1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * eCryptfs: Linux filesystem encryption layer
4 * In-kernel key management code. Includes functions to parse and
5 * write authentication token-related packets with the underlying
6 * file.
7 *
8 * Copyright (C) 2004-2006 International Business Machines Corp.
9 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
10 * Michael C. Thompson <mcthomps@us.ibm.com>
11 * Trevor S. Highland <trevor.highland@gmail.com>
12 */
13
14 #include <crypto/hash.h>
15 #include <crypto/skcipher.h>
16 #include <linux/string.h>
17 #include <linux/pagemap.h>
18 #include <linux/key.h>
19 #include <linux/random.h>
20 #include <linux/scatterlist.h>
21 #include <linux/slab.h>
22 #include "ecryptfs_kernel.h"
23
24 /*
25 * request_key returned an error instead of a valid key address;
26 * determine the type of error, make appropriate log entries, and
27 * return an error code.
28 */
process_request_key_err(long err_code)29 static int process_request_key_err(long err_code)
30 {
31 int rc = 0;
32
33 switch (err_code) {
34 case -ENOKEY:
35 ecryptfs_printk(KERN_WARNING, "No key\n");
36 rc = -ENOENT;
37 break;
38 case -EKEYEXPIRED:
39 ecryptfs_printk(KERN_WARNING, "Key expired\n");
40 rc = -ETIME;
41 break;
42 case -EKEYREVOKED:
43 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
44 rc = -EINVAL;
45 break;
46 default:
47 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
48 "[0x%.16lx]\n", err_code);
49 rc = -EINVAL;
50 }
51 return rc;
52 }
53
process_find_global_auth_tok_for_sig_err(int err_code)54 static int process_find_global_auth_tok_for_sig_err(int err_code)
55 {
56 int rc = err_code;
57
58 switch (err_code) {
59 case -ENOENT:
60 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
61 break;
62 case -EINVAL:
63 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
64 break;
65 default:
66 rc = process_request_key_err(err_code);
67 break;
68 }
69 return rc;
70 }
71
72 /**
73 * ecryptfs_parse_packet_length
74 * @data: Pointer to memory containing length at offset
75 * @size: This function writes the decoded size to this memory
76 * address; zero on error
77 * @length_size: The number of bytes occupied by the encoded length
78 *
79 * Returns zero on success; non-zero on error
80 */
ecryptfs_parse_packet_length(unsigned char * data,size_t * size,size_t * length_size)81 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
82 size_t *length_size)
83 {
84 int rc = 0;
85
86 (*length_size) = 0;
87 (*size) = 0;
88 if (data[0] < 192) {
89 /* One-byte length */
90 (*size) = data[0];
91 (*length_size) = 1;
92 } else if (data[0] < 224) {
93 /* Two-byte length */
94 (*size) = (data[0] - 192) * 256;
95 (*size) += data[1] + 192;
96 (*length_size) = 2;
97 } else if (data[0] == 255) {
98 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
99 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
100 "supported\n");
101 rc = -EINVAL;
102 goto out;
103 } else {
104 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
105 rc = -EINVAL;
106 goto out;
107 }
108 out:
109 return rc;
110 }
111
112 /**
113 * ecryptfs_write_packet_length
114 * @dest: The byte array target into which to write the length. Must
115 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
116 * @size: The length to write.
117 * @packet_size_length: The number of bytes used to encode the packet
118 * length is written to this address.
119 *
120 * Returns zero on success; non-zero on error.
121 */
ecryptfs_write_packet_length(char * dest,size_t size,size_t * packet_size_length)122 int ecryptfs_write_packet_length(char *dest, size_t size,
123 size_t *packet_size_length)
124 {
125 int rc = 0;
126
127 if (size < 192) {
128 dest[0] = size;
129 (*packet_size_length) = 1;
130 } else if (size < 65536) {
131 dest[0] = (((size - 192) / 256) + 192);
132 dest[1] = ((size - 192) % 256);
133 (*packet_size_length) = 2;
134 } else {
135 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
136 rc = -EINVAL;
137 ecryptfs_printk(KERN_WARNING,
138 "Unsupported packet size: [%zd]\n", size);
139 }
140 return rc;
141 }
142
143 static int
write_tag_64_packet(char * signature,struct ecryptfs_session_key * session_key,char ** packet,size_t * packet_len)144 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
145 char **packet, size_t *packet_len)
146 {
147 size_t i = 0;
148 size_t data_len;
149 size_t packet_size_len;
150 char *message;
151 int rc;
152
153 /*
154 * ***** TAG 64 Packet Format *****
155 * | Content Type | 1 byte |
156 * | Key Identifier Size | 1 or 2 bytes |
157 * | Key Identifier | arbitrary |
158 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
159 * | Encrypted File Encryption Key | arbitrary |
160 */
161 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
162 + session_key->encrypted_key_size);
163 *packet = kmalloc(data_len, GFP_KERNEL);
164 message = *packet;
165 if (!message) {
166 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
167 rc = -ENOMEM;
168 goto out;
169 }
170 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
171 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
172 &packet_size_len);
173 if (rc) {
174 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
175 "header; cannot generate packet length\n");
176 goto out;
177 }
178 i += packet_size_len;
179 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
180 i += ECRYPTFS_SIG_SIZE_HEX;
181 rc = ecryptfs_write_packet_length(&message[i],
182 session_key->encrypted_key_size,
183 &packet_size_len);
184 if (rc) {
185 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
186 "header; cannot generate packet length\n");
187 goto out;
188 }
189 i += packet_size_len;
190 memcpy(&message[i], session_key->encrypted_key,
191 session_key->encrypted_key_size);
192 i += session_key->encrypted_key_size;
193 *packet_len = i;
194 out:
195 return rc;
196 }
197
198 static int
parse_tag_65_packet(struct ecryptfs_session_key * session_key,u8 * cipher_code,struct ecryptfs_message * msg)199 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
200 struct ecryptfs_message *msg)
201 {
202 size_t i = 0;
203 char *data;
204 size_t data_len;
205 size_t m_size;
206 size_t message_len;
207 u16 checksum = 0;
208 u16 expected_checksum = 0;
209 int rc;
210
211 /*
212 * ***** TAG 65 Packet Format *****
213 * | Content Type | 1 byte |
214 * | Status Indicator | 1 byte |
215 * | File Encryption Key Size | 1 or 2 bytes |
216 * | File Encryption Key | arbitrary |
217 */
218 message_len = msg->data_len;
219 data = msg->data;
220 if (message_len < 4) {
221 rc = -EIO;
222 goto out;
223 }
224 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
225 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
226 rc = -EIO;
227 goto out;
228 }
229 if (data[i++]) {
230 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
231 "[%d]\n", data[i-1]);
232 rc = -EIO;
233 goto out;
234 }
235 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
236 if (rc) {
237 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
238 "rc = [%d]\n", rc);
239 goto out;
240 }
241 i += data_len;
242 if (message_len < (i + m_size)) {
243 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
244 "is shorter than expected\n");
245 rc = -EIO;
246 goto out;
247 }
248 if (m_size < 3) {
249 ecryptfs_printk(KERN_ERR,
250 "The decrypted key is not long enough to "
251 "include a cipher code and checksum\n");
252 rc = -EIO;
253 goto out;
254 }
255 *cipher_code = data[i++];
256 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
257 session_key->decrypted_key_size = m_size - 3;
258 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
259 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
260 "the maximum key size [%d]\n",
261 session_key->decrypted_key_size,
262 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
263 rc = -EIO;
264 goto out;
265 }
266 memcpy(session_key->decrypted_key, &data[i],
267 session_key->decrypted_key_size);
268 i += session_key->decrypted_key_size;
269 expected_checksum += (unsigned char)(data[i++]) << 8;
270 expected_checksum += (unsigned char)(data[i++]);
271 for (i = 0; i < session_key->decrypted_key_size; i++)
272 checksum += session_key->decrypted_key[i];
273 if (expected_checksum != checksum) {
274 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
275 "encryption key; expected [%x]; calculated "
276 "[%x]\n", expected_checksum, checksum);
277 rc = -EIO;
278 }
279 out:
280 return rc;
281 }
282
283
284 static int
write_tag_66_packet(char * signature,u8 cipher_code,struct ecryptfs_crypt_stat * crypt_stat,char ** packet,size_t * packet_len)285 write_tag_66_packet(char *signature, u8 cipher_code,
286 struct ecryptfs_crypt_stat *crypt_stat, char **packet,
287 size_t *packet_len)
288 {
289 size_t i = 0;
290 size_t j;
291 size_t data_len;
292 size_t checksum = 0;
293 size_t packet_size_len;
294 char *message;
295 int rc;
296
297 /*
298 * ***** TAG 66 Packet Format *****
299 * | Content Type | 1 byte |
300 * | Key Identifier Size | 1 or 2 bytes |
301 * | Key Identifier | arbitrary |
302 * | File Encryption Key Size | 1 or 2 bytes |
303 * | Cipher Code | 1 byte |
304 * | File Encryption Key | arbitrary |
305 * | Checksum | 2 bytes |
306 */
307 data_len = (8 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
308 *packet = kmalloc(data_len, GFP_KERNEL);
309 message = *packet;
310 if (!message) {
311 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
312 rc = -ENOMEM;
313 goto out;
314 }
315 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
316 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
317 &packet_size_len);
