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ARM: 7747/1: pcpu: ensure __my_cpu_offset cannot be re-ordered across barrier()
[linux/fpc-iii.git] / fs / ecryptfs / keystore.c
blob7d52806c21197206a5932b08a68e7dc9d6899253
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 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
113 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
114 "supported\n");
115 rc = -EINVAL;
116 goto out;
117 } else {
118 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
119 rc = -EINVAL;
120 goto out;
121 }
122 out:
123 return rc;
124 }
125
126 /**
127 * ecryptfs_write_packet_length
128 * @dest: The byte array target into which to write the length. Must
129 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
130 * @size: The length to write.
131 * @packet_size_length: The number of bytes used to encode the packet
132 * length is written to this address.
133 *
134 * Returns zero on success; non-zero on error.
135 */
136 int ecryptfs_write_packet_length(char *dest, size_t size,
137 size_t *packet_size_length)
138 {
139 int rc = 0;
140
141 if (size < 192) {
142 dest[0] = size;
143 (*packet_size_length) = 1;
144 } else if (size < 65536) {
145 dest[0] = (((size - 192) / 256) + 192);
146 dest[1] = ((size - 192) % 256);
147 (*packet_size_length) = 2;
148 } else {
149 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
150 rc = -EINVAL;
151 ecryptfs_printk(KERN_WARNING,
152 "Unsupported packet size: [%zd]\n", size);
153 }
154 return rc;
155 }
156
157 static int
158 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
159 char **packet, size_t *packet_len)
160 {
161 size_t i = 0;
162 size_t data_len;
163 size_t packet_size_len;
164 char *message;
165 int rc;
166
167 /*
168 * ***** TAG 64 Packet Format *****
169 * | Content Type | 1 byte |
170 * | Key Identifier Size | 1 or 2 bytes |
171 * | Key Identifier | arbitrary |
172 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
173 * | Encrypted File Encryption Key | arbitrary |
174 */
175 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
176 + session_key->encrypted_key_size);
177 *packet = kmalloc(data_len, GFP_KERNEL);
178 message = *packet;
179 if (!message) {
180 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
181 rc = -ENOMEM;
182 goto out;
183 }
184 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
185 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
186 &packet_size_len);
187 if (rc) {
188 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
189 "header; cannot generate packet length\n");
190 goto out;
191 }
192 i += packet_size_len;
193 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
194 i += ECRYPTFS_SIG_SIZE_HEX;
195 rc = ecryptfs_write_packet_length(&message[i],
196 session_key->encrypted_key_size,
197 &packet_size_len);
198 if (rc) {
199 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
200 "header; cannot generate packet length\n");
201 goto out;
202 }
203 i += packet_size_len;
204 memcpy(&message[i], session_key->encrypted_key,
205 session_key->encrypted_key_size);
206 i += session_key->encrypted_key_size;
207 *packet_len = i;
208 out:
209 return rc;
210 }
211
212 static int
213 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
214 struct ecryptfs_message *msg)
215 {
216 size_t i = 0;
217 char *data;
218 size_t data_len;
219 size_t m_size;
220 size_t message_len;
221 u16 checksum = 0;
222 u16 expected_checksum = 0;
223 int rc;
224
225 /*
226 * ***** TAG 65 Packet Format *****
227 * | Content Type | 1 byte |
228 * | Status Indicator | 1 byte |
229 * | File Encryption Key Size | 1 or 2 bytes |
230 * | File Encryption Key | arbitrary |
231 */
232 message_len = msg->data_len;
233 data = msg->data;
234 if (message_len < 4) {
235 rc = -EIO;
236 goto out;
237 }
238 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
239 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
240 rc = -EIO;
241 goto out;
242 }
243 if (data[i++]) {
244 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
245 "[%d]\n", data[i-1]);
246 rc = -EIO;
247 goto out;
248 }
249 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
250 if (rc) {
251 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
252 "rc = [%d]\n", rc);
253 goto out;
254 }
255 i += data_len;
256 if (message_len < (i + m_size)) {
257 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
258 "is shorter than expected\n");
259 rc = -EIO;
260 goto out;
261 }
262 if (m_size < 3) {
263 ecryptfs_printk(KERN_ERR,
264 "The decrypted key is not long enough to "
265 "include a cipher code and checksum\n");
266 rc = -EIO;
267 goto out;
268 }
269 *cipher_code = data[i++];
270 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
271 session_key->decrypted_key_size = m_size - 3;
272 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
273 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
274 "the maximum key size [%d]\n",
275 session_key->decrypted_key_size,
276 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
277 rc = -EIO;
278 goto out;
279 }
280 memcpy(session_key->decrypted_key, &data[i],
281 session_key->decrypted_key_size);
282 i += session_key->decrypted_key_size;
283 expected_checksum += (unsigned char)(data[i++]) << 8;
284 expected_checksum += (unsigned char)(data[i++]);
285 for (i = 0; i < session_key->decrypted_key_size; i++)
286 checksum += session_key->decrypted_key[i];
287 if (expected_checksum != checksum) {
288 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
289 "encryption key; expected [%x]; calculated "
290 "[%x]\n", expected_checksum, checksum);
291 rc = -EIO;
292 }
293 out:
294 return rc;
295 }
296
297
298 static int
299 write_tag_66_packet(char *signature, u8 cipher_code,
300 struct ecryptfs_crypt_stat *crypt_stat, char **packet,
301 size_t *packet_len)
302 {
303 size_t i = 0;
304 size_t j;
305 size_t data_len;
306 size_t checksum = 0;
307 size_t packet_size_len;
308 char *message;
309 int rc;
310
311 /*
312 * ***** TAG 66 Packet Format *****
313 * | Content Type | 1 byte |
314 * | Key Identifier Size | 1 or 2 bytes |
315 * | Key Identifier | arbitrary |
316 * | File Encryption Key Size | 1 or 2 bytes |
317 * | File Encryption Key | arbitrary |
318 */
319 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
320 *packet = kmalloc(data_len, GFP_KERNEL);
321 message = *packet;
322 if (!message) {
323 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
324 rc = -ENOMEM;
325 goto out;
326 }
327 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
328 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
329 &packet_size_len);
330 if (rc) {
331 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
