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[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / ecryptfs / keystore.c
blob89dc18e7e9578053166fb014a4c17f907e384530
1 /**
2 * eCryptfs: Linux filesystem encryption layer
3 * In-kernel key management code. Includes functions to parse and
4 * write authentication token-related packets with the underlying
5 * file.
6 *
7 * Copyright (C) 2004-2006 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
9 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * Trevor S. Highland <trevor.highland@gmail.com>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
25 * 02111-1307, USA.
26 */
27
28 #include <linux/string.h>
29 #include <linux/syscalls.h>
30 #include <linux/pagemap.h>
31 #include <linux/key.h>
32 #include <linux/random.h>
33 #include <linux/crypto.h>
34 #include <linux/scatterlist.h>
35 #include <linux/slab.h>
36 #include "ecryptfs_kernel.h"
37
38 /**
39 * request_key returned an error instead of a valid key address;
40 * determine the type of error, make appropriate log entries, and
41 * return an error code.
42 */
43 static int process_request_key_err(long err_code)
44 {
45 int rc = 0;
46
47 switch (err_code) {
48 case -ENOKEY:
49 ecryptfs_printk(KERN_WARNING, "No key\n");
50 rc = -ENOENT;
51 break;
52 case -EKEYEXPIRED:
53 ecryptfs_printk(KERN_WARNING, "Key expired\n");
54 rc = -ETIME;
55 break;
56 case -EKEYREVOKED:
57 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
58 rc = -EINVAL;
59 break;
60 default:
61 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
62 "[0x%.16lx]\n", err_code);
63 rc = -EINVAL;
64 }
65 return rc;
66 }
67
68 static int process_find_global_auth_tok_for_sig_err(int err_code)
69 {
70 int rc = err_code;
71
72 switch (err_code) {
73 case -ENOENT:
74 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
75 break;
76 case -EINVAL:
77 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
78 break;
79 default:
80 rc = process_request_key_err(err_code);
81 break;
82 }
83 return rc;
84 }
85
86 /**
87 * ecryptfs_parse_packet_length
88 * @data: Pointer to memory containing length at offset
89 * @size: This function writes the decoded size to this memory
90 * address; zero on error
91 * @length_size: The number of bytes occupied by the encoded length
92 *
93 * Returns zero on success; non-zero on error
94 */
95 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
96 size_t *length_size)
97 {
98 int rc = 0;
99
100 (*length_size) = 0;
101 (*size) = 0;
102 if (data[0] < 192) {
103 /* One-byte length */
104 (*size) = (unsigned char)data[0];
105 (*length_size) = 1;
106 } else if (data[0] < 224) {
107 /* Two-byte length */
108 (*size) = (((unsigned char)(data[0]) - 192) * 256);
109 (*size) += ((unsigned char)(data[1]) + 192);
110 (*length_size) = 2;
111 } else if (data[0] == 255) {
112 /* Five-byte length; we're not supposed to see this */
113 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
114 "supported\n");
115 rc = -EINVAL;
116 goto out;
117 } else {
118 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
119 rc = -EINVAL;
120 goto out;
121 }
122 out:
123 return rc;
124 }
125
126 /**
127 * ecryptfs_write_packet_length
128 * @dest: The byte array target into which to write the length. Must
129 * have at least 5 bytes allocated.
130 * @size: The length to write.
131 * @packet_size_length: The number of bytes used to encode the packet
132 * length is written to this address.
133 *
134 * Returns zero on success; non-zero on error.
135 */
136 int ecryptfs_write_packet_length(char *dest, size_t size,
137 size_t *packet_size_length)
138 {
139 int rc = 0;
140
141 if (size < 192) {
142 dest[0] = size;
143 (*packet_size_length) = 1;
144 } else if (size < 65536) {
145 dest[0] = (((size - 192) / 256) + 192);
146 dest[1] = ((size - 192) % 256);
147 (*packet_size_length) = 2;
148 } else {
149 rc = -EINVAL;
150 ecryptfs_printk(KERN_WARNING,
151 "Unsupported packet size: [%zd]\n", size);
152 }
153 return rc;
154 }
155
156 static int
157 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
158 char **packet, size_t *packet_len)
159 {
160 size_t i = 0;
161 size_t data_len;
162 size_t packet_size_len;
163 char *message;
164 int rc;
165
166 /*
167 * ***** TAG 64 Packet Format *****
168 * | Content Type | 1 byte |
169 * | Key Identifier Size | 1 or 2 bytes |
170 * | Key Identifier | arbitrary |
171 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
172 * | Encrypted File Encryption Key | arbitrary |
173 */
174 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
175 + session_key->encrypted_key_size);
176 *packet = kmalloc(data_len, GFP_KERNEL);
177 message = *packet;
178 if (!message) {
179 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
180 rc = -ENOMEM;
181 goto out;
182 }
183 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
184 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
185 &packet_size_len);
186 if (rc) {
187 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
188 "header; cannot generate packet length\n");
189 goto out;
190 }
191 i += packet_size_len;
192 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
193 i += ECRYPTFS_SIG_SIZE_HEX;
194 rc = ecryptfs_write_packet_length(&message[i],
195 session_key->encrypted_key_size,
196 &packet_size_len);
197 if (rc) {
198 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
199 "header; cannot generate packet length\n");
200 goto out;
201 }
202 i += packet_size_len;
203 memcpy(&message[i], session_key->encrypted_key,
204 session_key->encrypted_key_size);
205 i += session_key->encrypted_key_size;
206 *packet_len = i;
207 out:
208 return rc;
209 }
210
211 static int
212 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
213 struct ecryptfs_message *msg)
214 {
215 size_t i = 0;
216 char *data;
217 size_t data_len;
218 size_t m_size;
219 size_t message_len;
220 u16 checksum = 0;
221 u16 expected_checksum = 0;
222 int rc;
223
224 /*
225 * ***** TAG 65 Packet Format *****
226 * | Content Type | 1 byte |
227 * | Status Indicator | 1 byte |
228 * | File Encryption Key Size | 1 or 2 bytes |
229 * | File Encryption Key | arbitrary |
230 */
231 message_len = msg->data_len;
232 data = msg->data;
233 if (message_len < 4) {
234 rc = -EIO;
235 goto out;
236 }
237 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
238 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
239 rc = -EIO;
240 goto out;
241 }
242 if (data[i++]) {
243 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
244 "[%d]\n", data[i-1]);
245 rc = -EIO;
246 goto out;
247 }
248 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
249 if (rc) {
250 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
251 "rc = [%d]\n", rc);
252 goto out;
253 }
254 i += data_len;
255 if (message_len < (i + m_size)) {
256 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
257 "is shorter than expected\n");
258 rc = -EIO;
259 goto out;
260 }
261 if (m_size < 3) {
262 ecryptfs_printk(KERN_ERR,
263 "The decrypted key is not long enough to "
264 "include a cipher code and checksum\n");
265 rc = -EIO;
266 goto out;
267 }
268 *cipher_code = data[i++];
269 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
270 session_key->decrypted_key_size = m_size - 3;
271 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
272 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
273 "the maximum key size [%d]\n",
274 session_key->decrypted_key_size,
275 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
276 rc = -EIO;
277 goto out;
278 }
279 memcpy(session_key->decrypted_key, &data[i],
280 session_key->decrypted_key_size);
281 i += session_key->decrypted_key_size;
282 expected_checksum += (unsigned char)(data[i++]) << 8;
283 expected_checksum += (unsigned char)(data[i++]);
284 for (i = 0; i < session_key->decrypted_key_size; i++)
285 checksum += session_key->decrypted_key[i];
286 if (expected_checksum != checksum) {
287 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
288 "encryption key; expected [%x]; calculated "
289 "[%x]\n", expected_checksum, checksum);
290 rc = -EIO;
291 }
292 out:
293 return rc;
294 }
295
296
297 static int
298 write_tag_66_packet(char *signature, u8 cipher_code,
299 struct ecryptfs_crypt_stat *crypt_stat, char **packet,
300 size_t *packet_len)
301 {
302 size_t i = 0;
303 size_t j;
304 size_t data_len;
305 size_t checksum = 0;
306 size_t packet_size_len;
307 char *message;
308 int rc;
309
310 /*
311 * ***** TAG 66 Packet Format *****
312 * | Content Type | 1 byte |
313 * | Key Identifier Size | 1 or 2 bytes |
314 * | Key Identifier | arbitrary |
315 * | File Encryption Key Size | 1 or 2 bytes |
316 * | File Encryption Key | arbitrary |
317 */
318 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
319 *packet = kmalloc(data_len, GFP_KERNEL);
320 message = *packet;
321 if (!message) {
322 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
323 rc = -ENOMEM;
324 goto out;
325 }
326 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
327 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
328 &packet_size_len);
329 if (rc) {
330 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
331 "header; cannot generate packet length\n");
332 goto out;
333 }
334 i += packet_size_len;
335 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
336 i += ECRYPTFS_SIG_SIZE_HEX;
337 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
338 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
339 &packet_size_len);
340 if (rc) {
341 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
342 "header; cannot generate packet length\n");
343 goto out;
344 }
345 i += packet_size_len;
346 message[i++] = cipher_code;
347 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
348 i += crypt_stat->key_size;
349 for (j = 0; j < crypt_stat->key_size; j++)
350 checksum += crypt_stat->key[j];
351 message[i++] = (checksum / 256) % 256;
352 message[i++] = (checksum % 256);
353 *packet_len = i;
354 out:
355 return rc;
356 }
357
358 static int
359 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
360 struct ecryptfs_message *msg)
361 {
362 size_t i = 0;
363 char *data;
364 size_t data_len;
365 size_t message_len;
366 int rc;
367
368 /*
369 * ***** TAG 65 Packet Format *****
370 * | Content Type | 1 byte |
371 * | Status Indicator | 1 byte |
372 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
373 * | Encrypted File Encryption Key | arbitrary |
374 */
375 message_len = msg->data_len;
376 data = msg->data;
377 /* verify that everything through the encrypted FEK size is present */
378 if (message_len < 4) {
379 rc = -EIO;
380 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
381 "message length is [%d]\n", __func__, message_len, 4);
382 goto out;
383 }
384 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
385 rc = -EIO;
386 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
387 __func__);
388 goto out;
389 }
390 if (data[i++]) {
391 rc = -EIO;
392 printk(KERN_ERR "%s: Status indicator has non zero "