318 if (rc) {
319 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
320 "header; cannot generate packet length\n");
321 goto out;
322 }
323 i += packet_size_len;
324 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
325 i += ECRYPTFS_SIG_SIZE_HEX;
326 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
327 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
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 message[i++] = cipher_code;
336 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
337 i += crypt_stat->key_size;
338 for (j = 0; j < crypt_stat->key_size; j++)
339 checksum += crypt_stat->key[j];
340 message[i++] = (checksum / 256) % 256;
341 message[i++] = (checksum % 256);
342 *packet_len = i;
343 out:
344 return rc;
345 }
346
347 static int
parse_tag_67_packet(struct ecryptfs_key_record * key_rec,struct ecryptfs_message * msg)348 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
349 struct ecryptfs_message *msg)
350 {
351 size_t i = 0;
352 char *data;
353 size_t data_len;
354 size_t message_len;
355 int rc;
356
357 /*
358 * ***** TAG 65 Packet Format *****
359 * | Content Type | 1 byte |
360 * | Status Indicator | 1 byte |
361 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
362 * | Encrypted File Encryption Key | arbitrary |
363 */
364 message_len = msg->data_len;
365 data = msg->data;
366 /* verify that everything through the encrypted FEK size is present */
367 if (message_len < 4) {
368 rc = -EIO;
369 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
370 "message length is [%d]\n", __func__, message_len, 4);
371 goto out;
372 }
373 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
374 rc = -EIO;
375 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
376 __func__);
377 goto out;
378 }
379 if (data[i++]) {
380 rc = -EIO;
381 printk(KERN_ERR "%s: Status indicator has non zero "
382 "value [%d]\n", __func__, data[i-1]);
383
384 goto out;
385 }
386 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
387 &data_len);
388 if (rc) {
389 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
390 "rc = [%d]\n", rc);
391 goto out;
392 }
393 i += data_len;
394 if (message_len < (i + key_rec->enc_key_size)) {
395 rc = -EIO;
396 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
397 __func__, message_len, (i + key_rec->enc_key_size));
398 goto out;
399 }
400 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
401 rc = -EIO;
402 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
403 "the maximum key size [%d]\n", __func__,
404 key_rec->enc_key_size,
405 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
406 goto out;
407 }
408 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
409 out:
410 return rc;
411 }
412
413 /**
414 * ecryptfs_verify_version
415 * @version: The version number to confirm
416 *
417 * Returns zero on good version; non-zero otherwise
418 */
ecryptfs_verify_version(u16 version)419 static int ecryptfs_verify_version(u16 version)
420 {
421 int rc = 0;
422 unsigned char major;
423 unsigned char minor;
424
425 major = ((version >> 8) & 0xFF);
426 minor = (version & 0xFF);
427 if (major != ECRYPTFS_VERSION_MAJOR) {
428 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
429 "Expected [%d]; got [%d]\n",
430 ECRYPTFS_VERSION_MAJOR, major);
431 rc = -EINVAL;
432 goto out;
433 }
434 if (minor != ECRYPTFS_VERSION_MINOR) {
435 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
436 "Expected [%d]; got [%d]\n",
437 ECRYPTFS_VERSION_MINOR, minor);
438 rc = -EINVAL;
439 goto out;
440 }
441 out:
442 return rc;
443 }
444
445 /**
446 * ecryptfs_verify_auth_tok_from_key
447 * @auth_tok_key: key containing the authentication token
448 * @auth_tok: authentication token
449 *
450 * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
451 * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
452 */
453 static int
ecryptfs_verify_auth_tok_from_key(struct key * auth_tok_key,struct ecryptfs_auth_tok ** auth_tok)454 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
455 struct ecryptfs_auth_tok **auth_tok)
456 {
457 int rc = 0;
458
459 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
460 if (IS_ERR(*auth_tok)) {
461 rc = PTR_ERR(*auth_tok);
462 *auth_tok = NULL;
463 goto out;
464 }
465
466 if (ecryptfs_verify_version((*auth_tok)->version)) {
467 printk(KERN_ERR "Data structure version mismatch. Userspace "
468 "tools must match eCryptfs kernel module with major "
469 "version [%d] and minor version [%d]\n",
470 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
471 rc = -EINVAL;
472 goto out;
473 }
474 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
475 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
476 printk(KERN_ERR "Invalid auth_tok structure "
477 "returned from key query\n");
478 rc = -EINVAL;
479 goto out;
480 }
481 out:
482 return rc;
483 }
484
485 static int
ecryptfs_find_global_auth_tok_for_sig(struct key ** auth_tok_key,struct ecryptfs_auth_tok ** auth_tok,struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * sig)486 ecryptfs_find_global_auth_tok_for_sig(
487 struct key **auth_tok_key,
488 struct ecryptfs_auth_tok **auth_tok,
489 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
490 {
491 struct ecryptfs_global_auth_tok *walker;
492 int rc = 0;
493
494 (*auth_tok_key) = NULL;
495 (*auth_tok) = NULL;
496 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
497 list_for_each_entry(walker,
498 &mount_crypt_stat->global_auth_tok_list,
499 mount_crypt_stat_list) {
500 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
501 continue;
502
503 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
504 rc = -EINVAL;
505 goto out;
506 }
507
508 rc = key_validate(walker->global_auth_tok_key);
509 if (rc) {
510 if (rc == -EKEYEXPIRED)
511 goto out;
512 goto out_invalid_auth_tok;
513 }
514
515 down_write(&(walker->global_auth_tok_key->sem));
516 rc = ecryptfs_verify_auth_tok_from_key(
517 walker->global_auth_tok_key, auth_tok);
518 if (rc)
519 goto out_invalid_auth_tok_unlock;
520
521 (*auth_tok_key) = walker->global_auth_tok_key;
522 key_get(*auth_tok_key);
523 goto out;
524 }
525 rc = -ENOENT;
526 goto out;
527 out_invalid_auth_tok_unlock:
528 up_write(&(walker->global_auth_tok_key->sem));
529 out_invalid_auth_tok:
530 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
531 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
532 key_put(walker->global_auth_tok_key);
533 walker->global_auth_tok_key = NULL;
534 out:
535 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
536 return rc;
537 }
538
539 /**
540 * ecryptfs_find_auth_tok_for_sig
541 * @auth_tok_key: key containing the authentication token
542 * @auth_tok: Set to the matching auth_tok; NULL if not found
543 * @mount_crypt_stat: inode crypt_stat crypto context
544 * @sig: Sig of auth_tok to find
545 *
546 * For now, this function simply looks at the registered auth_tok's
547 * linked off the mount_crypt_stat, so all the auth_toks that can be
548 * used must be registered at mount time. This function could
549 * potentially try a lot harder to find auth_tok's (e.g., by calling
550 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
551 * that static registration of auth_tok's will no longer be necessary.
552 *
553 * Returns zero on no error; non-zero on error
554 */
555 static int
ecryptfs_find_auth_tok_for_sig(struct key ** auth_tok_key,struct ecryptfs_auth_tok ** auth_tok,struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * sig)556 ecryptfs_find_auth_tok_for_sig(
557 struct key **auth_tok_key,
558 struct ecryptfs_auth_tok **auth_tok,
559 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
560 char *sig)
561 {
562 int rc = 0;
563
564 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
565 mount_crypt_stat, sig);
566 if (rc == -ENOENT) {
567 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
568 * mount_crypt_stat structure, we prevent to use auth toks that
569 * are not inserted through the ecryptfs_add_global_auth_tok
570 * function.
571 */
572 if (mount_crypt_stat->flags
573 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
574 return -EINVAL;
575
576 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
577 sig);
578 }
579 return rc;
580 }
581
582 /*
583 * write_tag_70_packet can gobble a lot of stack space. We stuff most
584 * of the function's parameters in a kmalloc'd struct to help reduce
585 * eCryptfs' overall stack usage.
586 */
587 struct ecryptfs_write_tag_70_packet_silly_stack {
588 u8 cipher_code;
589 size_t max_packet_size;
590 size_t packet_size_len;
591 size_t block_aligned_filename_size;
592 size_t block_size;
593 size_t i;
594 size_t j;
595 size_t num_rand_bytes;
596 struct mutex *tfm_mutex;
597 char *block_aligned_filename;
598 struct ecryptfs_auth_tok *auth_tok;
599 struct scatterlist src_sg[2];
600 struct scatterlist dst_sg[2];
601 struct crypto_skcipher *skcipher_tfm;
602 struct skcipher_request *skcipher_req;
603 char iv[ECRYPTFS_MAX_IV_BYTES];
604 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
605 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
606 struct crypto_shash *hash_tfm;
607 struct shash_desc *hash_desc;
608 };
609
610 /*
611 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
612 * @filename: NULL-terminated filename string
613 *
614 * This is the simplest mechanism for achieving filename encryption in
615 * eCryptfs. It encrypts the given filename with the mount-wide
616 * filename encryption key (FNEK) and stores it in a packet to @dest,
617 * which the callee will encode and write directly into the dentry
618 * name.