332 "header; cannot generate packet length\n");
333 goto out;
334 }
335 i += packet_size_len;
336 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
337 i += ECRYPTFS_SIG_SIZE_HEX;
338 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
339 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
340 &packet_size_len);
341 if (rc) {
342 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
343 "header; cannot generate packet length\n");
344 goto out;
345 }
346 i += packet_size_len;
347 message[i++] = cipher_code;
348 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
349 i += crypt_stat->key_size;
350 for (j = 0; j < crypt_stat->key_size; j++)
351 checksum += crypt_stat->key[j];
352 message[i++] = (checksum / 256) % 256;
353 message[i++] = (checksum % 256);
354 *packet_len = i;
355 out:
356 return rc;
357 }
358
359 static int
360 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
361 struct ecryptfs_message *msg)
362 {
363 size_t i = 0;
364 char *data;
365 size_t data_len;
366 size_t message_len;
367 int rc;
368
369 /*
370 * ***** TAG 65 Packet Format *****
371 * | Content Type | 1 byte |
372 * | Status Indicator | 1 byte |
373 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
374 * | Encrypted File Encryption Key | arbitrary |
375 */
376 message_len = msg->data_len;
377 data = msg->data;
378 /* verify that everything through the encrypted FEK size is present */
379 if (message_len < 4) {
380 rc = -EIO;
381 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
382 "message length is [%d]\n", __func__, message_len, 4);
383 goto out;
384 }
385 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
386 rc = -EIO;
387 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
388 __func__);
389 goto out;
390 }
391 if (data[i++]) {
392 rc = -EIO;
393 printk(KERN_ERR "%s: Status indicator has non zero "
394 "value [%d]\n", __func__, data[i-1]);
395
396 goto out;
397 }
398 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
399 &data_len);
400 if (rc) {
401 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
402 "rc = [%d]\n", rc);
403 goto out;
404 }
405 i += data_len;
406 if (message_len < (i + key_rec->enc_key_size)) {
407 rc = -EIO;
408 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
409 __func__, message_len, (i + key_rec->enc_key_size));
410 goto out;
411 }
412 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
413 rc = -EIO;
414 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
415 "the maximum key size [%d]\n", __func__,
416 key_rec->enc_key_size,
417 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
418 goto out;
419 }
420 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
421 out:
422 return rc;
423 }
424
425 /**
426 * ecryptfs_verify_version
427 * @version: The version number to confirm
428 *
429 * Returns zero on good version; non-zero otherwise
430 */
431 static int ecryptfs_verify_version(u16 version)
432 {
433 int rc = 0;
434 unsigned char major;
435 unsigned char minor;
436
437 major = ((version >> 8) & 0xFF);
438 minor = (version & 0xFF);
439 if (major != ECRYPTFS_VERSION_MAJOR) {
440 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
441 "Expected [%d]; got [%d]\n",
442 ECRYPTFS_VERSION_MAJOR, major);
443 rc = -EINVAL;
444 goto out;
445 }
446 if (minor != ECRYPTFS_VERSION_MINOR) {
447 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
448 "Expected [%d]; got [%d]\n",
449 ECRYPTFS_VERSION_MINOR, minor);
450 rc = -EINVAL;
451 goto out;
452 }
453 out:
454 return rc;
455 }
456
457 /**
458 * ecryptfs_verify_auth_tok_from_key
459 * @auth_tok_key: key containing the authentication token
460 * @auth_tok: authentication token
461 *
462 * Returns zero on valid auth tok; -EINVAL otherwise
463 */
464 static int
465 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
466 struct ecryptfs_auth_tok **auth_tok)
467 {
468 int rc = 0;
469
470 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
471 if (ecryptfs_verify_version((*auth_tok)->version)) {
472 printk(KERN_ERR "Data structure version mismatch. Userspace "
473 "tools must match eCryptfs kernel module with major "
474 "version [%d] and minor version [%d]\n",
475 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
476 rc = -EINVAL;
477 goto out;
478 }
479 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
480 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
481 printk(KERN_ERR "Invalid auth_tok structure "
482 "returned from key query\n");
483 rc = -EINVAL;
484 goto out;
485 }
486 out:
487 return rc;
488 }
489
490 static int
491 ecryptfs_find_global_auth_tok_for_sig(
492 struct key **auth_tok_key,
493 struct ecryptfs_auth_tok **auth_tok,
494 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
495 {
496 struct ecryptfs_global_auth_tok *walker;
497 int rc = 0;
498
499 (*auth_tok_key) = NULL;
500 (*auth_tok) = NULL;
501 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
502 list_for_each_entry(walker,
503 &mount_crypt_stat->global_auth_tok_list,
504 mount_crypt_stat_list) {
505 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
506 continue;
507
508 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
509 rc = -EINVAL;
510 goto out;
511 }
512
513 rc = key_validate(walker->global_auth_tok_key);
514 if (rc) {
515 if (rc == -EKEYEXPIRED)
516 goto out;
517 goto out_invalid_auth_tok;
518 }
519
520 down_write(&(walker->global_auth_tok_key->sem));
521 rc = ecryptfs_verify_auth_tok_from_key(
522 walker->global_auth_tok_key, auth_tok);
523 if (rc)
524 goto out_invalid_auth_tok_unlock;
525
526 (*auth_tok_key) = walker->global_auth_tok_key;
527 key_get(*auth_tok_key);
528 goto out;
529 }
530 rc = -ENOENT;
531 goto out;
532 out_invalid_auth_tok_unlock:
533 up_write(&(walker->global_auth_tok_key->sem));
534 out_invalid_auth_tok:
535 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
536 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
537 key_put(walker->global_auth_tok_key);
538 walker->global_auth_tok_key = NULL;
539 out:
540 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
541 return rc;
542 }
543
544 /**
545 * ecryptfs_find_auth_tok_for_sig
546 * @auth_tok: Set to the matching auth_tok; NULL if not found
547 * @crypt_stat: inode crypt_stat crypto context
548 * @sig: Sig of auth_tok to find
549 *
550 * For now, this function simply looks at the registered auth_tok's
551 * linked off the mount_crypt_stat, so all the auth_toks that can be
552 * used must be registered at mount time. This function could
553 * potentially try a lot harder to find auth_tok's (e.g., by calling
554 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
555 * that static registration of auth_tok's will no longer be necessary.
