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 */
process_request_key_err(long err_code)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
process_find_global_auth_tok_for_sig_err(int err_code)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 */
ecryptfs_parse_packet_length(unsigned char * data,size_t * size,size_t * length_size)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 */
ecryptfs_write_packet_length(char * dest,size_t size,size_t * packet_size_length)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
write_tag_64_packet(char * signature,struct ecryptfs_session_key * session_key,char ** packet,size_t * packet_len)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
parse_tag_65_packet(struct ecryptfs_session_key * session_key,u8 * cipher_code,struct ecryptfs_message * msg)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
write_tag_66_packet(char * signature,u8 cipher_code,struct ecryptfs_crypt_stat * crypt_stat,char ** packet,size_t * packet_len)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
parse_tag_67_packet(struct ecryptfs_key_record * key_rec,struct ecryptfs_message * msg)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 */
ecryptfs_verify_version(u16 version)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
ecryptfs_verify_auth_tok_from_key(struct key * auth_tok_key,struct ecryptfs_auth_tok ** auth_tok)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
ecryptfs_find_global_auth_tok_for_sig(struct key ** auth_tok_key,struct ecryptfs_auth_tok ** auth_tok,struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * sig)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
ecryptfs_find_auth_tok_for_sig(struct key ** auth_tok_key,struct ecryptfs_auth_tok ** auth_tok,struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * sig)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
ecryptfs_write_tag_70_packet(char * dest,size_t * remaining_bytes,size_t * packet_size,struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * filename,size_t filename_size)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 return -ENOMEM;
644
645 (*packet_size) = 0;
646 rc = ecryptfs_find_auth_tok_for_sig(
647 &auth_tok_key,
648 &s->auth_tok, mount_crypt_stat,
649 mount_crypt_stat->global_default_fnek_sig);
650 if (rc) {
651 printk(KERN_ERR "%s: Error attempting to find auth tok for "
652 "fnek sig [%s]; rc = [%d]\n", __func__,
653 mount_crypt_stat->global_default_fnek_sig, rc);
654 goto out;
655 }
656 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
657 &s->skcipher_tfm,
658 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
659 if (unlikely(rc)) {
660 printk(KERN_ERR "Internal error whilst attempting to get "
661 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
662 mount_crypt_stat->global_default_fn_cipher_name, rc);
663 goto out;
664 }
665 mutex_lock(s->tfm_mutex);
666 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
667 /* Plus one for the \0 separator between the random prefix
668 * and the plaintext filename */
669 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
670 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
671 if ((s->block_aligned_filename_size % s->block_size) != 0) {
672 s->num_rand_bytes += (s->block_size
673 - (s->block_aligned_filename_size
674 % s->block_size));
675 s->block_aligned_filename_size = (s->num_rand_bytes
676 + filename_size);
677 }
678 /* Octet 0: Tag 70 identifier
679 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
680 * and block-aligned encrypted filename size)
681 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
682 * Octet N2-N3: Cipher identifier (1 octet)
683 * Octets N3-N4: Block-aligned encrypted filename
684 * - Consists of a minimum number of random characters, a \0
685 * separator, and then the filename */
686 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
687 + s->block_aligned_filename_size);
688 if (!dest) {
689 (*packet_size) = s->max_packet_size;
690 goto out_unlock;
691 }
692 if (s->max_packet_size > (*remaining_bytes)) {
693 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
694 "[%zd] available\n", __func__, s->max_packet_size,
695 (*remaining_bytes));
696 rc = -EINVAL;
697 goto out_unlock;
698 }
699
700 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
701 if (!s->skcipher_req) {
702 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
703 "skcipher_request_alloc for %s\n", __func__,
704 crypto_skcipher_driver_name(s->skcipher_tfm));
705 rc = -ENOMEM;
706 goto out_unlock;
707 }
708
709 skcipher_request_set_callback(s->skcipher_req,
710 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
711
712 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
713 GFP_KERNEL);
714 if (!s->block_aligned_filename) {
715 rc = -ENOMEM;
716 goto out_unlock;
717 }
718 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
719 rc = ecryptfs_write_packet_length(&dest[s->i],
720 (ECRYPTFS_SIG_SIZE
721 + 1 /* Cipher code */
722 + s->block_aligned_filename_size),
723 &s->packet_size_len);
724 if (rc) {
725 printk(KERN_ERR "%s: Error generating tag 70 packet "
726 "header; cannot generate packet length; rc = [%d]\n",
727 __func__, rc);
728 goto out_free_unlock;
729 }
730 s->i += s->packet_size_len;
731 ecryptfs_from_hex(&dest[s->i],
732 mount_crypt_stat->global_default_fnek_sig,
733 ECRYPTFS_SIG_SIZE);
734 s->i += ECRYPTFS_SIG_SIZE;
735 s->cipher_code = ecryptfs_code_for_cipher_string(
736 mount_crypt_stat->global_default_fn_cipher_name,
737 mount_crypt_stat->global_default_fn_cipher_key_bytes);
738 if (s->cipher_code == 0) {
739 printk(KERN_WARNING "%s: Unable to generate code for "
740 "cipher [%s] with key bytes [%zd]\n", __func__,
741 mount_crypt_stat->global_default_fn_cipher_name,
742 mount_crypt_stat->global_default_fn_cipher_key_bytes);
743 rc = -EINVAL;
744 goto out_free_unlock;
745 }
746 dest[s->i++] = s->cipher_code;
747 /* TODO: Support other key modules than passphrase for
748 * filename encryption */
749 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
750 rc = -EOPNOTSUPP;
751 printk(KERN_INFO "%s: Filename encryption only supports "
752 "password tokens\n", __func__);
753 goto out_free_unlock;
754 }
755 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
756 if (IS_ERR(s->hash_tfm)) {
757 rc = PTR_ERR(s->hash_tfm);
758 printk(KERN_ERR "%s: Error attempting to "
759 "allocate hash crypto context; rc = [%d]\n",
760 __func__, rc);
761 goto out_free_unlock;
762 }
763
764 s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
765 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
766 if (!s->hash_desc) {
767 rc = -ENOMEM;
768 goto out_release_free_unlock;
769 }
770
771 s->hash_desc->tfm = s->hash_tfm;
772 s->hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
773
774 rc = crypto_shash_digest(s->hash_desc,
775 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
776 s->auth_tok->token.password.session_key_encryption_key_bytes,
777 s->hash);
778 if (rc) {
779 printk(KERN_ERR
780 "%s: Error computing crypto hash; rc = [%d]\n",
781 __func__, rc);
782 goto out_release_free_unlock;
783 }
784 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
785 s->block_aligned_filename[s->j] =
786 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
787 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
788 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
789 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
790 ECRYPTFS_TAG_70_DIGEST_SIZE,
791 s->tmp_hash);
792 if (rc) {
793 printk(KERN_ERR
794 "%s: Error computing crypto hash; "
795 "rc = [%d]\n", __func__, rc);
796 goto out_release_free_unlock;
797 }
798 memcpy(s->hash, s->tmp_hash,
799 ECRYPTFS_TAG_70_DIGEST_SIZE);
800 }
801 if (s->block_aligned_filename[s->j] == '\0')
802 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
803 }
804 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
805 filename_size);
806 rc = virt_to_scatterlist(s->block_aligned_filename,
807 s->block_aligned_filename_size, s->src_sg, 2);
808 if (rc < 1) {
809 printk(KERN_ERR "%s: Internal error whilst attempting to "
810 "convert filename memory to scatterlist; rc = [%d]. "
811 "block_aligned_filename_size = [%zd]\n", __func__, rc,
812 s->block_aligned_filename_size);
813 goto out_release_free_unlock;
814 }
815 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
816 s->dst_sg, 2);
817 if (rc < 1) {
818 printk(KERN_ERR "%s: Internal error whilst attempting to "
819 "convert encrypted filename memory to scatterlist; "
820 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
821 __func__, rc, s->block_aligned_filename_size);
822 goto out_release_free_unlock;
823 }
824 /* The characters in the first block effectively do the job
825 * of the IV here, so we just use 0's for the IV. Note the
826 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
827 * >= ECRYPTFS_MAX_IV_BYTES. */
828 rc = crypto_skcipher_setkey(
829 s->skcipher_tfm,
830 s->auth_tok->token.password.session_key_encryption_key,
831 mount_crypt_stat->global_default_fn_cipher_key_bytes);
832 if (rc < 0) {
833 printk(KERN_ERR "%s: Error setting key for crypto context; "
834 "rc = [%d]. s->auth_tok->token.password.session_key_"
835 "encryption_key = [0x%p]; mount_crypt_stat->"
836 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
837 rc,
838 s->auth_tok->token.password.session_key_encryption_key,
839 mount_crypt_stat->global_default_fn_cipher_key_bytes);
840 goto out_release_free_unlock;
841 }
842 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
843 s->block_aligned_filename_size, s->iv);
844 rc = crypto_skcipher_encrypt(s->skcipher_req);
845 if (rc) {
846 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
847 "rc = [%d]\n", __func__, rc);
848 goto out_release_free_unlock;
849 }
850 s->i += s->block_aligned_filename_size;
851 (*packet_size) = s->i;
852 (*remaining_bytes) -= (*packet_size);
853 out_release_free_unlock:
854 crypto_free_shash(s->hash_tfm);
855 out_free_unlock:
856 kzfree(s->block_aligned_filename);
857 out_unlock:
858 mutex_unlock(s->tfm_mutex);
859 out:
860 if (auth_tok_key) {
861 up_write(&(auth_tok_key->sem));
862 key_put(auth_tok_key);
863 }
864 skcipher_request_free(s->skcipher_req);
865 kzfree(s->hash_desc);
866 kfree(s);
867 return rc;
868 }
869
870 struct ecryptfs_parse_tag_70_packet_silly_stack {
871 u8 cipher_code;
872 size_t max_packet_size;
873 size_t packet_size_len;
874 size_t parsed_tag_70_packet_size;
875 size_t block_aligned_filename_size;
876 size_t block_size;
877 size_t i;
878 struct mutex *tfm_mutex;
879 char *decrypted_filename;
880 struct ecryptfs_auth_tok *auth_tok;
881 struct scatterlist src_sg[2];
882 struct scatterlist dst_sg[2];
883 struct crypto_skcipher *skcipher_tfm;
884 struct skcipher_request *skcipher_req;
885 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
886 char iv[ECRYPTFS_MAX_IV_BYTES];
887 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
888 };
889
890 /**
891 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
892 * @filename: This function kmalloc's the memory for the filename
893 * @filename_size: This function sets this to the amount of memory
894 * kmalloc'd for the filename
895 * @packet_size: This function sets this to the the number of octets
896 * in the packet parsed
897 * @mount_crypt_stat: The mount-wide cryptographic context
898 * @data: The memory location containing the start of the tag 70
899 * packet
900 * @max_packet_size: The maximum legal size of the packet to be parsed
901 * from @data
902 *
903 * Returns zero on success; non-zero otherwise
904 */
905 int
ecryptfs_parse_tag_70_packet(char ** filename,size_t * filename_size,size_t * packet_size,struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * data,size_t max_packet_size)906 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
907 size_t *packet_size,
908 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
909 char *data, size_t max_packet_size)
910 {
911 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
912 struct key *auth_tok_key = NULL;
913 int rc = 0;
914
915 (*packet_size) = 0;
916 (*filename_size) = 0;
917 (*filename) = NULL;
918 s = kzalloc(sizeof(*s), GFP_KERNEL);
919 if (!s)
920 return -ENOMEM;
921
922 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
923 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
924 "at least [%d]\n", __func__, max_packet_size,
925 ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
926 rc = -EINVAL;
927 goto out;
928 }
929 /* Octet 0: Tag 70 identifier
930 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
931 * and block-aligned encrypted filename size)
932 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
933 * Octet N2-N3: Cipher identifier (1 octet)
934 * Octets N3-N4: Block-aligned encrypted filename
935 * - Consists of a minimum number of random numbers, a \0
936 * separator, and then the filename */
937 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
938 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
939 "tag [0x%.2x]\n", __func__,
940 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
941 rc = -EINVAL;
942 goto out;
943 }
944 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
945 &s->parsed_tag_70_packet_size,
946 &s->packet_size_len);
947 if (rc) {
948 printk(KERN_WARNING "%s: Error parsing packet length; "
949 "rc = [%d]\n", __func__, rc);
950 goto out;
951 }
952 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
953 - ECRYPTFS_SIG_SIZE - 1);
954 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
955 > max_packet_size) {
956 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
957 "size is [%zd]\n", __func__, max_packet_size,
958 (1 + s->packet_size_len + 1
959 + s->block_aligned_filename_size));
960 rc = -EINVAL;
961 goto out;
962 }
963 (*packet_size) += s->packet_size_len;
964 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
965 ECRYPTFS_SIG_SIZE);
966 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
967 (*packet_size) += ECRYPTFS_SIG_SIZE;
968 s->cipher_code = data[(*packet_size)++];
969 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
970 if (rc) {
971 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
972 __func__, s->cipher_code);
973 goto out;
974 }
975 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
976 &s->auth_tok, mount_crypt_stat,
977 s->fnek_sig_hex);
978 if (rc) {
979 printk(KERN_ERR "%s: Error attempting to find auth tok for "
980 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
981 rc);
982 goto out;
983 }
984 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
985 &s->tfm_mutex,
986 s->cipher_string);
987 if (unlikely(rc)) {
988 printk(KERN_ERR "Internal error whilst attempting to get "
989 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
990 s->cipher_string, rc);
991 goto out;
992 }
993 mutex_lock(s->tfm_mutex);
994 rc = virt_to_scatterlist(&data[(*packet_size)],
995 s->block_aligned_filename_size, s->src_sg, 2);
996 if (rc < 1) {
997 printk(KERN_ERR "%s: Internal error whilst attempting to "
998 "convert encrypted filename memory to scatterlist; "
999 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1000 __func__, rc, s->block_aligned_filename_size);
1001 goto out_unlock;
1002 }
1003 (*packet_size) += s->block_aligned_filename_size;
1004 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1005 GFP_KERNEL);
1006 if (!s->decrypted_filename) {
1007 rc = -ENOMEM;
1008 goto out_unlock;
1009 }
1010 rc = virt_to_scatterlist(s->decrypted_filename,
1011 s->block_aligned_filename_size, s->dst_sg, 2);
1012 if (rc < 1) {
1013 printk(KERN_ERR "%s: Internal error whilst attempting to "
1014 "convert decrypted filename memory to scatterlist; "
1015 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1016 __func__, rc, s->block_aligned_filename_size);
1017 goto out_free_unlock;
1018 }
1019
1020 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
1021 if (!s->skcipher_req) {
1022 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1023 "skcipher_request_alloc for %s\n", __func__,
1024 crypto_skcipher_driver_name(s->skcipher_tfm));
1025 rc = -ENOMEM;
1026 goto out_free_unlock;
1027 }
1028
1029 skcipher_request_set_callback(s->skcipher_req,
1030 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
1031
1032 /* The characters in the first block effectively do the job of
1033 * the IV here, so we just use 0's for the IV. Note the
1034 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1035 * >= ECRYPTFS_MAX_IV_BYTES. */
1036 /* TODO: Support other key modules than passphrase for
1037 * filename encryption */
1038 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1039 rc = -EOPNOTSUPP;
1040 printk(KERN_INFO "%s: Filename encryption only supports "
1041 "password tokens\n", __func__);
1042 goto out_free_unlock;
1043 }
1044 rc = crypto_skcipher_setkey(
1045 s->skcipher_tfm,
1046 s->auth_tok->token.password.session_key_encryption_key,
1047 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1048 if (rc < 0) {
1049 printk(KERN_ERR "%s: Error setting key for crypto context; "
1050 "rc = [%d]. s->auth_tok->token.password.session_key_"
1051 "encryption_key = [0x%p]; mount_crypt_stat->"
1052 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1053 rc,
1054 s->auth_tok->token.password.session_key_encryption_key,
1055 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1056 goto out_free_unlock;
1057 }
1058 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
1059 s->block_aligned_filename_size, s->iv);
1060 rc = crypto_skcipher_decrypt(s->skcipher_req);
1061 if (rc) {
1062 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1063 "rc = [%d]\n", __func__, rc);
1064 goto out_free_unlock;
1065 }
1066 while (s->decrypted_filename[s->i] != '\0'
1067 && s->i < s->block_aligned_filename_size)
1068 s->i++;
1069 if (s->i == s->block_aligned_filename_size) {
1070 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1071 "find valid separator between random characters and "
1072 "the filename\n", __func__);
1073 rc = -EINVAL;
1074 goto out_free_unlock;
1075 }
1076 s->i++;
1077 (*filename_size) = (s->block_aligned_filename_size - s->i);
1078 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1079 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1080 "invalid\n", __func__, (*filename_size));
1081 rc = -EINVAL;
1082 goto out_free_unlock;
1083 }
1084 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1085 if (!(*filename)) {
1086 rc = -ENOMEM;
1087 goto out_free_unlock;
1088 }
1089 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1090 (*filename)[(*filename_size)] = '\0';
1091 out_free_unlock:
1092 kfree(s->decrypted_filename);
1093 out_unlock:
1094 mutex_unlock(s->tfm_mutex);
1095 out:
1096 if (rc) {
1097 (*packet_size) = 0;
1098 (*filename_size) = 0;
1099 (*filename) = NULL;
1100 }
1101 if (auth_tok_key) {
1102 up_write(&(auth_tok_key->sem));
1103 key_put(auth_tok_key);
1104 }
1105 skcipher_request_free(s->skcipher_req);
1106 kfree(s);
1107 return rc;
1108 }
1109
1110 static int
ecryptfs_get_auth_tok_sig(char ** sig,struct ecryptfs_auth_tok * auth_tok)1111 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1112 {
1113 int rc = 0;
1114
1115 (*sig) = NULL;
1116 switch (auth_tok->token_type) {
1117 case ECRYPTFS_PASSWORD:
1118 (*sig) = auth_tok->token.password.signature;
1119 break;
1120 case ECRYPTFS_PRIVATE_KEY:
1121 (*sig) = auth_tok->token.private_key.signature;
1122 break;
1123 default:
1124 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1125 auth_tok->token_type);
1126 rc = -EINVAL;
1127 }
1128 return rc;
1129 }
1130
1131 /**
1132 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1133 * @auth_tok: The key authentication token used to decrypt the session key
1134 * @crypt_stat: The cryptographic context
1135 *
1136 * Returns zero on success; non-zero error otherwise.