619 */
620 int
ecryptfs_write_tag_70_packet(char * dest,size_t * remaining_bytes,size_t * packet_size,struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * filename,size_t filename_size)621 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
622 size_t *packet_size,
623 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
624 char *filename, size_t filename_size)
625 {
626 struct ecryptfs_write_tag_70_packet_silly_stack *s;
627 struct key *auth_tok_key = NULL;
628 int rc = 0;
629
630 s = kzalloc(sizeof(*s), GFP_KERNEL);
631 if (!s)
632 return -ENOMEM;
633
634 (*packet_size) = 0;
635 rc = ecryptfs_find_auth_tok_for_sig(
636 &auth_tok_key,
637 &s->auth_tok, mount_crypt_stat,
638 mount_crypt_stat->global_default_fnek_sig);
639 if (rc) {
640 printk(KERN_ERR "%s: Error attempting to find auth tok for "
641 "fnek sig [%s]; rc = [%d]\n", __func__,
642 mount_crypt_stat->global_default_fnek_sig, rc);
643 goto out;
644 }
645 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
646 &s->skcipher_tfm,
647 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
648 if (unlikely(rc)) {
649 printk(KERN_ERR "Internal error whilst attempting to get "
650 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
651 mount_crypt_stat->global_default_fn_cipher_name, rc);
652 goto out;
653 }
654 mutex_lock(s->tfm_mutex);
655 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
656 /* Plus one for the \0 separator between the random prefix
657 * and the plaintext filename */
658 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
659 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
660 if ((s->block_aligned_filename_size % s->block_size) != 0) {
661 s->num_rand_bytes += (s->block_size
662 - (s->block_aligned_filename_size
663 % s->block_size));
664 s->block_aligned_filename_size = (s->num_rand_bytes
665 + filename_size);
666 }
667 /* Octet 0: Tag 70 identifier
668 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
669 * and block-aligned encrypted filename size)
670 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
671 * Octet N2-N3: Cipher identifier (1 octet)
672 * Octets N3-N4: Block-aligned encrypted filename
673 * - Consists of a minimum number of random characters, a \0
674 * separator, and then the filename */
675 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
676 + s->block_aligned_filename_size);
677 if (!dest) {
678 (*packet_size) = s->max_packet_size;
679 goto out_unlock;
680 }
681 if (s->max_packet_size > (*remaining_bytes)) {
682 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
683 "[%zd] available\n", __func__, s->max_packet_size,
684 (*remaining_bytes));
685 rc = -EINVAL;
686 goto out_unlock;
687 }
688
689 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
690 if (!s->skcipher_req) {
691 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
692 "skcipher_request_alloc for %s\n", __func__,
693 crypto_skcipher_driver_name(s->skcipher_tfm));
694 rc = -ENOMEM;
695 goto out_unlock;
696 }
697
698 skcipher_request_set_callback(s->skcipher_req,
699 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
700
701 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
702 GFP_KERNEL);
703 if (!s->block_aligned_filename) {
704 rc = -ENOMEM;
705 goto out_unlock;
706 }
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 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
745 if (IS_ERR(s->hash_tfm)) {
746 rc = PTR_ERR(s->hash_tfm);
747 printk(KERN_ERR "%s: Error attempting to "
748 "allocate hash crypto context; rc = [%d]\n",
749 __func__, rc);
750 goto out_free_unlock;
751 }
752
753 s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
754 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
755 if (!s->hash_desc) {
756 rc = -ENOMEM;
757 goto out_release_free_unlock;
758 }
759
760 s->hash_desc->tfm = s->hash_tfm;
761
762 rc = crypto_shash_digest(s->hash_desc,
763 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
764 s->auth_tok->token.password.session_key_encryption_key_bytes,
765 s->hash);
766 if (rc) {
767 printk(KERN_ERR
768 "%s: Error computing crypto hash; rc = [%d]\n",
769 __func__, rc);
770 goto out_release_free_unlock;
771 }
772 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
773 s->block_aligned_filename[s->j] =
774 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
775 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
776 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
777 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
778 ECRYPTFS_TAG_70_DIGEST_SIZE,
779 s->tmp_hash);
780 if (rc) {
781 printk(KERN_ERR
782 "%s: Error computing crypto hash; "
783 "rc = [%d]\n", __func__, rc);
784 goto out_release_free_unlock;
785 }
786 memcpy(s->hash, s->tmp_hash,
787 ECRYPTFS_TAG_70_DIGEST_SIZE);
788 }
789 if (s->block_aligned_filename[s->j] == '\0')
790 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
791 }
792 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
793 filename_size);
794 rc = virt_to_scatterlist(s->block_aligned_filename,
795 s->block_aligned_filename_size, s->src_sg, 2);
796 if (rc < 1) {
797 printk(KERN_ERR "%s: Internal error whilst attempting to "
798 "convert filename memory to scatterlist; rc = [%d]. "
799 "block_aligned_filename_size = [%zd]\n", __func__, rc,
800 s->block_aligned_filename_size);
801 goto out_release_free_unlock;
802 }
803 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
804 s->dst_sg, 2);
805 if (rc < 1) {
806 printk(KERN_ERR "%s: Internal error whilst attempting to "
807 "convert encrypted filename memory to scatterlist; "
808 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
809 __func__, rc, s->block_aligned_filename_size);
810 goto out_release_free_unlock;
811 }
812 /* The characters in the first block effectively do the job
813 * of the IV here, so we just use 0's for the IV. Note the
814 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
815 * >= ECRYPTFS_MAX_IV_BYTES. */
816 rc = crypto_skcipher_setkey(
817 s->skcipher_tfm,
818 s->auth_tok->token.password.session_key_encryption_key,
819 mount_crypt_stat->global_default_fn_cipher_key_bytes);
820 if (rc < 0) {
821 printk(KERN_ERR "%s: Error setting key for crypto context; "
822 "rc = [%d]. s->auth_tok->token.password.session_key_"
823 "encryption_key = [0x%p]; mount_crypt_stat->"
824 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
825 rc,
826 s->auth_tok->token.password.session_key_encryption_key,
827 mount_crypt_stat->global_default_fn_cipher_key_bytes);
828 goto out_release_free_unlock;
829 }
830 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
831 s->block_aligned_filename_size, s->iv);
832 rc = crypto_skcipher_encrypt(s->skcipher_req);
833 if (rc) {
834 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
835 "rc = [%d]\n", __func__, rc);
836 goto out_release_free_unlock;
837 }
838 s->i += s->block_aligned_filename_size;
839 (*packet_size) = s->i;
840 (*remaining_bytes) -= (*packet_size);
841 out_release_free_unlock:
842 crypto_free_shash(s->hash_tfm);
843 out_free_unlock:
844 kfree_sensitive(s->block_aligned_filename);
845 out_unlock:
846 mutex_unlock(s->tfm_mutex);
847 out:
848 if (auth_tok_key) {
849 up_write(&(auth_tok_key->sem));
850 key_put(auth_tok_key);
851 }
852 skcipher_request_free(s->skcipher_req);
853 kfree_sensitive(s->hash_desc);
854 kfree(s);
855 return rc;
856 }
857
858 struct ecryptfs_parse_tag_70_packet_silly_stack {
859 u8 cipher_code;
860 size_t max_packet_size;
861 size_t packet_size_len;
862 size_t parsed_tag_70_packet_size;
863 size_t block_aligned_filename_size;
864 size_t block_size;
865 size_t i;
866 struct mutex *tfm_mutex;
867 char *decrypted_filename;
868 struct ecryptfs_auth_tok *auth_tok;
869 struct scatterlist src_sg[2];
870 struct scatterlist dst_sg[2];
871 struct crypto_skcipher *skcipher_tfm;
872 struct skcipher_request *skcipher_req;
873 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
874 char iv[ECRYPTFS_MAX_IV_BYTES];
875 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
876 };
877
878 /**
879 * ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
880 * @filename: This function kmalloc's the memory for the filename
881 * @filename_size: This function sets this to the amount of memory
882 * kmalloc'd for the filename
883 * @packet_size: This function sets this to the the number of octets
884 * in the packet parsed
885 * @mount_crypt_stat: The mount-wide cryptographic context
886 * @data: The memory location containing the start of the tag 70
887 * packet
888 * @max_packet_size: The maximum legal size of the packet to be parsed
889 * from @data
890 *
891 * Returns zero on success; non-zero otherwise
892 */
893 int
ecryptfs_parse_tag_70_packet(char ** filename,size_t * filename_size,size_t * packet_size,struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * data,size_t max_packet_size)894 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
895 size_t *packet_size,
896 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
897 char *data, size_t max_packet_size)
898 {
899 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
900 struct key *auth_tok_key = NULL;
901 int rc = 0;
902
903 (*packet_size) = 0;
904 (*filename_size) = 0;
905 (*filename) = NULL;
906 s = kzalloc(sizeof(*s), GFP_KERNEL);
907 if (!s)
908 return -ENOMEM;
909
910 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
911 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
912 "at least [%d]\n", __func__, max_packet_size,
913 ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
914 rc = -EINVAL;
915 goto out;
916 }
917 /* Octet 0: Tag 70 identifier
918 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
919 * and block-aligned encrypted filename size)
920 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
921 * Octet N2-N3: Cipher identifier (1 octet)
922 * Octets N3-N4: Block-aligned encrypted filename
923 * - Consists of a minimum number of random numbers, a \0
924 * separator, and then the filename */
925 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
926 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
927 "tag [0x%.2x]\n", __func__,
928 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
929 rc = -EINVAL;
930 goto out;
931 }
932 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
933 &s->parsed_tag_70_packet_size,
934 &s->packet_size_len);
935 if (rc) {
936 printk(KERN_WARNING "%s: Error parsing packet length; "
937 "rc = [%d]\n", __func__, rc);
938 goto out;
939 }
940 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
941 - ECRYPTFS_SIG_SIZE - 1);
942 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
943 > max_packet_size) {
944 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
945 "size is [%zd]\n", __func__, max_packet_size,
946 (1 + s->packet_size_len + 1
947 + s->block_aligned_filename_size));
948 rc = -EINVAL;
949 goto out;
950 }
951 (*packet_size) += s->packet_size_len;
952 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
953 ECRYPTFS_SIG_SIZE);
954 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
955 (*packet_size) += ECRYPTFS_SIG_SIZE;
956 s->cipher_code = data[(*packet_size)++];
957 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
958 if (rc) {
959 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
960 __func__, s->cipher_code);
961 goto out;
962 }
963 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
964 &s->auth_tok, mount_crypt_stat,
965 s->fnek_sig_hex);
966 if (rc) {
967 printk(KERN_ERR "%s: Error attempting to find auth tok for "
968 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
969 rc);
970 goto out;
971 }
972 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
973 &s->tfm_mutex,
974 s->cipher_string);
975 if (unlikely(rc)) {
976 printk(KERN_ERR "Internal error whilst attempting to get "
977 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
978 s->cipher_string, rc);
979 goto out;
980 }
981 mutex_lock(s->tfm_mutex);
982 rc = virt_to_scatterlist(&data[(*packet_size)],
983 s->block_aligned_filename_size, s->src_sg, 2);
984 if (rc < 1) {
985 printk(KERN_ERR "%s: Internal error whilst attempting to "
986 "convert encrypted filename memory to scatterlist; "
987 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
988 __func__, rc, s->block_aligned_filename_size);
989 goto out_unlock;
990 }
991 (*packet_size) += s->block_aligned_filename_size;
992 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
993 GFP_KERNEL);
994 if (!s->decrypted_filename) {
995 rc = -ENOMEM;
996 goto out_unlock;
997 }
998 rc = virt_to_scatterlist(s->decrypted_filename,
999 s->block_aligned_filename_size, s->dst_sg, 2);
1000 if (rc < 1) {
1001 printk(KERN_ERR "%s: Internal error whilst attempting to "
1002 "convert decrypted filename memory to scatterlist; "
1003 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1004 __func__, rc, s->block_aligned_filename_size);
1005 goto out_free_unlock;
1006 }
1007
1008 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
1009 if (!s->skcipher_req) {
1010 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1011 "skcipher_request_alloc for %s\n", __func__,
1012 crypto_skcipher_driver_name(s->skcipher_tfm));
1013 rc = -ENOMEM;
1014 goto out_free_unlock;
1015 }
1016
1017 skcipher_request_set_callback(s->skcipher_req,
1018 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
1019
1020 /* The characters in the first block effectively do the job of
1021 * the IV here, so we just use 0's for the IV. Note the
1022 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1023 * >= ECRYPTFS_MAX_IV_BYTES. */
1024 /* TODO: Support other key modules than passphrase for
1025 * filename encryption */
1026 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1027 rc = -EOPNOTSUPP;
1028 printk(KERN_INFO "%s: Filename encryption only supports "
1029 "password tokens\n", __func__);
1030 goto out_free_unlock;
1031 }
1032 rc = crypto_skcipher_setkey(
1033 s->skcipher_tfm,
1034 s->auth_tok->token.password.session_key_encryption_key,
1035 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1036 if (rc < 0) {
1037 printk(KERN_ERR "%s: Error setting key for crypto context; "
1038 "rc = [%d]. s->auth_tok->token.password.session_key_"
1039 "encryption_key = [0x%p]; mount_crypt_stat->"
1040 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1041 rc,
1042 s->auth_tok->token.password.session_key_encryption_key,
1043 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1044 goto out_free_unlock;
1045 }
1046 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
1047 s->block_aligned_filename_size, s->iv);
1048 rc = crypto_skcipher_decrypt(s->skcipher_req);
1049 if (rc) {
1050 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1051 "rc = [%d]\n", __func__, rc);
1052 goto out_free_unlock;
1053 }
1054
1055 while (s->i < s->block_aligned_filename_size &&
1056 s->decrypted_filename[s->i] != '\0')
1057 s->i++;
1058 if (s->i == s->block_aligned_filename_size) {
1059 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1060 "find valid separator between random characters and "
1061 "the filename\n", __func__);
1062 rc = -EINVAL;
1063 goto out_free_unlock;
1064 }
1065 s->i++;
1066 (*filename_size) = (s->block_aligned_filename_size - s->i);
1067 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1068 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1069 "invalid\n", __func__, (*filename_size));
1070 rc = -EINVAL;
1071 goto out_free_unlock;
1072 }
1073 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1074 if (!(*filename)) {
1075 rc = -ENOMEM;
1076 goto out_free_unlock;
1077 }
1078 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1079 (*filename)[(*filename_size)] = '\0';
1080 out_free_unlock:
1081 kfree(s->decrypted_filename);
1082 out_unlock:
1083 mutex_unlock(s->tfm_mutex);
1084 out:
1085 if (rc) {
1086 (*packet_size) = 0;
1087 (*filename_size) = 0;
1088 (*filename) = NULL;
1089 }
1090 if (auth_tok_key) {
1091 up_write(&(auth_tok_key->sem));
1092 key_put(auth_tok_key);
1093 }
1094 skcipher_request_free(s->skcipher_req);
1095 kfree(s);
1096 return rc;
1097 }
1098
1099 static int
ecryptfs_get_auth_tok_sig(char ** sig,struct ecryptfs_auth_tok * auth_tok)1100 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1101 {
1102 int rc = 0;
1103
1104 (*sig) = NULL;
1105 switch (auth_tok->token_type) {
1106 case ECRYPTFS_PASSWORD:
1107 (*sig) = auth_tok->token.password.signature;
1108 break;
1109 case ECRYPTFS_PRIVATE_KEY:
1110 (*sig) = auth_tok->token.private_key.signature;
1111 break;
1112 default:
1113 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1114 auth_tok->token_type);
1115 rc = -EINVAL;
1116 }
1117 return rc;
1118 }
1119
1120 /**
1121 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1122 * @auth_tok: The key authentication token used to decrypt the session key
1123 * @crypt_stat: The cryptographic context
1124 *
1125 * Returns zero on success; non-zero error otherwise.