556 *
557 * Returns zero on no error; non-zero on error
558 */
559 static int
560 ecryptfs_find_auth_tok_for_sig(
561 struct key **auth_tok_key,
562 struct ecryptfs_auth_tok **auth_tok,
563 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
564 char *sig)
565 {
566 int rc = 0;
567
568 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
569 mount_crypt_stat, sig);
570 if (rc == -ENOENT) {
571 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
572 * mount_crypt_stat structure, we prevent to use auth toks that
573 * are not inserted through the ecryptfs_add_global_auth_tok
574 * function.
575 */
576 if (mount_crypt_stat->flags
577 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
578 return -EINVAL;
579
580 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
581 sig);
582 }
583 return rc;
584 }
585
586 /**
587 * write_tag_70_packet can gobble a lot of stack space. We stuff most
588 * of the function's parameters in a kmalloc'd struct to help reduce
589 * eCryptfs' overall stack usage.
590 */
591 struct ecryptfs_write_tag_70_packet_silly_stack {
592 u8 cipher_code;
593 size_t max_packet_size;
594 size_t packet_size_len;
595 size_t block_aligned_filename_size;
596 size_t block_size;
597 size_t i;
598 size_t j;
599 size_t num_rand_bytes;
600 struct mutex *tfm_mutex;
601 char *block_aligned_filename;
602 struct ecryptfs_auth_tok *auth_tok;
603 struct scatterlist src_sg[2];
604 struct scatterlist dst_sg[2];
605 struct blkcipher_desc desc;
606 char iv[ECRYPTFS_MAX_IV_BYTES];
607 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
608 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
609 struct hash_desc hash_desc;
610 struct scatterlist hash_sg;
611 };
612
613 /**
614 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
615 * @filename: NULL-terminated filename string
616 *
617 * This is the simplest mechanism for achieving filename encryption in
618 * eCryptfs. It encrypts the given filename with the mount-wide
619 * filename encryption key (FNEK) and stores it in a packet to @dest,
620 * which the callee will encode and write directly into the dentry
621 * name.
622 */
623 int
624 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
625 size_t *packet_size,
626 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
627 char *filename, size_t filename_size)
628 {
629 struct ecryptfs_write_tag_70_packet_silly_stack *s;
630 struct key *auth_tok_key = NULL;
631 int rc = 0;
632
633 s = kmalloc(sizeof(*s), GFP_KERNEL);
634 if (!s) {
635 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
636 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
637 rc = -ENOMEM;
638 goto out;
639 }
640 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
641 (*packet_size) = 0;
642 rc = ecryptfs_find_auth_tok_for_sig(
643 &auth_tok_key,
644 &s->auth_tok, mount_crypt_stat,
645 mount_crypt_stat->global_default_fnek_sig);
646 if (rc) {
647 printk(KERN_ERR "%s: Error attempting to find auth tok for "
648 "fnek sig [%s]; rc = [%d]\n", __func__,
649 mount_crypt_stat->global_default_fnek_sig, rc);
650 goto out;
651 }
652 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
653 &s->desc.tfm,
654 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
655 if (unlikely(rc)) {
656 printk(KERN_ERR "Internal error whilst attempting to get "
657 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
658 mount_crypt_stat->global_default_fn_cipher_name, rc);
659 goto out;
660 }
661 mutex_lock(s->tfm_mutex);
662 s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
663 /* Plus one for the \0 separator between the random prefix
664 * and the plaintext filename */
665 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
666 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
667 if ((s->block_aligned_filename_size % s->block_size) != 0) {
668 s->num_rand_bytes += (s->block_size
669 - (s->block_aligned_filename_size
670 % s->block_size));
671 s->block_aligned_filename_size = (s->num_rand_bytes
672 + filename_size);
673 }
674 /* Octet 0: Tag 70 identifier
675 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
676 * and block-aligned encrypted filename size)
677 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
678 * Octet N2-N3: Cipher identifier (1 octet)
679 * Octets N3-N4: Block-aligned encrypted filename
680 * - Consists of a minimum number of random characters, a \0
681 * separator, and then the filename */
682 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
683 + s->block_aligned_filename_size);
684 if (dest == NULL) {
685 (*packet_size) = s->max_packet_size;
686 goto out_unlock;
687 }
688 if (s->max_packet_size > (*remaining_bytes)) {
689 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
690 "[%zd] available\n", __func__, s->max_packet_size,
691 (*remaining_bytes));
692 rc = -EINVAL;
693 goto out_unlock;
694 }
695 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
696 GFP_KERNEL);
697 if (!s->block_aligned_filename) {
698 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
699 "kzalloc [%zd] bytes\n", __func__,
700 s->block_aligned_filename_size);
701 rc = -ENOMEM;
702 goto out_unlock;
703 }
704 s->i = 0;
705 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
706 rc = ecryptfs_write_packet_length(&dest[s->i],
707 (ECRYPTFS_SIG_SIZE
708 + 1 /* Cipher code */
709 + s->block_aligned_filename_size),
710 &s->packet_size_len);
711 if (rc) {
712 printk(KERN_ERR "%s: Error generating tag 70 packet "
713 "header; cannot generate packet length; rc = [%d]\n",
714 __func__, rc);
715 goto out_free_unlock;
716 }
717 s->i += s->packet_size_len;
718 ecryptfs_from_hex(&dest[s->i],
719 mount_crypt_stat->global_default_fnek_sig,
720 ECRYPTFS_SIG_SIZE);
721 s->i += ECRYPTFS_SIG_SIZE;
722 s->cipher_code = ecryptfs_code_for_cipher_string(
723 mount_crypt_stat->global_default_fn_cipher_name,
724 mount_crypt_stat->global_default_fn_cipher_key_bytes);
725 if (s->cipher_code == 0) {
