [%d]\n",
1982 crypt_stat->cipher, rc);
1983 }
1984 out_wipe_list:
1985 wipe_auth_tok_list(&auth_tok_list);
1986 out:
1987 return rc;
1988 }
1989
1990 static int
1991 pki_encrypt_session_key(struct key *auth_tok_key,
1992 struct ecryptfs_auth_tok *auth_tok,
1993 struct ecryptfs_crypt_stat *crypt_stat,
1994 struct ecryptfs_key_record *key_rec)
1995 {
1996 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1997 char *payload = NULL;
1998 size_t payload_len = 0;
1999 struct ecryptfs_message *msg;
2000 int rc;
2001
2002 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
2003 ecryptfs_code_for_cipher_string(
2004 crypt_stat->cipher,
2005 crypt_stat->key_size),
2006 crypt_stat, &payload, &payload_len);
2007 up_write(&(auth_tok_key->sem));
2008 key_put(auth_tok_key);
2009 if (rc) {
2010 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
2011 goto out;
2012 }
2013 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
2014 if (rc) {
2015 ecryptfs_printk(KERN_ERR, "Error sending message to "
2016 "ecryptfsd: %d\n", rc);
2017 goto out;
2018 }
2019 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
2020 if (rc) {
2021 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2022 "from the user space daemon\n");
2023 rc = -EIO;
2024 goto out;
2025 }
2026 rc = parse_tag_67_packet(key_rec, msg);
2027 if (rc)
2028 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2029 kfree(msg);
2030 out:
2031 kfree(payload);
2032 return rc;
2033 }
2034 /**
2035 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2036 * @dest: Buffer into which to write the packet
2037 * @remaining_bytes: Maximum number of bytes that can be writtn
2038 * @auth_tok_key: The authentication token key to unlock and put when done with
2039 * @auth_tok
2040 * @auth_tok: The authentication token used for generating the tag 1 packet
2041 * @crypt_stat: The cryptographic context
2042 * @key_rec: The key record struct for the tag 1 packet
2043 * @packet_size: This function will write the number of bytes that end
2044 * up constituting the packet; set to zero on error
2045 *
2046 * Returns zero on success; non-zero on error.
2047 */
2048 static int
2049 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2050 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2051 struct ecryptfs_crypt_stat *crypt_stat,
2052 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2053 {
2054 size_t i;
2055 size_t encrypted_session_key_valid = 0;
2056 size_t packet_size_length;
2057 size_t max_packet_size;
2058 int rc = 0;
2059
2060 (*packet_size) = 0;
2061 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2062 ECRYPTFS_SIG_SIZE);
2063 encrypted_session_key_valid = 0;
2064 for (i = 0; i < crypt_stat->key_size; i++)
2065 encrypted_session_key_valid |=
2066 auth_tok->session_key.encrypted_key[i];
2067 if (encrypted_session_key_valid) {
2068 memcpy(key_rec->enc_key,
2069 auth_tok->session_key.encrypted_key,
2070 auth_tok->session_key.encrypted_key_size);
2071 up_write(&(auth_tok_key->sem));
2072 key_put(auth_tok_key);
2073 goto encrypted_session_key_set;
2074 }
2075 if (auth_tok->session_key.encrypted_key_size == 0)
2076 auth_tok->session_key.encrypted_key_size =
2077 auth_tok->token.private_key.key_size;
2078 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2079 key_rec);
2080 if (rc) {
2081 printk(KERN_ERR "Failed to encrypt session key via a key "
2082 "module; rc = [%d]\n", rc);
2083 goto out;
2084 }
2085 if (ecryptfs_verbosity > 0) {
2086 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2087 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2088 }
2089 encrypted_session_key_set:
2090 /* This format is inspired by OpenPGP; see RFC 2440
2091 * packet tag 1 */
2092 max_packet_size = (1 /* Tag 1 identifier */
2093 + 3 /* Max Tag 1 packet size */
2094 + 1 /* Version */