1126 */
1127 static int
decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat)1128 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1129 struct ecryptfs_crypt_stat *crypt_stat)
1130 {
1131 u8 cipher_code = 0;
1132 struct ecryptfs_msg_ctx *msg_ctx;
1133 struct ecryptfs_message *msg = NULL;
1134 char *auth_tok_sig;
1135 char *payload = NULL;
1136 size_t payload_len = 0;
1137 int rc;
1138
1139 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1140 if (rc) {
1141 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1142 auth_tok->token_type);
1143 goto out;
1144 }
1145 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1146 &payload, &payload_len);
1147 if (rc) {
1148 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1149 goto out;
1150 }
1151 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1152 if (rc) {
1153 ecryptfs_printk(KERN_ERR, "Error sending message to "
1154 "ecryptfsd: %d\n", rc);
1155 goto out;
1156 }
1157 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1158 if (rc) {
1159 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1160 "from the user space daemon\n");
1161 rc = -EIO;
1162 goto out;
1163 }
1164 rc = parse_tag_65_packet(&(auth_tok->session_key),
1165 &cipher_code, msg);
1166 if (rc) {
1167 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1168 rc);
1169 goto out;
1170 }
1171 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1172 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1173 auth_tok->session_key.decrypted_key_size);
1174 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1175 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1176 if (rc) {
1177 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1178 cipher_code);
1179 goto out;
1180 }
1181 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1182 if (ecryptfs_verbosity > 0) {
1183 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1184 ecryptfs_dump_hex(crypt_stat->key,
1185 crypt_stat->key_size);
1186 }
1187 out:
1188 kfree(msg);
1189 kfree(payload);
1190 return rc;
1191 }
1192
wipe_auth_tok_list(struct list_head * auth_tok_list_head)1193 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1194 {
1195 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1196 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1197
1198 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1199 auth_tok_list_head, list) {
1200 list_del(&auth_tok_list_item->list);
1201 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1202 auth_tok_list_item);
1203 }
1204 }
1205
1206 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1207
1208 /**
1209 * parse_tag_1_packet
1210 * @crypt_stat: The cryptographic context to modify based on packet contents
1211 * @data: The raw bytes of the packet.
1212 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1213 * a new authentication token will be placed at the
1214 * end of this list for this packet.
1215 * @new_auth_tok: Pointer to a pointer to memory that this function
1216 * allocates; sets the memory address of the pointer to
1217 * NULL on error. This object is added to the
1218 * auth_tok_list.
1219 * @packet_size: This function writes the size of the parsed packet
1220 * into this memory location; zero on error.
1221 * @max_packet_size: The maximum allowable packet size
1222 *
1223 * Returns zero on success; non-zero on error.
1224 */
1225 static int
parse_tag_1_packet(struct ecryptfs_crypt_stat * crypt_stat,unsigned char * data,struct list_head * auth_tok_list,struct ecryptfs_auth_tok ** new_auth_tok,size_t * packet_size,size_t max_packet_size)1226 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1227 unsigned char *data, struct list_head *auth_tok_list,
1228 struct ecryptfs_auth_tok **new_auth_tok,
1229 size_t *packet_size, size_t max_packet_size)
1230 {
1231 size_t body_size;
1232 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1233 size_t length_size;
1234 int rc = 0;
1235
1236 (*packet_size) = 0;
1237 (*new_auth_tok) = NULL;
1238 /**
1239 * This format is inspired by OpenPGP; see RFC 2440
1240 * packet tag 1
1241 *
1242 * Tag 1 identifier (1 byte)
1243 * Max Tag 1 packet size (max 3 bytes)
1244 * Version (1 byte)
1245 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1246 * Cipher identifier (1 byte)
1247 * Encrypted key size (arbitrary)
1248 *
1249 * 12 bytes minimum packet size
1250 */
1251 if (unlikely(max_packet_size < 12)) {
1252 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1253 rc = -EINVAL;
1254 goto out;
1255 }
1256 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1257 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1258 ECRYPTFS_TAG_1_PACKET_TYPE);
1259 rc = -EINVAL;
1260 goto out;
1261 }
1262 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1263 * at end of function upon failure */
1264 auth_tok_list_item =
1265 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1266 GFP_KERNEL);
1267 if (!auth_tok_list_item) {
1268 printk(KERN_ERR "Unable to allocate memory\n");
1269 rc = -ENOMEM;
1270 goto out;
1271 }
1272 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1273 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1274 &length_size);
1275 if (rc) {
1276 printk(KERN_WARNING "Error parsing packet length; "
1277 "rc = [%d]\n", rc);
1278 goto out_free;
1279 }
1280 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1281 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1282 rc = -EINVAL;
1283 goto out_free;
1284 }
1285 (*packet_size) += length_size;
1286 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1287 printk(KERN_WARNING "Packet size exceeds max\n");
1288 rc = -EINVAL;
1289 goto out_free;
1290 }
1291 if (unlikely(data[(*packet_size)++] != 0x03)) {
1292 printk(KERN_WARNING "Unknown version number [%d]\n",
1293 data[(*packet_size) - 1]);
1294 rc = -EINVAL;
1295 goto out_free;
1296 }
1297 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1298 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1299 *packet_size += ECRYPTFS_SIG_SIZE;
1300 /* This byte is skipped because the kernel does not need to
1301 * know which public key encryption algorithm was used */
1302 (*packet_size)++;
1303 (*new_auth_tok)->session_key.encrypted_key_size =
1304 body_size - (ECRYPTFS_SIG_SIZE + 2);
1305 if ((*new_auth_tok)->session_key.encrypted_key_size
1306 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1307 printk(KERN_WARNING "Tag 1 packet contains key larger "
1308 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1309 rc = -EINVAL;
1310 goto out_free;
1311 }
1312 memcpy((*new_auth_tok)->session_key.encrypted_key,
1313 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1314 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1315 (*new_auth_tok)->session_key.flags &=
1316 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1317 (*new_auth_tok)->session_key.flags |=
1318 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1319 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1320 (*new_auth_tok)->flags = 0;
1321 (*new_auth_tok)->session_key.flags &=
1322 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1323 (*new_auth_tok)->session_key.flags &=
1324 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1325 list_add(&auth_tok_list_item->list, auth_tok_list);
1326 goto out;
1327 out_free:
1328 (*new_auth_tok) = NULL;
1329 memset(auth_tok_list_item, 0,
1330 sizeof(struct ecryptfs_auth_tok_list_item));
1331 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1332 auth_tok_list_item);
1333 out:
1334 if (rc)
1335 (*packet_size) = 0;
1336 return rc;
1337 }
1338
1339 /**
1340 * parse_tag_3_packet
1341 * @crypt_stat: The cryptographic context to modify based on packet
1342 * contents.
1343 * @data: The raw bytes of the packet.
1344 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1345 * a new authentication token will be placed at the end
1346 * of this list for this packet.
1347 * @new_auth_tok: Pointer to a pointer to memory that this function
1348 * allocates; sets the memory address of the pointer to
1349 * NULL on error. This object is added to the
1350 * auth_tok_list.
1351 * @packet_size: This function writes the size of the parsed packet
1352 * into this memory location; zero on error.
1353 * @max_packet_size: maximum number of bytes to parse
1354 *
1355 * Returns zero on success; non-zero on error.
