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 * | File Encryption Key | arbitrary |
304 */
305 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
306 *packet = kmalloc(data_len, GFP_KERNEL);
307 message = *packet;
308 if (!message) {
309 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
310 rc = -ENOMEM;
311 goto out;
312 }
313 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
314 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
315 &packet_size_len);
316 if (rc) {
317 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
318 "header; cannot generate packet length\n");
319 goto out;
320 }
321 i += packet_size_len;
322 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
323 i += ECRYPTFS_SIG_SIZE_HEX;
324 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
325 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
326 &packet_size_len);
327 if (rc) {
328 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
329 "header; cannot generate packet length\n");
330 goto out;
331 }
332 i += packet_size_len;
333 message[i++] = cipher_code;
334 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
335 i += crypt_stat->key_size;
336 for (j = 0; j < crypt_stat->key_size; j++)
337 checksum += crypt_stat->key[j];
338 message[i++] = (checksum / 256) % 256;
339 message[i++] = (checksum % 256);
340 *packet_len = i;
341 out:
342 return rc;
343 }
344
345 static int
parse_tag_67_packet(struct ecryptfs_key_record * key_rec,struct ecryptfs_message * msg)346 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
347 struct ecryptfs_message *msg)
348 {
349 size_t i = 0;
350 char *data;
351 size_t data_len;
352 size_t message_len;
353 int rc;
354
355 /*
356 * ***** TAG 65 Packet Format *****
357 * | Content Type | 1 byte |
358 * | Status Indicator | 1 byte |
359 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
360 * | Encrypted File Encryption Key | arbitrary |
361 */
362 message_len = msg->data_len;
363 data = msg->data;
364 /* verify that everything through the encrypted FEK size is present */
365 if (message_len < 4) {
366 rc = -EIO;
367 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
368 "message length is [%d]\n", __func__, message_len, 4);
369 goto out;
370 }
371 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
372 rc = -EIO;
373 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
374 __func__);
375 goto out;
376 }
377 if (data[i++]) {
378 rc = -EIO;
379 printk(KERN_ERR "%s: Status indicator has non zero "
380 "value [%d]\n", __func__, data[i-1]);
381
382 goto out;
383 }
384 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
385 &data_len);
386 if (rc) {
387 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
388 "rc = [%d]\n", rc);
389 goto out;
390 }
391 i += data_len;
392 if (message_len < (i + key_rec->enc_key_size)) {
393 rc = -EIO;
394 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
395 __func__, message_len, (i + key_rec->enc_key_size));
396 goto out;
397 }
398 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
399 rc = -EIO;
400 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
401 "the maximum key size [%d]\n", __func__,
402 key_rec->enc_key_size,
403 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
404 goto out;
405 }
406 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
407 out:
408 return rc;
409 }
410
411 /**
412 * ecryptfs_verify_version
413 * @version: The version number to confirm
414 *
415 * Returns zero on good version; non-zero otherwise
416 */
ecryptfs_verify_version(u16 version)417 static int ecryptfs_verify_version(u16 version)
418 {
419 int rc = 0;
420 unsigned char major;
421 unsigned char minor;
422
423 major = ((version >> 8) & 0xFF);
424 minor = (version & 0xFF);
425 if (major != ECRYPTFS_VERSION_MAJOR) {
426 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
427 "Expected [%d]; got [%d]\n",
428 ECRYPTFS_VERSION_MAJOR, major);
429 rc = -EINVAL;
430 goto out;
431 }
432 if (minor != ECRYPTFS_VERSION_MINOR) {
433 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
434 "Expected [%d]; got [%d]\n",
435 ECRYPTFS_VERSION_MINOR, minor);
436 rc = -EINVAL;
437 goto out;
438 }
439 out:
440 return rc;
441 }
442
443 /**
444 * ecryptfs_verify_auth_tok_from_key
445 * @auth_tok_key: key containing the authentication token
446 * @auth_tok: authentication token
447 *
448 * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
449 * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
450 */
451 static int
ecryptfs_verify_auth_tok_from_key(struct key * auth_tok_key,struct ecryptfs_auth_tok ** auth_tok)452 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
453 struct ecryptfs_auth_tok **auth_tok)
454 {
455 int rc = 0;
456
457 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
458 if (IS_ERR(*auth_tok)) {
459 rc = PTR_ERR(*auth_tok);
460 *auth_tok = NULL;
461 goto out;
462 }
463
464 if (ecryptfs_verify_version((*auth_tok)->version)) {
465 printk(KERN_ERR "Data structure version mismatch. Userspace "
466 "tools must match eCryptfs kernel module with major "
467 "version [%d] and minor version [%d]\n",
468 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
469 rc = -EINVAL;
470 goto out;
471 }
472 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
473 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
474 printk(KERN_ERR "Invalid auth_tok structure "
475 "returned from key query\n");
476 rc = -EINVAL;
477 goto out;
478 }
479 out:
480 return rc;
481 }
482
483 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)484 ecryptfs_find_global_auth_tok_for_sig(
485 struct key **auth_tok_key,
486 struct ecryptfs_auth_tok **auth_tok,
487 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
488 {
489 struct ecryptfs_global_auth_tok *walker;
490 int rc = 0;
491
492 (*auth_tok_key) = NULL;
493 (*auth_tok) = NULL;
494 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
495 list_for_each_entry(walker,
496 &mount_crypt_stat->global_auth_tok_list,
497 mount_crypt_stat_list) {
498 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
499 continue;
500
501 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
502 rc = -EINVAL;
503 goto out;
504 }
505
506 rc = key_validate(walker->global_auth_tok_key);
507 if (rc) {
508 if (rc == -EKEYEXPIRED)
509 goto out;
510 goto out_invalid_auth_tok;
511 }
512
513 down_write(&(walker->global_auth_tok_key->sem));
514 rc = ecryptfs_verify_auth_tok_from_key(
515 walker->global_auth_tok_key, auth_tok);
516 if (rc)
517 goto out_invalid_auth_tok_unlock;
518
519 (*auth_tok_key) = walker->global_auth_tok_key;
520 key_get(*auth_tok_key);
521 goto out;
522 }
523 rc = -ENOENT;
524 goto out;
525 out_invalid_auth_tok_unlock:
526 up_write(&(walker->global_auth_tok_key->sem));
527 out_invalid_auth_tok:
528 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
529 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
530 key_put(walker->global_auth_tok_key);
531 walker->global_auth_tok_key = NULL;
532 out:
533 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
534 return rc;
535 }
536
537 /**
538 * ecryptfs_find_auth_tok_for_sig
539 * @auth_tok_key: key containing the authentication token
540 * @auth_tok: Set to the matching auth_tok; NULL if not found
541 * @mount_crypt_stat: inode crypt_stat crypto context
542 * @sig: Sig of auth_tok to find
543 *
544 * For now, this function simply looks at the registered auth_tok's
545 * linked off the mount_crypt_stat, so all the auth_toks that can be
546 * used must be registered at mount time. This function could
547 * potentially try a lot harder to find auth_tok's (e.g., by calling
548 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
549 * that static registration of auth_tok's will no longer be necessary.
550 *
551 * Returns zero on no error; non-zero on error
552 */
553 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)554 ecryptfs_find_auth_tok_for_sig(
555 struct key **auth_tok_key,
556 struct ecryptfs_auth_tok **auth_tok,
557 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
558 char *sig)
559 {
560 int rc = 0;
561
562 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
563 mount_crypt_stat, sig);
564 if (rc == -ENOENT) {
565 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
566 * mount_crypt_stat structure, we prevent to use auth toks that
567 * are not inserted through the ecryptfs_add_global_auth_tok
568 * function.
569 */
570 if (mount_crypt_stat->flags
571 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
572 return -EINVAL;
573
574 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
575 sig);
576 }
577 return rc;
578 }
579
580 /*
581 * write_tag_70_packet can gobble a lot of stack space. We stuff most
582 * of the function's parameters in a kmalloc'd struct to help reduce
583 * eCryptfs' overall stack usage.
584 */
585 struct ecryptfs_write_tag_70_packet_silly_stack {
586 u8 cipher_code;
587 size_t max_packet_size;
588 size_t packet_size_len;
589 size_t block_aligned_filename_size;
590 size_t block_size;
591 size_t i;
592 size_t j;
593 size_t num_rand_bytes;
594 struct mutex *tfm_mutex;
595 char *block_aligned_filename;
596 struct ecryptfs_auth_tok *auth_tok;
597 struct scatterlist src_sg[2];
598 struct scatterlist dst_sg[2];
599 struct crypto_skcipher *skcipher_tfm;
600 struct skcipher_request *skcipher_req;
601 char iv[ECRYPTFS_MAX_IV_BYTES];
602 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
603 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
604 struct crypto_shash *hash_tfm;
605 struct shash_desc *hash_desc;
606 };
607
608 /*
609 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
610 * @filename: NULL-terminated filename string
611 *
612 * This is the simplest mechanism for achieving filename encryption in
613 * eCryptfs. It encrypts the given filename with the mount-wide
614 * filename encryption key (FNEK) and stores it in a packet to @dest,
615 * which the callee will encode and write directly into the dentry
616 * name.