393 "value [%d]\n", __func__, data[i-1]);
394
395 goto out;
396 }
397 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
398 &data_len);
399 if (rc) {
400 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
401 "rc = [%d]\n", rc);
402 goto out;
403 }
404 i += data_len;
405 if (message_len < (i + key_rec->enc_key_size)) {
406 rc = -EIO;
407 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
408 __func__, message_len, (i + key_rec->enc_key_size));
409 goto out;
410 }
411 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
412 rc = -EIO;
413 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
414 "the maximum key size [%d]\n", __func__,
415 key_rec->enc_key_size,
416 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
417 goto out;
418 }
419 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
420 out:
421 return rc;
422 }
423
424 /**
425 * ecryptfs_verify_version
426 * @version: The version number to confirm
427 *
428 * Returns zero on good version; non-zero otherwise
429 */
430 static int ecryptfs_verify_version(u16 version)
431 {
432 int rc = 0;
433 unsigned char major;
434 unsigned char minor;
435
436 major = ((version >> 8) & 0xFF);
437 minor = (version & 0xFF);
438 if (major != ECRYPTFS_VERSION_MAJOR) {
439 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
440 "Expected [%d]; got [%d]\n",
441 ECRYPTFS_VERSION_MAJOR, major);
442 rc = -EINVAL;
443 goto out;
444 }
445 if (minor != ECRYPTFS_VERSION_MINOR) {
446 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
447 "Expected [%d]; got [%d]\n",
448 ECRYPTFS_VERSION_MINOR, minor);
449 rc = -EINVAL;
450 goto out;
451 }
452 out:
453 return rc;
454 }
455
456 /**
457 * ecryptfs_verify_auth_tok_from_key
458 * @auth_tok_key: key containing the authentication token
459 * @auth_tok: authentication token
460 *
461 * Returns zero on valid auth tok; -EINVAL otherwise
462 */
463 static int
464 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
465 struct ecryptfs_auth_tok **auth_tok)
466 {
467 int rc = 0;
468
469 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
470 if (ecryptfs_verify_version((*auth_tok)->version)) {
471 printk(KERN_ERR "Data structure version mismatch. Userspace "
472 "tools must match eCryptfs kernel module with major "
473 "version [%d] and minor version [%d]\n",
474 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
475 rc = -EINVAL;
476 goto out;
477 }
478 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
479 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
480 printk(KERN_ERR "Invalid auth_tok structure "
481 "returned from key query\n");
482 rc = -EINVAL;
483 goto out;
484 }
485 out:
486 return rc;
487 }
488
489 static int
490 ecryptfs_find_global_auth_tok_for_sig(
491 struct key **auth_tok_key,
492 struct ecryptfs_auth_tok **auth_tok,
493 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
494 {
495 struct ecryptfs_global_auth_tok *walker;
496 int rc = 0;
497
498 (*auth_tok_key) = NULL;
499 (*auth_tok) = NULL;
500 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
501 list_for_each_entry(walker,
502 &mount_crypt_stat->global_auth_tok_list,
503 mount_crypt_stat_list) {
504 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
505 continue;
506
507 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
508 rc = -EINVAL;
509 goto out;
510 }
511
512 rc = key_validate(walker->global_auth_tok_key);
513 if (rc) {
514 if (rc == -EKEYEXPIRED)
515 goto out;
516 goto out_invalid_auth_tok;
517 }
518
519 down_write(&(walker->global_auth_tok_key->sem));
520 rc = ecryptfs_verify_auth_tok_from_key(
521 walker->global_auth_tok_key, auth_tok);
522 if (rc)
523 goto out_invalid_auth_tok_unlock;
524
525 (*auth_tok_key) = walker->global_auth_tok_key;
526 key_get(*auth_tok_key);
527 goto out;
528 }
529 rc = -ENOENT;
530 goto out;
531 out_invalid_auth_tok_unlock:
532 up_write(&(walker->global_auth_tok_key->sem));
533 out_invalid_auth_tok:
534 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
535 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
536 key_put(walker->global_auth_tok_key);
537 walker->global_auth_tok_key = NULL;
538 out:
539 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
540 return rc;
541 }
542
543 /**
544 * ecryptfs_find_auth_tok_for_sig
545 * @auth_tok: Set to the matching auth_tok; NULL if not found
546 * @crypt_stat: inode crypt_stat crypto context
547 * @sig: Sig of auth_tok to find
548 *
549 * For now, this function simply looks at the registered auth_tok's
550 * linked off the mount_crypt_stat, so all the auth_toks that can be
551 * used must be registered at mount time. This function could
552 * potentially try a lot harder to find auth_tok's (e.g., by calling
553 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
554 * that static registration of auth_tok's will no longer be necessary.
555 *
556 * Returns zero on no error; non-zero on error
557 */
558 static int
559 ecryptfs_find_auth_tok_for_sig(
560 struct key **auth_tok_key,
561 struct ecryptfs_auth_tok **auth_tok,
562 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
563 char *sig)
564 {
565 int rc = 0;
566
567 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
568 mount_crypt_stat, sig);
569 if (rc == -ENOENT) {
570 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
571 * mount_crypt_stat structure, we prevent to use auth toks that
572 * are not inserted through the ecryptfs_add_global_auth_tok
573 * function.
574 */
575 if (mount_crypt_stat->flags
576 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
577 return -EINVAL;
578
579 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
580 sig);
581 }
582 return rc;
583 }
584
585 /**
586 * write_tag_70_packet can gobble a lot of stack space. We stuff most
587 * of the function's parameters in a kmalloc'd struct to help reduce
588 * eCryptfs' overall stack usage.
589 */
590 struct ecryptfs_write_tag_70_packet_silly_stack {
591 u8 cipher_code;
592 size_t max_packet_size;
593 size_t packet_size_len;
594 size_t block_aligned_filename_size;
595 size_t block_size;
596 size_t i;
597 size_t j;
598 size_t num_rand_bytes;
599 struct mutex *tfm_mutex;
600 char *block_aligned_filename;
601 struct ecryptfs_auth_tok *auth_tok;
602 struct scatterlist src_sg[2];
603 struct scatterlist dst_sg[2];
604 struct blkcipher_desc desc;
605 char iv[ECRYPTFS_MAX_IV_BYTES];
606 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
607 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
608 struct hash_desc hash_desc;
609 struct scatterlist hash_sg;
610 };
611
612 /**
613 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
614 * @filename: NULL-terminated filename string
615 *
616 * This is the simplest mechanism for achieving filename encryption in
617 * eCryptfs. It encrypts the given filename with the mount-wide
618 * filename encryption key (FNEK) and stores it in a packet to @dest,
619 * which the callee will encode and write directly into the dentry
620 * name.
621 */
622 int
623 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
624 size_t *packet_size,
625 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
626 char *filename, size_t filename_size)
627 {
628 struct ecryptfs_write_tag_70_packet_silly_stack *s;
629 struct key *auth_tok_key = NULL;
630 int rc = 0;
631
632 s = kmalloc(sizeof(*s), GFP_KERNEL);
633 if (!s) {
634 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
635 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
636 rc = -ENOMEM;
637 goto out;
638 }
639 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
640 (*packet_size) = 0;
641 rc = ecryptfs_find_auth_tok_for_sig(
642 &auth_tok_key,
643 &s->auth_tok, mount_crypt_stat,
644 mount_crypt_stat->global_default_fnek_sig);
645 if (rc) {
646 printk(KERN_ERR "%s: Error attempting to find auth tok for "
647 "fnek sig [%s]; rc = [%d]\n", __func__,
648 mount_crypt_stat->global_default_fnek_sig, rc);
649 goto out;
650 }
651 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
652 &s->desc.tfm,
653 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
654 if (unlikely(rc)) {
655 printk(KERN_ERR "Internal error whilst attempting to get "
656 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
657 mount_crypt_stat->global_default_fn_cipher_name, rc);
658 goto out;
659 }
660 mutex_lock(s->tfm_mutex);
661 s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
662 /* Plus one for the \0 separator between the random prefix
663 * and the plaintext filename */
664 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
665 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
666 if ((s->block_aligned_filename_size % s->block_size) != 0) {
667 s->num_rand_bytes += (s->block_size
668 - (s->block_aligned_filename_size
669 % s->block_size));
670 s->block_aligned_filename_size = (s->num_rand_bytes
671 + filename_size);
672 }
673 /* Octet 0: Tag 70 identifier
674 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
675 * and block-aligned encrypted filename size)
676 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
677 * Octet N2-N3: Cipher identifier (1 octet)
678 * Octets N3-N4: Block-aligned encrypted filename
679 * - Consists of a minimum number of random characters, a \0
680 * separator, and then the filename */
681 s->max_packet_size = (1 /* Tag 70 identifier */
682 + 3 /* Max Tag 70 packet size */
683 + ECRYPTFS_SIG_SIZE /* FNEK sig */
684 + 1 /* Cipher identifier */
685 + s->block_aligned_filename_size);
686 if (dest == NULL) {
687 (*packet_size) = s->max_packet_size;
688 goto out_unlock;
689 }
690 if (s->max_packet_size > (*remaining_bytes)) {
691 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
692 "[%zd] available\n", __func__, s->max_packet_size,
693 (*remaining_bytes));
694 rc = -EINVAL;
695 goto out_unlock;
696 }
697 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
698 GFP_KERNEL);
699 if (!s->block_aligned_filename) {
700 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
701 "kzalloc [%zd] bytes\n", __func__,
702 s->block_aligned_filename_size);
703 rc = -ENOMEM;
704 goto out_unlock;
705 }
706 s->i = 0;
707 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
708 rc = ecryptfs_write_packet_length(&dest[s->i],
709 (ECRYPTFS_SIG_SIZE
710 + 1 /* Cipher code */
711 + s->block_aligned_filename_size),
712 &s->packet_size_len);
713 if (rc) {
714 printk(KERN_ERR "%s: Error generating tag 70 packet "
715 "header; cannot generate packet length; rc = [%d]\n",
716 __func__, rc);
717 goto out_free_unlock;
718 }
719 s->i += s->packet_size_len;
720 ecryptfs_from_hex(&dest[s->i],
721 mount_crypt_stat->global_default_fnek_sig,
722 ECRYPTFS_SIG_SIZE);
723 s->i += ECRYPTFS_SIG_SIZE;
724 s->cipher_code = ecryptfs_code_for_cipher_string(
725 mount_crypt_stat->global_default_fn_cipher_name,
726 mount_crypt_stat->global_default_fn_cipher_key_bytes);
727 if (s->cipher_code == 0) {
728 printk(KERN_WARNING "%s: Unable to generate code for "