1356 */
1357 static int
parse_tag_3_packet(struct ecryptfs_crypt_stat * crypt_stat,unsigned char * data,struct list_head * auth_tok_list,struct ecryptfs_auth_tok ** new_auth_tok,size_t * packet_size,size_t max_packet_size)1358 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1359 unsigned char *data, struct list_head *auth_tok_list,
1360 struct ecryptfs_auth_tok **new_auth_tok,
1361 size_t *packet_size, size_t max_packet_size)
1362 {
1363 size_t body_size;
1364 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1365 size_t length_size;
1366 int rc = 0;
1367
1368 (*packet_size) = 0;
1369 (*new_auth_tok) = NULL;
1370 /**
1371 *This format is inspired by OpenPGP; see RFC 2440
1372 * packet tag 3
1373 *
1374 * Tag 3 identifier (1 byte)
1375 * Max Tag 3 packet size (max 3 bytes)
1376 * Version (1 byte)
1377 * Cipher code (1 byte)
1378 * S2K specifier (1 byte)
1379 * Hash identifier (1 byte)
1380 * Salt (ECRYPTFS_SALT_SIZE)
1381 * Hash iterations (1 byte)
1382 * Encrypted key (arbitrary)
1383 *
1384 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1385 */
1386 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1387 printk(KERN_ERR "Max packet size too large\n");
1388 rc = -EINVAL;
1389 goto out;
1390 }
1391 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1392 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1393 ECRYPTFS_TAG_3_PACKET_TYPE);
1394 rc = -EINVAL;
1395 goto out;
1396 }
1397 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1398 * at end of function upon failure */
1399 auth_tok_list_item =
1400 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1401 if (!auth_tok_list_item) {
1402 printk(KERN_ERR "Unable to allocate memory\n");
1403 rc = -ENOMEM;
1404 goto out;
1405 }
1406 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1407 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1408 &length_size);
1409 if (rc) {
1410 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1411 rc);
1412 goto out_free;
1413 }
1414 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1415 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1416 rc = -EINVAL;
1417 goto out_free;
1418 }
1419 (*packet_size) += length_size;
1420 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1421 printk(KERN_ERR "Packet size exceeds max\n");
1422 rc = -EINVAL;
1423 goto out_free;
1424 }
1425 (*new_auth_tok)->session_key.encrypted_key_size =
1426 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1427 if ((*new_auth_tok)->session_key.encrypted_key_size
1428 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1429 printk(KERN_WARNING "Tag 3 packet contains key larger "
1430 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1431 rc = -EINVAL;
1432 goto out_free;
1433 }
1434 if (unlikely(data[(*packet_size)++] != 0x04)) {
1435 printk(KERN_WARNING "Unknown version number [%d]\n",
1436 data[(*packet_size) - 1]);
1437 rc = -EINVAL;
1438 goto out_free;
1439 }
1440 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1441 (u16)data[(*packet_size)]);
1442 if (rc)
1443 goto out_free;
1444 /* A little extra work to differentiate among the AES key
1445 * sizes; see RFC2440 */
1446 switch(data[(*packet_size)++]) {
1447 case RFC2440_CIPHER_AES_192:
1448 crypt_stat->key_size = 24;
1449 break;
1450 default:
1451 crypt_stat->key_size =
1452 (*new_auth_tok)->session_key.encrypted_key_size;
1453 }
1454 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1455 if (rc)
1456 goto out_free;
1457 if (unlikely(data[(*packet_size)++] != 0x03)) {
1458 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1459 rc = -ENOSYS;
1460 goto out_free;
1461 }
1462 /* TODO: finish the hash mapping */
1463 switch (data[(*packet_size)++]) {
1464 case 0x01: /* See RFC2440 for these numbers and their mappings */
1465 /* Choose MD5 */
1466 memcpy((*new_auth_tok)->token.password.salt,
1467 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1468 (*packet_size) += ECRYPTFS_SALT_SIZE;
1469 /* This conversion was taken straight from RFC2440 */
1470 (*new_auth_tok)->token.password.hash_iterations =
1471 ((u32) 16 + (data[(*packet_size)] & 15))
1472 << ((data[(*packet_size)] >> 4) + 6);
1473 (*packet_size)++;
1474 /* Friendly reminder:
1475 * (*new_auth_tok)->session_key.encrypted_key_size =
1476 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1477 memcpy((*new_auth_tok)->session_key.encrypted_key,
1478 &data[(*packet_size)],
1479 (*new_auth_tok)->session_key.encrypted_key_size);
1480 (*packet_size) +=
1481 (*new_auth_tok)->session_key.encrypted_key_size;
1482 (*new_auth_tok)->session_key.flags &=
1483 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1484 (*new_auth_tok)->session_key.flags |=
1485 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1486 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1487 break;
1488 default:
1489 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1490 "[%d]\n", data[(*packet_size) - 1]);
1491 rc = -ENOSYS;
1492 goto out_free;
1493 }
1494 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1495 /* TODO: Parametarize; we might actually want userspace to
1496 * decrypt the session key. */
1497 (*new_auth_tok)->session_key.flags &=
1498 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1499 (*new_auth_tok)->session_key.flags &=
1500 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1501 list_add(&auth_tok_list_item->list, auth_tok_list);
1502 goto out;
1503 out_free:
1504 (*new_auth_tok) = NULL;
1505 memset(auth_tok_list_item, 0,
1506 sizeof(struct ecryptfs_auth_tok_list_item));
1507 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1508 auth_tok_list_item);
1509 out:
1510 if (rc)
1511 (*packet_size) = 0;
1512 return rc;
1513 }
1514
1515 /**
1516 * parse_tag_11_packet
1517 * @data: The raw bytes of the packet
1518 * @contents: This function writes the data contents of the literal
1519 * packet into this memory location
1520 * @max_contents_bytes: The maximum number of bytes that this function
1521 * is allowed to write into contents
1522 * @tag_11_contents_size: This function writes the size of the parsed
1523 * contents into this memory location; zero on
1524 * error
1525 * @packet_size: This function writes the size of the parsed packet
1526 * into this memory location; zero on error
1527 * @max_packet_size: maximum number of bytes to parse
1528 *
1529 * Returns zero on success; non-zero on error.
1530 */
1531 static int
parse_tag_11_packet(unsigned char * data,unsigned char * contents,size_t max_contents_bytes,size_t * tag_11_contents_size,size_t * packet_size,size_t max_packet_size)1532 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1533 size_t max_contents_bytes, size_t *tag_11_contents_size,
1534 size_t *packet_size, size_t max_packet_size)
1535 {
1536 size_t body_size;
1537 size_t length_size;
1538 int rc = 0;
1539
1540 (*packet_size) = 0;
1541 (*tag_11_contents_size) = 0;
1542 /* This format is inspired by OpenPGP; see RFC 2440
1543 * packet tag 11
1544 *
1545 * Tag 11 identifier (1 byte)
1546 * Max Tag 11 packet size (max 3 bytes)
1547 * Binary format specifier (1 byte)
1548 * Filename length (1 byte)
1549 * Filename ("_CONSOLE") (8 bytes)
1550 * Modification date (4 bytes)
1551 * Literal data (arbitrary)
1552 *
1553 * We need at least 16 bytes of data for the packet to even be
1554 * valid.
1555 */
1556 if (max_packet_size < 16) {
1557 printk(KERN_ERR "Maximum packet size too small\n");
1558 rc = -EINVAL;
1559 goto out;
1560 }
1561 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1562 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1563 rc = -EINVAL;
1564 goto out;
1565 }
1566 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1567 &length_size);
1568 if (rc) {
1569 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1570 goto out;
1571 }
1572 if (body_size < 14) {
1573 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1574 rc = -EINVAL;
1575 goto out;
1576 }
1577 (*packet_size) += length_size;
1578 (*tag_11_contents_size) = (body_size - 14);
1579 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1580 printk(KERN_ERR "Packet size exceeds max\n");
1581 rc = -EINVAL;
1582 goto out;
1583 }
1584 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1585 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1586 "expected size\n");
1587 rc = -EINVAL;
1588 goto out;
1589 }
1590 if (data[(*packet_size)++] != 0x62) {
1591 printk(KERN_WARNING "Unrecognizable packet\n");
1592 rc = -EINVAL;
1593 goto out;
1594 }
1595 if (data[(*packet_size)++] != 0x08) {
1596 printk(KERN_WARNING "Unrecognizable packet\n");
1597 rc = -EINVAL;
1598 goto out;
1599 }
1600 (*packet_size) += 12; /* Ignore filename and modification date */
1601 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1602 (*packet_size) += (*tag_11_contents_size);
1603 out:
1604 if (rc) {
1605 (*packet_size) = 0;
1606 (*tag_11_contents_size) = 0;
1607 }
1608 return rc;
1609 }
1610
ecryptfs_keyring_auth_tok_for_sig(struct key ** auth_tok_key,struct ecryptfs_auth_tok ** auth_tok,char * sig)1611 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1612 struct ecryptfs_auth_tok **auth_tok,
1613 char *sig)
1614 {
1615 int rc = 0;
1616
1617 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1618 if (IS_ERR(*auth_tok_key)) {
1619 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1620 if (IS_ERR(*auth_tok_key)) {
1621 printk(KERN_ERR "Could not find key with description: [%s]\n",
1622 sig);
1623 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1624 (*auth_tok_key) = NULL;
1625 goto out;
1626 }
1627 }
1628 down_write(&(*auth_tok_key)->sem);
1629 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1630 if (rc) {
1631 up_write(&(*auth_tok_key)->sem);
1632 key_put(*auth_tok_key);
1633 (*auth_tok_key) = NULL;
1634 goto out;
1635 }
1636 out:
1637 return rc;
1638 }
1639
1640 /**
1641 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1642 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1643 * @crypt_stat: The cryptographic context
1644 *
1645 * Returns zero on success; non-zero error otherwise
1646 */
1647 static int
decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat)1648 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1649 struct ecryptfs_crypt_stat *crypt_stat)
1650 {
1651 struct scatterlist dst_sg[2];
1652 struct scatterlist src_sg[2];
1653 struct mutex *tfm_mutex;
1654 struct crypto_skcipher *tfm;
1655 struct skcipher_request *req = NULL;
1656 int rc = 0;
1657
1658 if (unlikely(ecryptfs_verbosity > 0)) {
1659 ecryptfs_printk(
1660 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1661 auth_tok->token.password.session_key_encryption_key_bytes);
1662 ecryptfs_dump_hex(
1663 auth_tok->token.password.session_key_encryption_key,
1664 auth_tok->token.password.session_key_encryption_key_bytes);
1665 }
1666 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
1667 crypt_stat->cipher);
1668 if (unlikely(rc)) {
1669 printk(KERN_ERR "Internal error whilst attempting to get "
1670 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1671 crypt_stat->cipher, rc);
1672 goto out;
1673 }
1674 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1675 auth_tok->session_key.encrypted_key_size,
1676 src_sg, 2);
1677 if (rc < 1 || rc > 2) {
1678 printk(KERN_ERR "Internal error whilst attempting to convert "
1679 "auth_tok->session_key.encrypted_key to scatterlist; "
1680 "expected rc = 1; got rc = [%d]. "
1681 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1682 auth_tok->session_key.encrypted_key_size);
1683 goto out;
1684 }
1685 auth_tok->session_key.decrypted_key_size =
1686 auth_tok->session_key.encrypted_key_size;
1687 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1688 auth_tok->session_key.decrypted_key_size,
1689 dst_sg, 2);
1690 if (rc < 1 || rc > 2) {
1691 printk(KERN_ERR "Internal error whilst attempting to convert "
1692 "auth_tok->session_key.decrypted_key to scatterlist; "
1693 "expected rc = 1; got rc = [%d]\n", rc);
1694 goto out;
1695 }
1696 mutex_lock(tfm_mutex);
1697 req = skcipher_request_alloc(tfm, GFP_KERNEL);
1698 if (!req) {
1699 mutex_unlock(tfm_mutex);
1700 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1701 "skcipher_request_alloc for %s\n", __func__,
1702 crypto_skcipher_driver_name(tfm));
1703 rc = -ENOMEM;
1704 goto out;
1705 }
1706
1707 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
1708 NULL, NULL);
1709 rc = crypto_skcipher_setkey(
1710 tfm, auth_tok->token.password.session_key_encryption_key,
1711 crypt_stat->key_size);
1712 if (unlikely(rc < 0)) {
1713 mutex_unlock(tfm_mutex);
1714 printk(KERN_ERR "Error setting key for crypto context\n");
1715 rc = -EINVAL;
1716 goto out;
1717 }
1718 skcipher_request_set_crypt(req, src_sg, dst_sg,
1719 auth_tok->session_key.encrypted_key_size,
1720 NULL);
1721 rc = crypto_skcipher_decrypt(req);
1722 mutex_unlock(tfm_mutex);
1723 if (unlikely(rc)) {
1724 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1725 goto out;
1726 }
1727 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1728 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1729 auth_tok->session_key.decrypted_key_size);
1730 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1731 if (unlikely(ecryptfs_verbosity > 0)) {
1732 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1733 crypt_stat->key_size);
1734 ecryptfs_dump_hex(crypt_stat->key,
1735 crypt_stat->key_size);
1736 }
1737 out:
1738 skcipher_request_free(req);
1739 return rc;
1740 }
1741
1742 /**
1743 * ecryptfs_parse_packet_set
1744 * @crypt_stat: The cryptographic context
1745 * @src: Virtual address of region of memory containing the packets
1746 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1747 *
1748 * Get crypt_stat to have the file's session key if the requisite key
1749 * is available to decrypt the session key.