617 */
618 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)619 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
620 size_t *packet_size,
621 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
622 char *filename, size_t filename_size)
623 {
624 struct ecryptfs_write_tag_70_packet_silly_stack *s;
625 struct key *auth_tok_key = NULL;
626 int rc = 0;
627
628 s = kzalloc(sizeof(*s), GFP_KERNEL);
629 if (!s)
630 return -ENOMEM;
631
632 (*packet_size) = 0;
633 rc = ecryptfs_find_auth_tok_for_sig(
634 &auth_tok_key,
635 &s->auth_tok, mount_crypt_stat,
636 mount_crypt_stat->global_default_fnek_sig);
637 if (rc) {
638 printk(KERN_ERR "%s: Error attempting to find auth tok for "
639 "fnek sig [%s]; rc = [%d]\n", __func__,
640 mount_crypt_stat->global_default_fnek_sig, rc);
641 goto out;
642 }
643 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
644 &s->skcipher_tfm,
645 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
646 if (unlikely(rc)) {
647 printk(KERN_ERR "Internal error whilst attempting to get "
648 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
649 mount_crypt_stat->global_default_fn_cipher_name, rc);
650 goto out;
651 }
652 mutex_lock(s->tfm_mutex);
653 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
654 /* Plus one for the \0 separator between the random prefix
655 * and the plaintext filename */
656 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
657 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
658 if ((s->block_aligned_filename_size % s->block_size) != 0) {
659 s->num_rand_bytes += (s->block_size
660 - (s->block_aligned_filename_size
661 % s->block_size));
662 s->block_aligned_filename_size = (s->num_rand_bytes
663 + filename_size);
664 }
665 /* Octet 0: Tag 70 identifier
666 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
667 * and block-aligned encrypted filename size)
668 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
669 * Octet N2-N3: Cipher identifier (1 octet)
670 * Octets N3-N4: Block-aligned encrypted filename
671 * - Consists of a minimum number of random characters, a \0
672 * separator, and then the filename */
673 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
674 + s->block_aligned_filename_size);
675 if (!dest) {
676 (*packet_size) = s->max_packet_size;
677 goto out_unlock;
678 }
679 if (s->max_packet_size > (*remaining_bytes)) {
680 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
681 "[%zd] available\n", __func__, s->max_packet_size,
682 (*remaining_bytes));
683 rc = -EINVAL;
684 goto out_unlock;
685 }
686
687 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
688 if (!s->skcipher_req) {
689 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
690 "skcipher_request_alloc for %s\n", __func__,
691 crypto_skcipher_driver_name(s->skcipher_tfm));
692 rc = -ENOMEM;
693 goto out_unlock;
694 }
695
696 skcipher_request_set_callback(s->skcipher_req,
697 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
698
699 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
700 GFP_KERNEL);
701 if (!s->block_aligned_filename) {
702 rc = -ENOMEM;
703 goto out_unlock;
704 }
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 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
743 if (IS_ERR(s->hash_tfm)) {
744 rc = PTR_ERR(s->hash_tfm);
745 printk(KERN_ERR "%s: Error attempting to "
746 "allocate hash crypto context; rc = [%d]\n",
747 __func__, rc);
748 goto out_free_unlock;
749 }
750
751 s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
752 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
753 if (!s->hash_desc) {
754 rc = -ENOMEM;
755 goto out_release_free_unlock;
756 }
757
758 s->hash_desc->tfm = s->hash_tfm;
759
760 rc = crypto_shash_digest(s->hash_desc,
761 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
762 s->auth_tok->token.password.session_key_encryption_key_bytes,
763 s->hash);
764 if (rc) {
765 printk(KERN_ERR
766 "%s: Error computing crypto hash; rc = [%d]\n",
767 __func__, rc);
768 goto out_release_free_unlock;
769 }
770 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
771 s->block_aligned_filename[s->j] =
772 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
773 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
774 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
775 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
776 ECRYPTFS_TAG_70_DIGEST_SIZE,
777 s->tmp_hash);
778 if (rc) {
779 printk(KERN_ERR
780 "%s: Error computing crypto hash; "
781 "rc = [%d]\n", __func__, rc);
782 goto out_release_free_unlock;
783 }
784 memcpy(s->hash, s->tmp_hash,
785 ECRYPTFS_TAG_70_DIGEST_SIZE);
786 }
787 if (s->block_aligned_filename[s->j] == '\0')
788 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
789 }
790 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
791 filename_size);
792 rc = virt_to_scatterlist(s->block_aligned_filename,
793 s->block_aligned_filename_size, s->src_sg, 2);
794 if (rc < 1) {
795 printk(KERN_ERR "%s: Internal error whilst attempting to "
796 "convert filename memory to scatterlist; rc = [%d]. "
797 "block_aligned_filename_size = [%zd]\n", __func__, rc,
798 s->block_aligned_filename_size);
799 goto out_release_free_unlock;
800 }
801 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
802 s->dst_sg, 2);
803 if (rc < 1) {
804 printk(KERN_ERR "%s: Internal error whilst attempting to "
805 "convert encrypted filename memory to scatterlist; "
806 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
807 __func__, rc, s->block_aligned_filename_size);
808 goto out_release_free_unlock;
809 }
810 /* The characters in the first block effectively do the job
811 * of the IV here, so we just use 0's for the IV. Note the
812 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
813 * >= ECRYPTFS_MAX_IV_BYTES. */
814 rc = crypto_skcipher_setkey(
815 s->skcipher_tfm,
816 s->auth_tok->token.password.session_key_encryption_key,
817 mount_crypt_stat->global_default_fn_cipher_key_bytes);
818 if (rc < 0) {
819 printk(KERN_ERR "%s: Error setting key for crypto context; "
820 "rc = [%d]. s->auth_tok->token.password.session_key_"
821 "encryption_key = [0x%p]; mount_crypt_stat->"
822 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
823 rc,
824 s->auth_tok->token.password.session_key_encryption_key,
825 mount_crypt_stat->global_default_fn_cipher_key_bytes);
826 goto out_release_free_unlock;
827 }
828 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
829 s->block_aligned_filename_size, s->iv);
830 rc = crypto_skcipher_encrypt(s->skcipher_req);
831 if (rc) {
832 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
833 "rc = [%d]\n", __func__, rc);
834 goto out_release_free_unlock;
835 }
836 s->i += s->block_aligned_filename_size;
837 (*packet_size) = s->i;
838 (*remaining_bytes) -= (*packet_size);
839 out_release_free_unlock:
840 crypto_free_shash(s->hash_tfm);
841 out_free_unlock:
842 kfree_sensitive(s->block_aligned_filename);
843 out_unlock:
844 mutex_unlock(s->tfm_mutex);
845 out:
846 if (auth_tok_key) {
847 up_write(&(auth_tok_key->sem));
848 key_put(auth_tok_key);
849 }
850 skcipher_request_free(s->skcipher_req);
851 kfree_sensitive(s->hash_desc);
852 kfree(s);
853 return rc;
854 }
855
856 struct ecryptfs_parse_tag_70_packet_silly_stack {
857 u8 cipher_code;
858 size_t max_packet_size;
859 size_t packet_size_len;
860 size_t parsed_tag_70_packet_size;
861 size_t block_aligned_filename_size;
862 size_t block_size;
863 size_t i;
864 struct mutex *tfm_mutex;
865 char *decrypted_filename;
866 struct ecryptfs_auth_tok *auth_tok;
867 struct scatterlist src_sg[2];
868 struct scatterlist dst_sg[2];
869 struct crypto_skcipher *skcipher_tfm;
870 struct skcipher_request *skcipher_req;
871 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
872 char iv[ECRYPTFS_MAX_IV_BYTES];
873 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
874 };
875
876 /**
877 * ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
878 * @filename: This function kmalloc's the memory for the filename
879 * @filename_size: This function sets this to the amount of memory
880 * kmalloc'd for the filename
881 * @packet_size: This function sets this to the the number of octets
882 * in the packet parsed
883 * @mount_crypt_stat: The mount-wide cryptographic context
884 * @data: The memory location containing the start of the tag 70
885 * packet
886 * @max_packet_size: The maximum legal size of the packet to be parsed
887 * from @data
888 *
889 * Returns zero on success; non-zero otherwise
890 */
891 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)892 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
893 size_t *packet_size,
894 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
895 char *data, size_t max_packet_size)
896 {
897 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
898 struct key *auth_tok_key = NULL;
899 int rc = 0;
900
901 (*packet_size) = 0;
902 (*filename_size) = 0;
903 (*filename) = NULL;
904 s = kzalloc(sizeof(*s), GFP_KERNEL);
905 if (!s)
906 return -ENOMEM;
907
908 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
909 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
910 "at least [%d]\n", __func__, max_packet_size,
911 ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
912 rc = -EINVAL;
913 goto out;
914 }
915 /* Octet 0: Tag 70 identifier
916 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
917 * and block-aligned encrypted filename size)
918 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
919 * Octet N2-N3: Cipher identifier (1 octet)
920 * Octets N3-N4: Block-aligned encrypted filename
921 * - Consists of a minimum number of random numbers, a \0
922 * separator, and then the filename */