1137 */
1138 static int
decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat)1139 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1140 struct ecryptfs_crypt_stat *crypt_stat)
1141 {
1142 u8 cipher_code = 0;
1143 struct ecryptfs_msg_ctx *msg_ctx;
1144 struct ecryptfs_message *msg = NULL;
1145 char *auth_tok_sig;
1146 char *payload = NULL;
1147 size_t payload_len = 0;
1148 int rc;
1149
1150 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1151 if (rc) {
1152 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1153 auth_tok->token_type);
1154 goto out;
1155 }
1156 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1157 &payload, &payload_len);
1158 if (rc) {
1159 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1160 goto out;
1161 }
1162 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1163 if (rc) {
1164 ecryptfs_printk(KERN_ERR, "Error sending message to "
1165 "ecryptfsd: %d\n", rc);
1166 goto out;
1167 }
1168 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1169 if (rc) {
1170 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1171 "from the user space daemon\n");
1172 rc = -EIO;
1173 goto out;
1174 }
1175 rc = parse_tag_65_packet(&(auth_tok->session_key),
1176 &cipher_code, msg);
1177 if (rc) {
1178 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1179 rc);
1180 goto out;
1181 }
1182 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1183 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1184 auth_tok->session_key.decrypted_key_size);
1185 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1186 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1187 if (rc) {
1188 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1189 cipher_code)
1190 goto out;
1191 }
1192 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1193 if (ecryptfs_verbosity > 0) {
1194 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1195 ecryptfs_dump_hex(crypt_stat->key,
1196 crypt_stat->key_size);
1197 }
1198 out:
1199 kfree(msg);
1200 kfree(payload);
1201 return rc;
1202 }
1203
wipe_auth_tok_list(struct list_head * auth_tok_list_head)1204 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1205 {
1206 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1207 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1208
1209 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1210 auth_tok_list_head, list) {
1211 list_del(&auth_tok_list_item->list);
1212 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1213 auth_tok_list_item);
1214 }
1215 }
1216
1217 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1218
1219 /**
1220 * parse_tag_1_packet
1221 * @crypt_stat: The cryptographic context to modify based on packet contents
1222 * @data: The raw bytes of the packet.
1223 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1224 * a new authentication token will be placed at the
1225 * end of this list for this packet.
1226 * @new_auth_tok: Pointer to a pointer to memory that this function
1227 * allocates; sets the memory address of the pointer to
1228 * NULL on error. This object is added to the
1229 * auth_tok_list.
1230 * @packet_size: This function writes the size of the parsed packet
1231 * into this memory location; zero on error.
1232 * @max_packet_size: The maximum allowable packet size
1233 *
1234 * Returns zero on success; non-zero on error.
1235 */
1236 static int
parse_tag_1_packet(struct ecryptfs_crypt_stat * crypt_stat,unsigned char * data,struct list_head * auth_tok_list,struct ecryptfs_auth_tok ** new_auth_tok,size_t * packet_size,size_t max_packet_size)1237 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1238 unsigned char *data, struct list_head *auth_tok_list,
1239 struct ecryptfs_auth_tok **new_auth_tok,
1240 size_t *packet_size, size_t max_packet_size)
1241 {
1242 size_t body_size;
1243 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1244 size_t length_size;
1245 int rc = 0;
1246
1247 (*packet_size) = 0;
1248 (*new_auth_tok) = NULL;
1249 /**
1250 * This format is inspired by OpenPGP; see RFC 2440
1251 * packet tag 1
1252 *
1253 * Tag 1 identifier (1 byte)
1254 * Max Tag 1 packet size (max 3 bytes)
1255 * Version (1 byte)
1256 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1257 * Cipher identifier (1 byte)
1258 * Encrypted key size (arbitrary)
1259 *
1260 * 12 bytes minimum packet size
1261 */
1262 if (unlikely(max_packet_size < 12)) {
1263 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1264 rc = -EINVAL;
1265 goto out;
1266 }
1267 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1268 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1269 ECRYPTFS_TAG_1_PACKET_TYPE);
1270 rc = -EINVAL;
1271 goto out;
1272 }
1273 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1274 * at end of function upon failure */
1275 auth_tok_list_item =
1276 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1277 GFP_KERNEL);
1278 if (!auth_tok_list_item) {
1279 printk(KERN_ERR "Unable to allocate memory\n");
1280 rc = -ENOMEM;
1281 goto out;
1282 }
1283 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1284 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1285 &length_size);
1286 if (rc) {
1287 printk(KERN_WARNING "Error parsing packet length; "
1288 "rc = [%d]\n", rc);
1289 goto out_free;
1290 }
1291 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1292 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1293 rc = -EINVAL;
1294 goto out_free;
1295 }
1296 (*packet_size) += length_size;
1297 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1298 printk(KERN_WARNING "Packet size exceeds max\n");
1299 rc = -EINVAL;
1300 goto out_free;
1301 }
1302 if (unlikely(data[(*packet_size)++] != 0x03)) {
1303 printk(KERN_WARNING "Unknown version number [%d]\n",
1304 data[(*packet_size) - 1]);
1305 rc = -EINVAL;
1306 goto out_free;
1307 }
1308 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1309 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1310 *packet_size += ECRYPTFS_SIG_SIZE;
1311 /* This byte is skipped because the kernel does not need to
1312 * know which public key encryption algorithm was used */
1313 (*packet_size)++;
1314 (*new_auth_tok)->session_key.encrypted_key_size =
1315 body_size - (ECRYPTFS_SIG_SIZE + 2);
1316 if ((*new_auth_tok)->session_key.encrypted_key_size
1317 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1318 printk(KERN_WARNING "Tag 1 packet contains key larger "
1319 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1320 rc = -EINVAL;
1321 goto out;
1322 }
1323 memcpy((*new_auth_tok)->session_key.encrypted_key,
1324 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1325 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1326 (*new_auth_tok)->session_key.flags &=
1327 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1328 (*new_auth_tok)->session_key.flags |=
1329 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1330 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1331 (*new_auth_tok)->flags = 0;
1332 (*new_auth_tok)->session_key.flags &=
1333 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1334 (*new_auth_tok)->session_key.flags &=
1335 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1336 list_add(&auth_tok_list_item->list, auth_tok_list);
1337 goto out;
1338 out_free:
1339 (*new_auth_tok) = NULL;
1340 memset(auth_tok_list_item, 0,
1341 sizeof(struct ecryptfs_auth_tok_list_item));
1342 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1343 auth_tok_list_item);
1344 out:
1345 if (rc)
1346 (*packet_size) = 0;
1347 return rc;
1348 }
1349
1350 /**
1351 * parse_tag_3_packet
1352 * @crypt_stat: The cryptographic context to modify based on packet
1353 * contents.