1750 *
1751 * Returns Zero if a valid authentication token was retrieved and
1752 * processed; negative value for file not encrypted or for error
1753 * conditions.
1754 */
ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat * crypt_stat,unsigned char * src,struct dentry * ecryptfs_dentry)1755 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1756 unsigned char *src,
1757 struct dentry *ecryptfs_dentry)
1758 {
1759 size_t i = 0;
1760 size_t found_auth_tok;
1761 size_t next_packet_is_auth_tok_packet;
1762 struct list_head auth_tok_list;
1763 struct ecryptfs_auth_tok *matching_auth_tok;
1764 struct ecryptfs_auth_tok *candidate_auth_tok;
1765 char *candidate_auth_tok_sig;
1766 size_t packet_size;
1767 struct ecryptfs_auth_tok *new_auth_tok;
1768 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1769 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1770 size_t tag_11_contents_size;
1771 size_t tag_11_packet_size;
1772 struct key *auth_tok_key = NULL;
1773 int rc = 0;
1774
1775 INIT_LIST_HEAD(&auth_tok_list);
1776 /* Parse the header to find as many packets as we can; these will be
1777 * added the our &auth_tok_list */
1778 next_packet_is_auth_tok_packet = 1;
1779 while (next_packet_is_auth_tok_packet) {
1780 size_t max_packet_size = ((PAGE_SIZE - 8) - i);
1781
1782 switch (src[i]) {
1783 case ECRYPTFS_TAG_3_PACKET_TYPE:
1784 rc = parse_tag_3_packet(crypt_stat,
1785 (unsigned char *)&src[i],
1786 &auth_tok_list, &new_auth_tok,
1787 &packet_size, max_packet_size);
1788 if (rc) {
1789 ecryptfs_printk(KERN_ERR, "Error parsing "
1790 "tag 3 packet\n");
1791 rc = -EIO;
1792 goto out_wipe_list;
1793 }
1794 i += packet_size;
1795 rc = parse_tag_11_packet((unsigned char *)&src[i],
1796 sig_tmp_space,
1797 ECRYPTFS_SIG_SIZE,
1798 &tag_11_contents_size,
1799 &tag_11_packet_size,
1800 max_packet_size);
1801 if (rc) {
1802 ecryptfs_printk(KERN_ERR, "No valid "
1803 "(ecryptfs-specific) literal "
1804 "packet containing "
1805 "authentication token "
1806 "signature found after "
1807 "tag 3 packet\n");
1808 rc = -EIO;
1809 goto out_wipe_list;
1810 }
1811 i += tag_11_packet_size;
1812 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1813 ecryptfs_printk(KERN_ERR, "Expected "
1814 "signature of size [%d]; "
1815 "read size [%zd]\n",
1816 ECRYPTFS_SIG_SIZE,
1817 tag_11_contents_size);
1818 rc = -EIO;
1819 goto out_wipe_list;
1820 }
1821 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1822 sig_tmp_space, tag_11_contents_size);
1823 new_auth_tok->token.password.signature[
1824 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1825 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1826 break;
1827 case ECRYPTFS_TAG_1_PACKET_TYPE:
1828 rc = parse_tag_1_packet(crypt_stat,
1829 (unsigned char *)&src[i],
1830 &auth_tok_list, &new_auth_tok,
1831 &packet_size, max_packet_size);
1832 if (rc) {
1833 ecryptfs_printk(KERN_ERR, "Error parsing "
1834 "tag 1 packet\n");
1835 rc = -EIO;
1836 goto out_wipe_list;
1837 }
1838 i += packet_size;
1839 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1840 break;
1841 case ECRYPTFS_TAG_11_PACKET_TYPE:
1842 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1843 "(Tag 11 not allowed by itself)\n");
1844 rc = -EIO;
1845 goto out_wipe_list;
1846 default:
1847 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1848 "of the file header; hex value of "
1849 "character is [0x%.2x]\n", i, src[i]);
1850 next_packet_is_auth_tok_packet = 0;
1851 }
1852 }
1853 if (list_empty(&auth_tok_list)) {
1854 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1855 "eCryptfs file; this is not supported in this version "
1856 "of the eCryptfs kernel module\n");
1857 rc = -EINVAL;
1858 goto out;
1859 }
1860 /* auth_tok_list contains the set of authentication tokens
1861 * parsed from the metadata. We need to find a matching
1862 * authentication token that has the secret component(s)
1863 * necessary to decrypt the EFEK in the auth_tok parsed from
1864 * the metadata. There may be several potential matches, but
1865 * just one will be sufficient to decrypt to get the FEK. */
1866 find_next_matching_auth_tok:
1867 found_auth_tok = 0;
1868 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1869 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1870 if (unlikely(ecryptfs_verbosity > 0)) {
1871 ecryptfs_printk(KERN_DEBUG,
1872 "Considering candidate auth tok:\n");
1873 ecryptfs_dump_auth_tok(candidate_auth_tok);
1874 }
1875 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1876 candidate_auth_tok);
1877 if (rc) {
1878 printk(KERN_ERR
1879 "Unrecognized candidate auth tok type: [%d]\n",
1880 candidate_auth_tok->token_type);
1881 rc = -EINVAL;
1882 goto out_wipe_list;
1883 }
1884 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1885 &matching_auth_tok,
1886 crypt_stat->mount_crypt_stat,
1887 candidate_auth_tok_sig);
1888 if (!rc) {
1889 found_auth_tok = 1;
1890 goto found_matching_auth_tok;
1891 }
1892 }
1893 if (!found_auth_tok) {
1894 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1895 "authentication token\n");
1896 rc = -EIO;
1897 goto out_wipe_list;
1898 }
1899 found_matching_auth_tok:
1900 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1901 memcpy(&(candidate_auth_tok->token.private_key),
1902 &(matching_auth_tok->token.private_key),
1903 sizeof(struct ecryptfs_private_key));
1904 up_write(&(auth_tok_key->sem));
1905 key_put(auth_tok_key);
1906 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1907 crypt_stat);
1908 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1909 memcpy(&(candidate_auth_tok->token.password),
1910 &(matching_auth_tok->token.password),
1911 sizeof(struct ecryptfs_password));
1912 up_write(&(auth_tok_key->sem));
1913 key_put(auth_tok_key);
1914 rc = decrypt_passphrase_encrypted_session_key(
1915 candidate_auth_tok, crypt_stat);
1916 } else {
1917 up_write(&(auth_tok_key->sem));
1918 key_put(auth_tok_key);
1919 rc = -EINVAL;
1920 }
1921 if (rc) {
1922 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1923
1924 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1925 "session key for authentication token with sig "
1926 "[%.*s]; rc = [%d]. Removing auth tok "
1927 "candidate from the list and searching for "
1928 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1929 candidate_auth_tok_sig, rc);
1930 list_for_each_entry_safe(auth_tok_list_item,
1931 auth_tok_list_item_tmp,
1932 &auth_tok_list, list) {
1933 if (candidate_auth_tok
1934 == &auth_tok_list_item->auth_tok) {
1935 list_del(&auth_tok_list_item->list);
1936 kmem_cache_free(
1937 ecryptfs_auth_tok_list_item_cache,
1938 auth_tok_list_item);
1939 goto find_next_matching_auth_tok;
1940 }
1941 }
1942 BUG();
1943 }
1944 rc = ecryptfs_compute_root_iv(crypt_stat);
1945 if (rc) {
1946 ecryptfs_printk(KERN_ERR, "Error computing "
1947 "the root IV\n");
1948 goto out_wipe_list;
1949 }
1950 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1951 if (rc) {
1952 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1953 "context for cipher [%s]; rc = [%d]\n",
1954 crypt_stat->cipher, rc);
1955 }
1956 out_wipe_list:
1957 wipe_auth_tok_list(&auth_tok_list);
1958 out:
1959 return rc;
1960 }
1961
1962 static int
pki_encrypt_session_key(struct key * auth_tok_key,struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_key_record * key_rec)1963 pki_encrypt_session_key(struct key *auth_tok_key,
1964 struct ecryptfs_auth_tok *auth_tok,
1965 struct ecryptfs_crypt_stat *crypt_stat,
1966 struct ecryptfs_key_record *key_rec)
1967 {
1968 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1969 char *payload = NULL;
1970 size_t payload_len = 0;
1971 struct ecryptfs_message *msg;
1972 int rc;
1973
1974 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1975 ecryptfs_code_for_cipher_string(
1976 crypt_stat->cipher,
1977 crypt_stat->key_size),
1978 crypt_stat, &payload, &payload_len);
1979 up_write(&(auth_tok_key->sem));
1980 key_put(auth_tok_key);
1981 if (rc) {
1982 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1983 goto out;
1984 }
1985 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1986 if (rc) {
1987 ecryptfs_printk(KERN_ERR, "Error sending message to "
1988 "ecryptfsd: %d\n", rc);
1989 goto out;
1990 }
1991 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1992 if (rc) {
1993 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1994 "from the user space daemon\n");
1995 rc = -EIO;
1996 goto out;
1997 }
1998 rc = parse_tag_67_packet(key_rec, msg);
1999 if (rc)
2000 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2001 kfree(msg);
2002 out:
2003 kfree(payload);
2004 return rc;
2005 }
2006 /**
2007 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2008 * @dest: Buffer into which to write the packet
2009 * @remaining_bytes: Maximum number of bytes that can be writtn
2010 * @auth_tok_key: The authentication token key to unlock and put when done with
2011 * @auth_tok
2012 * @auth_tok: The authentication token used for generating the tag 1 packet
2013 * @crypt_stat: The cryptographic context
2014 * @key_rec: The key record struct for the tag 1 packet
2015 * @packet_size: This function will write the number of bytes that end
2016 * up constituting the packet; set to zero on error
2017 *
2018 * Returns zero on success; non-zero on error.