2095 + ECRYPTFS_SIG_SIZE /* Key identifier */
2096 + 1 /* Cipher identifier */
2097 + key_rec->enc_key_size); /* Encrypted key size */
2098 if (max_packet_size > (*remaining_bytes)) {
2099 printk(KERN_ERR "Packet length larger than maximum allowable; "
2100 "need up to [%td] bytes, but there are only [%td] "
2101 "available\n", max_packet_size, (*remaining_bytes));
2102 rc = -EINVAL;
2103 goto out;
2104 }
2105 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2106 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2107 (max_packet_size - 4),
2108 &packet_size_length);
2109 if (rc) {
2110 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2111 "header; cannot generate packet length\n");
2112 goto out;
2113 }
2114 (*packet_size) += packet_size_length;
2115 dest[(*packet_size)++] = 0x03; /* version 3 */
2116 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2117 (*packet_size) += ECRYPTFS_SIG_SIZE;
2118 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2119 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2120 key_rec->enc_key_size);
2121 (*packet_size) += key_rec->enc_key_size;
2122 out:
2123 if (rc)
2124 (*packet_size) = 0;
2125 else
2126 (*remaining_bytes) -= (*packet_size);
2127 return rc;
2128 }
2129
2130 /**
2131 * write_tag_11_packet
2132 * @dest: Target into which Tag 11 packet is to be written
2133 * @remaining_bytes: Maximum packet length
2134 * @contents: Byte array of contents to copy in
2135 * @contents_length: Number of bytes in contents
2136 * @packet_length: Length of the Tag 11 packet written; zero on error
2137 *
2138 * Returns zero on success; non-zero on error.
2139 */
2140 static int
2141 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2142 size_t contents_length, size_t *packet_length)
2143 {
2144 size_t packet_size_length;
2145 size_t max_packet_size;
2146 int rc = 0;
2147
2148 (*packet_length) = 0;
2149 /* This format is inspired by OpenPGP; see RFC 2440
2150 * packet tag 11 */
2151 max_packet_size = (1 /* Tag 11 identifier */
2152 + 3 /* Max Tag 11 packet size */
2153 + 1 /* Binary format specifier */
2154 + 1 /* Filename length */
2155 + 8 /* Filename ("_CONSOLE") */
2156 + 4 /* Modification date */
2157 + contents_length); /* Literal data */
2158 if (max_packet_size > (*remaining_bytes)) {
2159 printk(KERN_ERR "Packet length larger than maximum allowable; "
2160 "need up to [%td] bytes, but there are only [%td] "
2161 "available\n", max_packet_size, (*remaining_bytes));
2162 rc = -EINVAL;
2163 goto out;
2164 }
2165 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2166 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2167 (max_packet_size - 4),
2168 &packet_size_length);
2169 if (rc) {
2170 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2171 "generate packet length. rc = [%d]\n", rc);
2172 goto out;
2173 }
2174 (*packet_length) += packet_size_length;
2175 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2176 dest[(*packet_length)++] = 8;
2177 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2178 (*packet_length) += 8;
2179 memset(&dest[(*packet_length)], 0x00, 4);
2180 (*packet_length) += 4;
2181 memcpy(&dest[(*packet_length)], contents, contents_length);
2182 (*packet_length) += contents_length;
2183 out:
2184 if (rc)
2185 (*packet_length) = 0;
2186 else
2187 (*remaining_bytes) -= (*packet_length);
2188 return rc;
2189 }
2190
2191 /**
2192 * write_tag_3_packet
2193 * @dest: Buffer into which to write the packet
2194 * @remaining_bytes: Maximum number of bytes that can be written
2195 * @auth_tok: Authentication token
2196 * @crypt_stat: The cryptographic context
2197 * @key_rec: encrypted key
2198 * @packet_size: This function will write the number of bytes that end
2199 * up constituting the packet; set to zero on error
2200 *
2201 * Returns zero on success; non-zero on error.