1354 * @data: The raw bytes of the packet.
1355 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1356 * a new authentication token will be placed at the end
1357 * of this list for this packet.
1358 * @new_auth_tok: Pointer to a pointer to memory that this function
1359 * allocates; sets the memory address of the pointer to
1360 * NULL on error. This object is added to the
1361 * auth_tok_list.
1362 * @packet_size: This function writes the size of the parsed packet
1363 * into this memory location; zero on error.
1364 * @max_packet_size: maximum number of bytes to parse
1365 *
1366 * Returns zero on success; non-zero on error.
1367 */
1368 static int
parse_tag_3_packet(struct ecryptfs_crypt_stat * crypt_stat,unsigned char * data,struct list_head * auth_tok_list,struct ecryptfs_auth_tok ** new_auth_tok,size_t * packet_size,size_t max_packet_size)1369 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1370 unsigned char *data, struct list_head *auth_tok_list,
1371 struct ecryptfs_auth_tok **new_auth_tok,
1372 size_t *packet_size, size_t max_packet_size)
1373 {
1374 size_t body_size;
1375 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1376 size_t length_size;
1377 int rc = 0;
1378
1379 (*packet_size) = 0;
1380 (*new_auth_tok) = NULL;
1381 /**
1382 *This format is inspired by OpenPGP; see RFC 2440
1383 * packet tag 3
1384 *
1385 * Tag 3 identifier (1 byte)
1386 * Max Tag 3 packet size (max 3 bytes)
1387 * Version (1 byte)
1388 * Cipher code (1 byte)
1389 * S2K specifier (1 byte)
1390 * Hash identifier (1 byte)
1391 * Salt (ECRYPTFS_SALT_SIZE)
1392 * Hash iterations (1 byte)
1393 * Encrypted key (arbitrary)
1394 *
1395 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1396 */
1397 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1398 printk(KERN_ERR "Max packet size too large\n");
1399 rc = -EINVAL;
1400 goto out;
1401 }
1402 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1403 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1404 ECRYPTFS_TAG_3_PACKET_TYPE);
1405 rc = -EINVAL;
1406 goto out;
1407 }
1408 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1409 * at end of function upon failure */
1410 auth_tok_list_item =
1411 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1412 if (!auth_tok_list_item) {
1413 printk(KERN_ERR "Unable to allocate memory\n");
1414 rc = -ENOMEM;
1415 goto out;
1416 }
1417 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1418 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1419 &length_size);
1420 if (rc) {
1421 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1422 rc);
1423 goto out_free;
1424 }
1425 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1426 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1427 rc = -EINVAL;
1428 goto out_free;
1429 }
1430 (*packet_size) += length_size;
1431 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1432 printk(KERN_ERR "Packet size exceeds max\n");
1433 rc = -EINVAL;
1434 goto out_free;
1435 }
1436 (*new_auth_tok)->session_key.encrypted_key_size =
1437 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1438 if ((*new_auth_tok)->session_key.encrypted_key_size
1439 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1440 printk(KERN_WARNING "Tag 3 packet contains key larger "
1441 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1442 rc = -EINVAL;
1443 goto out_free;
1444 }
1445 if (unlikely(data[(*packet_size)++] != 0x04)) {
1446 printk(KERN_WARNING "Unknown version number [%d]\n",
1447 data[(*packet_size) - 1]);
1448 rc = -EINVAL;
1449 goto out_free;
1450 }
1451 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1452 (u16)data[(*packet_size)]);
1453 if (rc)
1454 goto out_free;
1455 /* A little extra work to differentiate among the AES key
1456 * sizes; see RFC2440 */
1457 switch(data[(*packet_size)++]) {
1458 case RFC2440_CIPHER_AES_192:
1459 crypt_stat->key_size = 24;
1460 break;
1461 default:
1462 crypt_stat->key_size =
1463 (*new_auth_tok)->session_key.encrypted_key_size;
1464 }
1465 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1466 if (rc)
1467 goto out_free;
1468 if (unlikely(data[(*packet_size)++] != 0x03)) {
1469 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1470 rc = -ENOSYS;
1471 goto out_free;
1472 }
1473 /* TODO: finish the hash mapping */
1474 switch (data[(*packet_size)++]) {
1475 case 0x01: /* See RFC2440 for these numbers and their mappings */
1476 /* Choose MD5 */
1477 memcpy((*new_auth_tok)->token.password.salt,
1478 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1479 (*packet_size) += ECRYPTFS_SALT_SIZE;
1480 /* This conversion was taken straight from RFC2440 */
1481 (*new_auth_tok)->token.password.hash_iterations =
1482 ((u32) 16 + (data[(*packet_size)] & 15))
1483 << ((data[(*packet_size)] >> 4) + 6);
1484 (*packet_size)++;
1485 /* Friendly reminder:
1486 * (*new_auth_tok)->session_key.encrypted_key_size =
1487 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1488 memcpy((*new_auth_tok)->session_key.encrypted_key,
1489 &data[(*packet_size)],
1490 (*new_auth_tok)->session_key.encrypted_key_size);
1491 (*packet_size) +=
1492 (*new_auth_tok)->session_key.encrypted_key_size;
1493 (*new_auth_tok)->session_key.flags &=
1494 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1495 (*new_auth_tok)->session_key.flags |=
1496 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1497 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1498 break;
1499 default:
1500 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1501 "[%d]\n", data[(*packet_size) - 1]);
1502 rc = -ENOSYS;
1503 goto out_free;
1504 }
1505 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1506 /* TODO: Parametarize; we might actually want userspace to
1507 * decrypt the session key. */
1508 (*new_auth_tok)->session_key.flags &=
1509 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1510 (*new_auth_tok)->session_key.flags &=
1511 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1512 list_add(&auth_tok_list_item->list, auth_tok_list);
1513 goto out;
1514 out_free:
1515 (*new_auth_tok) = NULL;
1516 memset(auth_tok_list_item, 0,
1517 sizeof(struct ecryptfs_auth_tok_list_item));
1518 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1519 auth_tok_list_item);
1520 out:
1521 if (rc)
1522 (*packet_size) = 0;
1523 return rc;
1524 }
1525
1526 /**
1527 * parse_tag_11_packet
1528 * @data: The raw bytes of the packet
1529 * @contents: This function writes the data contents of the literal
1530 * packet into this memory location
1531 * @max_contents_bytes: The maximum number of bytes that this function
1532 * is allowed to write into contents
1533 * @tag_11_contents_size: This function writes the size of the parsed
1534 * contents into this memory location; zero on
1535 * error
1536 * @packet_size: This function writes the size of the parsed packet
1537 * into this memory location; zero on error
1538 * @max_packet_size: maximum number of bytes to parse
1539 *
1540 * Returns zero on success; non-zero on error.
1541 */
1542 static int
parse_tag_11_packet(unsigned char * data,unsigned char * contents,size_t max_contents_bytes,size_t * tag_11_contents_size,size_t * packet_size,size_t max_packet_size)1543 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1544 size_t max_contents_bytes, size_t *tag_11_contents_size,
1545 size_t *packet_size, size_t max_packet_size)
1546 {
1547 size_t body_size;
1548 size_t length_size;
1549 int rc = 0;
1550
1551 (*packet_size) = 0;
1552 (*tag_11_contents_size) = 0;
1553 /* This format is inspired by OpenPGP; see RFC 2440
1554 * packet tag 11
1555 *
1556 * Tag 11 identifier (1 byte)
1557 * Max Tag 11 packet size (max 3 bytes)
1558 * Binary format specifier (1 byte)
1559 * Filename length (1 byte)
1560 * Filename ("_CONSOLE") (8 bytes)
1561 * Modification date (4 bytes)
1562 * Literal data (arbitrary)
1563 *
1564 * We need at least 16 bytes of data for the packet to even be
1565 * valid.