2019 */
2020 static int
write_tag_1_packet(char * dest,size_t * remaining_bytes,struct key * auth_tok_key,struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_key_record * key_rec,size_t * packet_size)2021 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2022 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2023 struct ecryptfs_crypt_stat *crypt_stat,
2024 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2025 {
2026 size_t i;
2027 size_t encrypted_session_key_valid = 0;
2028 size_t packet_size_length;
2029 size_t max_packet_size;
2030 int rc = 0;
2031
2032 (*packet_size) = 0;
2033 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2034 ECRYPTFS_SIG_SIZE);
2035 encrypted_session_key_valid = 0;
2036 for (i = 0; i < crypt_stat->key_size; i++)
2037 encrypted_session_key_valid |=
2038 auth_tok->session_key.encrypted_key[i];
2039 if (encrypted_session_key_valid) {
2040 memcpy(key_rec->enc_key,
2041 auth_tok->session_key.encrypted_key,
2042 auth_tok->session_key.encrypted_key_size);
2043 up_write(&(auth_tok_key->sem));
2044 key_put(auth_tok_key);
2045 goto encrypted_session_key_set;
2046 }
2047 if (auth_tok->session_key.encrypted_key_size == 0)
2048 auth_tok->session_key.encrypted_key_size =
2049 auth_tok->token.private_key.key_size;
2050 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2051 key_rec);
2052 if (rc) {
2053 printk(KERN_ERR "Failed to encrypt session key via a key "
2054 "module; rc = [%d]\n", rc);
2055 goto out;
2056 }
2057 if (ecryptfs_verbosity > 0) {
2058 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2059 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2060 }
2061 encrypted_session_key_set:
2062 /* This format is inspired by OpenPGP; see RFC 2440
2063 * packet tag 1 */
2064 max_packet_size = (1 /* Tag 1 identifier */
2065 + 3 /* Max Tag 1 packet size */
2066 + 1 /* Version */
2067 + ECRYPTFS_SIG_SIZE /* Key identifier */
2068 + 1 /* Cipher identifier */
2069 + key_rec->enc_key_size); /* Encrypted key size */
2070 if (max_packet_size > (*remaining_bytes)) {
2071 printk(KERN_ERR "Packet length larger than maximum allowable; "
2072 "need up to [%td] bytes, but there are only [%td] "
2073 "available\n", max_packet_size, (*remaining_bytes));
2074 rc = -EINVAL;
2075 goto out;
2076 }
2077 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2078 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2079 (max_packet_size - 4),
2080 &packet_size_length);
2081 if (rc) {
2082 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2083 "header; cannot generate packet length\n");
2084 goto out;
2085 }
2086 (*packet_size) += packet_size_length;
2087 dest[(*packet_size)++] = 0x03; /* version 3 */
2088 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2089 (*packet_size) += ECRYPTFS_SIG_SIZE;
2090 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2091 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2092 key_rec->enc_key_size);
2093 (*packet_size) += key_rec->enc_key_size;
2094 out:
2095 if (rc)
2096 (*packet_size) = 0;
2097 else
2098 (*remaining_bytes) -= (*packet_size);
2099 return rc;
2100 }
2101
2102 /**
2103 * write_tag_11_packet
2104 * @dest: Target into which Tag 11 packet is to be written
2105 * @remaining_bytes: Maximum packet length
2106 * @contents: Byte array of contents to copy in
2107 * @contents_length: Number of bytes in contents
2108 * @packet_length: Length of the Tag 11 packet written; zero on error
2109 *
2110 * Returns zero on success; non-zero on error.
2111 */
2112 static int
write_tag_11_packet(char * dest,size_t * remaining_bytes,char * contents,size_t contents_length,size_t * packet_length)2113 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2114 size_t contents_length, size_t *packet_length)
2115 {
2116 size_t packet_size_length;
2117 size_t max_packet_size;
2118 int rc = 0;
2119
2120 (*packet_length) = 0;
2121 /* This format is inspired by OpenPGP; see RFC 2440
2122 * packet tag 11 */
2123 max_packet_size = (1 /* Tag 11 identifier */
2124 + 3 /* Max Tag 11 packet size */
2125 + 1 /* Binary format specifier */
2126 + 1 /* Filename length */
2127 + 8 /* Filename ("_CONSOLE") */
2128 + 4 /* Modification date */
2129 + contents_length); /* Literal data */
2130 if (max_packet_size > (*remaining_bytes)) {
2131 printk(KERN_ERR "Packet length larger than maximum allowable; "
2132 "need up to [%td] bytes, but there are only [%td] "
2133 "available\n", max_packet_size, (*remaining_bytes));
2134 rc = -EINVAL;
2135 goto out;
2136 }
2137 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2138 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2139 (max_packet_size - 4),
2140 &packet_size_length);
2141 if (rc) {
2142 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2143 "generate packet length. rc = [%d]\n", rc);
2144 goto out;
2145 }
2146 (*packet_length) += packet_size_length;
2147 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2148 dest[(*packet_length)++] = 8;
2149 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2150 (*packet_length) += 8;
2151 memset(&dest[(*packet_length)], 0x00, 4);
2152 (*packet_length) += 4;
2153 memcpy(&dest[(*packet_length)], contents, contents_length);
2154 (*packet_length) += contents_length;
2155 out:
2156 if (rc)
2157 (*packet_length) = 0;
2158 else
2159 (*remaining_bytes) -= (*packet_length);
2160 return rc;
2161 }
2162
2163 /**
2164 * write_tag_3_packet
2165 * @dest: Buffer into which to write the packet
2166 * @remaining_bytes: Maximum number of bytes that can be written
2167 * @auth_tok: Authentication token
2168 * @crypt_stat: The cryptographic context
2169 * @key_rec: encrypted key
2170 * @packet_size: This function will write the number of bytes that end
2171 * up constituting the packet; set to zero on error
2172 *
2173 * Returns zero on success; non-zero on error.
2174 */
2175 static int
write_tag_3_packet(char * dest,size_t * remaining_bytes,struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat,struct ecryptfs_key_record * key_rec,size_t * packet_size)2176 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2177 struct ecryptfs_auth_tok *auth_tok,
2178 struct ecryptfs_crypt_stat *crypt_stat,
2179 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2180 {
2181 size_t i;
2182 size_t encrypted_session_key_valid = 0;
2183 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2184 struct scatterlist dst_sg[2];
2185 struct scatterlist src_sg[2];
2186 struct mutex *tfm_mutex = NULL;
2187 u8 cipher_code;
2188 size_t packet_size_length;
2189 size_t max_packet_size;
2190 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2191 crypt_stat->mount_crypt_stat;
2192 struct crypto_skcipher *tfm;
2193 struct skcipher_request *req;
2194 int rc = 0;
2195
2196 (*packet_size) = 0;
2197 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2198 ECRYPTFS_SIG_SIZE);
2199 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
2200 crypt_stat->cipher);
2201 if (unlikely(rc)) {
2202 printk(KERN_ERR "Internal error whilst attempting to get "
2203 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2204 crypt_stat->cipher, rc);
2205 goto out;
2206 }
2207 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2208 printk(KERN_WARNING "No key size specified at mount; "
2209 "defaulting to [%d]\n",
2210 crypto_skcipher_max_keysize(tfm));
2211 mount_crypt_stat->global_default_cipher_key_size =
2212 crypto_skcipher_max_keysize(tfm);
2213 }
2214 if (crypt_stat->key_size == 0)
2215 crypt_stat->key_size =
2216 mount_crypt_stat->global_default_cipher_key_size;
2217 if (auth_tok->session_key.encrypted_key_size == 0)
2218 auth_tok->session_key.encrypted_key_size =
2219 crypt_stat->key_size;
2220 if (crypt_stat->key_size == 24
2221 && strcmp("aes", crypt_stat->cipher) == 0) {
2222 memset((crypt_stat->key + 24), 0, 8);
2223 auth_tok->session_key.encrypted_key_size = 32;
2224 } else
2225 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2226 key_rec->enc_key_size =
2227 auth_tok->session_key.encrypted_key_size;
2228 encrypted_session_key_valid = 0;
2229 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2230 encrypted_session_key_valid |=
2231 auth_tok->session_key.encrypted_key[i];
2232 if (encrypted_session_key_valid) {
2233 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2234 "using auth_tok->session_key.encrypted_key, "
2235 "where key_rec->enc_key_size = [%zd]\n",
2236 key_rec->enc_key_size);
2237 memcpy(key_rec->enc_key,
2238 auth_tok->session_key.encrypted_key,
2239 key_rec->enc_key_size);
2240 goto encrypted_session_key_set;
2241 }
2242 if (auth_tok->token.password.flags &
2243 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2244 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2245 "session key encryption key of size [%d]\n",
2246 auth_tok->token.password.