726 printk(KERN_WARNING "%s: Unable to generate code for "
727 "cipher [%s] with key bytes [%zd]\n", __func__,
728 mount_crypt_stat->global_default_fn_cipher_name,
729 mount_crypt_stat->global_default_fn_cipher_key_bytes);
730 rc = -EINVAL;
731 goto out_free_unlock;
732 }
733 dest[s->i++] = s->cipher_code;
734 /* TODO: Support other key modules than passphrase for
735 * filename encryption */
736 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
737 rc = -EOPNOTSUPP;
738 printk(KERN_INFO "%s: Filename encryption only supports "
739 "password tokens\n", __func__);
740 goto out_free_unlock;
741 }
742 sg_init_one(
743 &s->hash_sg,
744 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
745 s->auth_tok->token.password.session_key_encryption_key_bytes);
746 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
747 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
748 CRYPTO_ALG_ASYNC);
749 if (IS_ERR(s->hash_desc.tfm)) {
750 rc = PTR_ERR(s->hash_desc.tfm);
751 printk(KERN_ERR "%s: Error attempting to "
752 "allocate hash crypto context; rc = [%d]\n",
753 __func__, rc);
754 goto out_free_unlock;
755 }
756 rc = crypto_hash_init(&s->hash_desc);
757 if (rc) {
758 printk(KERN_ERR
759 "%s: Error initializing crypto hash; rc = [%d]\n",
760 __func__, rc);
761 goto out_release_free_unlock;
762 }
763 rc = crypto_hash_update(
764 &s->hash_desc, &s->hash_sg,
765 s->auth_tok->token.password.session_key_encryption_key_bytes);
766 if (rc) {
767 printk(KERN_ERR
768 "%s: Error updating crypto hash; rc = [%d]\n",
769 __func__, rc);
770 goto out_release_free_unlock;
771 }
772 rc = crypto_hash_final(&s->hash_desc, s->hash);
773 if (rc) {
774 printk(KERN_ERR
775 "%s: Error finalizing crypto hash; rc = [%d]\n",
776 __func__, rc);
777 goto out_release_free_unlock;
778 }
779 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
780 s->block_aligned_filename[s->j] =
781 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
782 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
783 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
784 sg_init_one(&s->hash_sg, (u8 *)s->hash,
785 ECRYPTFS_TAG_70_DIGEST_SIZE);
786 rc = crypto_hash_init(&s->hash_desc);
787 if (rc) {
788 printk(KERN_ERR
789 "%s: Error initializing crypto hash; "
790 "rc = [%d]\n", __func__, rc);
791 goto out_release_free_unlock;
792 }
793 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
794 ECRYPTFS_TAG_70_DIGEST_SIZE);
795 if (rc) {
796 printk(KERN_ERR
797 "%s: Error updating crypto hash; "
798 "rc = [%d]\n", __func__, rc);
799 goto out_release_free_unlock;
800 }
801 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
802 if (rc) {
803 printk(KERN_ERR
804 "%s: Error finalizing crypto hash; "
805 "rc = [%d]\n", __func__, rc);
806 goto out_release_free_unlock;
807 }
808 memcpy(s->hash, s->tmp_hash,
809 ECRYPTFS_TAG_70_DIGEST_SIZE);
810 }
811 if (s->block_aligned_filename[s->j] == '\0')
812 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
813 }
814 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
815 filename_size);
816 rc = virt_to_scatterlist(s->block_aligned_filename,
817 s->block_aligned_filename_size, s->src_sg, 2);
818 if (rc < 1) {
819 printk(KERN_ERR "%s: Internal error whilst attempting to "
820 "convert filename memory to scatterlist; rc = [%d]. "
821 "block_aligned_filename_size = [%zd]\n", __func__, rc,
822 s->block_aligned_filename_size);
823 goto out_release_free_unlock;
824 }
825 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
826 s->dst_sg, 2);
827 if (rc < 1) {
828 printk(KERN_ERR "%s: Internal error whilst attempting to "
829 "convert encrypted filename memory to scatterlist; "
830 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
831 __func__, rc, s->block_aligned_filename_size);
832 goto out_release_free_unlock;
833 }
834 /* The characters in the first block effectively do the job
835 * of the IV here, so we just use 0's for the IV. Note the
836 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
837 * >= ECRYPTFS_MAX_IV_BYTES. */
838 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
839 s->desc.info = s->iv;
840 rc = crypto_blkcipher_setkey(
841 s->desc.tfm,
842 s->auth_tok->token.password.session_key_encryption_key,
843 mount_crypt_stat->global_default_fn_cipher_key_bytes);
844 if (rc < 0) {
845 printk(KERN_ERR "%s: Error setting key for crypto context; "
846 "rc = [%d]. s->auth_tok->token.password.session_key_"
847 "encryption_key = [0x%p]; mount_crypt_stat->"
848 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
849 rc,
850 s->auth_tok->token.password.session_key_encryption_key,
851 mount_crypt_stat->global_default_fn_cipher_key_bytes);
852 goto out_release_free_unlock;
853 }
854 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
855 s->block_aligned_filename_size);
856 if (rc) {
857 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
858 "rc = [%d]\n", __func__, rc);
859 goto out_release_free_unlock;
860 }
861 s->i += s->block_aligned_filename_size;
862 (*packet_size) = s->i;
863 (*remaining_bytes) -= (*packet_size);
864 out_release_free_unlock:
865 crypto_free_hash(s->hash_desc.tfm);
866 out_free_unlock:
867 kzfree(s->block_aligned_filename);
868 out_unlock:
869 mutex_unlock(s->tfm_mutex);
870 out:
871 if (auth_tok_key) {
872 up_write(&(auth_tok_key->sem));
873 key_put(auth_tok_key);
874 }
875 kfree(s);
876 return rc;
877 }
878
879 struct ecryptfs_parse_tag_70_packet_silly_stack {
880 u8 cipher_code;
881 size_t max_packet_size;
882 size_t packet_size_len;
883 size_t parsed_tag_70_packet_size;
884 size_t block_aligned_filename_size;
885 size_t block_size;
886 size_t i;
887 struct mutex *tfm_mutex;
888 char *decrypted_filename;
889 struct ecryptfs_auth_tok *auth_tok;
890 struct scatterlist src_sg[2];
891 struct scatterlist dst_sg[2];
892 struct blkcipher_desc desc;
893 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
894 char iv[ECRYPTFS_MAX_IV_BYTES];
895 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