1566 */
1567 if (max_packet_size < 16) {
1568 printk(KERN_ERR "Maximum packet size too small\n");
1569 rc = -EINVAL;
1570 goto out;
1571 }
1572 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1573 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1574 rc = -EINVAL;
1575 goto out;
1576 }
1577 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1578 &length_size);
1579 if (rc) {
1580 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1581 goto out;
1582 }
1583 if (body_size < 14) {
1584 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1585 rc = -EINVAL;
1586 goto out;
1587 }
1588 (*packet_size) += length_size;
1589 (*tag_11_contents_size) = (body_size - 14);
1590 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1591 printk(KERN_ERR "Packet size exceeds max\n");
1592 rc = -EINVAL;
1593 goto out;
1594 }
1595 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1596 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1597 "expected size\n");
1598 rc = -EINVAL;
1599 goto out;
1600 }
1601 if (data[(*packet_size)++] != 0x62) {
1602 printk(KERN_WARNING "Unrecognizable packet\n");
1603 rc = -EINVAL;
1604 goto out;
1605 }
1606 if (data[(*packet_size)++] != 0x08) {
1607 printk(KERN_WARNING "Unrecognizable packet\n");
1608 rc = -EINVAL;
1609 goto out;
1610 }
1611 (*packet_size) += 12; /* Ignore filename and modification date */
1612 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1613 (*packet_size) += (*tag_11_contents_size);
1614 out:
1615 if (rc) {
1616 (*packet_size) = 0;
1617 (*tag_11_contents_size) = 0;
1618 }
1619 return rc;
1620 }
1621
ecryptfs_keyring_auth_tok_for_sig(struct key ** auth_tok_key,struct ecryptfs_auth_tok ** auth_tok,char * sig)1622 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1623 struct ecryptfs_auth_tok **auth_tok,
1624 char *sig)
1625 {
1626 int rc = 0;
1627
1628 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1629 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1630 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1631 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1632 printk(KERN_ERR "Could not find key with description: [%s]\n",
1633 sig);
1634 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1635 (*auth_tok_key) = NULL;
1636 goto out;
1637 }
1638 }
1639 down_write(&(*auth_tok_key)->sem);
1640 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1641 if (rc) {
1642 up_write(&(*auth_tok_key)->sem);
1643 key_put(*auth_tok_key);
1644 (*auth_tok_key) = NULL;
1645 goto out;
1646 }
1647 out:
1648 return rc;
1649 }
1650
1651 /**
1652 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1653 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1654 * @crypt_stat: The cryptographic context
1655 *
1656 * Returns zero on success; non-zero error otherwise
1657 */
1658 static int
decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat)1659 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1660 struct ecryptfs_crypt_stat *crypt_stat)
1661 {
1662 struct scatterlist dst_sg[2];
1663 struct scatterlist src_sg[2];
1664 struct mutex *tfm_mutex;
1665 struct crypto_skcipher *tfm;
1666 struct skcipher_request *req = NULL;
1667 int rc = 0;
1668
1669 if (unlikely(ecryptfs_verbosity > 0)) {
1670 ecryptfs_printk(
1671 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1672 auth_tok->token.password.session_key_encryption_key_bytes);
1673 ecryptfs_dump_hex(
1674 auth_tok->token.password.session_key_encryption_key,
1675 auth_tok->token.password.session_key_encryption_key_bytes);
1676 }
1677 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
1678 crypt_stat->cipher);
1679 if (unlikely(rc)) {
1680 printk(KERN_ERR "Internal error whilst attempting to get "
1681 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1682 crypt_stat->cipher, rc);
1683 goto out;
1684 }
1685 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1686 auth_tok->session_key.encrypted_key_size,
1687 src_sg, 2);
1688 if (rc < 1 || rc > 2) {
1689 printk(KERN_ERR "Internal error whilst attempting to convert "
1690 "auth_tok->session_key.encrypted_key to scatterlist; "
1691 "expected rc = 1; got rc = [%d]. "
1692 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1693 auth_tok->session_key.encrypted_key_size);
1694 goto out;
1695 }
1696 auth_tok->session_key.decrypted_key_size =
1697 auth_tok->session_key.encrypted_key_size;
1698 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1699 auth_tok->session_key.decrypted_key_size,
1700 dst_sg, 2);
1701 if (rc < 1 || rc > 2) {
1702 printk(KERN_ERR "Internal error whilst attempting to convert "
1703 "auth_tok->session_key.decrypted_key to scatterlist; "
1704 "expected rc = 1; got rc = [%d]\n", rc);
1705 goto out;
1706 }
1707 mutex_lock(tfm_mutex);
1708 req = skcipher_request_alloc(tfm, GFP_KERNEL);
1709 if (!req) {
1710 mutex_unlock(tfm_mutex);
1711 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1712 "skcipher_request_alloc for %s\n", __func__,
1713 crypto_skcipher_driver_name(tfm));
1714 rc = -ENOMEM;
1715 goto out;
1716 }
1717
1718 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
1719 NULL, NULL);
1720 rc = crypto_skcipher_setkey(
1721 tfm, auth_tok->token.password.session_key_encryption_key,
1722 crypt_stat->key_size);
1723 if (unlikely(rc < 0)) {
1724 mutex_unlock(tfm_mutex);
1725 printk(KERN_ERR "Error setting key for crypto context\n");
1726 rc = -EINVAL;
1727 goto out;
1728 }
1729 skcipher_request_set_crypt(req, src_sg, dst_sg,
1730 auth_tok->session_key.encrypted_key_size,
1731 NULL);
1732 rc = crypto_skcipher_decrypt(req);
1733 mutex_unlock(tfm_mutex);
1734 if (unlikely(rc)) {
1735 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1736 goto out;
1737 }
1738 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1739 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1740 auth_tok->session_key.decrypted_key_size);
1741 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1742 if (unlikely(ecryptfs_verbosity > 0)) {
1743 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1744 crypt_stat->key_size);
1745 ecryptfs_dump_hex(crypt_stat->key,
1746 crypt_stat->key_size);
1747 }
1748 out:
1749 skcipher_request_free(req);
1750 return rc;
1751 }
1752
1753 /**
1754 * ecryptfs_parse_packet_set
1755 * @crypt_stat: The cryptographic context
1756 * @src: Virtual address of region of memory containing the packets
1757 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1758 *
1759 * Get crypt_stat to have the file's session key if the requisite key
1760 * is available to decrypt the session key.
1761 *
1762 * Returns Zero if a valid authentication token was retrieved and
1763 * processed; negative value for file not encrypted or for error
1764 * conditions.