729 "cipher [%s] with key bytes [%zd]\n", __func__,
730 mount_crypt_stat->global_default_fn_cipher_name,
731 mount_crypt_stat->global_default_fn_cipher_key_bytes);
732 rc = -EINVAL;
733 goto out_free_unlock;
734 }
735 dest[s->i++] = s->cipher_code;
736 /* TODO: Support other key modules than passphrase for
737 * filename encryption */
738 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
739 rc = -EOPNOTSUPP;
740 printk(KERN_INFO "%s: Filename encryption only supports "
741 "password tokens\n", __func__);
742 goto out_free_unlock;
743 }
744 sg_init_one(
745 &s->hash_sg,
746 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
747 s->auth_tok->token.password.session_key_encryption_key_bytes);
748 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
749 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
750 CRYPTO_ALG_ASYNC);
751 if (IS_ERR(s->hash_desc.tfm)) {
752 rc = PTR_ERR(s->hash_desc.tfm);
753 printk(KERN_ERR "%s: Error attempting to "
754 "allocate hash crypto context; rc = [%d]\n",
755 __func__, rc);
756 goto out_free_unlock;
757 }
758 rc = crypto_hash_init(&s->hash_desc);
759 if (rc) {
760 printk(KERN_ERR
761 "%s: Error initializing crypto hash; rc = [%d]\n",
762 __func__, rc);
763 goto out_release_free_unlock;
764 }
765 rc = crypto_hash_update(
766 &s->hash_desc, &s->hash_sg,
767 s->auth_tok->token.password.session_key_encryption_key_bytes);
768 if (rc) {
769 printk(KERN_ERR
770 "%s: Error updating crypto hash; rc = [%d]\n",
771 __func__, rc);
772 goto out_release_free_unlock;
773 }
774 rc = crypto_hash_final(&s->hash_desc, s->hash);
775 if (rc) {
776 printk(KERN_ERR
777 "%s: Error finalizing crypto hash; rc = [%d]\n",
778 __func__, rc);
779 goto out_release_free_unlock;
780 }
781 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
782 s->block_aligned_filename[s->j] =
783 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
784 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
785 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
786 sg_init_one(&s->hash_sg, (u8 *)s->hash,
787 ECRYPTFS_TAG_70_DIGEST_SIZE);
788 rc = crypto_hash_init(&s->hash_desc);
789 if (rc) {
790 printk(KERN_ERR
791 "%s: Error initializing crypto hash; "
792 "rc = [%d]\n", __func__, rc);
793 goto out_release_free_unlock;
794 }
795 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
796 ECRYPTFS_TAG_70_DIGEST_SIZE);
797 if (rc) {
798 printk(KERN_ERR
799 "%s: Error updating crypto hash; "
800 "rc = [%d]\n", __func__, rc);
801 goto out_release_free_unlock;
802 }
803 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
804 if (rc) {
805 printk(KERN_ERR
806 "%s: Error finalizing crypto hash; "
807 "rc = [%d]\n", __func__, rc);
808 goto out_release_free_unlock;
809 }
810 memcpy(s->hash, s->tmp_hash,
811 ECRYPTFS_TAG_70_DIGEST_SIZE);
812 }
813 if (s->block_aligned_filename[s->j] == '\0')
814 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
815 }
816 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
817 filename_size);
818 rc = virt_to_scatterlist(s->block_aligned_filename,
819 s->block_aligned_filename_size, s->src_sg, 2);
820 if (rc < 1) {
821 printk(KERN_ERR "%s: Internal error whilst attempting to "
822 "convert filename memory to scatterlist; rc = [%d]. "
823 "block_aligned_filename_size = [%zd]\n", __func__, rc,
824 s->block_aligned_filename_size);
825 goto out_release_free_unlock;
826 }
827 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
828 s->dst_sg, 2);
829 if (rc < 1) {
830 printk(KERN_ERR "%s: Internal error whilst attempting to "
831 "convert encrypted filename memory to scatterlist; "
832 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
833 __func__, rc, s->block_aligned_filename_size);
834 goto out_release_free_unlock;
835 }
836 /* The characters in the first block effectively do the job
837 * of the IV here, so we just use 0's for the IV. Note the
838 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
839 * >= ECRYPTFS_MAX_IV_BYTES. */
840 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
841 s->desc.info = s->iv;
842 rc = crypto_blkcipher_setkey(
843 s->desc.tfm,
844 s->auth_tok->token.password.session_key_encryption_key,
845 mount_crypt_stat->global_default_fn_cipher_key_bytes);
846 if (rc < 0) {
847 printk(KERN_ERR "%s: Error setting key for crypto context; "
848 "rc = [%d]. s->auth_tok->token.password.session_key_"
849 "encryption_key = [0x%p]; mount_crypt_stat->"
850 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
851 rc,
852 s->auth_tok->token.password.session_key_encryption_key,
853 mount_crypt_stat->global_default_fn_cipher_key_bytes);
854 goto out_release_free_unlock;
855 }
856 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
857 s->block_aligned_filename_size);
858 if (rc) {
859 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
860 "rc = [%d]\n", __func__, rc);
861 goto out_release_free_unlock;
862 }
863 s->i += s->block_aligned_filename_size;
864 (*packet_size) = s->i;
865 (*remaining_bytes) -= (*packet_size);
866 out_release_free_unlock:
867 crypto_free_hash(s->hash_desc.tfm);
868 out_free_unlock:
869 kzfree(s->block_aligned_filename);
870 out_unlock:
871 mutex_unlock(s->tfm_mutex);
872 out:
873 if (auth_tok_key) {
874 up_write(&(auth_tok_key->sem));
875 key_put(auth_tok_key);
876 }
877 kfree(s);
878 return rc;
879 }
880
881 struct ecryptfs_parse_tag_70_packet_silly_stack {
882 u8 cipher_code;
883 size_t max_packet_size;
884 size_t packet_size_len;
885 size_t parsed_tag_70_packet_size;
886 size_t block_aligned_filename_size;
887 size_t block_size;
888 size_t i;
889 struct mutex *tfm_mutex;
890 char *decrypted_filename;
891 struct ecryptfs_auth_tok *auth_tok;
892 struct scatterlist src_sg[2];
893 struct scatterlist dst_sg[2];
894 struct blkcipher_desc desc;
895 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
896 char iv[ECRYPTFS_MAX_IV_BYTES];
897 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
898 };
899
900 /**
901 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
902 * @filename: This function kmalloc's the memory for the filename
903 * @filename_size: This function sets this to the amount of memory
904 * kmalloc'd for the filename
905 * @packet_size: This function sets this to the the number of octets
906 * in the packet parsed
907 * @mount_crypt_stat: The mount-wide cryptographic context
908 * @data: The memory location containing the start of the tag 70
909 * packet
910 * @max_packet_size: The maximum legal size of the packet to be parsed
911 * from @data
912 *
913 * Returns zero on success; non-zero otherwise
914 */
915 int
916 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
917 size_t *packet_size,
918 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
919 char *data, size_t max_packet_size)
920 {
921 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
922 struct key *auth_tok_key = NULL;
923 int rc = 0;
924
925 (*packet_size) = 0;
926 (*filename_size) = 0;
927 (*filename) = NULL;
928 s = kmalloc(sizeof(*s), GFP_KERNEL);
929 if (!s) {
930 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
931 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
932 rc = -ENOMEM;
933 goto out;
934 }
935 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
936 if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
937 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
938 "at least [%d]\n", __func__, max_packet_size,
939 (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
940 rc = -EINVAL;
941 goto out;
942 }
943 /* Octet 0: Tag 70 identifier
944 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
945 * and block-aligned encrypted filename size)
946 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
947 * Octet N2-N3: Cipher identifier (1 octet)
948 * Octets N3-N4: Block-aligned encrypted filename
949 * - Consists of a minimum number of random numbers, a \0
950 * separator, and then the filename */
951 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
952 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
953 "tag [0x%.2x]\n", __func__,
954 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
955 rc = -EINVAL;
956 goto out;
957 }
958 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
959 &s->parsed_tag_70_packet_size,
960 &s->packet_size_len);
961 if (rc) {
962 printk(KERN_WARNING "%s: Error parsing packet length; "
963 "rc = [%d]\n", __func__, rc);
964 goto out;
965 }
966 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
967 - ECRYPTFS_SIG_SIZE - 1);
968 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
969 > max_packet_size) {
970 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
971 "size is [%zd]\n", __func__, max_packet_size,
972 (1 + s->packet_size_len + 1
973 + s->block_aligned_filename_size));
974 rc = -EINVAL;
975 goto out;
976 }
977 (*packet_size) += s->packet_size_len;
978 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
979 ECRYPTFS_SIG_SIZE);
980 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
981 (*packet_size) += ECRYPTFS_SIG_SIZE;
982 s->cipher_code = data[(*packet_size)++];
983 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
984 if (rc) {
985 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
986 __func__, s->cipher_code);
987 goto out;
988 }
989 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
990 &s->auth_tok, mount_crypt_stat,
991 s->fnek_sig_hex);
992 if (rc) {
993 printk(KERN_ERR "%s: Error attempting to find auth tok for "
994 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
995 rc);
996 goto out;
997 }
998 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
999 &s->tfm_mutex,
1000 s->cipher_string);
1001 if (unlikely(rc)) {
1002 printk(KERN_ERR "Internal error whilst attempting to get "
1003 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1004 s->cipher_string, rc);
1005 goto out;
1006 }
1007 mutex_lock(s->tfm_mutex);
1008 rc = virt_to_scatterlist(&data[(*packet_size)],
1009 s->block_aligned_filename_size, s->src_sg, 2);
1010 if (rc < 1) {
1011 printk(KERN_ERR "%s: Internal error whilst attempting to "
1012 "convert encrypted filename memory to scatterlist; "
1013 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1014 __func__, rc, s->block_aligned_filename_size);
1015 goto out_unlock;
1016 }
1017 (*packet_size) += s->block_aligned_filename_size;
1018 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1019 GFP_KERNEL);
1020 if (!s->decrypted_filename) {
1021 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1022 "kmalloc [%zd] bytes\n", __func__,
1023 s->block_aligned_filename_size);
1024 rc = -ENOMEM;
1025 goto out_unlock;
1026 }
1027 rc = virt_to_scatterlist(s->decrypted_filename,
1028 s->block_aligned_filename_size, s->dst_sg, 2);
1029 if (rc < 1) {
1030 printk(KERN_ERR "%s: Internal error whilst attempting to "
1031 "convert decrypted filename memory to scatterlist; "
1032 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1033 __func__, rc, s->block_aligned_filename_size);
1034 goto out_free_unlock;