896 };
897
898 /**
899 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
900 * @filename: This function kmalloc's the memory for the filename
901 * @filename_size: This function sets this to the amount of memory
902 * kmalloc'd for the filename
903 * @packet_size: This function sets this to the the number of octets
904 * in the packet parsed
905 * @mount_crypt_stat: The mount-wide cryptographic context
906 * @data: The memory location containing the start of the tag 70
907 * packet
908 * @max_packet_size: The maximum legal size of the packet to be parsed
909 * from @data
910 *
911 * Returns zero on success; non-zero otherwise
912 */
913 int
914 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
915 size_t *packet_size,
916 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
917 char *data, size_t max_packet_size)
918 {
919 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
920 struct key *auth_tok_key = NULL;
921 int rc = 0;
922
923 (*packet_size) = 0;
924 (*filename_size) = 0;
925 (*filename) = NULL;
926 s = kmalloc(sizeof(*s), GFP_KERNEL);
927 if (!s) {
928 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
929 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
930 rc = -ENOMEM;
931 goto out;
932 }
933 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
934 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
935 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
936 "at least [%d]\n", __func__, max_packet_size,
937 ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
938 rc = -EINVAL;
939 goto out;
940 }
941 /* Octet 0: Tag 70 identifier
942 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
943 * and block-aligned encrypted filename size)
944 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
945 * Octet N2-N3: Cipher identifier (1 octet)
946 * Octets N3-N4: Block-aligned encrypted filename
947 * - Consists of a minimum number of random numbers, a \0
948 * separator, and then the filename */
949 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
950 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
951 "tag [0x%.2x]\n", __func__,
952 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
953 rc = -EINVAL;
954 goto out;
955 }
956 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
957 &s->parsed_tag_70_packet_size,
958 &s->packet_size_len);
959 if (rc) {
960 printk(KERN_WARNING "%s: Error parsing packet length; "
961 "rc = [%d]\n", __func__, rc);
962 goto out;
963 }
964 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
965 - ECRYPTFS_SIG_SIZE - 1);
966 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
967 > max_packet_size) {
968 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
969 "size is [%zd]\n", __func__, max_packet_size,
970 (1 + s->packet_size_len + 1
971 + s->block_aligned_filename_size));
972 rc = -EINVAL;
973 goto out;
974 }
975 (*packet_size) += s->packet_size_len;
976 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
977 ECRYPTFS_SIG_SIZE);
978 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
979 (*packet_size) += ECRYPTFS_SIG_SIZE;
980 s->cipher_code = data[(*packet_size)++];
981 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
982 if (rc) {
983 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
984 __func__, s->cipher_code);
985 goto out;
986 }
987 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
988 &s->auth_tok, mount_crypt_stat,
989 s->fnek_sig_hex);
990 if (rc) {
991 printk(KERN_ERR "%s: Error attempting to find auth tok for "
992 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
993 rc);
994 goto out;
995 }
996 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
997 &s->tfm_mutex,
998 s->cipher_string);
999 if (unlikely(rc)) {
1000 printk(KERN_ERR "Internal error whilst attempting to get "
1001 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1002 s->cipher_string, rc);
1003 goto out;
1004 }
1005 mutex_lock(s->tfm_mutex);
1006 rc = virt_to_scatterlist(&data[(*packet_size)],
1007 s->block_aligned_filename_size, s->src_sg, 2);
1008 if (rc < 1) {
1009 printk(KERN_ERR "%s: Internal error whilst attempting to "
1010 "convert encrypted filename memory to scatterlist; "
1011 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1012 __func__, rc, s->block_aligned_filename_size);
1013 goto out_unlock;
1014 }
1015 (*packet_size) += s->block_aligned_filename_size;
1016 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1017 GFP_KERNEL);
1018 if (!s->decrypted_filename) {
1019 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1020 "kmalloc [%zd] bytes\n", __func__,
1021 s->block_aligned_filename_size);
1022 rc = -ENOMEM;
1023 goto out_unlock;
1024 }
1025 rc = virt_to_scatterlist(s->decrypted_filename,
1026 s->block_aligned_filename_size, s->dst_sg, 2);
1027 if (rc < 1) {
1028 printk(KERN_ERR "%s: Internal error whilst attempting to "
1029 "convert decrypted filename memory to scatterlist; "
1030 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1031 __func__, rc, s->block_aligned_filename_size);
1032 goto out_free_unlock;
1033 }
1034 /* The characters in the first block effectively do the job of
1035 * the IV here, so we just use 0's for the IV. Note the
1036 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1037 * >= ECRYPTFS_MAX_IV_BYTES. */
1038 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1039 s->desc.info = s->iv;
1040 /* TODO: Support other key modules than passphrase for
1041 * filename encryption */
1042 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1043 rc = -EOPNOTSUPP;
1044 printk(KERN_INFO "%s: Filename encryption only supports "
1045 "password tokens\n", __func__);
1046 goto out_free_unlock;
1047 }
1048 rc = crypto_blkcipher_setkey(
1049 s->desc.tfm,
1050 s->auth_tok->token.password.session_key_encryption_key,
1051 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1052 if (rc < 0) {
1053 printk(KERN_ERR "%s: Error setting key for crypto context; "