2247 session_key_encryption_key_bytes);
2248 memcpy(session_key_encryption_key,
2249 auth_tok->token.password.session_key_encryption_key,
2250 crypt_stat->key_size);
2251 ecryptfs_printk(KERN_DEBUG,
2252 "Cached session key encryption key:\n");
2253 if (ecryptfs_verbosity > 0)
2254 ecryptfs_dump_hex(session_key_encryption_key, 16);
2255 }
2256 if (unlikely(ecryptfs_verbosity > 0)) {
2257 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2258 ecryptfs_dump_hex(session_key_encryption_key, 16);
2259 }
2260 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2261 src_sg, 2);
2262 if (rc < 1 || rc > 2) {
2263 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2264 "for crypt_stat session key; expected rc = 1; "
2265 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2266 rc, key_rec->enc_key_size);
2267 rc = -ENOMEM;
2268 goto out;
2269 }
2270 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2271 dst_sg, 2);
2272 if (rc < 1 || rc > 2) {
2273 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2274 "for crypt_stat encrypted session key; "
2275 "expected rc = 1; got rc = [%d]. "
2276 "key_rec->enc_key_size = [%zd]\n", rc,
2277 key_rec->enc_key_size);
2278 rc = -ENOMEM;
2279 goto out;
2280 }
2281 mutex_lock(tfm_mutex);
2282 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
2283 crypt_stat->key_size);
2284 if (rc < 0) {
2285 mutex_unlock(tfm_mutex);
2286 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2287 "context; rc = [%d]\n", rc);
2288 goto out;
2289 }
2290
2291 req = skcipher_request_alloc(tfm, GFP_KERNEL);
2292 if (!req) {
2293 mutex_unlock(tfm_mutex);
2294 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
2295 "attempting to skcipher_request_alloc for "
2296 "%s\n", crypto_skcipher_driver_name(tfm));
2297 rc = -ENOMEM;
2298 goto out;
2299 }
2300
2301 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
2302 NULL, NULL);
2303
2304 rc = 0;
2305 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2306 crypt_stat->key_size);
2307 skcipher_request_set_crypt(req, src_sg, dst_sg,
2308 (*key_rec).enc_key_size, NULL);
2309 rc = crypto_skcipher_encrypt(req);
2310 mutex_unlock(tfm_mutex);
2311 skcipher_request_free(req);
2312 if (rc) {
2313 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2314 goto out;
2315 }
2316 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2317 if (ecryptfs_verbosity > 0) {
2318 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2319 key_rec->enc_key_size);
2320 ecryptfs_dump_hex(key_rec->enc_key,
2321 key_rec->enc_key_size);
2322 }
2323 encrypted_session_key_set:
2324 /* This format is inspired by OpenPGP; see RFC 2440
2325 * packet tag 3 */
2326 max_packet_size = (1 /* Tag 3 identifier */
2327 + 3 /* Max Tag 3 packet size */
2328 + 1 /* Version */
2329 + 1 /* Cipher code */
2330 + 1 /* S2K specifier */
2331 + 1 /* Hash identifier */
2332 + ECRYPTFS_SALT_SIZE /* Salt */
2333 + 1 /* Hash iterations */
2334 + key_rec->enc_key_size); /* Encrypted key size */
2335 if (max_packet_size > (*remaining_bytes)) {
2336 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2337 "there are only [%td] available\n", max_packet_size,
2338 (*remaining_bytes));
2339 rc = -EINVAL;
2340 goto out;
2341 }
2342 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2343 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2344 * to get the number of octets in the actual Tag 3 packet */
2345 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2346 (max_packet_size - 4),
2347 &packet_size_length);
2348 if (rc) {
2349 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2350 "generate packet length. rc = [%d]\n", rc);
2351 goto out;
2352 }
2353 (*packet_size) += packet_size_length;
2354 dest[(*packet_size)++] = 0x04; /* version 4 */
2355 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2356 * specified with strings */
2357 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2358 crypt_stat->key_size);
2359 if (cipher_code == 0) {
2360 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2361 "cipher [%s]\n", crypt_stat->cipher);
2362 rc = -EINVAL;
2363 goto out;
2364 }
2365 dest[(*packet_size)++] = cipher_code;
2366 dest[(*packet_size)++] = 0x03; /* S2K */
2367 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2368 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2369 ECRYPTFS_SALT_SIZE);
2370 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2371 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2372 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2373 key_rec->enc_key_size);
2374 (*packet_size) += key_rec->enc_key_size;
2375 out:
2376 if (rc)
2377 (*packet_size) = 0;
2378 else
2379 (*remaining_bytes) -= (*packet_size);
2380 return rc;
2381 }
2382
2383 struct kmem_cache *ecryptfs_key_record_cache;
2384
2385 /**
2386 * ecryptfs_generate_key_packet_set
2387 * @dest_base: Virtual address from which to write the key record set
2388 * @crypt_stat: The cryptographic context from which the
2389 * authentication tokens will be retrieved
2390 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2391 * for the global parameters
2392 * @len: The amount written
2393 * @max: The maximum amount of data allowed to be written
2394 *
2395 * Generates a key packet set and writes it to the virtual address
2396 * passed in.
2397 *
2398 * Returns zero on success; non-zero on error.
2399 */
2400 int
ecryptfs_generate_key_packet_set(char * dest_base,struct ecryptfs_crypt_stat * crypt_stat,struct dentry * ecryptfs_dentry,size_t * len,size_t max)2401 ecryptfs_generate_key_packet_set(char *dest_base,
2402 struct ecryptfs_crypt_stat *crypt_stat,
2403 struct dentry *ecryptfs_dentry, size_t *len,
2404 size_t max)
2405 {
2406 struct ecryptfs_auth_tok *auth_tok;
2407 struct key *auth_tok_key = NULL;
2408 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2409 &ecryptfs_superblock_to_private(
2410 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2411 size_t written;
2412 struct ecryptfs_key_record *key_rec;
2413 struct ecryptfs_key_sig *key_sig;
2414 int rc = 0;
2415
2416 (*len) = 0;
2417 mutex_lock(&crypt_stat->keysig_list_mutex);
2418 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2419 if (!key_rec) {
2420 rc = -ENOMEM;
2421 goto out;
2422 }
2423 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2424 crypt_stat_list) {
2425 memset(key_rec, 0, sizeof(*key_rec));
2426 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2427 &auth_tok,
2428 mount_crypt_stat,
2429 key_sig->keysig);
2430 if (rc) {
2431 printk(KERN_WARNING "Unable to retrieve auth tok with "
2432 "sig = [%s]\n", key_sig->keysig);
2433 rc = process_find_global_auth_tok_for_sig_err(rc);
2434 goto out_free;
2435 }
2436 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2437 rc = write_tag_3_packet((dest_base + (*len)),
2438 &max, auth_tok,
2439 crypt_stat, key_rec,
2440 &written);
2441 up_write(&(auth_tok_key->sem));
2442 key_put(auth_tok_key);
2443 if (rc) {
2444 ecryptfs_printk(KERN_WARNING, "Error "
2445 "writing tag 3 packet\n");
2446 goto out_free;
2447 }
2448 (*len) += written;
2449 /* Write auth tok signature packet */
2450 rc = write_tag_11_packet((dest_base + (*len)), &max,
2451 key_rec->sig,
2452 ECRYPTFS_SIG_SIZE, &written);
2453 if (rc) {
2454 ecryptfs_printk(KERN_ERR, "Error writing "
2455 "auth tok signature packet\n");
2456 goto out_free;
2457 }
2458 (*len) += written;
2459 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2460 rc = write_tag_1_packet(dest_base + (*len), &max,
2461 auth_tok_key, auth_tok,
2462 crypt_stat, key_rec, &written);
2463 if (rc) {
2464 ecryptfs_printk(KERN_WARNING, "Error "
2465 "writing tag 1 packet\n");
2466 goto out_free;
2467 }
2468 (*len) += written;
2469 } else {
2470 up_write(&(auth_tok_key->sem));
2471 key_put(auth_tok_key);
2472 ecryptfs_printk(KERN_WARNING, "Unsupported "
2473 "authentication token type\n");
2474 rc = -EINVAL;
2475 goto out_free;
2476 }
2477 }
2478 if (likely(max > 0)) {
2479 dest_base[(*len)] = 0x00;
2480 } else {
2481 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2482 rc = -EIO;
2483 }
2484 out_free:
2485 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2486 out:
2487 if (rc)
2488 (*len) = 0;
2489 mutex_unlock(&crypt_stat->keysig_list_mutex);
2490 return rc;
2491 }
2492
2493 struct kmem_cache *ecryptfs_key_sig_cache;
2494
ecryptfs_add_keysig(struct ecryptfs_crypt_stat * crypt_stat,char * sig)2495 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2496 {
2497 struct ecryptfs_key_sig *new_key_sig;
2498
2499 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2500 if (!new_key_sig)
2501 return -ENOMEM;
2502
2503 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2504 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2505 /* Caller must hold keysig_list_mutex */
2506 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2507
2508 return 0;
2509 }
2510
2511 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2512
2513 int
ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * sig,u32 global_auth_tok_flags)2514 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2515 char *sig, u32 global_auth_tok_flags)
2516 {
2517 struct ecryptfs_global_auth_tok *new_auth_tok;
2518
2519 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2520 GFP_KERNEL);
2521 if (!new_auth_tok)
2522 return -ENOMEM;
2523
2524 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2525 new_auth_tok->flags = global_auth_tok_flags;
2526 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2527 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2528 list_add(&new_auth_tok->mount_crypt_stat_list,
2529 &mount_crypt_stat->global_auth_tok_list);
2530 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2531 return 0;
2532 }
2533
2534