1765 */
ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat * crypt_stat,unsigned char * src,struct dentry * ecryptfs_dentry)1766 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1767 unsigned char *src,
1768 struct dentry *ecryptfs_dentry)
1769 {
1770 size_t i = 0;
1771 size_t found_auth_tok;
1772 size_t next_packet_is_auth_tok_packet;
1773 struct list_head auth_tok_list;
1774 struct ecryptfs_auth_tok *matching_auth_tok;
1775 struct ecryptfs_auth_tok *candidate_auth_tok;
1776 char *candidate_auth_tok_sig;
1777 size_t packet_size;
1778 struct ecryptfs_auth_tok *new_auth_tok;
1779 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1780 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1781 size_t tag_11_contents_size;
1782 size_t tag_11_packet_size;
1783 struct key *auth_tok_key = NULL;
1784 int rc = 0;
1785
1786 INIT_LIST_HEAD(&auth_tok_list);
1787 /* Parse the header to find as many packets as we can; these will be
1788 * added the our &auth_tok_list */
1789 next_packet_is_auth_tok_packet = 1;
1790 while (next_packet_is_auth_tok_packet) {
1791 size_t max_packet_size = ((PAGE_SIZE - 8) - i);
1792
1793 switch (src[i]) {
1794 case ECRYPTFS_TAG_3_PACKET_TYPE:
1795 rc = parse_tag_3_packet(crypt_stat,
1796 (unsigned char *)&src[i],
1797 &auth_tok_list, &new_auth_tok,
1798 &packet_size, max_packet_size);
1799 if (rc) {
1800 ecryptfs_printk(KERN_ERR, "Error parsing "
1801 "tag 3 packet\n");
1802 rc = -EIO;
1803 goto out_wipe_list;
1804 }
1805 i += packet_size;
1806 rc = parse_tag_11_packet((unsigned char *)&src[i],
1807 sig_tmp_space,
1808 ECRYPTFS_SIG_SIZE,
1809 &tag_11_contents_size,
1810 &tag_11_packet_size,
1811 max_packet_size);
1812 if (rc) {
1813 ecryptfs_printk(KERN_ERR, "No valid "
1814 "(ecryptfs-specific) literal "
1815 "packet containing "
1816 "authentication token "
1817 "signature found after "
1818 "tag 3 packet\n");
1819 rc = -EIO;
1820 goto out_wipe_list;
1821 }
1822 i += tag_11_packet_size;
1823 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1824 ecryptfs_printk(KERN_ERR, "Expected "
1825 "signature of size [%d]; "
1826 "read size [%zd]\n",
1827 ECRYPTFS_SIG_SIZE,
1828 tag_11_contents_size);
1829 rc = -EIO;
1830 goto out_wipe_list;
1831 }
1832 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1833 sig_tmp_space, tag_11_contents_size);
1834 new_auth_tok->token.password.signature[
1835 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1836 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1837 break;
1838 case ECRYPTFS_TAG_1_PACKET_TYPE:
1839 rc = parse_tag_1_packet(crypt_stat,
1840 (unsigned char *)&src[i],
1841 &auth_tok_list, &new_auth_tok,
1842 &packet_size, max_packet_size);
1843 if (rc) {
1844 ecryptfs_printk(KERN_ERR, "Error parsing "
1845 "tag 1 packet\n");
1846 rc = -EIO;
1847 goto out_wipe_list;
1848 }
1849 i += packet_size;
1850 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1851 break;
1852 case ECRYPTFS_TAG_11_PACKET_TYPE:
1853 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1854 "(Tag 11 not allowed by itself)\n");
1855 rc = -EIO;
1856 goto out_wipe_list;
1857 default:
1858 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1859 "of the file header; hex value of "
1860 "character is [0x%.2x]\n", i, src[i]);
1861 next_packet_is_auth_tok_packet = 0;
1862 }
1863 }
1864 if (list_empty(&auth_tok_list)) {
1865 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1866 "eCryptfs file; this is not supported in this version "
1867 "of the eCryptfs kernel module\n");
1868 rc = -EINVAL;
1869 goto out;
1870 }
1871 /* auth_tok_list contains the set of authentication tokens
1872 * parsed from the metadata. We need to find a matching
1873 * authentication token that has the secret component(s)
1874 * necessary to decrypt the EFEK in the auth_tok parsed from
1875 * the metadata. There may be several potential matches, but
1876 * just one will be sufficient to decrypt to get the FEK. */
1877 find_next_matching_auth_tok:
1878 found_auth_tok = 0;
1879 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1880 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1881 if (unlikely(ecryptfs_verbosity > 0)) {
1882 ecryptfs_printk(KERN_DEBUG,
1883 "Considering candidate auth tok:\n");
1884 ecryptfs_dump_auth_tok(candidate_auth_tok);
1885 }
1886 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1887 candidate_auth_tok);
1888 if (rc) {
1889 printk(KERN_ERR
1890 "Unrecognized candidate auth tok type: [%d]\n",
1891 candidate_auth_tok->token_type);
1892 rc = -EINVAL;
1893 goto out_wipe_list;
1894 }
1895 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1896 &matching_auth_tok,
1897 crypt_stat->mount_crypt_stat,
1898 candidate_auth_tok_sig);
1899 if (!rc) {
1900 found_auth_tok = 1;
1901 goto found_matching_auth_tok;
1902 }
1903 }
1904 if (!found_auth_tok) {
1905 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1906 "authentication token\n");
1907 rc = -EIO;
1908 goto out_wipe_list;
1909 }
1910 found_matching_auth_tok:
1911 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1912 memcpy(&(candidate_auth_tok->token.private_key),
1913 &(matching_auth_tok->token.private_key),
1914 sizeof(struct ecryptfs_private_key));
1915 up_write(&(auth_tok_key->sem));
1916 key_put(auth_tok_key);
1917 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1918 crypt_stat);
1919 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1920 memcpy(&(candidate_auth_tok->token.password),
1921 &(matching_auth_tok->token.password),
1922 sizeof(struct ecryptfs_password));
1923 up_write(&(auth_tok_key->sem));
1924 key_put(auth_tok_key);
1925 rc = decrypt_passphrase_encrypted_session_key(
1926 candidate_auth_tok, crypt_stat);
1927 } else {
1928 up_write(&(auth_tok_key->sem));
1929 key_put(auth_tok_key);
1930 rc = -EINVAL;
1931 }
1932 if (rc) {
1933 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1934
1935 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1936 "session key for authentication token with sig "
1937 "[%.*s]; rc = [%d]. Removing auth tok "
1938 "candidate from the list and searching for "
1939 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1940 candidate_auth_tok_sig, rc);
1941 list_for_each_entry_safe(auth_tok_list_item,
1942 auth_tok_list_item_tmp,
1943 &auth_tok_list, list) {
1944 if (candidate_auth_tok
1945 == &auth_tok_list_item->auth_tok) {
1946 list_del(&auth_tok_list_item->list);
1947 kmem_cache_free(
1948 ecryptfs_auth_tok_list_item_cache,
1949 auth_tok_list_item);
1950 goto find_next_matching_auth_tok;
1951 }
1952 }
1953 BUG();
1954 }
1955 rc = ecryptfs_compute_root_iv(crypt_stat);
1956 if (rc) {
1957 ecryptfs_printk(KERN_ERR, "Error computing "
1958 "the root IV\n");
1959 goto out_wipe_list;
1960 }
1961 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1962 if (rc) {
1963 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1964 "context for cipher [%s]; rc = [%d]\n",
1965 crypt_stat->cipher, rc);
1966 }
1967 out_wipe_list:
1968 wipe_auth_tok_list(&auth_tok_list);
1969 out:
1970 return rc;
1971 }
1972
1973 static int
pki_encrypt_session_key(struct key * auth_tok_key,struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_key_record * key_rec)1974 pki_encrypt_session_key(struct key *auth_tok_key,
1975 struct ecryptfs_auth_tok *auth_tok,
1976 struct ecryptfs_crypt_stat *crypt_stat,
1977 struct ecryptfs_key_record *key_rec)
1978 {
1979 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1980 char *payload = NULL;
1981 size_t payload_len = 0;
1982 struct ecryptfs_message *msg;
1983 int rc;
1984
1985 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1986 ecryptfs_code_for_cipher_string(
1987 crypt_stat->cipher,
1988 crypt_stat->key_size),
1989 crypt_stat, &payload, &payload_len);
1990 up_write(&(auth_tok_key->sem));
1991 key_put(auth_tok_key);
1992 if (rc) {
1993 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1994 goto out;
1995 }
1996 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1997 if (rc) {
1998 ecryptfs_printk(KERN_ERR, "Error sending message to "
1999 "ecryptfsd: %d\n", rc);
2000 goto out;
2001 }
2002 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
2003 if (rc) {
2004 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2005 "from the user space daemon\n");
2006 rc = -EIO;
2007 goto out;
2008 }
2009 rc = parse_tag_67_packet(key_rec, msg);
2010 if (rc)
2011 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2012 kfree(msg);
2013 out:
2014 kfree(payload);
2015 return rc;
2016 }
2017 /**
2018 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2019 * @dest: Buffer into which to write the packet
2020 * @remaining_bytes: Maximum number of bytes that can be writtn
2021 * @auth_tok_key: The authentication token key to unlock and put when done with
2022 * @auth_tok
2023 * @auth_tok: The authentication token used for generating the tag 1 packet
2024 * @crypt_stat: The cryptographic context
2025 * @key_rec: The key record struct for the tag 1 packet
2026 * @packet_size: This function will write the number of bytes that end
2027 * up constituting the packet; set to zero on error
2028 *
2029 * Returns zero on success; non-zero on error.