2202 */
2203 static int
2204 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2205 struct ecryptfs_auth_tok *auth_tok,
2206 struct ecryptfs_crypt_stat *crypt_stat,
2207 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2208 {
2209 size_t i;
2210 size_t encrypted_session_key_valid = 0;
2211 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2212 struct scatterlist dst_sg[2];
2213 struct scatterlist src_sg[2];
2214 struct mutex *tfm_mutex = NULL;
2215 u8 cipher_code;
2216 size_t packet_size_length;
2217 size_t max_packet_size;
2218 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2219 crypt_stat->mount_crypt_stat;
2220 struct crypto_skcipher *tfm;
2221 struct skcipher_request *req;
2222 int rc = 0;
2223
2224 (*packet_size) = 0;
2225 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2226 ECRYPTFS_SIG_SIZE);
2227 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
2228 crypt_stat->cipher);
2229 if (unlikely(rc)) {
2230 printk(KERN_ERR "Internal error whilst attempting to get "
2231 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2232 crypt_stat->cipher, rc);
2233 goto out;
2234 }
2235 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2236 printk(KERN_WARNING "No key size specified at mount; "
2237 "defaulting to [%d]\n",
2238 crypto_skcipher_default_keysize(tfm));
2239 mount_crypt_stat->global_default_cipher_key_size =
2240 crypto_skcipher_default_keysize(tfm);
2241 }
2242 if (crypt_stat->key_size == 0)
2243 crypt_stat->key_size =
2244 mount_crypt_stat->global_default_cipher_key_size;
2245 if (auth_tok->session_key.encrypted_key_size == 0)
2246 auth_tok->session_key.encrypted_key_size =
2247 crypt_stat->key_size;
2248 if (crypt_stat->key_size == 24
2249 && strcmp("aes", crypt_stat->cipher) == 0) {
2250 memset((crypt_stat->key + 24), 0, 8);
2251 auth_tok->session_key.encrypted_key_size = 32;
2252 } else
2253 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2254 key_rec->enc_key_size =
2255 auth_tok->session_key.encrypted_key_size;
2256 encrypted_session_key_valid = 0;
2257 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2258 encrypted_session_key_valid |=
2259 auth_tok->session_key.encrypted_key[i];
2260 if (encrypted_session_key_valid) {
2261 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2262 "using auth_tok->session_key.encrypted_key, "
2263 "where key_rec->enc_key_size = [%zd]\n",
2264 key_rec->enc_key_size);
2265 memcpy(key_rec->enc_key,
2266 auth_tok->session_key.encrypted_key,
2267 key_rec->enc_key_size);
2268 goto encrypted_session_key_set;
2269 }
2270 if (auth_tok->token.password.flags &
2271 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2272 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2273 "session key encryption key of size [%d]\n",
2274 auth_tok->token.password.
2275 session_key_encryption_key_bytes);
2276 memcpy(session_key_encryption_key,
2277 auth_tok->token.password.session_key_encryption_key,
2278 crypt_stat->key_size);
2279 ecryptfs_printk(KERN_DEBUG,
2280 "Cached session key encryption key:\n");
2281 if (ecryptfs_verbosity > 0)
2282 ecryptfs_dump_hex(session_key_encryption_key, 16);
2283 }
2284 if (unlikely(ecryptfs_verbosity > 0)) {
2285 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2286 ecryptfs_dump_hex(session_key_encryption_key, 16);
2287 }
2288 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2289 src_sg, 2);
2290 if (rc < 1 || rc > 2) {
2291 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2292 "for crypt_stat session key; expected rc = 1; "
2293 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2294 rc, key_rec->enc_key_size);
2295 rc = -ENOMEM;
2296 goto out;
2297 }
2298 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2299 dst_sg, 2);
2300 if (rc < 1 || rc > 2) {
2301 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2302 "for crypt_stat encrypted session key; "
2303 "expected rc = 1; got rc = [%d]. "
2304 "key_rec->enc_key_size = [%zd]\n", rc,
2305 key_rec->enc_key_size);
2306 rc = -ENOMEM;
2307 goto out;
2308 }
2309 mutex_lock(tfm_mutex);