923 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
924 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
925 "tag [0x%.2x]\n", __func__,
926 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
927 rc = -EINVAL;
928 goto out;
929 }
930 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
931 &s->parsed_tag_70_packet_size,
932 &s->packet_size_len);
933 if (rc) {
934 printk(KERN_WARNING "%s: Error parsing packet length; "
935 "rc = [%d]\n", __func__, rc);
936 goto out;
937 }
938 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
939 - ECRYPTFS_SIG_SIZE - 1);
940 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
941 > max_packet_size) {
942 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
943 "size is [%zd]\n", __func__, max_packet_size,
944 (1 + s->packet_size_len + 1
945 + s->block_aligned_filename_size));
946 rc = -EINVAL;
947 goto out;
948 }
949 (*packet_size) += s->packet_size_len;
950 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
951 ECRYPTFS_SIG_SIZE);
952 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
953 (*packet_size) += ECRYPTFS_SIG_SIZE;
954 s->cipher_code = data[(*packet_size)++];
955 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
956 if (rc) {
957 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
958 __func__, s->cipher_code);
959 goto out;
960 }
961 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
962 &s->auth_tok, mount_crypt_stat,
963 s->fnek_sig_hex);
964 if (rc) {
965 printk(KERN_ERR "%s: Error attempting to find auth tok for "
966 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
967 rc);
968 goto out;
969 }
970 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
971 &s->tfm_mutex,
972 s->cipher_string);
973 if (unlikely(rc)) {
974 printk(KERN_ERR "Internal error whilst attempting to get "
975 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
976 s->cipher_string, rc);
977 goto out;
978 }
979 mutex_lock(s->tfm_mutex);
980 rc = virt_to_scatterlist(&data[(*packet_size)],
981 s->block_aligned_filename_size, s->src_sg, 2);
982 if (rc < 1) {
983 printk(KERN_ERR "%s: Internal error whilst attempting to "
984 "convert encrypted filename memory to scatterlist; "
985 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
986 __func__, rc, s->block_aligned_filename_size);
987 goto out_unlock;
988 }
989 (*packet_size) += s->block_aligned_filename_size;
990 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
991 GFP_KERNEL);
992 if (!s->decrypted_filename) {
993 rc = -ENOMEM;
994 goto out_unlock;
995 }
996 rc = virt_to_scatterlist(s->decrypted_filename,
997 s->block_aligned_filename_size, s->dst_sg, 2);
998 if (rc < 1) {
999 printk(KERN_ERR "%s: Internal error whilst attempting to "
1000 "convert decrypted filename memory to scatterlist; "
1001 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1002 __func__, rc, s->block_aligned_filename_size);
1003 goto out_free_unlock;
1004 }
1005
1006 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
1007 if (!s->skcipher_req) {
1008 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1009 "skcipher_request_alloc for %s\n", __func__,
1010 crypto_skcipher_driver_name(s->skcipher_tfm));
1011 rc = -ENOMEM;
1012 goto out_free_unlock;
1013 }
1014
1015 skcipher_request_set_callback(s->skcipher_req,
1016 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
1017
1018 /* The characters in the first block effectively do the job of
1019 * the IV here, so we just use 0's for the IV. Note the
1020 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1021 * >= ECRYPTFS_MAX_IV_BYTES. */
1022 /* TODO: Support other key modules than passphrase for
1023 * filename encryption */
1024 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1025 rc = -EOPNOTSUPP;
1026 printk(KERN_INFO "%s: Filename encryption only supports "
1027 "password tokens\n", __func__);
1028 goto out_free_unlock;
1029 }
1030 rc = crypto_skcipher_setkey(
1031 s->skcipher_tfm,
1032 s->auth_tok->token.password.session_key_encryption_key,
1033 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1034 if (rc < 0) {
1035 printk(KERN_ERR "%s: Error setting key for crypto context; "
1036 "rc = [%d]. s->auth_tok->token.password.session_key_"
1037 "encryption_key = [0x%p]; mount_crypt_stat->"
1038 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1039 rc,
1040 s->auth_tok->token.password.session_key_encryption_key,
1041 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1042 goto out_free_unlock;
1043 }
1044 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
1045 s->block_aligned_filename_size, s->iv);
1046 rc = crypto_skcipher_decrypt(s->skcipher_req);
1047 if (rc) {
1048 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1049 "rc = [%d]\n", __func__, rc);
1050 goto out_free_unlock;
1051 }
1052
1053 while (s->i < s->block_aligned_filename_size &&
1054 s->decrypted_filename[s->i] != '\0')
1055 s->i++;
1056 if (s->i == s->block_aligned_filename_size) {
1057 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1058 "find valid separator between random characters and "
1059 "the filename\n", __func__);
1060 rc = -EINVAL;
1061 goto out_free_unlock;
1062 }
1063 s->i++;
1064 (*filename_size) = (s->block_aligned_filename_size - s->i);
1065 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1066 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1067 "invalid\n", __func__, (*filename_size));
1068 rc = -EINVAL;
1069 goto out_free_unlock;
1070 }
1071 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1072 if (!(*filename)) {
1073 rc = -ENOMEM;
1074 goto out_free_unlock;
1075 }
1076 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1077 (*filename)[(*filename_size)] = '\0';
1078 out_free_unlock:
1079 kfree(s->decrypted_filename);
1080 out_unlock:
1081 mutex_unlock(s->tfm_mutex);
1082 out:
1083 if (rc) {
1084 (*packet_size) = 0;
1085 (*filename_size) = 0;
1086 (*filename) = NULL;
1087 }
1088 if (auth_tok_key) {
1089 up_write(&(auth_tok_key->sem));
1090 key_put(auth_tok_key);
1091 }
1092 skcipher_request_free(s->skcipher_req);
1093 kfree(s);
1094 return rc;
1095 }
1096
1097 static int
ecryptfs_get_auth_tok_sig(char ** sig,struct ecryptfs_auth_tok * auth_tok)1098 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1099 {
1100 int rc = 0;
1101
1102 (*sig) = NULL;
1103 switch (auth_tok->token_type) {
1104 case ECRYPTFS_PASSWORD:
1105 (*sig) = auth_tok->token.password.signature;
1106 break;
1107 case ECRYPTFS_PRIVATE_KEY:
1108 (*sig) = auth_tok->token.private_key.signature;
1109 break;
1110 default:
1111 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1112 auth_tok->token_type);
1113 rc = -EINVAL;
1114 }
1115 return rc;
1116 }
1117
1118 /**
1119 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1120 * @auth_tok: The key authentication token used to decrypt the session key
1121 * @crypt_stat: The cryptographic context
1122 *
1123 * Returns zero on success; non-zero error otherwise.
1124 */
1125 static int
decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat)1126 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1127 struct ecryptfs_crypt_stat *crypt_stat)
1128 {
1129 u8 cipher_code = 0;
1130 struct ecryptfs_msg_ctx *msg_ctx;
1131 struct ecryptfs_message *msg = NULL;
1132 char *auth_tok_sig;
1133 char *payload = NULL;
1134 size_t payload_len = 0;
1135 int rc;
1136
1137 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1138 if (rc) {
1139 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1140 auth_tok->token_type);
1141 goto out;
1142 }
1143 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1144 &payload, &payload_len);
1145 if (rc) {
1146 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1147 goto out;
1148 }
1149 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1150 if (rc) {
1151 ecryptfs_printk(KERN_ERR, "Error sending message to "
1152 "ecryptfsd: %d\n", rc);
1153 goto out;
1154 }
1155 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1156 if (rc) {
1157 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1158 "from the user space daemon\n");
1159 rc = -EIO;
1160 goto out;
1161 }
1162 rc = parse_tag_65_packet(&(auth_tok->session_key),
1163 &cipher_code, msg);
1164 if (rc) {
1165 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1166 rc);
1167 goto out;
1168 }
1169 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1170 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1171 auth_tok->session_key.decrypted_key_size);
1172 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1173 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1174 if (rc) {
1175 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1176 cipher_code);
1177 goto out;
1178 }
1179 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1180 if (ecryptfs_verbosity > 0) {
1181 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1182 ecryptfs_dump_hex(crypt_stat->key,
1183 crypt_stat->key_size);
1184 }
1185 out:
1186 kfree(msg);
1187 kfree(payload);
1188 return rc;
1189 }
1190
wipe_auth_tok_list(struct list_head * auth_tok_list_head)1191 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1192 {
1193 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1194 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1195
1196 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1197 auth_tok_list_head, list) {
1198 list_del(&auth_tok_list_item->list);
1199 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1200 auth_tok_list_item);
1201 }
1202 }
1203
1204 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1205
1206 /**
1207 * parse_tag_1_packet
1208 * @crypt_stat: The cryptographic context to modify based on packet contents
1209 * @data: The raw bytes of the packet.