2030 */
2031 static int
write_tag_1_packet(char * dest,size_t * remaining_bytes,struct key * auth_tok_key,struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_key_record * key_rec,size_t * packet_size)2032 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2033 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2034 struct ecryptfs_crypt_stat *crypt_stat,
2035 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2036 {
2037 size_t i;
2038 size_t encrypted_session_key_valid = 0;
2039 size_t packet_size_length;
2040 size_t max_packet_size;
2041 int rc = 0;
2042
2043 (*packet_size) = 0;
2044 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2045 ECRYPTFS_SIG_SIZE);
2046 encrypted_session_key_valid = 0;
2047 for (i = 0; i < crypt_stat->key_size; i++)
2048 encrypted_session_key_valid |=
2049 auth_tok->session_key.encrypted_key[i];
2050 if (encrypted_session_key_valid) {
2051 memcpy(key_rec->enc_key,
2052 auth_tok->session_key.encrypted_key,
2053 auth_tok->session_key.encrypted_key_size);
2054 up_write(&(auth_tok_key->sem));
2055 key_put(auth_tok_key);
2056 goto encrypted_session_key_set;
2057 }
2058 if (auth_tok->session_key.encrypted_key_size == 0)
2059 auth_tok->session_key.encrypted_key_size =
2060 auth_tok->token.private_key.key_size;
2061 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2062 key_rec);
2063 if (rc) {
2064 printk(KERN_ERR "Failed to encrypt session key via a key "
2065 "module; rc = [%d]\n", rc);
2066 goto out;
2067 }
2068 if (ecryptfs_verbosity > 0) {
2069 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2070 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2071 }
2072 encrypted_session_key_set:
2073 /* This format is inspired by OpenPGP; see RFC 2440
2074 * packet tag 1 */
2075 max_packet_size = (1 /* Tag 1 identifier */
2076 + 3 /* Max Tag 1 packet size */
2077 + 1 /* Version */
2078 + ECRYPTFS_SIG_SIZE /* Key identifier */
2079 + 1 /* Cipher identifier */
2080 + key_rec->enc_key_size); /* Encrypted key size */
2081 if (max_packet_size > (*remaining_bytes)) {
2082 printk(KERN_ERR "Packet length larger than maximum allowable; "
2083 "need up to [%td] bytes, but there are only [%td] "
2084 "available\n", max_packet_size, (*remaining_bytes));
2085 rc = -EINVAL;
2086 goto out;
2087 }
2088 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2089 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2090 (max_packet_size - 4),
2091 &packet_size_length);
2092 if (rc) {
2093 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2094 "header; cannot generate packet length\n");
2095 goto out;
2096 }
2097 (*packet_size) += packet_size_length;
2098 dest[(*packet_size)++] = 0x03; /* version 3 */
2099 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2100 (*packet_size) += ECRYPTFS_SIG_SIZE;
2101 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2102 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2103 key_rec->enc_key_size);
2104 (*packet_size) += key_rec->enc_key_size;
2105 out:
2106 if (rc)
2107 (*packet_size) = 0;
2108 else
2109 (*remaining_bytes) -= (*packet_size);
2110 return rc;
2111 }
2112
2113 /**
2114 * write_tag_11_packet
2115 * @dest: Target into which Tag 11 packet is to be written
2116 * @remaining_bytes: Maximum packet length
2117 * @contents: Byte array of contents to copy in
2118 * @contents_length: Number of bytes in contents
2119 * @packet_length: Length of the Tag 11 packet written; zero on error
2120 *
2121 * Returns zero on success; non-zero on error.
2122 */
2123 static int
write_tag_11_packet(char * dest,size_t * remaining_bytes,char * contents,size_t contents_length,size_t * packet_length)2124 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2125 size_t contents_length, size_t *packet_length)
2126 {
2127 size_t packet_size_length;
2128 size_t max_packet_size;
2129 int rc = 0;
2130
2131 (*packet_length) = 0;
2132 /* This format is inspired by OpenPGP; see RFC 2440
2133 * packet tag 11 */
2134 max_packet_size = (1 /* Tag 11 identifier */
2135 + 3 /* Max Tag 11 packet size */
2136 + 1 /* Binary format specifier */
2137 + 1 /* Filename length */
2138 + 8 /* Filename ("_CONSOLE") */
2139 + 4 /* Modification date */
2140 + contents_length); /* Literal data */
2141 if (max_packet_size > (*remaining_bytes)) {
2142 printk(KERN_ERR "Packet length larger than maximum allowable; "
2143 "need up to [%td] bytes, but there are only [%td] "
2144 "available\n", max_packet_size, (*remaining_bytes));
2145 rc = -EINVAL;
2146 goto out;
2147 }
2148 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2149 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2150 (max_packet_size - 4),
2151 &packet_size_length);
2152 if (rc) {
2153 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2154 "generate packet length. rc = [%d]\n", rc);
2155 goto out;
2156 }
2157 (*packet_length) += packet_size_length;
2158 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2159 dest[(*packet_length)++] = 8;
2160 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2161 (*packet_length) += 8;
2162 memset(&dest[(*packet_length)], 0x00, 4);
2163 (*packet_length) += 4;
2164 memcpy(&dest[(*packet_length)], contents, contents_length);
2165 (*packet_length) += contents_length;
2166 out:
2167 if (rc)
2168 (*packet_length) = 0;
2169 else
2170 (*remaining_bytes) -= (*packet_length);
2171 return rc;
2172 }
2173
2174 /**
2175 * write_tag_3_packet
2176 * @dest: Buffer into which to write the packet
2177 * @remaining_bytes: Maximum number of bytes that can be written
2178 * @auth_tok: Authentication token
2179 * @crypt_stat: The cryptographic context
2180 * @key_rec: encrypted key
2181 * @packet_size: This function will write the number of bytes that end
2182 * up constituting the packet; set to zero on error
2183 *
2184 * Returns zero on success; non-zero on error.
2185 */
2186 static int
write_tag_3_packet(char * dest,size_t * remaining_bytes,struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_key_record * key_rec,size_t * packet_size)2187 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2188 struct ecryptfs_auth_tok *auth_tok,
2189 struct ecryptfs_crypt_stat *crypt_stat,
2190 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2191 {
2192 size_t i;
2193 size_t encrypted_session_key_valid = 0;
2194 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2195 struct scatterlist dst_sg[2];
2196 struct scatterlist src_sg[2];
2197 struct mutex *tfm_mutex = NULL;
2198 u8 cipher_code;
2199 size_t packet_size_length;
2200 size_t max_packet_size;
2201 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2202 crypt_stat->mount_crypt_stat;
2203 struct crypto_skcipher *tfm;
2204 struct skcipher_request *req;
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(&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 printk(KERN_WARNING "No key size specified at mount; "
2220 "defaulting to [%d]\n",
2221 crypto_skcipher_default_keysize(tfm));
2222 mount_crypt_stat->global_default_cipher_key_size =
2223 crypto_skcipher_default_keysize(tfm);
2224 }
2225 if (crypt_stat->key_size == 0)
2226 crypt_stat->key_size =
2227 mount_crypt_stat->global_default_cipher_key_size;
2228 if (auth_tok->session_key.encrypted_key_size == 0)
2229 auth_tok->session_key.encrypted_key_size =
2230 crypt_stat->key_size;
2231 if (crypt_stat->key_size == 24
2232 && strcmp("aes", crypt_stat->cipher) == 0) {
2233 memset((crypt_stat->key + 24), 0, 8);
2234 auth_tok->session_key.encrypted_key_size = 32;
2235 } else
2236 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2237 key_rec->enc_key_size =
2238 auth_tok->session_key.encrypted_key_size;
2239 encrypted_session_key_valid = 0;
2240 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2241 encrypted_session_key_valid |=
2242 auth_tok->session_key.encrypted_key[i];
2243 if (encrypted_session_key_valid) {
2244 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2245 "using auth_tok->session_key.encrypted_key, "
2246 "where key_rec->enc_key_size = [%zd]\n",
2247 key_rec->enc_key_size);
2248 memcpy(key_rec->enc_key,
2249 auth_tok->session_key.encrypted_key,
2250 key_rec->enc_key_size);
2251 goto encrypted_session_key_set;
2252 }
2253 if (auth_tok->token.password.flags &
2254 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2255 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2256 "session key encryption key of size [%d]\n",
2257 auth_tok->token.password.