1035 }
1036 /* The characters in the first block effectively do the job of
1037 * the IV here, so we just use 0's for the IV. Note the
1038 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1039 * >= ECRYPTFS_MAX_IV_BYTES. */
1040 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1041 s->desc.info = s->iv;
1042 /* TODO: Support other key modules than passphrase for
1043 * filename encryption */
1044 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1045 rc = -EOPNOTSUPP;
1046 printk(KERN_INFO "%s: Filename encryption only supports "
1047 "password tokens\n", __func__);
1048 goto out_free_unlock;
1049 }
1050 rc = crypto_blkcipher_setkey(
1051 s->desc.tfm,
1052 s->auth_tok->token.password.session_key_encryption_key,
1053 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1054 if (rc < 0) {
1055 printk(KERN_ERR "%s: Error setting key for crypto context; "
1056 "rc = [%d]. s->auth_tok->token.password.session_key_"
1057 "encryption_key = [0x%p]; mount_crypt_stat->"
1058 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1059 rc,
1060 s->auth_tok->token.password.session_key_encryption_key,
1061 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1062 goto out_free_unlock;
1063 }
1064 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
1065 s->block_aligned_filename_size);
1066 if (rc) {
1067 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1068 "rc = [%d]\n", __func__, rc);
1069 goto out_free_unlock;
1070 }
1071 s->i = 0;
1072 while (s->decrypted_filename[s->i] != '\0'
1073 && s->i < s->block_aligned_filename_size)
1074 s->i++;
1075 if (s->i == s->block_aligned_filename_size) {
1076 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1077 "find valid separator between random characters and "
1078 "the filename\n", __func__);
1079 rc = -EINVAL;
1080 goto out_free_unlock;
1081 }
1082 s->i++;
1083 (*filename_size) = (s->block_aligned_filename_size - s->i);
1084 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1085 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1086 "invalid\n", __func__, (*filename_size));
1087 rc = -EINVAL;
1088 goto out_free_unlock;
1089 }
1090 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1091 if (!(*filename)) {
1092 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1093 "kmalloc [%zd] bytes\n", __func__,
1094 ((*filename_size) + 1));
1095 rc = -ENOMEM;
1096 goto out_free_unlock;
1097 }
1098 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1099 (*filename)[(*filename_size)] = '\0';
1100 out_free_unlock:
1101 kfree(s->decrypted_filename);
1102 out_unlock:
1103 mutex_unlock(s->tfm_mutex);
1104 out:
1105 if (rc) {
1106 (*packet_size) = 0;
1107 (*filename_size) = 0;
1108 (*filename) = NULL;
1109 }
1110 if (auth_tok_key) {
1111 up_write(&(auth_tok_key->sem));
1112 key_put(auth_tok_key);
1113 }
1114 kfree(s);
1115 return rc;
1116 }
1117
1118 static int
1119 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1120 {
1121 int rc = 0;
1122
1123 (*sig) = NULL;
1124 switch (auth_tok->token_type) {
1125 case ECRYPTFS_PASSWORD:
1126 (*sig) = auth_tok->token.password.signature;
1127 break;
1128 case ECRYPTFS_PRIVATE_KEY:
1129 (*sig) = auth_tok->token.private_key.signature;
1130 break;
1131 default:
1132 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1133 auth_tok->token_type);
1134 rc = -EINVAL;
1135 }
1136 return rc;
1137 }
1138
1139 /**
1140 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1141 * @auth_tok: The key authentication token used to decrypt the session key
1142 * @crypt_stat: The cryptographic context
1143 *
1144 * Returns zero on success; non-zero error otherwise.
1145 */
1146 static int
1147 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1148 struct ecryptfs_crypt_stat *crypt_stat)
1149 {
1150 u8 cipher_code = 0;
1151 struct ecryptfs_msg_ctx *msg_ctx;
1152 struct ecryptfs_message *msg = NULL;
1153 char *auth_tok_sig;
1154 char *payload;
1155 size_t payload_len;
1156 int rc;
1157
1158 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1159 if (rc) {
1160 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1161 auth_tok->token_type);
1162 goto out;
1163 }
1164 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1165 &payload, &payload_len);
1166 if (rc) {
1167 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1168 goto out;
1169 }
1170 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1171 if (rc) {
1172 ecryptfs_printk(KERN_ERR, "Error sending message to "
1173 "ecryptfsd\n");
1174 goto out;
1175 }
1176 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1177 if (rc) {
1178 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1179 "from the user space daemon\n");
1180 rc = -EIO;
1181 goto out;
1182 }
1183 rc = parse_tag_65_packet(&(auth_tok->session_key),
1184 &cipher_code, msg);
1185 if (rc) {
1186 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1187 rc);
1188 goto out;
1189 }
1190 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1191 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1192 auth_tok->session_key.decrypted_key_size);
1193 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1194 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1195 if (rc) {
1196 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1197 cipher_code)
1198 goto out;
1199 }
1200 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1201 if (ecryptfs_verbosity > 0) {
1202 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1203 ecryptfs_dump_hex(crypt_stat->key,
1204 crypt_stat->key_size);
1205 }
1206 out:
1207 if (msg)
1208 kfree(msg);
1209 return rc;
1210 }
1211
1212 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1213 {
1214 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1215 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1216
1217 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1218 auth_tok_list_head, list) {
1219 list_del(&auth_tok_list_item->list);
1220 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1221 auth_tok_list_item);
1222 }
1223 }
1224
1225 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1226
1227 /**
1228 * parse_tag_1_packet
1229 * @crypt_stat: The cryptographic context to modify based on packet contents
1230 * @data: The raw bytes of the packet.
1231 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1232 * a new authentication token will be placed at the
1233 * end of this list for this packet.
1234 * @new_auth_tok: Pointer to a pointer to memory that this function
1235 * allocates; sets the memory address of the pointer to
1236 * NULL on error. This object is added to the
1237 * auth_tok_list.
1238 * @packet_size: This function writes the size of the parsed packet
1239 * into this memory location; zero on error.
1240 * @max_packet_size: The maximum allowable packet size
1241 *
1242 * Returns zero on success; non-zero on error.
1243 */
1244 static int
1245 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1246 unsigned char *data, struct list_head *auth_tok_list,
1247 struct ecryptfs_auth_tok **new_auth_tok,
1248 size_t *packet_size, size_t max_packet_size)
1249 {
1250 size_t body_size;
1251 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1252 size_t length_size;
1253 int rc = 0;
1254
1255 (*packet_size) = 0;
1256 (*new_auth_tok) = NULL;
1257 /**
1258 * This format is inspired by OpenPGP; see RFC 2440
1259 * packet tag 1
1260 *
1261 * Tag 1 identifier (1 byte)
1262 * Max Tag 1 packet size (max 3 bytes)
1263 * Version (1 byte)
1264 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1265 * Cipher identifier (1 byte)
1266 * Encrypted key size (arbitrary)
1267 *
1268 * 12 bytes minimum packet size
1269 */
1270 if (unlikely(max_packet_size < 12)) {
1271 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1272 rc = -EINVAL;
1273 goto out;
1274 }
1275 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1276 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1277 ECRYPTFS_TAG_1_PACKET_TYPE);
1278 rc = -EINVAL;
1279 goto out;
1280 }
1281 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1282 * at end of function upon failure */
1283 auth_tok_list_item =
1284 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1285 GFP_KERNEL);
1286 if (!auth_tok_list_item) {
1287 printk(KERN_ERR "Unable to allocate memory\n");
1288 rc = -ENOMEM;
1289 goto out;
1290 }
1291 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1292 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1293 &length_size);
1294 if (rc) {
1295 printk(KERN_WARNING "Error parsing packet length; "
1296 "rc = [%d]\n", rc);
1297 goto out_free;
1298 }
1299 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1300 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1301 rc = -EINVAL;
1302 goto out_free;
1303 }
1304 (*packet_size) += length_size;
1305 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1306 printk(KERN_WARNING "Packet size exceeds max\n");
1307 rc = -EINVAL;
1308 goto out_free;
1309 }
1310 if (unlikely(data[(*packet_size)++] != 0x03)) {
1311 printk(KERN_WARNING "Unknown version number [%d]\n",
1312 data[(*packet_size) - 1]);
1313 rc = -EINVAL;
1314 goto out_free;
1315 }
1316 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1317 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1318 *packet_size += ECRYPTFS_SIG_SIZE;
1319 /* This byte is skipped because the kernel does not need to
1320 * know which public key encryption algorithm was used */
1321 (*packet_size)++;
1322 (*new_auth_tok)->session_key.encrypted_key_size =
1323 body_size - (ECRYPTFS_SIG_SIZE + 2);
1324 if ((*new_auth_tok)->session_key.encrypted_key_size
1325 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1326 printk(KERN_WARNING "Tag 1 packet contains key larger "
1327 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1328 rc = -EINVAL;
1329 goto out;
1330 }
1331 memcpy((*new_auth_tok)->session_key.encrypted_key,
1332 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1333 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1334 (*new_auth_tok)->session_key.flags &=
1335 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1336 (*new_auth_tok)->session_key.flags |=
1337 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1338 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1339 (*new_auth_tok)->flags = 0;
1340 (*new_auth_tok)->session_key.flags &=
1341 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1342 (*new_auth_tok)->session_key.flags &=
1343 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1344 list_add(&auth_tok_list_item->list, auth_tok_list);
1345 goto out;
1346 out_free:
1347 (*new_auth_tok) = NULL;
1348 memset(auth_tok_list_item, 0,
1349 sizeof(struct ecryptfs_auth_tok_list_item));
1350 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1351 auth_tok_list_item);
1352 out:
1353 if (rc)
1354 (*packet_size) = 0;
1355 return rc;
1356 }
1357
1358 /**
1359 * parse_tag_3_packet
1360 * @crypt_stat: The cryptographic context to modify based on packet
1361 * contents.