1210 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1211 * a new authentication token will be placed at the
1212 * end of this list for this packet.
1213 * @new_auth_tok: Pointer to a pointer to memory that this function
1214 * allocates; sets the memory address of the pointer to
1215 * NULL on error. This object is added to the
1216 * auth_tok_list.
1217 * @packet_size: This function writes the size of the parsed packet
1218 * into this memory location; zero on error.
1219 * @max_packet_size: The maximum allowable packet size
1220 *
1221 * Returns zero on success; non-zero on error.
1222 */
1223 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)1224 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1225 unsigned char *data, struct list_head *auth_tok_list,
1226 struct ecryptfs_auth_tok **new_auth_tok,
1227 size_t *packet_size, size_t max_packet_size)
1228 {
1229 size_t body_size;
1230 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1231 size_t length_size;
1232 int rc = 0;
1233
1234 (*packet_size) = 0;
1235 (*new_auth_tok) = NULL;
1236 /**
1237 * This format is inspired by OpenPGP; see RFC 2440
1238 * packet tag 1
1239 *
1240 * Tag 1 identifier (1 byte)
1241 * Max Tag 1 packet size (max 3 bytes)
1242 * Version (1 byte)
1243 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1244 * Cipher identifier (1 byte)
1245 * Encrypted key size (arbitrary)
1246 *
1247 * 12 bytes minimum packet size
1248 */
1249 if (unlikely(max_packet_size < 12)) {
1250 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1251 rc = -EINVAL;
1252 goto out;
1253 }
1254 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1255 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1256 ECRYPTFS_TAG_1_PACKET_TYPE);
1257 rc = -EINVAL;
1258 goto out;
1259 }
1260 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1261 * at end of function upon failure */
1262 auth_tok_list_item =
1263 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1264 GFP_KERNEL);
1265 if (!auth_tok_list_item) {
1266 printk(KERN_ERR "Unable to allocate memory\n");
1267 rc = -ENOMEM;
1268 goto out;
1269 }
1270 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1271 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1272 &length_size);
1273 if (rc) {
1274 printk(KERN_WARNING "Error parsing packet length; "
1275 "rc = [%d]\n", rc);
1276 goto out_free;
1277 }
1278 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1279 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1280 rc = -EINVAL;
1281 goto out_free;
1282 }
1283 (*packet_size) += length_size;
1284 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1285 printk(KERN_WARNING "Packet size exceeds max\n");
1286 rc = -EINVAL;
1287 goto out_free;
1288 }
1289 if (unlikely(data[(*packet_size)++] != 0x03)) {
1290 printk(KERN_WARNING "Unknown version number [%d]\n",
1291 data[(*packet_size) - 1]);
1292 rc = -EINVAL;
1293 goto out_free;
1294 }
1295 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1296 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1297 *packet_size += ECRYPTFS_SIG_SIZE;
1298 /* This byte is skipped because the kernel does not need to
1299 * know which public key encryption algorithm was used */
1300 (*packet_size)++;
1301 (*new_auth_tok)->session_key.encrypted_key_size =
1302 body_size - (ECRYPTFS_SIG_SIZE + 2);
1303 if ((*new_auth_tok)->session_key.encrypted_key_size
1304 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1305 printk(KERN_WARNING "Tag 1 packet contains key larger "
1306 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1307 rc = -EINVAL;
1308 goto out_free;
1309 }
1310 memcpy((*new_auth_tok)->session_key.encrypted_key,
1311 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1312 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1313 (*new_auth_tok)->session_key.flags &=
1314 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1315 (*new_auth_tok)->session_key.flags |=
1316 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1317 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1318 (*new_auth_tok)->flags = 0;
1319 (*new_auth_tok)->session_key.flags &=
1320 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1321 (*new_auth_tok)->session_key.flags &=
1322 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1323 list_add(&auth_tok_list_item->list, auth_tok_list);
1324 goto out;
1325 out_free:
1326 (*new_auth_tok) = NULL;
1327 memset(auth_tok_list_item, 0,
1328 sizeof(struct ecryptfs_auth_tok_list_item));
1329 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1330 auth_tok_list_item);
1331 out:
1332 if (rc)
1333 (*packet_size) = 0;
1334 return rc;
1335 }
1336
1337 /**
1338 * parse_tag_3_packet
1339 * @crypt_stat: The cryptographic context to modify based on packet
1340 * contents.
1341 * @data: The raw bytes of the packet.
1342 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1343 * a new authentication token will be placed at the end
1344 * of this list for this packet.
1345 * @new_auth_tok: Pointer to a pointer to memory that this function
1346 * allocates; sets the memory address of the pointer to
1347 * NULL on error. This object is added to the
1348 * auth_tok_list.
1349 * @packet_size: This function writes the size of the parsed packet
1350 * into this memory location; zero on error.
1351 * @max_packet_size: maximum number of bytes to parse
1352 *
1353 * Returns zero on success; non-zero on error.
1354 */
1355 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)1356 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1357 unsigned char *data, struct list_head *auth_tok_list,
1358 struct ecryptfs_auth_tok **new_auth_tok,
1359 size_t *packet_size, size_t max_packet_size)
1360 {
1361 size_t body_size;
1362 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1363 size_t length_size;
1364 int rc = 0;
1365
1366 (*packet_size) = 0;
1367 (*new_auth_tok) = NULL;
1368 /**
1369 *This format is inspired by OpenPGP; see RFC 2440
1370 * packet tag 3
1371 *
1372 * Tag 3 identifier (1 byte)
1373 * Max Tag 3 packet size (max 3 bytes)
1374 * Version (1 byte)
1375 * Cipher code (1 byte)
1376 * S2K specifier (1 byte)
1377 * Hash identifier (1 byte)
1378 * Salt (ECRYPTFS_SALT_SIZE)
1379 * Hash iterations (1 byte)
1380 * Encrypted key (arbitrary)
1381 *
1382 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1383 */
1384 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1385 printk(KERN_ERR "Max packet size too large\n");
1386 rc = -EINVAL;
1387 goto out;
1388 }
1389 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1390 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1391 ECRYPTFS_TAG_3_PACKET_TYPE);
1392 rc = -EINVAL;
1393 goto out;
1394 }
1395 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1396 * at end of function upon failure */
1397 auth_tok_list_item =
1398 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1399 if (!auth_tok_list_item) {
1400 printk(KERN_ERR "Unable to allocate memory\n");
1401 rc = -ENOMEM;
1402 goto out;
1403 }
1404 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1405 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1406 &length_size);
1407 if (rc) {
1408 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1409 rc);
1410 goto out_free;
1411 }
1412 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1413 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1414 rc = -EINVAL;
1415 goto out_free;
1416 }
1417 (*packet_size) += length_size;
1418 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1419 printk(KERN_ERR "Packet size exceeds max\n");
1420 rc = -EINVAL;
1421 goto out_free;
1422 }
1423 (*new_auth_tok)->session_key.encrypted_key_size =
1424 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1425 if ((*new_auth_tok)->session_key.encrypted_key_size
1426 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1427 printk(KERN_WARNING "Tag 3 packet contains key larger "
1428 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1429 rc = -EINVAL;
1430 goto out_free;
1431 }
1432 if (unlikely(data[(*packet_size)++] != 0x04)) {
1433 printk(KERN_WARNING "Unknown version number [%d]\n",
1434 data[(*packet_size) - 1]);
1435 rc = -EINVAL;
1436 goto out_free;
1437 }
1438 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1439 (u16)data[(*packet_size)]);
1440 if (rc)
1441 goto out_free;
1442 /* A little extra work to differentiate among the AES key
1443 * sizes; see RFC2440 */
1444 switch(data[(*packet_size)++]) {
1445 case RFC2440_CIPHER_AES_192:
1446 crypt_stat->key_size = 24;
1447 break;
1448 default:
1449 crypt_stat->key_size =
1450 (*new_auth_tok)->session_key.encrypted_key_size;
1451 }
1452 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1453 if (rc)
1454 goto out_free;
1455 if (unlikely(data[(*packet_size)++] != 0x03)) {
1456 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1457 rc = -ENOSYS;
1458 goto out_free;
1459 }
1460 /* TODO: finish the hash mapping */
1461 switch (data[(*packet_size)++]) {
1462 case 0x01: /* See RFC2440 for these numbers and their mappings */
1463 /* Choose MD5 */
1464 memcpy((*new_auth_tok)->token.password.salt,
1465 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1466 (*packet_size) += ECRYPTFS_SALT_SIZE;
1467 /* This conversion was taken straight from RFC2440 */
1468 (*new_auth_tok)->token.password.hash_iterations =
1469 ((u32) 16 + (data[(*packet_size)] & 15))
1470 << ((data[(*packet_size)] >> 4) + 6);
1471 (*packet_size)++;
1472 /* Friendly reminder:
1473 * (*new_auth_tok)->session_key.encrypted_key_size =
1474 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1475 memcpy((*new_auth_tok)->session_key.encrypted_key,
1476 &data[(*packet_size)],
1477 (*new_auth_tok)->session_key.encrypted_key_size);
1478 (*packet_size) +=
1479 (*new_auth_tok)->session_key.encrypted_key_size;
1480 (*new_auth_tok)->session_key.flags &=
1481 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1482 (*new_auth_tok)->session_key.flags |=
1483 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1484 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1485 break;
1486 default:
1487 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1488 "[%d]\n", data[(*packet_size) - 1]);
1489 rc = -ENOSYS;
1490 goto out_free;
1491 }
1492 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1493 /* TODO: Parametarize; we might actually want userspace to
1494 * decrypt the session key. */
1495 (*new_auth_tok)->session_key.flags &=
1496 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1497 (*new_auth_tok)->session_key.flags &=
1498 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1499 list_add(&auth_tok_list_item->list, auth_tok_list);
1500 goto out;
1501 out_free:
1502 (*new_auth_tok) = NULL;
1503 memset(auth_tok_list_item, 0,
1504 sizeof(struct ecryptfs_auth_tok_list_item));
1505 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1506 auth_tok_list_item);
1507 out:
1508 if (rc)
1509 (*packet_size) = 0;
1510 return rc;
1511 }
1512
1513 /**
1514 * parse_tag_11_packet
1515 * @data: The raw bytes of the packet
1516 * @contents: This function writes the data contents of the literal
1517 * packet into this memory location
1518 * @max_contents_bytes: The maximum number of bytes that this function
1519 * is allowed to write into contents
1520 * @tag_11_contents_size: This function writes the size of the parsed
1521 * contents into this memory location; zero on
1522 * error
1523 * @packet_size: This function writes the size of the parsed packet
1524 * into this memory location; zero on error
1525 * @max_packet_size: maximum number of bytes to parse
1526 *
1527 * Returns zero on success; non-zero on error.