2258 session_key_encryption_key_bytes);
2259 memcpy(session_key_encryption_key,
2260 auth_tok->token.password.session_key_encryption_key,
2261 crypt_stat->key_size);
2262 ecryptfs_printk(KERN_DEBUG,
2263 "Cached session key encryption key:\n");
2264 if (ecryptfs_verbosity > 0)
2265 ecryptfs_dump_hex(session_key_encryption_key, 16);
2266 }
2267 if (unlikely(ecryptfs_verbosity > 0)) {
2268 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2269 ecryptfs_dump_hex(session_key_encryption_key, 16);
2270 }
2271 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2272 src_sg, 2);
2273 if (rc < 1 || rc > 2) {
2274 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2275 "for crypt_stat session key; expected rc = 1; "
2276 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2277 rc, key_rec->enc_key_size);
2278 rc = -ENOMEM;
2279 goto out;
2280 }
2281 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2282 dst_sg, 2);
2283 if (rc < 1 || rc > 2) {
2284 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2285 "for crypt_stat encrypted session key; "
2286 "expected rc = 1; got rc = [%d]. "
2287 "key_rec->enc_key_size = [%zd]\n", rc,
2288 key_rec->enc_key_size);
2289 rc = -ENOMEM;
2290 goto out;
2291 }
2292 mutex_lock(tfm_mutex);
2293 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
2294 crypt_stat->key_size);
2295 if (rc < 0) {
2296 mutex_unlock(tfm_mutex);
2297 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2298 "context; rc = [%d]\n", rc);
2299 goto out;
2300 }
2301
2302 req = skcipher_request_alloc(tfm, GFP_KERNEL);
2303 if (!req) {
2304 mutex_unlock(tfm_mutex);
2305 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
2306 "attempting to skcipher_request_alloc for "
2307 "%s\n", crypto_skcipher_driver_name(tfm));
2308 rc = -ENOMEM;
2309 goto out;
2310 }
2311
2312 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
2313 NULL, NULL);
2314
2315 rc = 0;
2316 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2317 crypt_stat->key_size);
2318 skcipher_request_set_crypt(req, src_sg, dst_sg,
2319 (*key_rec).enc_key_size, NULL);
2320 rc = crypto_skcipher_encrypt(req);
2321 mutex_unlock(tfm_mutex);
2322 skcipher_request_free(req);
2323 if (rc) {
2324 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2325 goto out;
2326 }
2327 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2328 if (ecryptfs_verbosity > 0) {
2329 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2330 key_rec->enc_key_size);
2331 ecryptfs_dump_hex(key_rec->enc_key,
2332 key_rec->enc_key_size);
2333 }
2334 encrypted_session_key_set:
2335 /* This format is inspired by OpenPGP; see RFC 2440
2336 * packet tag 3 */
2337 max_packet_size = (1 /* Tag 3 identifier */
2338 + 3 /* Max Tag 3 packet size */
2339 + 1 /* Version */
2340 + 1 /* Cipher code */
2341 + 1 /* S2K specifier */
2342 + 1 /* Hash identifier */
2343 + ECRYPTFS_SALT_SIZE /* Salt */
2344 + 1 /* Hash iterations */
2345 + key_rec->enc_key_size); /* Encrypted key size */
2346 if (max_packet_size > (*remaining_bytes)) {
2347 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2348 "there are only [%td] available\n", max_packet_size,
2349 (*remaining_bytes));
2350 rc = -EINVAL;
2351 goto out;
2352 }
2353 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2354 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2355 * to get the number of octets in the actual Tag 3 packet */
2356 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2357 (max_packet_size - 4),
2358 &packet_size_length);
2359 if (rc) {
2360 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2361 "generate packet length. rc = [%d]\n", rc);
2362 goto out;
2363 }
2364 (*packet_size) += packet_size_length;
2365 dest[(*packet_size)++] = 0x04; /* version 4 */
2366 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2367 * specified with strings */
2368 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2369 crypt_stat->key_size);
2370 if (cipher_code == 0) {
2371 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2372 "cipher [%s]\n", crypt_stat->cipher);
2373 rc = -EINVAL;
2374 goto out;
2375 }
2376 dest[(*packet_size)++] = cipher_code;
2377 dest[(*packet_size)++] = 0x03; /* S2K */
2378 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2379 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2380 ECRYPTFS_SALT_SIZE);
2381 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2382 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2383 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2384 key_rec->enc_key_size);
2385 (*packet_size) += key_rec->enc_key_size;
2386 out:
2387 if (rc)
2388 (*packet_size) = 0;
2389 else
2390 (*remaining_bytes) -= (*packet_size);
2391 return rc;
2392 }
2393
2394 struct kmem_cache *ecryptfs_key_record_cache;
2395
2396 /**
2397 * ecryptfs_generate_key_packet_set
2398 * @dest_base: Virtual address from which to write the key record set
2399 * @crypt_stat: The cryptographic context from which the
2400 * authentication tokens will be retrieved
2401 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2402 * for the global parameters
2403 * @len: The amount written
2404 * @max: The maximum amount of data allowed to be written
2405 *
2406 * Generates a key packet set and writes it to the virtual address
2407 * passed in.
2408 *
2409 * Returns zero on success; non-zero on error.
2410 */
2411 int
ecryptfs_generate_key_packet_set(char * dest_base,struct ecryptfs_crypt_stat * crypt_stat,struct dentry * ecryptfs_dentry,size_t * len,size_t max)2412 ecryptfs_generate_key_packet_set(char *dest_base,
2413 struct ecryptfs_crypt_stat *crypt_stat,
2414 struct dentry *ecryptfs_dentry, size_t *len,
2415 size_t max)
2416 {
2417 struct ecryptfs_auth_tok *auth_tok;
2418 struct key *auth_tok_key = NULL;
2419 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2420 &ecryptfs_superblock_to_private(
2421 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2422 size_t written;
2423 struct ecryptfs_key_record *key_rec;
2424 struct ecryptfs_key_sig *key_sig;
2425 int rc = 0;
2426
2427 (*len) = 0;
2428 mutex_lock(&crypt_stat->keysig_list_mutex);
2429 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2430 if (!key_rec) {
2431 rc = -ENOMEM;
2432 goto out;
2433 }
2434 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2435 crypt_stat_list) {
2436 memset(key_rec, 0, sizeof(*key_rec));
2437 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2438 &auth_tok,
2439 mount_crypt_stat,
2440 key_sig->keysig);
2441 if (rc) {
2442 printk(KERN_WARNING "Unable to retrieve auth tok with "
2443 "sig = [%s]\n", key_sig->keysig);
2444 rc = process_find_global_auth_tok_for_sig_err(rc);
2445 goto out_free;
2446 }
2447 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2448 rc = write_tag_3_packet((dest_base + (*len)),
2449 &max, auth_tok,
2450 crypt_stat, key_rec,
2451 &written);
2452 up_write(&(auth_tok_key->sem));
2453 key_put(auth_tok_key);
2454 if (rc) {
2455 ecryptfs_printk(KERN_WARNING, "Error "
2456 "writing tag 3 packet\n");
2457 goto out_free;
2458 }
2459 (*len) += written;
2460 /* Write auth tok signature packet */
2461 rc = write_tag_11_packet((dest_base + (*len)), &max,
2462 key_rec->sig,
2463 ECRYPTFS_SIG_SIZE, &written);
2464 if (rc) {
2465 ecryptfs_printk(KERN_ERR, "Error writing "
2466 "auth tok signature packet\n");
2467 goto out_free;
2468 }
2469 (*len) += written;
2470 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2471 rc = write_tag_1_packet(dest_base + (*len), &max,
2472 auth_tok_key, auth_tok,
2473 crypt_stat, key_rec, &written);
2474 if (rc) {
2475 ecryptfs_printk(KERN_WARNING, "Error "
2476 "writing tag 1 packet\n");
2477 goto out_free;
2478 }
2479 (*len) += written;
2480 } else {
2481 up_write(&(auth_tok_key->sem));
2482 key_put(auth_tok_key);
2483 ecryptfs_printk(KERN_WARNING, "Unsupported "
2484 "authentication token type\n");
2485 rc = -EINVAL;
2486 goto out_free;
2487 }
2488 }
2489 if (likely(max > 0)) {
2490 dest_base[(*len)] = 0x00;
2491 } else {
2492 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2493 rc = -EIO;
2494 }
2495 out_free:
2496 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2497 out:
2498 if (rc)
2499 (*len) = 0;
2500 mutex_unlock(&crypt_stat->keysig_list_mutex);
2501 return rc;
2502 }
2503
2504 struct kmem_cache *ecryptfs_key_sig_cache;
2505
ecryptfs_add_keysig(struct ecryptfs_crypt_stat * crypt_stat,char * sig)2506 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2507 {
2508 struct ecryptfs_key_sig *new_key_sig;
2509
2510 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2511 if (!new_key_sig)
2512 return -ENOMEM;
2513
2514 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2515 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2516 /* Caller must hold keysig_list_mutex */
2517 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2518
2519 return 0;
2520 }
2521
2522 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2523
2524 int
ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * sig,u32 global_auth_tok_flags)2525 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2526 char *sig, u32 global_auth_tok_flags)
2527 {
2528 struct ecryptfs_global_auth_tok *new_auth_tok;
2529
2530 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2531 GFP_KERNEL);
2532 if (!new_auth_tok)
2533 return -ENOMEM;
2534
2535 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2536 new_auth_tok->flags = global_auth_tok_flags;
2537 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2538 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2539 list_add(&new_auth_tok->mount_crypt_stat_list,
2540 &mount_crypt_stat->global_auth_tok_list);
2541 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2542 return 0;
2543 }
2544
2545