1362 * @data: The raw bytes of the packet.
1363 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1364 * a new authentication token will be placed at the end
1365 * of this list for this packet.
1366 * @new_auth_tok: Pointer to a pointer to memory that this function
1367 * allocates; sets the memory address of the pointer to
1368 * NULL on error. This object is added to the
1369 * auth_tok_list.
1370 * @packet_size: This function writes the size of the parsed packet
1371 * into this memory location; zero on error.
1372 * @max_packet_size: maximum number of bytes to parse
1373 *
1374 * Returns zero on success; non-zero on error.
1375 */
1376 static int
1377 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1378 unsigned char *data, struct list_head *auth_tok_list,
1379 struct ecryptfs_auth_tok **new_auth_tok,
1380 size_t *packet_size, size_t max_packet_size)
1381 {
1382 size_t body_size;
1383 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1384 size_t length_size;
1385 int rc = 0;
1386
1387 (*packet_size) = 0;
1388 (*new_auth_tok) = NULL;
1389 /**
1390 *This format is inspired by OpenPGP; see RFC 2440
1391 * packet tag 3
1392 *
1393 * Tag 3 identifier (1 byte)
1394 * Max Tag 3 packet size (max 3 bytes)
1395 * Version (1 byte)
1396 * Cipher code (1 byte)
1397 * S2K specifier (1 byte)
1398 * Hash identifier (1 byte)
1399 * Salt (ECRYPTFS_SALT_SIZE)
1400 * Hash iterations (1 byte)
1401 * Encrypted key (arbitrary)
1402 *
1403 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1404 */
1405 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1406 printk(KERN_ERR "Max packet size too large\n");
1407 rc = -EINVAL;
1408 goto out;
1409 }
1410 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1411 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1412 ECRYPTFS_TAG_3_PACKET_TYPE);
1413 rc = -EINVAL;
1414 goto out;
1415 }
1416 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1417 * at end of function upon failure */
1418 auth_tok_list_item =
1419 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1420 if (!auth_tok_list_item) {
1421 printk(KERN_ERR "Unable to allocate memory\n");
1422 rc = -ENOMEM;
1423 goto out;
1424 }
1425 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1426 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1427 &length_size);
1428 if (rc) {
1429 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1430 rc);
1431 goto out_free;
1432 }
1433 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1434 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1435 rc = -EINVAL;
1436 goto out_free;
1437 }
1438 (*packet_size) += length_size;
1439 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1440 printk(KERN_ERR "Packet size exceeds max\n");
1441 rc = -EINVAL;
1442 goto out_free;
1443 }
1444 (*new_auth_tok)->session_key.encrypted_key_size =
1445 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1446 if ((*new_auth_tok)->session_key.encrypted_key_size
1447 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1448 printk(KERN_WARNING "Tag 3 packet contains key larger "
1449 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1450 rc = -EINVAL;
1451 goto out_free;
1452 }
1453 if (unlikely(data[(*packet_size)++] != 0x04)) {
1454 printk(KERN_WARNING "Unknown version number [%d]\n",
1455 data[(*packet_size) - 1]);
1456 rc = -EINVAL;
1457 goto out_free;
1458 }
1459 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1460 (u16)data[(*packet_size)]);
1461 if (rc)
1462 goto out_free;
1463 /* A little extra work to differentiate among the AES key
1464 * sizes; see RFC2440 */
1465 switch(data[(*packet_size)++]) {
1466 case RFC2440_CIPHER_AES_192:
1467 crypt_stat->key_size = 24;
1468 break;
1469 default:
1470 crypt_stat->key_size =
1471 (*new_auth_tok)->session_key.encrypted_key_size;
1472 }
1473 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1474 if (rc)
1475 goto out_free;
1476 if (unlikely(data[(*packet_size)++] != 0x03)) {
1477 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1478 rc = -ENOSYS;
1479 goto out_free;
1480 }
1481 /* TODO: finish the hash mapping */
1482 switch (data[(*packet_size)++]) {
1483 case 0x01: /* See RFC2440 for these numbers and their mappings */
1484 /* Choose MD5 */
1485 memcpy((*new_auth_tok)->token.password.salt,
1486 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1487 (*packet_size) += ECRYPTFS_SALT_SIZE;
1488 /* This conversion was taken straight from RFC2440 */
1489 (*new_auth_tok)->token.password.hash_iterations =
1490 ((u32) 16 + (data[(*packet_size)] & 15))
1491 << ((data[(*packet_size)] >> 4) + 6);
1492 (*packet_size)++;
1493 /* Friendly reminder:
1494 * (*new_auth_tok)->session_key.encrypted_key_size =
1495 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1496 memcpy((*new_auth_tok)->session_key.encrypted_key,
1497 &data[(*packet_size)],
1498 (*new_auth_tok)->session_key.encrypted_key_size);
1499 (*packet_size) +=
1500 (*new_auth_tok)->session_key.encrypted_key_size;
1501 (*new_auth_tok)->session_key.flags &=
1502 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1503 (*new_auth_tok)->session_key.flags |=
1504 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1505 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1506 break;
1507 default:
1508 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1509 "[%d]\n", data[(*packet_size) - 1]);
1510 rc = -ENOSYS;
1511 goto out_free;
1512 }
1513 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1514 /* TODO: Parametarize; we might actually want userspace to
1515 * decrypt the session key. */
1516 (*new_auth_tok)->session_key.flags &=
1517 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1518 (*new_auth_tok)->session_key.flags &=
1519 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1520 list_add(&auth_tok_list_item->list, auth_tok_list);
1521 goto out;
1522 out_free:
1523 (*new_auth_tok) = NULL;
1524 memset(auth_tok_list_item, 0,
1525 sizeof(struct ecryptfs_auth_tok_list_item));
1526 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1527 auth_tok_list_item);
1528 out:
1529 if (rc)
1530 (*packet_size) = 0;
1531 return rc;
1532 }
1533
1534 /**
1535 * parse_tag_11_packet
1536 * @data: The raw bytes of the packet
1537 * @contents: This function writes the data contents of the literal
1538 * packet into this memory location
1539 * @max_contents_bytes: The maximum number of bytes that this function
1540 * is allowed to write into contents
1541 * @tag_11_contents_size: This function writes the size of the parsed
1542 * contents into this memory location; zero on
1543 * error
1544 * @packet_size: This function writes the size of the parsed packet
1545 * into this memory location; zero on error
1546 * @max_packet_size: maximum number of bytes to parse
1547 *
1548 * Returns zero on success; non-zero on error.
1549 */
1550 static int
1551 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1552 size_t max_contents_bytes, size_t *tag_11_contents_size,
1553 size_t *packet_size, size_t max_packet_size)
1554 {
1555 size_t body_size;
1556 size_t length_size;
1557 int rc = 0;
1558
1559 (*packet_size) = 0;
1560 (*tag_11_contents_size) = 0;
1561 /* This format is inspired by OpenPGP; see RFC 2440
1562 * packet tag 11
1563 *
1564 * Tag 11 identifier (1 byte)
1565 * Max Tag 11 packet size (max 3 bytes)
1566 * Binary format specifier (1 byte)
1567 * Filename length (1 byte)
1568 * Filename ("_CONSOLE") (8 bytes)
1569 * Modification date (4 bytes)
1570 * Literal data (arbitrary)
1571 *
1572 * We need at least 16 bytes of data for the packet to even be
1573 * valid.