1528 */
1529 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)1530 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1531 size_t max_contents_bytes, size_t *tag_11_contents_size,
1532 size_t *packet_size, size_t max_packet_size)
1533 {
1534 size_t body_size;
1535 size_t length_size;
1536 int rc = 0;
1537
1538 (*packet_size) = 0;
1539 (*tag_11_contents_size) = 0;
1540 /* This format is inspired by OpenPGP; see RFC 2440
1541 * packet tag 11
1542 *
1543 * Tag 11 identifier (1 byte)
1544 * Max Tag 11 packet size (max 3 bytes)
1545 * Binary format specifier (1 byte)
1546 * Filename length (1 byte)
1547 * Filename ("_CONSOLE") (8 bytes)
1548 * Modification date (4 bytes)
1549 * Literal data (arbitrary)
1550 *
1551 * We need at least 16 bytes of data for the packet to even be
1552 * valid.
1553 */
1554 if (max_packet_size < 16) {
1555 printk(KERN_ERR "Maximum packet size too small\n");
1556 rc = -EINVAL;
1557 goto out;
1558 }
1559 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1560 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1561 rc = -EINVAL;
1562 goto out;
1563 }
1564 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1565 &length_size);
1566 if (rc) {
1567 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1568 goto out;
1569 }
1570 if (body_size < 14) {
1571 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1572 rc = -EINVAL;
1573 goto out;
1574 }
1575 (*packet_size) += length_size;
1576 (*tag_11_contents_size) = (body_size - 14);
1577 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1578 printk(KERN_ERR "Packet size exceeds max\n");
1579 rc = -EINVAL;
1580 goto out;
1581 }
1582 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1583 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1584 "expected size\n");
1585 rc = -EINVAL;
1586 goto out;
1587 }
1588 if (data[(*packet_size)++] != 0x62) {
1589 printk(KERN_WARNING "Unrecognizable packet\n");
1590 rc = -EINVAL;
1591 goto out;
1592 }
1593 if (data[(*packet_size)++] != 0x08) {
1594 printk(KERN_WARNING "Unrecognizable packet\n");
1595 rc = -EINVAL;
1596 goto out;
1597 }
1598 (*packet_size) += 12; /* Ignore filename and modification date */
1599 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1600 (*packet_size) += (*tag_11_contents_size);
1601 out:
1602 if (rc) {
1603 (*packet_size) = 0;
1604 (*tag_11_contents_size) = 0;
1605 }
1606 return rc;
1607 }
1608
ecryptfs_keyring_auth_tok_for_sig(struct key ** auth_tok_key,struct ecryptfs_auth_tok ** auth_tok,char * sig)1609 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1610 struct ecryptfs_auth_tok **auth_tok,
1611 char *sig)
1612 {
1613 int rc = 0;
1614
1615 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1616 if (IS_ERR(*auth_tok_key)) {
1617 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1618 if (IS_ERR(*auth_tok_key)) {
1619 printk(KERN_ERR "Could not find key with description: [%s]\n",
1620 sig);
1621 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1622 (*auth_tok_key) = NULL;
1623 goto out;
1624 }
1625 }
1626 down_write(&(*auth_tok_key)->sem);
1627 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1628 if (rc) {
1629 up_write(&(*auth_tok_key)->sem);
1630 key_put(*auth_tok_key);
1631 (*auth_tok_key) = NULL;
1632 goto out;
1633 }
1634 out:
1635 return rc;
1636 }
1637
1638 /**
1639 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1640 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1641 * @crypt_stat: The cryptographic context
1642 *
1643 * Returns zero on success; non-zero error otherwise
1644 */
1645 static int
decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok * auth_tok,struct ecryptfs_crypt_stat * crypt_stat)1646 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1647 struct ecryptfs_crypt_stat *crypt_stat)
1648 {
1649 struct scatterlist dst_sg[2];
1650 struct scatterlist src_sg[2];
1651 struct mutex *tfm_mutex;
1652 struct crypto_skcipher *tfm;
1653 struct skcipher_request *req = NULL;
1654 int rc = 0;
1655
1656 if (unlikely(ecryptfs_verbosity > 0)) {
1657 ecryptfs_printk(
1658 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1659 auth_tok->token.password.session_key_encryption_key_bytes);
1660 ecryptfs_dump_hex(
1661 auth_tok->token.password.session_key_encryption_key,
1662 auth_tok->token.password.session_key_encryption_key_bytes);
1663 }
1664 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
1665 crypt_stat->cipher);
1666 if (unlikely(rc)) {
1667 printk(KERN_ERR "Internal error whilst attempting to get "
1668 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1669 crypt_stat->cipher, rc);
1670 goto out;
1671 }
1672 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1673 auth_tok->session_key.encrypted_key_size,
1674 src_sg, 2);
1675 if (rc < 1 || rc > 2) {
1676 printk(KERN_ERR "Internal error whilst attempting to convert "
1677 "auth_tok->session_key.encrypted_key to scatterlist; "
1678 "expected rc = 1; got rc = [%d]. "
1679 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1680 auth_tok->session_key.encrypted_key_size);
1681 goto out;
1682 }
1683 auth_tok->session_key.decrypted_key_size =
1684 auth_tok->session_key.encrypted_key_size;
1685 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1686 auth_tok->session_key.decrypted_key_size,
1687 dst_sg, 2);
1688 if (rc < 1 || rc > 2) {
1689 printk(KERN_ERR "Internal error whilst attempting to convert "
1690 "auth_tok->session_key.decrypted_key to scatterlist; "
1691 "expected rc = 1; got rc = [%d]\n", rc);
1692 goto out;
1693 }
1694 mutex_lock(tfm_mutex);
1695 req = skcipher_request_alloc(tfm, GFP_KERNEL);
1696 if (!req) {
1697 mutex_unlock(tfm_mutex);
1698 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1699 "skcipher_request_alloc for %s\n", __func__,
1700 crypto_skcipher_driver_name(tfm));
1701 rc = -ENOMEM;
1702 goto out;
1703 }
1704
1705 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
1706 NULL, NULL);
1707 rc = crypto_skcipher_setkey(
1708 tfm, auth_tok->token.password.session_key_encryption_key,
1709 crypt_stat->key_size);
1710 if (unlikely(rc < 0)) {
1711 mutex_unlock(tfm_mutex);
1712 printk(KERN_ERR "Error setting key for crypto context\n");
1713 rc = -EINVAL;
1714 goto out;
1715 }
1716 skcipher_request_set_crypt(req, src_sg, dst_sg,
1717 auth_tok->session_key.encrypted_key_size,
1718 NULL);
1719 rc = crypto_skcipher_decrypt(req);
1720 mutex_unlock(tfm_mutex);
1721 if (unlikely(rc)) {
1722 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1723 goto out;
1724 }
1725 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1726 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1727 auth_tok->session_key.decrypted_key_size);
1728 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1729 if (unlikely(ecryptfs_verbosity > 0)) {
1730 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1731 crypt_stat->key_size);
1732 ecryptfs_dump_hex(crypt_stat->key,
1733 crypt_stat->key_size);
1734 }
1735 out:
1736 skcipher_request_free(req);
1737 return rc;
1738 }
1739
1740 /**
1741 * ecryptfs_parse_packet_set
1742 * @crypt_stat: The cryptographic context
1743 * @src: Virtual address of region of memory containing the packets
1744 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1745 *
1746 * Get crypt_stat to have the file's session key if the requisite key
1747 * is available to decrypt the session key.