2310 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
2311 crypt_stat->key_size);
2312 if (rc < 0) {
2313 mutex_unlock(tfm_mutex);
2314 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2315 "context; rc = [%d]\n", rc);
2316 goto out;
2317 }
2318
2319 req = skcipher_request_alloc(tfm, GFP_KERNEL);
2320 if (!req) {
2321 mutex_unlock(tfm_mutex);
2322 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
2323 "attempting to skcipher_request_alloc for "
2324 "%s\n", crypto_skcipher_driver_name(tfm));
2325 rc = -ENOMEM;
2326 goto out;
2327 }
2328
2329 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
2330 NULL, NULL);
2331
2332 rc = 0;
2333 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2334 crypt_stat->key_size);
2335 skcipher_request_set_crypt(req, src_sg, dst_sg,
2336 (*key_rec).enc_key_size, NULL);
2337 rc = crypto_skcipher_encrypt(req);
2338 mutex_unlock(tfm_mutex);
2339 skcipher_request_free(req);
2340 if (rc) {
2341 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2342 goto out;
2343 }
2344 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2345 if (ecryptfs_verbosity > 0) {
2346 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2347 key_rec->enc_key_size);
2348 ecryptfs_dump_hex(key_rec->enc_key,
2349 key_rec->enc_key_size);
2350 }
2351 encrypted_session_key_set:
2352 /* This format is inspired by OpenPGP; see RFC 2440
2353 * packet tag 3 */
2354 max_packet_size = (1 /* Tag 3 identifier */
2355 + 3 /* Max Tag 3 packet size */
2356 + 1 /* Version */
2357 + 1 /* Cipher code */
2358 + 1 /* S2K specifier */
2359 + 1 /* Hash identifier */
2360 + ECRYPTFS_SALT_SIZE /* Salt */
2361 + 1 /* Hash iterations */
2362 + key_rec->enc_key_size); /* Encrypted key size */
2363 if (max_packet_size > (*remaining_bytes)) {
2364 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2365 "there are only [%td] available\n", max_packet_size,
2366 (*remaining_bytes));
2367 rc = -EINVAL;
2368 goto out;
2369 }
2370 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2371 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2372 * to get the number of octets in the actual Tag 3 packet */
2373 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2374 (max_packet_size - 4),
2375 &packet_size_length);
2376 if (rc) {
2377 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2378 "generate packet length. rc = [%d]\n", rc);
2379 goto out;
2380 }
2381 (*packet_size) += packet_size_length;
2382 dest[(*packet_size)++] = 0x04; /* version 4 */
2383 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2384 * specified with strings */
2385 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2386 crypt_stat->key_size);
2387 if (cipher_code == 0) {
2388 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2389 "cipher [%s]\n", crypt_stat->cipher);
2390 rc = -EINVAL;
2391 goto out;
2392 }
2393 dest[(*packet_size)++] = cipher_code;
2394 dest[(*packet_size)++] = 0x03; /* S2K */
2395 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2396 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2397 ECRYPTFS_SALT_SIZE);
2398 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2399 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2400 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2401 key_rec->enc_key_size);
2402 (*packet_size) += key_rec->enc_key_size;
2403 out:
2404 if (rc)
2405 (*packet_size) = 0;
2406 else
2407 (*remaining_bytes) -= (*packet_size);
2408 return rc;
2409 }
2410
2411 struct kmem_cache *ecryptfs_key_record_cache;
2412
2413 /**
2414 * ecryptfs_generate_key_packet_set
2415 * @dest_base: Virtual address from which to write the key record set
2416 * @crypt_stat: The cryptographic context from which the
2417 * authentication tokens will be retrieved
2418 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2419 * for the global parameters
2420 * @len: The amount written
2421 * @max: The maximum amount of data allowed to be written
2422 *
2423 * Generates a key packet set and writes it to the virtual address
2424 * passed in.
2425 *
2426 * Returns zero on success; non-zero on error.