1574 */
1575 if (max_packet_size < 16) {
1576 printk(KERN_ERR "Maximum packet size too small\n");
1577 rc = -EINVAL;
1578 goto out;
1579 }
1580 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1581 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1582 rc = -EINVAL;
1583 goto out;
1584 }
1585 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1586 &length_size);
1587 if (rc) {
1588 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1589 goto out;
1590 }
1591 if (body_size < 14) {
1592 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1593 rc = -EINVAL;
1594 goto out;
1595 }
1596 (*packet_size) += length_size;
1597 (*tag_11_contents_size) = (body_size - 14);
1598 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1599 printk(KERN_ERR "Packet size exceeds max\n");
1600 rc = -EINVAL;
1601 goto out;
1602 }
1603 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1604 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1605 "expected size\n");
1606 rc = -EINVAL;
1607 goto out;
1608 }
1609 if (data[(*packet_size)++] != 0x62) {
1610 printk(KERN_WARNING "Unrecognizable packet\n");
1611 rc = -EINVAL;
1612 goto out;
1613 }
1614 if (data[(*packet_size)++] != 0x08) {
1615 printk(KERN_WARNING "Unrecognizable packet\n");
1616 rc = -EINVAL;
1617 goto out;
1618 }
1619 (*packet_size) += 12; /* Ignore filename and modification date */
1620 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1621 (*packet_size) += (*tag_11_contents_size);
1622 out:
1623 if (rc) {
1624 (*packet_size) = 0;
1625 (*tag_11_contents_size) = 0;
1626 }
1627 return rc;
1628 }
1629
1630 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1631 struct ecryptfs_auth_tok **auth_tok,
1632 char *sig)
1633 {
1634 int rc = 0;
1635
1636 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1637 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1638 printk(KERN_ERR "Could not find key with description: [%s]\n",
1639 sig);
1640 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1641 (*auth_tok_key) = NULL;
1642 goto out;
1643 }
1644 down_write(&(*auth_tok_key)->sem);
1645 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1646 if (rc) {
1647 up_write(&(*auth_tok_key)->sem);
1648 key_put(*auth_tok_key);
1649 (*auth_tok_key) = NULL;
1650 goto out;
1651 }
1652 out:
1653 return rc;
1654 }
1655
1656 /**
1657 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1658 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1659 * @crypt_stat: The cryptographic context
1660 *
1661 * Returns zero on success; non-zero error otherwise
1662 */
1663 static int
1664 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1665 struct ecryptfs_crypt_stat *crypt_stat)
1666 {
1667 struct scatterlist dst_sg[2];
1668 struct scatterlist src_sg[2];
1669 struct mutex *tfm_mutex;
1670 struct blkcipher_desc desc = {
1671 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1672 };
1673 int rc = 0;
1674
1675 if (unlikely(ecryptfs_verbosity > 0)) {
1676 ecryptfs_printk(
1677 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1678 auth_tok->token.password.session_key_encryption_key_bytes);
1679 ecryptfs_dump_hex(
1680 auth_tok->token.password.session_key_encryption_key,
1681 auth_tok->token.password.session_key_encryption_key_bytes);
1682 }
1683 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1684 crypt_stat->cipher);
1685 if (unlikely(rc)) {
1686 printk(KERN_ERR "Internal error whilst attempting to get "
1687 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1688 crypt_stat->cipher, rc);
1689 goto out;
1690 }
1691 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1692 auth_tok->session_key.encrypted_key_size,
1693 src_sg, 2);
1694 if (rc < 1 || rc > 2) {
1695 printk(KERN_ERR "Internal error whilst attempting to convert "
1696 "auth_tok->session_key.encrypted_key to scatterlist; "
1697 "expected rc = 1; got rc = [%d]. "
1698 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1699 auth_tok->session_key.encrypted_key_size);
1700 goto out;
1701 }
1702 auth_tok->session_key.decrypted_key_size =
1703 auth_tok->session_key.encrypted_key_size;
1704 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1705 auth_tok->session_key.decrypted_key_size,
1706 dst_sg, 2);
1707 if (rc < 1 || rc > 2) {
1708 printk(KERN_ERR "Internal error whilst attempting to convert "
1709 "auth_tok->session_key.decrypted_key to scatterlist; "
1710 "expected rc = 1; got rc = [%d]\n", rc);
1711 goto out;
1712 }
1713 mutex_lock(tfm_mutex);
1714 rc = crypto_blkcipher_setkey(
1715 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1716 crypt_stat->key_size);
1717 if (unlikely(rc < 0)) {
1718 mutex_unlock(tfm_mutex);
1719 printk(KERN_ERR "Error setting key for crypto context\n");
1720 rc = -EINVAL;
1721 goto out;
1722 }
1723 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1724 auth_tok->session_key.encrypted_key_size);
1725 mutex_unlock(tfm_mutex);
1726 if (unlikely(rc)) {
1727 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1728 goto out;
1729 }
1730 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1731 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1732 auth_tok->session_key.decrypted_key_size);
1733 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1734 if (unlikely(ecryptfs_verbosity > 0)) {
1735 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1736 crypt_stat->key_size);
1737 ecryptfs_dump_hex(crypt_stat->key,
1738 crypt_stat->key_size);
1739 }
1740 out:
1741 return rc;
1742 }
1743
1744 /**
1745 * ecryptfs_parse_packet_set
1746 * @crypt_stat: The cryptographic context
1747 * @src: Virtual address of region of memory containing the packets
1748 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1749 *
1750 * Get crypt_stat to have the file's session key if the requisite key
1751 * is available to decrypt the session key.
1752 *
1753 * Returns Zero if a valid authentication token was retrieved and
1754 * processed; negative value for file not encrypted or for error
1755 * conditions.
1756 */
1757 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1758 unsigned char *src,
1759 struct dentry *ecryptfs_dentry)
1760 {
1761 size_t i = 0;
1762 size_t found_auth_tok;
1763 size_t next_packet_is_auth_tok_packet;
1764 struct list_head auth_tok_list;
1765 struct ecryptfs_auth_tok *matching_auth_tok;
1766 struct ecryptfs_auth_tok *candidate_auth_tok;
1767 char *candidate_auth_tok_sig;
1768 size_t packet_size;
1769 struct ecryptfs_auth_tok *new_auth_tok;
1770 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1771 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1772 size_t tag_11_contents_size;
1773 size_t tag_11_packet_size;
1774 struct key *auth_tok_key = NULL;
1775 int rc = 0;
1776
1777 INIT_LIST_HEAD(&auth_tok_list);
1778 /* Parse the header to find as many packets as we can; these will be
1779 * added the our &auth_tok_list */
1780 next_packet_is_auth_tok_packet = 1;
1781 while (next_packet_is_auth_tok_packet) {
1782 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1783
1784 switch (src[i]) {
1785 case ECRYPTFS_TAG_3_PACKET_TYPE:
1786 rc = parse_tag_3_packet(crypt_stat,
1787 (unsigned char *)&src[i],
1788 &auth_tok_list, &new_auth_tok,
1789 &packet_size, max_packet_size);
1790 if (rc) {
1791 ecryptfs_printk(KERN_ERR, "Error parsing "
1792 "tag 3 packet\n");
1793 rc = -EIO;
1794 goto out_wipe_list;
1795 }
1796 i += packet_size;
1797 rc = parse_tag_11_packet((unsigned char *)&src[i],
1798 sig_tmp_space,
1799 ECRYPTFS_SIG_SIZE,
1800 &tag_11_contents_size,
1801 &tag_11_packet_size,
1802 max_packet_size);
1803 if (rc) {
1804 ecryptfs_printk(KERN_ERR, "No valid "
1805 "(ecryptfs-specific) literal "
1806 "packet containing "
1807 "authentication token "
1808 "signature found after "
1809 "tag 3 packet\n");
1810 rc = -EIO;
1811 goto out_wipe_list;
1812 }
1813 i += tag_11_packet_size;
1814 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1815 ecryptfs_printk(KERN_ERR, "Expected "
1816 "signature of size [%d]; "
1817 "read size [%zd]\n",
1818 ECRYPTFS_SIG_SIZE,
1819 tag_11_contents_size);
1820 rc = -EIO;
1821 goto out_wipe_list;
1822 }
1823 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1824 sig_tmp_space, tag_11_contents_size);
1825 new_auth_tok->token.password.signature[
1826 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1827 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1828 break;
1829 case ECRYPTFS_TAG_1_PACKET_TYPE:
1830 rc = parse_tag_1_packet(crypt_stat,
1831 (unsigned char *)&src[i],
1832 &auth_tok_list, &new_auth_tok,
1833 &packet_size, max_packet_size);
1834 if (rc) {
1835 ecryptfs_printk(KERN_ERR, "Error parsing "
1836 "tag 1 packet\n");
1837 rc = -EIO;
1838 goto out_wipe_list;
1839 }
1840 i += packet_size;
1841 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1842 break;
1843 case ECRYPTFS_TAG_11_PACKET_TYPE:
1844 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1845 "(Tag 11 not allowed by itself)\n");
1846 rc = -EIO;
1847 goto out_wipe_list;
1848 break;
1849 default:
1850 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1851 "of the file header; hex value of "
1852 "character is [0x%.2x]\n", i, src[i]);
1853 next_packet_is_auth_tok_packet = 0;
1854 }
1855 }
1856 if (list_empty(&auth_tok_list)) {
1857 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1858 "eCryptfs file; this is not supported in this version "
1859 "of the eCryptfs kernel module\n");
1860 rc = -EINVAL;
1861 goto out;
1862 }
1863 /* auth_tok_list contains the set of authentication tokens
1864 * parsed from the metadata. We need to find a matching
1865 * authentication token that has the secret component(s)
1866 * necessary to decrypt the EFEK in the auth_tok parsed from
1867 * the metadata. There may be several potential matches, but
1868 * just one will be sufficient to decrypt to get the FEK. */
1869 find_next_matching_auth_tok:
1870 found_auth_tok = 0;
1871 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1872 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1873 if (unlikely(ecryptfs_verbosity > 0)) {
1874 ecryptfs_printk(KERN_DEBUG,
1875 "Considering cadidate auth tok:\n");
1876 ecryptfs_dump_auth_tok(candidate_auth_tok);
1877 }
1878 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1879 candidate_auth_tok);
1880 if (rc) {
1881 printk(KERN_ERR
1882 "Unrecognized candidate auth tok type: [%d]\n",
1883 candidate_auth_tok->token_type);
1884 rc = -EINVAL;
1885 goto out_wipe_list;
1886 }
1887 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1888 &matching_auth_tok,
1889 crypt_stat->mount_crypt_stat,
1890 candidate_auth_tok_sig);
1891 if (!rc) {
1892 found_auth_tok = 1;
1893 goto found_matching_auth_tok;
1894 }
1895 }
1896 if (!found_auth_tok) {
1897 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1898 "authentication token\n");
1899 rc = -EIO;
1900 goto out_wipe_list;
1901 }
1902 found_matching_auth_tok:
1903 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1904 memcpy(&(candidate_auth_tok->token.private_key),
1905 &(matching_auth_tok->token.private_key),
1906 sizeof(struct ecryptfs_private_key));
1907 up_write(&(auth_tok_key->sem));
1908 key_put(auth_tok_key);
1909 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1910 crypt_stat);
1911 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1912 memcpy(&(candidate_auth_tok->token.password),
1913 &(matching_auth_tok->token.password),
1914 sizeof(struct ecryptfs_password));
1915 up_write(&(auth_tok_key->sem));
1916 key_put(auth_tok_key);
1917 rc = decrypt_passphrase_encrypted_session_key(
1918 candidate_auth_tok, crypt_stat);
1919 } else {
1920 up_write(&(auth_tok_key->sem));
1921 key_put(auth_tok_key);
1922 rc = -EINVAL;
1923 }
1924 if (rc) {
1925 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1926
1927 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1928 "session key for authentication token with sig "
1929 "[%.*s]; rc = [%d]. Removing auth tok "
1930 "candidate from the list and searching for "
1931 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1932 candidate_auth_tok_sig, rc);
1933 list_for_each_entry_safe(auth_tok_list_item,
1934 auth_tok_list_item_tmp,
1935 &auth_tok_list, list) {
1936 if (candidate_auth_tok
1937 == &auth_tok_list_item->auth_tok) {
1938 list_del(&auth_tok_list_item->list);
1939 kmem_cache_free(
1940 ecryptfs_auth_tok_list_item_cache,
1941 auth_tok_list_item);
1942 goto find_next_matching_auth_tok;
1943 }
1944 }
1945 BUG();
1946 }
1947 rc = ecryptfs_compute_root_iv(crypt_stat);
1948 if (rc) {
1949 ecryptfs_printk(KERN_ERR, "Error computing "
1950 "the root IV\n");
1951 goto out_wipe_list;
1952 }
1953 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1954 if (rc) {
1955 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1956 "context for cipher [%s]; rc = [%d]\n",
1957 crypt_stat->cipher, rc);
1958 }
1959 out_wipe_list:
1960 wipe_auth_tok_list(&auth_tok_list);
1961 out:
1962 return rc;
1963 }
1964
1965 static int
1966 pki_encrypt_session_key(struct key *auth_tok_key,
1967 struct ecryptfs_auth_tok *auth_tok,
1968 struct ecryptfs_crypt_stat *crypt_stat,
1969 struct ecryptfs_key_record *key_rec)
1970 {
1971 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1972 char *payload = NULL;
1973 size_t payload_len;
1974 struct ecryptfs_message *msg;
1975 int rc;
1976
1977 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1978 ecryptfs_code_for_cipher_string(
1979 crypt_stat->cipher,
1980 crypt_stat->key_size),
1981 crypt_stat, &payload, &payload_len);
1982 up_write(&(auth_tok_key->sem));
1983 key_put(auth_tok_key);
1984 if (rc) {
1985 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1986 goto out;
1987 }
1988 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1989 if (rc) {
1990 ecryptfs_printk(KERN_ERR, "Error sending message to "
1991 "ecryptfsd\n");
1992 goto out;
1993 }
1994 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1995 if (rc) {
1996 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1997 "from the user space daemon\n");
1998 rc = -EIO;
1999 goto out;
2000 }
2001 rc = parse_tag_67_packet(key_rec, msg);
2002 if (rc)
2003 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2004 kfree(msg);
2005 out:
2006 kfree(payload);
2007 return rc;
2008 }
2009 /**
2010 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2011 * @dest: Buffer into which to write the packet
2012 * @remaining_bytes: Maximum number of bytes that can be writtn
2013 * @auth_tok_key: The authentication token key to unlock and put when done with
2014 * @auth_tok
2015 * @auth_tok: The authentication token used for generating the tag 1 packet
2016 * @crypt_stat: The cryptographic context
2017 * @key_rec: The key record struct for the tag 1 packet
2018 * @packet_size: This function will write the number of bytes that end
2019 * up constituting the packet; set to zero on error
2020 *
2021 * Returns zero on success; non-zero on error.