1748 *
1749 * Returns Zero if a valid authentication token was retrieved and
1750 * processed; negative value for file not encrypted or for error
1751 * conditions.
1752 */
ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat * crypt_stat,unsigned char * src,struct dentry * ecryptfs_dentry)1753 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1754 unsigned char *src,
1755 struct dentry *ecryptfs_dentry)
1756 {
1757 size_t i = 0;
1758 size_t found_auth_tok;
1759 size_t next_packet_is_auth_tok_packet;
1760 struct list_head auth_tok_list;
1761 struct ecryptfs_auth_tok *matching_auth_tok;
1762 struct ecryptfs_auth_tok *candidate_auth_tok;
1763 char *candidate_auth_tok_sig;
1764 size_t packet_size;
1765 struct ecryptfs_auth_tok *new_auth_tok;
1766 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1767 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1768 size_t tag_11_contents_size;
1769 size_t tag_11_packet_size;
1770 struct key *auth_tok_key = NULL;
1771 int rc = 0;
1772
1773 INIT_LIST_HEAD(&auth_tok_list);
1774 /* Parse the header to find as many packets as we can; these will be
1775 * added the our &auth_tok_list */
1776 next_packet_is_auth_tok_packet = 1;
1777 while (next_packet_is_auth_tok_packet) {
1778 size_t max_packet_size = ((PAGE_SIZE - 8) - i);
1779
1780 switch (src[i]) {
1781 case ECRYPTFS_TAG_3_PACKET_TYPE:
1782 rc = parse_tag_3_packet(crypt_stat,
1783 (unsigned char *)&src[i],
1784 &auth_tok_list, &new_auth_tok,
1785 &packet_size, max_packet_size);
1786 if (rc) {
1787 ecryptfs_printk(KERN_ERR, "Error parsing "
1788 "tag 3 packet\n");
1789 rc = -EIO;
1790 goto out_wipe_list;
1791 }
1792 i += packet_size;
1793 rc = parse_tag_11_packet((unsigned char *)&src[i],
1794 sig_tmp_space,
1795 ECRYPTFS_SIG_SIZE,
1796 &tag_11_contents_size,
1797 &tag_11_packet_size,
1798 max_packet_size);
1799 if (rc) {
1800 ecryptfs_printk(KERN_ERR, "No valid "
1801 "(ecryptfs-specific) literal "
1802 "packet containing "
1803 "authentication token "
1804 "signature found after "
1805 "tag 3 packet\n");
1806 rc = -EIO;
1807 goto out_wipe_list;
1808 }
1809 i += tag_11_packet_size;
1810 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1811 ecryptfs_printk(KERN_ERR, "Expected "
1812 "signature of size [%d]; "
1813 "read size [%zd]\n",
1814 ECRYPTFS_SIG_SIZE,
1815 tag_11_contents_size);
1816 rc = -EIO;
1817 goto out_wipe_list;
1818 }
1819 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1820 sig_tmp_space, tag_11_contents_size);
1821 new_auth_tok->token.password.signature[
1822 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1823 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1824 break;
1825 case ECRYPTFS_TAG_1_PACKET_TYPE:
1826 rc = parse_tag_1_packet(crypt_stat,
1827 (unsigned char *)&src[i],
1828 &auth_tok_list, &new_auth_tok,
1829 &packet_size, max_packet_size);
1830 if (rc) {
1831 ecryptfs_printk(KERN_ERR, "Error parsing "
1832 "tag 1 packet\n");
1833 rc = -EIO;
1834 goto out_wipe_list;
1835 }
1836 i += packet_size;
1837 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1838 break;
1839 case ECRYPTFS_TAG_11_PACKET_TYPE:
1840 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1841 "(Tag 11 not allowed by itself)\n");
1842 rc = -EIO;
1843 goto out_wipe_list;
1844 default:
1845 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1846 "of the file header; hex value of "
1847 "character is [0x%.2x]\n", i, src[i]);
1848 next_packet_is_auth_tok_packet = 0;
1849 }
1850 }
1851 if (list_empty(&auth_tok_list)) {
1852 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1853 "eCryptfs file; this is not supported in this version "
1854 "of the eCryptfs kernel module\n");
1855 rc = -EINVAL;
1856 goto out;
1857 }
1858 /* auth_tok_list contains the set of authentication tokens
1859 * parsed from the metadata. We need to find a matching
1860 * authentication token that has the secret component(s)
1861 * necessary to decrypt the EFEK in the auth_tok parsed from
1862 * the metadata. There may be several potential matches, but
1863 * just one will be sufficient to decrypt to get the FEK. */
1864 find_next_matching_auth_tok:
1865 found_auth_tok = 0;
1866 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1867 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1868 if (unlikely(ecryptfs_verbosity > 0)) {
1869 ecryptfs_printk(KERN_DEBUG,
1870 "Considering candidate auth tok:\n");
1871 ecryptfs_dump_auth_tok(candidate_auth_tok);
1872 }
1873 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1874 candidate_auth_tok);
1875 if (rc) {
1876 printk(KERN_ERR
1877 "Unrecognized candidate auth tok type: [%d]\n",
1878 candidate_auth_tok->token_type);
1879 rc = -EINVAL;
1880 goto out_wipe_list;
1881 }
1882 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1883 &matching_auth_tok,
1884 crypt_stat->mount_crypt_stat,
1885 candidate_auth_tok_sig);
1886 if (!rc) {
1887 found_auth_tok = 1;
1888 goto found_matching_auth_tok;
1889 }
1890 }
1891 if (!found_auth_tok) {
1892 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1893 "authentication token\n");
1894 rc = -EIO;
1895 goto out_wipe_list;
1896 }
1897 found_matching_auth_tok:
1898 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1899 memcpy(&(candidate_auth_tok->token.private_key),
1900 &(matching_auth_tok->token.private_key),
1901 sizeof(struct ecryptfs_private_key));
1902 up_write(&(auth_tok_key->sem));
1903 key_put(auth_tok_key);
1904 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1905 crypt_stat);
1906 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1907 memcpy(&(candidate_auth_tok->token.password),
1908 &(matching_auth_tok->token.password),
1909 sizeof(struct ecryptfs_password));
1910 up_write(&(auth_tok_key->sem));
1911 key_put(auth_tok_key);
1912 rc = decrypt_passphrase_encrypted_session_key(
1913 candidate_auth_tok, crypt_stat);
1914 } else {
1915 up_write(&(auth_tok_key->sem));
1916 key_put(auth_tok_key);
1917 rc = -EINVAL;
1918 }
1919 if (rc) {
1920 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1921
1922 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1923 "session key for authentication token with sig "
1924 "[%.*s]; rc = [%d]. Removing auth tok "
1925 "candidate from the list and searching for "
1926 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1927 candidate_auth_tok_sig, rc);
1928 list_for_each_entry_safe(auth_tok_list_item,
1929 auth_tok_list_item_tmp,
1930 &auth_tok_list, list) {
1931 if (candidate_auth_tok
1932 == &auth_tok_list_item->auth_tok) {
1933 list_del(&auth_tok_list_item->list);
1934 kmem_cache_free(
1935 ecryptfs_auth_tok_list_item_cache,
1936 auth_tok_list_item);
1937 goto find_next_matching_auth_tok;
1938 }
1939 }
1940 BUG();
1941 }
1942 rc = ecryptfs_compute_root_iv(crypt_stat);
1943 if (rc) {
1944 ecryptfs_printk(KERN_ERR, "Error computing "
1945 "the root IV\n");
1946 goto out_wipe_list;
1947 }
1948 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1949 if (rc) {
1950 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1951 "context for cipher [%s]; rc = [%d]\n",
1952 crypt_stat->cipher, rc);
1953 }
1954 out_wipe_list:
1955 wipe_auth_tok_list(&auth_tok_list);
1956 out:
1957 return rc;
1958 }
1959
1960 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)1961 pki_encrypt_session_key(struct key *auth_tok_key,
1962 struct ecryptfs_auth_tok *auth_tok,
1963 struct ecryptfs_crypt_stat *crypt_stat,
1964 struct ecryptfs_key_record *key_rec)
1965 {
1966 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1967 char *payload = NULL;
1968 size_t payload_len = 0;
1969 struct ecryptfs_message *msg;
1970 int rc;
1971
1972 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1973 ecryptfs_code_for_cipher_string(
1974 crypt_stat->cipher,
1975 crypt_stat->key_size),
1976 crypt_stat, &payload, &payload_len);
1977 up_write(&(auth_tok_key->sem));
1978 key_put(auth_tok_key);
1979 if (rc) {
1980 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1981 goto out;
1982 }
1983 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1984 if (rc) {
1985 ecryptfs_printk(KERN_ERR, "Error sending message to "
1986 "ecryptfsd: %d\n", rc);
1987 goto out;
1988 }
1989 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1990 if (rc) {
1991 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1992 "from the user space daemon\n");
1993 rc = -EIO;
1994 goto out;
1995 }
1996 rc = parse_tag_67_packet(key_rec, msg);
1997 if (rc)
1998 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
1999 kfree(msg);
2000 out:
2001 kfree(payload);
2002 return rc;
2003 }
2004 /**
2005 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2006 * @dest: Buffer into which to write the packet
2007 * @remaining_bytes: Maximum number of bytes that can be writtn
2008 * @auth_tok_key: The authentication token key to unlock and put when done with
2009 * @auth_tok
2010 * @auth_tok: The authentication token used for generating the tag 1 packet
2011 * @crypt_stat: The cryptographic context
2012 * @key_rec: The key record struct for the tag 1 packet
2013 * @packet_size: This function will write the number of bytes that end
2014 * up constituting the packet; set to zero on error
2015 *
2016 * Returns zero on success; non-zero on error.