1054 "rc = [%d]. s->auth_tok->token.password.session_key_"
1055 "encryption_key = [0x%p]; mount_crypt_stat->"
1056 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1057 rc,
1058 s->auth_tok->token.password.session_key_encryption_key,
1059 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1060 goto out_free_unlock;
1061 }
1062 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
1063 s->block_aligned_filename_size);
1064 if (rc) {
1065 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1066 "rc = [%d]\n", __func__, rc);
1067 goto out_free_unlock;
1068 }
1069 s->i = 0;
1070 while (s->decrypted_filename[s->i] != '\0'
1071 && s->i < s->block_aligned_filename_size)
1072 s->i++;
1073 if (s->i == s->block_aligned_filename_size) {
1074 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1075 "find valid separator between random characters and "
1076 "the filename\n", __func__);
1077 rc = -EINVAL;
1078 goto out_free_unlock;
1079 }
1080 s->i++;
1081 (*filename_size) = (s->block_aligned_filename_size - s->i);
1082 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1083 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1084 "invalid\n", __func__, (*filename_size));
1085 rc = -EINVAL;
1086 goto out_free_unlock;
1087 }
1088 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1089 if (!(*filename)) {
1090 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1091 "kmalloc [%zd] bytes\n", __func__,
1092 ((*filename_size) + 1));
1093 rc = -ENOMEM;
1094 goto out_free_unlock;
1095 }
1096 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1097 (*filename)[(*filename_size)] = '\0';
1098 out_free_unlock:
1099 kfree(s->decrypted_filename);
1100 out_unlock:
1101 mutex_unlock(s->tfm_mutex);
1102 out:
1103 if (rc) {
1104 (*packet_size) = 0;
1105 (*filename_size) = 0;
1106 (*filename) = NULL;
1107 }
1108 if (auth_tok_key) {
1109 up_write(&(auth_tok_key->sem));
1110 key_put(auth_tok_key);
1111 }
1112 kfree(s);
1113 return rc;
1114 }
1115
1116 static int
1117 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1118 {
1119 int rc = 0;
1120
1121 (*sig) = NULL;
1122 switch (auth_tok->token_type) {
1123 case ECRYPTFS_PASSWORD:
1124 (*sig) = auth_tok->token.password.signature;
1125 break;
1126 case ECRYPTFS_PRIVATE_KEY:
1127 (*sig) = auth_tok->token.private_key.signature;
1128 break;
1129 default:
1130 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1131 auth_tok->token_type);
1132 rc = -EINVAL;
1133 }
1134 return rc;
1135 }
1136
1137 /**
1138 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1139 * @auth_tok: The key authentication token used to decrypt the session key
1140 * @crypt_stat: The cryptographic context
1141 *
1142 * Returns zero on success; non-zero error otherwise.
1143 */
1144 static int
1145 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1146 struct ecryptfs_crypt_stat *crypt_stat)
1147 {
1148 u8 cipher_code = 0;
1149 struct ecryptfs_msg_ctx *msg_ctx;
1150 struct ecryptfs_message *msg = NULL;
1151 char *auth_tok_sig;
1152 char *payload;
1153 size_t payload_len = 0;
1154 int rc;
1155
1156 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1157 if (rc) {
1158 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1159 auth_tok->token_type);
1160 goto out;
1161 }
1162 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1163 &payload, &payload_len);
1164 if (rc) {
1165 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1166 goto out;
1167 }
1168 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1169 if (rc) {
1170 ecryptfs_printk(KERN_ERR, "Error sending message to "
1171 "ecryptfsd: %d\n", rc);
1172 goto out;
1173 }
1174 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1175 if (rc) {
1176 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1177 "from the user space daemon\n");
1178 rc = -EIO;
1179 goto out;
1180 }
1181 rc = parse_tag_65_packet(&(auth_tok->session_key),
1182 &cipher_code, msg);
1183 if (rc) {
1184 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1185 rc);
1186 goto out;
1187 }
1188 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1189 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1190 auth_tok->session_key.decrypted_key_size);
1191 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1192 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1193 if (rc) {
1194 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1195 cipher_code)
1196 goto out;
1197 }
1198 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1199 if (ecryptfs_verbosity > 0) {
1200 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1201 ecryptfs_dump_hex(crypt_stat->key,
1202 crypt_stat->key_size);
1203 }
1204 out:
1205 kfree(msg);
1206 return rc;
1207 }
1208
1209 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1210 {
1211 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1212 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1213
1214 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1215 auth_tok_list_head, list) {
1216 list_del(&auth_tok_list_item->list);
1217 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1218 auth_tok_list_item);
1219 }
1220 }
1221
1222 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1223
1224 /**
1225 * parse_tag_1_packet
1226 * @crypt_stat: The cryptographic context to modify based on packet contents
1227 * @data: The raw bytes of the packet.
1228 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1229 * a new authentication token will be placed at the
1230 * end of this list for this packet.
1231 * @new_auth_tok: Pointer to a pointer to memory that this function
1232 * allocates; sets the memory address of the pointer to
1233 * NULL on error. This object is added to the
1234 * auth_tok_list.
1235 * @packet_size: This function writes the size of the parsed packet
1236 * into this memory location; zero on error.
1237 * @max_packet_size: The maximum allowable packet size
1238 *
1239 * Returns zero on success; non-zero on error.