2022 */
2023 static int
2024 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2025 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2026 struct ecryptfs_crypt_stat *crypt_stat,
2027 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2028 {
2029 size_t i;
2030 size_t encrypted_session_key_valid = 0;
2031 size_t packet_size_length;
2032 size_t max_packet_size;
2033 int rc = 0;
2034
2035 (*packet_size) = 0;
2036 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2037 ECRYPTFS_SIG_SIZE);
2038 encrypted_session_key_valid = 0;
2039 for (i = 0; i < crypt_stat->key_size; i++)
2040 encrypted_session_key_valid |=
2041 auth_tok->session_key.encrypted_key[i];
2042 if (encrypted_session_key_valid) {
2043 memcpy(key_rec->enc_key,
2044 auth_tok->session_key.encrypted_key,
2045 auth_tok->session_key.encrypted_key_size);
2046 up_write(&(auth_tok_key->sem));
2047 key_put(auth_tok_key);
2048 goto encrypted_session_key_set;
2049 }
2050 if (auth_tok->session_key.encrypted_key_size == 0)
2051 auth_tok->session_key.encrypted_key_size =
2052 auth_tok->token.private_key.key_size;
2053 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2054 key_rec);
2055 if (rc) {
2056 printk(KERN_ERR "Failed to encrypt session key via a key "
2057 "module; rc = [%d]\n", rc);
2058 goto out;
2059 }
2060 if (ecryptfs_verbosity > 0) {
2061 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2062 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2063 }
2064 encrypted_session_key_set:
2065 /* This format is inspired by OpenPGP; see RFC 2440
2066 * packet tag 1 */
2067 max_packet_size = (1 /* Tag 1 identifier */
2068 + 3 /* Max Tag 1 packet size */
2069 + 1 /* Version */
2070 + ECRYPTFS_SIG_SIZE /* Key identifier */
2071 + 1 /* Cipher identifier */
2072 + key_rec->enc_key_size); /* Encrypted key size */
2073 if (max_packet_size > (*remaining_bytes)) {
2074 printk(KERN_ERR "Packet length larger than maximum allowable; "
2075 "need up to [%td] bytes, but there are only [%td] "
2076 "available\n", max_packet_size, (*remaining_bytes));
2077 rc = -EINVAL;
2078 goto out;
2079 }
2080 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2081 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2082 (max_packet_size - 4),
2083 &packet_size_length);
2084 if (rc) {
2085 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2086 "header; cannot generate packet length\n");
2087 goto out;
2088 }
2089 (*packet_size) += packet_size_length;
2090 dest[(*packet_size)++] = 0x03; /* version 3 */
2091 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2092 (*packet_size) += ECRYPTFS_SIG_SIZE;
2093 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2094 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2095 key_rec->enc_key_size);
2096 (*packet_size) += key_rec->enc_key_size;
2097 out:
2098 if (rc)
2099 (*packet_size) = 0;
2100 else
2101 (*remaining_bytes) -= (*packet_size);
2102 return rc;
2103 }
2104
2105 /**
2106 * write_tag_11_packet
2107 * @dest: Target into which Tag 11 packet is to be written
2108 * @remaining_bytes: Maximum packet length
2109 * @contents: Byte array of contents to copy in
2110 * @contents_length: Number of bytes in contents
2111 * @packet_length: Length of the Tag 11 packet written; zero on error
2112 *
2113 * Returns zero on success; non-zero on error.
2114 */
2115 static int
2116 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2117 size_t contents_length, size_t *packet_length)
2118 {
2119 size_t packet_size_length;
2120 size_t max_packet_size;
2121 int rc = 0;
2122
2123 (*packet_length) = 0;
2124 /* This format is inspired by OpenPGP; see RFC 2440
2125 * packet tag 11 */
2126 max_packet_size = (1 /* Tag 11 identifier */
2127 + 3 /* Max Tag 11 packet size */
2128 + 1 /* Binary format specifier */
2129 + 1 /* Filename length */
2130 + 8 /* Filename ("_CONSOLE") */
2131 + 4 /* Modification date */
2132 + contents_length); /* Literal data */
2133 if (max_packet_size > (*remaining_bytes)) {
2134 printk(KERN_ERR "Packet length larger than maximum allowable; "
2135 "need up to [%td] bytes, but there are only [%td] "
2136 "available\n", max_packet_size, (*remaining_bytes));
2137 rc = -EINVAL;
2138 goto out;
2139 }
2140 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2141 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2142 (max_packet_size - 4),
2143 &packet_size_length);
2144 if (rc) {
2145 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2146 "generate packet length. rc = [%d]\n", rc);
2147 goto out;
2148 }
2149 (*packet_length) += packet_size_length;
2150 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2151 dest[(*packet_length)++] = 8;
2152 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2153 (*packet_length) += 8;
2154 memset(&dest[(*packet_length)], 0x00, 4);
2155 (*packet_length) += 4;
2156 memcpy(&dest[(*packet_length)], contents, contents_length);
2157 (*packet_length) += contents_length;
2158 out:
2159 if (rc)
2160 (*packet_length) = 0;
2161 else
2162 (*remaining_bytes) -= (*packet_length);
2163 return rc;
2164 }
2165
2166 /**
2167 * write_tag_3_packet
2168 * @dest: Buffer into which to write the packet
2169 * @remaining_bytes: Maximum number of bytes that can be written
2170 * @auth_tok: Authentication token
2171 * @crypt_stat: The cryptographic context
2172 * @key_rec: encrypted key
2173 * @packet_size: This function will write the number of bytes that end
2174 * up constituting the packet; set to zero on error
2175 *
2176 * Returns zero on success; non-zero on error.
2177 */
2178 static int
2179 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2180 struct ecryptfs_auth_tok *auth_tok,
2181 struct ecryptfs_crypt_stat *crypt_stat,
2182 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2183 {
2184 size_t i;
2185 size_t encrypted_session_key_valid = 0;
2186 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2187 struct scatterlist dst_sg[2];
2188 struct scatterlist src_sg[2];
2189 struct mutex *tfm_mutex = NULL;
2190 u8 cipher_code;
2191 size_t packet_size_length;
2192 size_t max_packet_size;
2193 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2194 crypt_stat->mount_crypt_stat;
2195 struct blkcipher_desc desc = {
2196 .tfm = NULL,
2197 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2198 };
2199 int rc = 0;
2200
2201 (*packet_size) = 0;
2202 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2203 ECRYPTFS_SIG_SIZE);
2204 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2205 crypt_stat->cipher);
2206 if (unlikely(rc)) {
2207 printk(KERN_ERR "Internal error whilst attempting to get "
2208 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2209 crypt_stat->cipher, rc);
2210 goto out;
2211 }
2212 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2213 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2214
2215 printk(KERN_WARNING "No key size specified at mount; "
2216 "defaulting to [%d]\n", alg->max_keysize);
2217 mount_crypt_stat->global_default_cipher_key_size =
2218 alg->max_keysize;
2219 }
2220 if (crypt_stat->key_size == 0)
2221 crypt_stat->key_size =
2222 mount_crypt_stat->global_default_cipher_key_size;
2223 if (auth_tok->session_key.encrypted_key_size == 0)
2224 auth_tok->session_key.encrypted_key_size =
2225 crypt_stat->key_size;
2226 if (crypt_stat->key_size == 24
2227 && strcmp("aes", crypt_stat->cipher) == 0) {
2228 memset((crypt_stat->key + 24), 0, 8);
2229 auth_tok->session_key.encrypted_key_size = 32;
2230 } else
2231 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2232 key_rec->enc_key_size =
2233 auth_tok->session_key.encrypted_key_size;
2234 encrypted_session_key_valid = 0;
2235 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2236 encrypted_session_key_valid |=
2237 auth_tok->session_key.encrypted_key[i];
2238 if (encrypted_session_key_valid) {
2239 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2240 "using auth_tok->session_key.encrypted_key, "
2241 "where key_rec->enc_key_size = [%zd]\n",
2242 key_rec->enc_key_size);
2243 memcpy(key_rec->enc_key,
2244 auth_tok->session_key.encrypted_key,
2245 key_rec->enc_key_size);
2246 goto encrypted_session_key_set;
2247 }
2248 if (auth_tok->token.password.flags &
2249 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2250 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2251 "session key encryption key of size [%d]\n",
2252 auth_tok->token.password.