2427 */
2428 int
2429 ecryptfs_generate_key_packet_set(char *dest_base,
2430 struct ecryptfs_crypt_stat *crypt_stat,
2431 struct dentry *ecryptfs_dentry, size_t *len,
2432 size_t max)
2433 {
2434 struct ecryptfs_auth_tok *auth_tok;
2435 struct key *auth_tok_key = NULL;
2436 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2437 &ecryptfs_superblock_to_private(
2438 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2439 size_t written;
2440 struct ecryptfs_key_record *key_rec;
2441 struct ecryptfs_key_sig *key_sig;
2442 int rc = 0;
2443
2444 (*len) = 0;
2445 mutex_lock(&crypt_stat->keysig_list_mutex);
2446 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2447 if (!key_rec) {
2448 rc = -ENOMEM;
2449 goto out;
2450 }
2451 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2452 crypt_stat_list) {
2453 memset(key_rec, 0, sizeof(*key_rec));
2454 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2455 &auth_tok,
2456 mount_crypt_stat,
2457 key_sig->keysig);
2458 if (rc) {
2459 printk(KERN_WARNING "Unable to retrieve auth tok with "
2460 "sig = [%s]\n", key_sig->keysig);
2461 rc = process_find_global_auth_tok_for_sig_err(rc);
2462 goto out_free;
2463 }
2464 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2465 rc = write_tag_3_packet((dest_base + (*len)),
2466 &max, auth_tok,
2467 crypt_stat, key_rec,
2468 &written);
2469 up_write(&(auth_tok_key->sem));
2470 key_put(auth_tok_key);
2471 if (rc) {
2472 ecryptfs_printk(KERN_WARNING, "Error "
2473 "writing tag 3 packet\n");
2474 goto out_free;
2475 }
2476 (*len) += written;
2477 /* Write auth tok signature packet */
2478 rc = write_tag_11_packet((dest_base + (*len)), &max,
2479 key_rec->sig,
2480 ECRYPTFS_SIG_SIZE, &written);
2481 if (rc) {
2482 ecryptfs_printk(KERN_ERR, "Error writing "
2483 "auth tok signature packet\n");
2484 goto out_free;
2485 }
2486 (*len) += written;
2487 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2488 rc = write_tag_1_packet(dest_base + (*len), &max,
2489 auth_tok_key, auth_tok,
2490 crypt_stat, key_rec, &written);
2491 if (rc) {
2492 ecryptfs_printk(KERN_WARNING, "Error "
2493 "writing tag 1 packet\n");
2494 goto out_free;
2495 }
2496 (*len) += written;
2497 } else {
2498 up_write(&(auth_tok_key->sem));
2499 key_put(auth_tok_key);
2500 ecryptfs_printk(KERN_WARNING, "Unsupported "
2501 "authentication token type\n");
2502 rc = -EINVAL;
2503 goto out_free;
2504 }
2505 }
2506 if (likely(max > 0)) {
2507 dest_base[(*len)] = 0x00;
2508 } else {
2509 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2510 rc = -EIO;
2511 }
2512 out_free:
2513 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2514 out:
2515 if (rc)
2516 (*len) = 0;
2517 mutex_unlock(&crypt_stat->keysig_list_mutex);
2518 return rc;
2519 }
2520
2521 struct kmem_cache *ecryptfs_key_sig_cache;
2522
2523 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2524 {
2525 struct ecryptfs_key_sig *new_key_sig;
2526
2527 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2528 if (!new_key_sig) {
2529 printk(KERN_ERR
2530 "Error allocating from ecryptfs_key_sig_cache\n");
2531 return -ENOMEM;
2532 }
2533 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2534 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2535 /* Caller must hold keysig_list_mutex */
2536 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2537
2538 return 0;
2539 }
2540
2541 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2542
2543 int
2544 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2545 char *sig, u32 global_auth_tok_flags)
2546 {
2547 struct ecryptfs_global_auth_tok *new_auth_tok;
2548 int rc = 0;
2549
2550 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2551 GFP_KERNEL);
2552 if (!new_auth_tok) {
2553 rc = -ENOMEM;
2554 printk(KERN_ERR "Error allocating from "
2555 "ecryptfs_global_auth_tok_cache\n");
2556 goto out;
2557 }
2558 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2559 new_auth_tok->flags = global_auth_tok_flags;
2560 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2561 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2562 list_add(&new_auth_tok->mount_crypt_stat_list,
2563 &mount_crypt_stat->global_auth_tok_list);
2564 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2565 out:
2566 return rc;
2567 }
2568
Linux with added FPC-III support