1240 */
1241 static int
1242 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1243 unsigned char *data, struct list_head *auth_tok_list,
1244 struct ecryptfs_auth_tok **new_auth_tok,
1245 size_t *packet_size, size_t max_packet_size)
1246 {
1247 size_t body_size;
1248 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1249 size_t length_size;
1250 int rc = 0;
1251
1252 (*packet_size) = 0;
1253 (*new_auth_tok) = NULL;
1254 /**
1255 * This format is inspired by OpenPGP; see RFC 2440
1256 * packet tag 1
1257 *
1258 * Tag 1 identifier (1 byte)
1259 * Max Tag 1 packet size (max 3 bytes)
1260 * Version (1 byte)
1261 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1262 * Cipher identifier (1 byte)
1263 * Encrypted key size (arbitrary)
1264 *
1265 * 12 bytes minimum packet size
1266 */
1267 if (unlikely(max_packet_size < 12)) {
1268 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1269 rc = -EINVAL;
1270 goto out;
1271 }
1272 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1273 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1274 ECRYPTFS_TAG_1_PACKET_TYPE);
1275 rc = -EINVAL;
1276 goto out;
1277 }
1278 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1279 * at end of function upon failure */
1280 auth_tok_list_item =
1281 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1282 GFP_KERNEL);
1283 if (!auth_tok_list_item) {
1284 printk(KERN_ERR "Unable to allocate memory\n");
1285 rc = -ENOMEM;
1286 goto out;
1287 }
1288 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1289 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1290 &length_size);
1291 if (rc) {
1292 printk(KERN_WARNING "Error parsing packet length; "
1293 "rc = [%d]\n", rc);
1294 goto out_free;
1295 }
1296 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1297 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1298 rc = -EINVAL;
1299 goto out_free;
1300 }
1301 (*packet_size) += length_size;
1302 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1303 printk(KERN_WARNING "Packet size exceeds max\n");
1304 rc = -EINVAL;
1305 goto out_free;
1306 }
1307 if (unlikely(data[(*packet_size)++] != 0x03)) {
1308 printk(KERN_WARNING "Unknown version number [%d]\n",
1309 data[(*packet_size) - 1]);
1310 rc = -EINVAL;
1311 goto out_free;
1312 }
1313 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1314 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1315 *packet_size += ECRYPTFS_SIG_SIZE;
1316 /* This byte is skipped because the kernel does not need to
1317 * know which public key encryption algorithm was used */
1318 (*packet_size)++;
1319 (*new_auth_tok)->session_key.encrypted_key_size =
1320 body_size - (ECRYPTFS_SIG_SIZE + 2);
1321 if ((*new_auth_tok)->session_key.encrypted_key_size
1322 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1323 printk(KERN_WARNING "Tag 1 packet contains key larger "
1324 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1325 rc = -EINVAL;
1326 goto out;
1327 }
1328 memcpy((*new_auth_tok)->session_key.encrypted_key,
1329 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1330 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1331 (*new_auth_tok)->session_key.flags &=
1332 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1333 (*new_auth_tok)->session_key.flags |=
1334 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1335 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1336 (*new_auth_tok)->flags = 0;
1337 (*new_auth_tok)->session_key.flags &=
1338 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1339 (*new_auth_tok)->session_key.flags &=
1340 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1341 list_add(&auth_tok_list_item->list, auth_tok_list);
1342 goto out;
1343 out_free:
1344 (*new_auth_tok) = NULL;
1345 memset(auth_tok_list_item, 0,
1346 sizeof(struct ecryptfs_auth_tok_list_item));
1347 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1348 auth_tok_list_item);
1349 out:
1350 if (rc)
1351 (*packet_size) = 0;
1352 return rc;
1353 }
1354
1355 /**
1356 * parse_tag_3_packet
1357 * @crypt_stat: The cryptographic context to modify based on packet
1358 * contents.
1359 * @data: The raw bytes of the packet.
1360 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1361 * a new authentication token will be placed at the end
1362 * of this list for this packet.
1363 * @new_auth_tok: Pointer to a pointer to memory that this function
1364 * allocates; sets the memory address of the pointer to
1365 * NULL on error. This object is added to the
1366 * auth_tok_list.
1367 * @packet_size: This function writes the size of the parsed packet
1368 * into this memory location; zero on error.
1369 * @max_packet_size: maximum number of bytes to parse
1370 *
1371 * Returns zero on success; non-zero on error.
1372 */
1373 static int
1374 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1375 unsigned char *data, struct list_head *auth_tok_list,
1376 struct ecryptfs_auth_tok **new_auth_tok,
1377 size_t *packet_size, size_t max_packet_size)
1378 {
1379 size_t body_size;
1380 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1381 size_t length_size;
1382 int rc = 0;
1383
1384 (*packet_size) = 0;
1385 (*new_auth_tok) = NULL;
1386 /**
1387 *This format is inspired by OpenPGP; see RFC 2440
1388 * packet tag 3
1389 *
1390 * Tag 3 identifier (1 byte)
1391 * Max Tag 3 packet size (max 3 bytes)
1392 * Version (1 byte)
1393 * Cipher code (1 byte)
1394 * S2K specifier (1 byte)
1395 * Hash identifier (1 byte)
1396 * Salt (ECRYPTFS_SALT_SIZE)
1397 * Hash iterations (1 byte)
1398 * Encrypted key (arbitrary)
1399 *
1400 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1401 */
1402 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1403 printk(KERN_ERR "Max packet size too large\n");
1404 rc = -EINVAL;
1405 goto out;
1406 }
1407 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1408 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1409 ECRYPTFS_TAG_3_PACKET_TYPE);
1410 rc = -EINVAL;
1411 goto out;
1412 }
1413 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1414 * at end of function upon failure */
1415 auth_tok_list_item =
1416 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1417 if (!auth_tok_list_item) {
1418 printk(KERN_ERR "Unable to allocate memory\n");
1419 rc = -ENOMEM;
1420 goto out;
1421 }
1422 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1423 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1424 &length_size);
1425 if (rc) {
1426 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1427 rc);
1428 goto out_free;
1429 }
1430 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1431 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1432 rc = -EINVAL;
1433 goto out_free;
1434 }
1435 (*packet_size) += length_size;
1436 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1437 printk(KERN_ERR "Packet size exceeds max\n");
1438 rc = -EINVAL;
1439 goto out_free;
1440 }
1441 (*new_auth_tok)->session_key.encrypted_key_size =
1442 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1443 if ((*new_auth_tok)->session_key.encrypted_key_size