2017 */
2018 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)2019 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2020 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2021 struct ecryptfs_crypt_stat *crypt_stat,
2022 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2023 {
2024 size_t i;
2025 size_t encrypted_session_key_valid = 0;
2026 size_t packet_size_length;
2027 size_t max_packet_size;
2028 int rc = 0;
2029
2030 (*packet_size) = 0;
2031 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2032 ECRYPTFS_SIG_SIZE);
2033 encrypted_session_key_valid = 0;
2034 for (i = 0; i < crypt_stat->key_size; i++)
2035 encrypted_session_key_valid |=
2036 auth_tok->session_key.encrypted_key[i];
2037 if (encrypted_session_key_valid) {
2038 memcpy(key_rec->enc_key,
2039 auth_tok->session_key.encrypted_key,
2040 auth_tok->session_key.encrypted_key_size);
2041 up_write(&(auth_tok_key->sem));
2042 key_put(auth_tok_key);
2043 goto encrypted_session_key_set;
2044 }
2045 if (auth_tok->session_key.encrypted_key_size == 0)
2046 auth_tok->session_key.encrypted_key_size =
2047 auth_tok->token.private_key.key_size;
2048 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2049 key_rec);
2050 if (rc) {
2051 printk(KERN_ERR "Failed to encrypt session key via a key "
2052 "module; rc = [%d]\n", rc);
2053 goto out;
2054 }
2055 if (ecryptfs_verbosity > 0) {
2056 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2057 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2058 }
2059 encrypted_session_key_set:
2060 /* This format is inspired by OpenPGP; see RFC 2440
2061 * packet tag 1 */
2062 max_packet_size = (1 /* Tag 1 identifier */
2063 + 3 /* Max Tag 1 packet size */
2064 + 1 /* Version */
2065 + ECRYPTFS_SIG_SIZE /* Key identifier */
2066 + 1 /* Cipher identifier */
2067 + key_rec->enc_key_size); /* Encrypted key size */
2068 if (max_packet_size > (*remaining_bytes)) {
2069 printk(KERN_ERR "Packet length larger than maximum allowable; "
2070 "need up to [%td] bytes, but there are only [%td] "
2071 "available\n", max_packet_size, (*remaining_bytes));
2072 rc = -EINVAL;
2073 goto out;
2074 }
2075 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2076 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2077 (max_packet_size - 4),
2078 &packet_size_length);
2079 if (rc) {
2080 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2081 "header; cannot generate packet length\n");
2082 goto out;
2083 }
2084 (*packet_size) += packet_size_length;
2085 dest[(*packet_size)++] = 0x03; /* version 3 */
2086 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2087 (*packet_size) += ECRYPTFS_SIG_SIZE;
2088 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2089 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2090 key_rec->enc_key_size);
2091 (*packet_size) += key_rec->enc_key_size;
2092 out:
2093 if (rc)
2094 (*packet_size) = 0;
2095 else
2096 (*remaining_bytes) -= (*packet_size);
2097 return rc;
2098 }
2099
2100 /**
2101 * write_tag_11_packet
2102 * @dest: Target into which Tag 11 packet is to be written
2103 * @remaining_bytes: Maximum packet length
2104 * @contents: Byte array of contents to copy in
2105 * @contents_length: Number of bytes in contents
2106 * @packet_length: Length of the Tag 11 packet written; zero on error
2107 *
2108 * Returns zero on success; non-zero on error.
2109 */
2110 static int
write_tag_11_packet(char * dest,size_t * remaining_bytes,char * contents,size_t contents_length,size_t * packet_length)2111 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2112 size_t contents_length, size_t *packet_length)
2113 {
2114 size_t packet_size_length;
2115 size_t max_packet_size;
2116 int rc = 0;
2117
2118 (*packet_length) = 0;
2119 /* This format is inspired by OpenPGP; see RFC 2440
2120 * packet tag 11 */
2121 max_packet_size = (1 /* Tag 11 identifier */
2122 + 3 /* Max Tag 11 packet size */
2123 + 1 /* Binary format specifier */
2124 + 1 /* Filename length */
2125 + 8 /* Filename ("_CONSOLE") */
2126 + 4 /* Modification date */
2127 + contents_length); /* Literal data */
2128 if (max_packet_size > (*remaining_bytes)) {
2129 printk(KERN_ERR "Packet length larger than maximum allowable; "
2130 "need up to [%td] bytes, but there are only [%td] "
2131 "available\n", max_packet_size, (*remaining_bytes));
2132 rc = -EINVAL;
2133 goto out;
2134 }
2135 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2136 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2137 (max_packet_size - 4),
2138 &packet_size_length);
2139 if (rc) {
2140 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2141 "generate packet length. rc = [%d]\n", rc);
2142 goto out;
2143 }
2144 (*packet_length) += packet_size_length;
2145 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2146 dest[(*packet_length)++] = 8;
2147 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2148 (*packet_length) += 8;
2149 memset(&dest[(*packet_length)], 0x00, 4);
2150 (*packet_length) += 4;
2151 memcpy(&dest[(*packet_length)], contents, contents_length);
2152 (*packet_length) += contents_length;
2153 out:
2154 if (rc)
2155 (*packet_length) = 0;
2156 else
2157 (*remaining_bytes) -= (*packet_length);
2158 return rc;
2159 }
2160
2161 /**
2162 * write_tag_3_packet
2163 * @dest: Buffer into which to write the packet
2164 * @remaining_bytes: Maximum number of bytes that can be written
2165 * @auth_tok: Authentication token
2166 * @crypt_stat: The cryptographic context
2167 * @key_rec: encrypted key
2168 * @packet_size: This function will write the number of bytes that end
2169 * up constituting the packet; set to zero on error
2170 *
2171 * Returns zero on success; non-zero on error.