2253 session_key_encryption_key_bytes);
2254 memcpy(session_key_encryption_key,
2255 auth_tok->token.password.session_key_encryption_key,
2256 crypt_stat->key_size);
2257 ecryptfs_printk(KERN_DEBUG,
2258 "Cached session key " "encryption key: \n");
2259 if (ecryptfs_verbosity > 0)
2260 ecryptfs_dump_hex(session_key_encryption_key, 16);
2261 }
2262 if (unlikely(ecryptfs_verbosity > 0)) {
2263 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2264 ecryptfs_dump_hex(session_key_encryption_key, 16);
2265 }
2266 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2267 src_sg, 2);
2268 if (rc < 1 || rc > 2) {
2269 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2270 "for crypt_stat session key; expected rc = 1; "
2271 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2272 rc, key_rec->enc_key_size);
2273 rc = -ENOMEM;
2274 goto out;
2275 }
2276 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2277 dst_sg, 2);
2278 if (rc < 1 || rc > 2) {
2279 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2280 "for crypt_stat encrypted session key; "
2281 "expected rc = 1; got rc = [%d]. "
2282 "key_rec->enc_key_size = [%zd]\n", rc,
2283 key_rec->enc_key_size);
2284 rc = -ENOMEM;
2285 goto out;
2286 }
2287 mutex_lock(tfm_mutex);
2288 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2289 crypt_stat->key_size);
2290 if (rc < 0) {
2291 mutex_unlock(tfm_mutex);
2292 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2293 "context; rc = [%d]\n", rc);
2294 goto out;
2295 }
2296 rc = 0;
2297 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2298 crypt_stat->key_size);
2299 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2300 (*key_rec).enc_key_size);
2301 mutex_unlock(tfm_mutex);
2302 if (rc) {
2303 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2304 goto out;
2305 }
2306 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2307 if (ecryptfs_verbosity > 0) {
2308 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2309 key_rec->enc_key_size);
2310 ecryptfs_dump_hex(key_rec->enc_key,
2311 key_rec->enc_key_size);
2312 }
2313 encrypted_session_key_set:
2314 /* This format is inspired by OpenPGP; see RFC 2440
2315 * packet tag 3 */
2316 max_packet_size = (1 /* Tag 3 identifier */
2317 + 3 /* Max Tag 3 packet size */
2318 + 1 /* Version */
2319 + 1 /* Cipher code */
2320 + 1 /* S2K specifier */
2321 + 1 /* Hash identifier */
2322 + ECRYPTFS_SALT_SIZE /* Salt */
2323 + 1 /* Hash iterations */
2324 + key_rec->enc_key_size); /* Encrypted key size */
2325 if (max_packet_size > (*remaining_bytes)) {
2326 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2327 "there are only [%td] available\n", max_packet_size,
2328 (*remaining_bytes));
2329 rc = -EINVAL;
2330 goto out;
2331 }
2332 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2333 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2334 * to get the number of octets in the actual Tag 3 packet */
2335 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2336 (max_packet_size - 4),
2337 &packet_size_length);
2338 if (rc) {
2339 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2340 "generate packet length. rc = [%d]\n", rc);
2341 goto out;
2342 }
2343 (*packet_size) += packet_size_length;
2344 dest[(*packet_size)++] = 0x04; /* version 4 */
2345 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2346 * specified with strings */
2347 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2348 crypt_stat->key_size);
2349 if (cipher_code == 0) {
2350 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2351 "cipher [%s]\n", crypt_stat->cipher);
2352 rc = -EINVAL;
2353 goto out;
2354 }
2355 dest[(*packet_size)++] = cipher_code;
2356 dest[(*packet_size)++] = 0x03; /* S2K */
2357 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2358 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2359 ECRYPTFS_SALT_SIZE);
2360 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2361 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2362 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2363 key_rec->enc_key_size);
2364 (*packet_size) += key_rec->enc_key_size;
2365 out:
2366 if (rc)
2367 (*packet_size) = 0;
2368 else
2369 (*remaining_bytes) -= (*packet_size);
2370 return rc;
2371 }
2372
2373 struct kmem_cache *ecryptfs_key_record_cache;
2374
2375 /**
2376 * ecryptfs_generate_key_packet_set
2377 * @dest_base: Virtual address from which to write the key record set
2378 * @crypt_stat: The cryptographic context from which the
2379 * authentication tokens will be retrieved
2380 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2381 * for the global parameters
2382 * @len: The amount written
2383 * @max: The maximum amount of data allowed to be written
2384 *
2385 * Generates a key packet set and writes it to the virtual address
2386 * passed in.
2387 *
2388 * Returns zero on success; non-zero on error.
2389 */
2390 int
2391 ecryptfs_generate_key_packet_set(char *dest_base,
2392 struct ecryptfs_crypt_stat *crypt_stat,
2393 struct dentry *ecryptfs_dentry, size_t *len,
2394 size_t max)
2395 {
2396 struct ecryptfs_auth_tok *auth_tok;
2397 struct key *auth_tok_key = NULL;
2398 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2399 &ecryptfs_superblock_to_private(
2400 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2401 size_t written;
2402 struct ecryptfs_key_record *key_rec;
2403 struct ecryptfs_key_sig *key_sig;
2404 int rc = 0;
2405
2406 (*len) = 0;
2407 mutex_lock(&crypt_stat->keysig_list_mutex);
2408 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2409 if (!key_rec) {
2410 rc = -ENOMEM;
2411 goto out;
2412 }
2413 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2414 crypt_stat_list) {
2415 memset(key_rec, 0, sizeof(*key_rec));
2416 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2417 &auth_tok,
2418 mount_crypt_stat,
2419 key_sig->keysig);
2420 if (rc) {
2421 printk(KERN_WARNING "Unable to retrieve auth tok with "
2422 "sig = [%s]\n", key_sig->keysig);
2423 rc = process_find_global_auth_tok_for_sig_err(rc);
2424 goto out_free;
2425 }
2426 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2427 rc = write_tag_3_packet((dest_base + (*len)),
2428 &max, auth_tok,
2429 crypt_stat, key_rec,
2430 &written);
2431 up_write(&(auth_tok_key->sem));
2432 key_put(auth_tok_key);
2433 if (rc) {
2434 ecryptfs_printk(KERN_WARNING, "Error "
2435 "writing tag 3 packet\n");
2436 goto out_free;
2437 }
2438 (*len) += written;
2439 /* Write auth tok signature packet */
2440 rc = write_tag_11_packet((dest_base + (*len)), &max,
2441 key_rec->sig,
2442 ECRYPTFS_SIG_SIZE, &written);
2443 if (rc) {
2444 ecryptfs_printk(KERN_ERR, "Error writing "
2445 "auth tok signature packet\n");
2446 goto out_free;
2447 }
2448 (*len) += written;
2449 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2450 rc = write_tag_1_packet(dest_base + (*len), &max,
2451 auth_tok_key, auth_tok,
2452 crypt_stat, key_rec, &written);
2453 if (rc) {
2454 ecryptfs_printk(KERN_WARNING, "Error "
2455 "writing tag 1 packet\n");
2456 goto out_free;
2457 }
2458 (*len) += written;
2459 } else {
2460 up_write(&(auth_tok_key->sem));
2461 key_put(auth_tok_key);
2462 ecryptfs_printk(KERN_WARNING, "Unsupported "
2463 "authentication token type\n");
2464 rc = -EINVAL;
2465 goto out_free;
2466 }
2467 }
2468 if (likely(max > 0)) {
2469 dest_base[(*len)] = 0x00;
2470 } else {
2471 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2472 rc = -EIO;
2473 }
2474 out_free:
2475 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2476 out:
2477 if (rc)
2478 (*len) = 0;
2479 mutex_unlock(&crypt_stat->keysig_list_mutex);
2480 return rc;
2481 }
2482
2483 struct kmem_cache *ecryptfs_key_sig_cache;
2484
2485 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2486 {
2487 struct ecryptfs_key_sig *new_key_sig;
2488
2489 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2490 if (!new_key_sig) {
2491 printk(KERN_ERR
2492 "Error allocating from ecryptfs_key_sig_cache\n");
2493 return -ENOMEM;
2494 }
2495 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2496 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2497 /* Caller must hold keysig_list_mutex */
2498 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2499
2500 return 0;
2501 }
2502
2503 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2504
2505 int
2506 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2507 char *sig, u32 global_auth_tok_flags)
2508 {
2509 struct ecryptfs_global_auth_tok *new_auth_tok;
2510 int rc = 0;
2511
2512 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2513 GFP_KERNEL);
2514 if (!new_auth_tok) {
2515 rc = -ENOMEM;
2516 printk(KERN_ERR "Error allocating from "
2517 "ecryptfs_global_auth_tok_cache\n");
2518 goto out;
2519 }
2520 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2521 new_auth_tok->flags = global_auth_tok_flags;
2522 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2523 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2524 list_add(&new_auth_tok->mount_crypt_stat_list,
2525 &mount_crypt_stat->global_auth_tok_list);
2526 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2527 out:
2528 return rc;
2529 }
2530
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