1444 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1445 printk(KERN_WARNING "Tag 3 packet contains key larger "
1446 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1447 rc = -EINVAL;
1448 goto out_free;
1449 }
1450 if (unlikely(data[(*packet_size)++] != 0x04)) {
1451 printk(KERN_WARNING "Unknown version number [%d]\n",
1452 data[(*packet_size) - 1]);
1453 rc = -EINVAL;
1454 goto out_free;
1455 }
1456 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1457 (u16)data[(*packet_size)]);
1458 if (rc)
1459 goto out_free;
1460 /* A little extra work to differentiate among the AES key
1461 * sizes; see RFC2440 */
1462 switch(data[(*packet_size)++]) {
1463 case RFC2440_CIPHER_AES_192:
1464 crypt_stat->key_size = 24;
1465 break;
1466 default:
1467 crypt_stat->key_size =
1468 (*new_auth_tok)->session_key.encrypted_key_size;
1469 }
1470 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1471 if (rc)
1472 goto out_free;
1473 if (unlikely(data[(*packet_size)++] != 0x03)) {
1474 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1475 rc = -ENOSYS;
1476 goto out_free;
1477 }
1478 /* TODO: finish the hash mapping */
1479 switch (data[(*packet_size)++]) {
1480 case 0x01: /* See RFC2440 for these numbers and their mappings */
1481 /* Choose MD5 */
1482 memcpy((*new_auth_tok)->token.password.salt,
1483 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1484 (*packet_size) += ECRYPTFS_SALT_SIZE;
1485 /* This conversion was taken straight from RFC2440 */
1486 (*new_auth_tok)->token.password.hash_iterations =
1487 ((u32) 16 + (data[(*packet_size)] & 15))
1488 << ((data[(*packet_size)] >> 4) + 6);
1489 (*packet_size)++;
1490 /* Friendly reminder:
1491 * (*new_auth_tok)->session_key.encrypted_key_size =
1492 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1493 memcpy((*new_auth_tok)->session_key.encrypted_key,
1494 &data[(*packet_size)],
1495 (*new_auth_tok)->session_key.encrypted_key_size);
1496 (*packet_size) +=
1497 (*new_auth_tok)->session_key.encrypted_key_size;
1498 (*new_auth_tok)->session_key.flags &=
1499 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1500 (*new_auth_tok)->session_key.flags |=
1501 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1502 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1503 break;
1504 default:
1505 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1506 "[%d]\n", data[(*packet_size) - 1]);
1507 rc = -ENOSYS;
1508 goto out_free;
1509 }
1510 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1511 /* TODO: Parametarize; we might actually want userspace to
1512 * decrypt the session key. */
1513 (*new_auth_tok)->session_key.flags &=
1514 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1515 (*new_auth_tok)->session_key.flags &=
1516 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1517 list_add(&auth_tok_list_item->list, auth_tok_list);
1518 goto out;
1519 out_free:
1520 (*new_auth_tok) = NULL;
1521 memset(auth_tok_list_item, 0,
1522 sizeof(struct ecryptfs_auth_tok_list_item));
1523 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1524 auth_tok_list_item);
1525 out:
1526 if (rc)
1527 (*packet_size) = 0;
1528 return rc;
1529 }
1530
1531 /**
1532 * parse_tag_11_packet
1533 * @data: The raw bytes of the packet
1534 * @contents: This function writes the data contents of the literal
1535 * packet into this memory location
1536 * @max_contents_bytes: The maximum number of bytes that this function
1537 * is allowed to write into contents
1538 * @tag_11_contents_size: This function writes the size of the parsed
1539 * contents into this memory location; zero on
1540 * error
1541 * @packet_size: This function writes the size of the parsed packet
1542 * into this memory location; zero on error
1543 * @max_packet_size: maximum number of bytes to parse
1544 *
1545 * Returns zero on success; non-zero on error.
1546 */
1547 static int
1548 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1549 size_t max_contents_bytes, size_t *tag_11_contents_size,
1550 size_t *packet_size, size_t max_packet_size)
1551 {
1552 size_t body_size;
1553 size_t length_size;
1554 int rc = 0;
1555
1556 (*packet_size) = 0;
1557 (*tag_11_contents_size) = 0;
1558 /* This format is inspired by OpenPGP; see RFC 2440
1559 * packet tag 11
1560 *
1561 * Tag 11 identifier (1 byte)
1562 * Max Tag 11 packet size (max 3 bytes)
1563 * Binary format specifier (1 byte)
1564 * Filename length (1 byte)
1565 * Filename ("_CONSOLE") (8 bytes)
1566 * Modification date (4 bytes)
1567 * Literal data (arbitrary)
1568 *
1569 * We need at least 16 bytes of data for the packet to even be
1570 * valid.
1571 */
1572 if (max_packet_size < 16) {
1573 printk(KERN_ERR "Maximum packet size too small\n");
1574 rc = -EINVAL;
1575 goto out;
1576 }
1577 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1578 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1579 rc = -EINVAL;
1580 goto out;
1581 }
1582 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1583 &length_size);
1584 if (rc) {
1585 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1586 goto out;
1587 }
1588 if (body_size < 14) {
1589 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1590 rc = -EINVAL;
1591 goto out;
1592 }
1593 (*packet_size) += length_size;
1594 (*tag_11_contents_size) = (body_size - 14);
1595 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1596 printk(KERN_ERR "Packet size exceeds max\n");
1597 rc = -EINVAL;
1598 goto out;
1599 }
1600 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1601 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1602 "expected size\n");
1603 rc = -EINVAL;
1604 goto out;
1605 }
1606 if (data[(*packet_size)++] != 0x62) {
1607 printk(KERN_WARNING "Unrecognizable packet\n");
1608 rc = -EINVAL;
1609 goto out;
1610 }
1611 if (data[(*packet_size)++] != 0x08) {
1612 printk(KERN_WARNING "Unrecognizable packet\n");
1613 rc = -EINVAL;
1614 goto out;
1615 }
1616 (*packet_size) += 12; /* Ignore filename and modification date */
1617 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1618 (*packet_size) += (*tag_11_contents_size);
1619 out:
1620 if (rc) {
1621 (*packet_size) = 0;
1622 (*tag_11_contents_size) = 0;
1623 }
1624 return rc;
1625 }
1626
1627 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1628 struct ecryptfs_auth_tok **auth_tok,
1629 char *sig)
1630 {
1631 int rc = 0;
1632
1633 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1634 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1635 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1636 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1637 printk(KERN_ERR "Could not find key with description: [%s]\n",
1638 sig);
1639 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1640 (*auth_tok_key) = NULL;
1641 goto out;
1642 }
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 = 0;
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: %d\n", rc);
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
Linux with added FPC-III support