2172 */
2173 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)2174 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2175 struct ecryptfs_auth_tok *auth_tok,
2176 struct ecryptfs_crypt_stat *crypt_stat,
2177 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2178 {
2179 size_t i;
2180 size_t encrypted_session_key_valid = 0;
2181 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2182 struct scatterlist dst_sg[2];
2183 struct scatterlist src_sg[2];
2184 struct mutex *tfm_mutex = NULL;
2185 u8 cipher_code;
2186 size_t packet_size_length;
2187 size_t max_packet_size;
2188 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2189 crypt_stat->mount_crypt_stat;
2190 struct crypto_skcipher *tfm;
2191 struct skcipher_request *req;
2192 int rc = 0;
2193
2194 (*packet_size) = 0;
2195 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2196 ECRYPTFS_SIG_SIZE);
2197 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
2198 crypt_stat->cipher);
2199 if (unlikely(rc)) {
2200 printk(KERN_ERR "Internal error whilst attempting to get "
2201 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2202 crypt_stat->cipher, rc);
2203 goto out;
2204 }
2205 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2206 printk(KERN_WARNING "No key size specified at mount; "
2207 "defaulting to [%d]\n",
2208 crypto_skcipher_max_keysize(tfm));
2209 mount_crypt_stat->global_default_cipher_key_size =
2210 crypto_skcipher_max_keysize(tfm);
2211 }
2212 if (crypt_stat->key_size == 0)
2213 crypt_stat->key_size =
2214 mount_crypt_stat->global_default_cipher_key_size;
2215 if (auth_tok->session_key.encrypted_key_size == 0)
2216 auth_tok->session_key.encrypted_key_size =
2217 crypt_stat->key_size;
2218 if (crypt_stat->key_size == 24
2219 && strcmp("aes", crypt_stat->cipher) == 0) {
2220 memset((crypt_stat->key + 24), 0, 8);
2221 auth_tok->session_key.encrypted_key_size = 32;
2222 } else
2223 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2224 key_rec->enc_key_size =
2225 auth_tok->session_key.encrypted_key_size;
2226 encrypted_session_key_valid = 0;
2227 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2228 encrypted_session_key_valid |=
2229 auth_tok->session_key.encrypted_key[i];
2230 if (encrypted_session_key_valid) {
2231 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2232 "using auth_tok->session_key.encrypted_key, "
2233 "where key_rec->enc_key_size = [%zd]\n",
2234 key_rec->enc_key_size);
2235 memcpy(key_rec->enc_key,
2236 auth_tok->session_key.encrypted_key,
2237 key_rec->enc_key_size);
2238 goto encrypted_session_key_set;
2239 }
2240 if (auth_tok->token.password.flags &
2241 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2242 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2243 "session key encryption key of size [%d]\n",
2244 auth_tok->token.password.
2245 session_key_encryption_key_bytes);
2246 memcpy(session_key_encryption_key,
2247 auth_tok->token.password.session_key_encryption_key,
2248 crypt_stat->key_size);
2249 ecryptfs_printk(KERN_DEBUG,
2250 "Cached session key encryption key:\n");
2251 if (ecryptfs_verbosity > 0)
2252 ecryptfs_dump_hex(session_key_encryption_key, 16);
2253 }
2254 if (unlikely(ecryptfs_verbosity > 0)) {
2255 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2256 ecryptfs_dump_hex(session_key_encryption_key, 16);
2257 }
2258 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2259 src_sg, 2);
2260 if (rc < 1 || rc > 2) {
2261 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2262 "for crypt_stat session key; expected rc = 1; "
2263 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2264 rc, key_rec->enc_key_size);
2265 rc = -ENOMEM;
2266 goto out;
2267 }
2268 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2269 dst_sg, 2);
2270 if (rc < 1 || rc > 2) {
2271 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2272 "for crypt_stat encrypted session key; "
2273 "expected rc = 1; got rc = [%d]. "
2274 "key_rec->enc_key_size = [%zd]\n", rc,
2275 key_rec->enc_key_size);
2276 rc = -ENOMEM;
2277 goto out;
2278 }
2279 mutex_lock(tfm_mutex);
2280 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
2281 crypt_stat->key_size);
2282 if (rc < 0) {
2283 mutex_unlock(tfm_mutex);
2284 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2285 "context; rc = [%d]\n", rc);
2286 goto out;
2287 }
2288
2289 req = skcipher_request_alloc(tfm, GFP_KERNEL);
2290 if (!req) {
2291 mutex_unlock(tfm_mutex);
2292 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
2293 "attempting to skcipher_request_alloc for "
2294 "%s\n", crypto_skcipher_driver_name(tfm));
2295 rc = -ENOMEM;
2296 goto out;
2297 }
2298
2299 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
2300 NULL, NULL);
2301
2302 rc = 0;
2303 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2304 crypt_stat->key_size);
2305 skcipher_request_set_crypt(req, src_sg, dst_sg,
2306 (*key_rec).enc_key_size, NULL);
2307 rc = crypto_skcipher_encrypt(req);
2308 mutex_unlock(tfm_mutex);
2309 skcipher_request_free(req);
2310 if (rc) {
2311 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2312 goto out;
2313 }
2314 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2315 if (ecryptfs_verbosity > 0) {
2316 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2317 key_rec->enc_key_size);
2318 ecryptfs_dump_hex(key_rec->enc_key,
2319 key_rec->enc_key_size);
2320 }
2321 encrypted_session_key_set:
2322 /* This format is inspired by OpenPGP; see RFC 2440
2323 * packet tag 3 */
2324 max_packet_size = (1 /* Tag 3 identifier */
2325 + 3 /* Max Tag 3 packet size */
2326 + 1 /* Version */
2327 + 1 /* Cipher code */
2328 + 1 /* S2K specifier */
2329 + 1 /* Hash identifier */
2330 + ECRYPTFS_SALT_SIZE /* Salt */
2331 + 1 /* Hash iterations */
2332 + key_rec->enc_key_size); /* Encrypted key size */
2333 if (max_packet_size > (*remaining_bytes)) {
2334 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2335 "there are only [%td] available\n", max_packet_size,
2336 (*remaining_bytes));
2337 rc = -EINVAL;
2338 goto out;
2339 }
2340 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2341 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2342 * to get the number of octets in the actual Tag 3 packet */
2343 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2344 (max_packet_size - 4),
2345 &packet_size_length);
2346 if (rc) {
2347 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2348 "generate packet length. rc = [%d]\n", rc);
2349 goto out;
2350 }
2351 (*packet_size) += packet_size_length;
2352 dest[(*packet_size)++] = 0x04; /* version 4 */
2353 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2354 * specified with strings */
2355 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2356 crypt_stat->key_size);
2357 if (cipher_code == 0) {
2358 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2359 "cipher [%s]\n", crypt_stat->cipher);
2360 rc = -EINVAL;
2361 goto out;
2362 }
2363 dest[(*packet_size)++] = cipher_code;
2364 dest[(*packet_size)++] = 0x03; /* S2K */
2365 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2366 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2367 ECRYPTFS_SALT_SIZE);
2368 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2369 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2370 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2371 key_rec->enc_key_size);
2372 (*packet_size) += key_rec->enc_key_size;
2373 out:
2374 if (rc)
2375 (*packet_size) = 0;
2376 else
2377 (*remaining_bytes) -= (*packet_size);
2378 return rc;
2379 }
2380
2381 struct kmem_cache *ecryptfs_key_record_cache;
2382
2383 /**
2384 * ecryptfs_generate_key_packet_set
2385 * @dest_base: Virtual address from which to write the key record set
2386 * @crypt_stat: The cryptographic context from which the
2387 * authentication tokens will be retrieved
2388 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2389 * for the global parameters
2390 * @len: The amount written
2391 * @max: The maximum amount of data allowed to be written
2392 *
2393 * Generates a key packet set and writes it to the virtual address
2394 * passed in.
2395 *
2396 * Returns zero on success; non-zero on error.
2397 */
2398 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)2399 ecryptfs_generate_key_packet_set(char *dest_base,
2400 struct ecryptfs_crypt_stat *crypt_stat,
2401 struct dentry *ecryptfs_dentry, size_t *len,
2402 size_t max)
2403 {
2404 struct ecryptfs_auth_tok *auth_tok;
2405 struct key *auth_tok_key = NULL;
2406 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2407 &ecryptfs_superblock_to_private(
2408 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2409 size_t written;
2410 struct ecryptfs_key_record *key_rec;
2411 struct ecryptfs_key_sig *key_sig;
2412 int rc = 0;
2413
2414 (*len) = 0;
2415 mutex_lock(&crypt_stat->keysig_list_mutex);
2416 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2417 if (!key_rec) {
2418 rc = -ENOMEM;
2419 goto out;
2420 }
2421 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2422 crypt_stat_list) {
2423 memset(key_rec, 0, sizeof(*key_rec));
2424 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2425 &auth_tok,
2426 mount_crypt_stat,
2427 key_sig->keysig);
2428 if (rc) {
2429 printk(KERN_WARNING "Unable to retrieve auth tok with "
2430 "sig = [%s]\n", key_sig->keysig);
2431 rc = process_find_global_auth_tok_for_sig_err(rc);
2432 goto out_free;
2433 }
2434 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2435 rc = write_tag_3_packet((dest_base + (*len)),
2436 &max, auth_tok,
2437 crypt_stat, key_rec,
2438 &written);
2439 up_write(&(auth_tok_key->sem));
2440 key_put(auth_tok_key);
2441 if (rc) {
2442 ecryptfs_printk(KERN_WARNING, "Error "
2443 "writing tag 3 packet\n");
2444 goto out_free;
2445 }
2446 (*len) += written;
2447 /* Write auth tok signature packet */
2448 rc = write_tag_11_packet((dest_base + (*len)), &max,
2449 key_rec->sig,
2450 ECRYPTFS_SIG_SIZE, &written);
2451 if (rc) {
2452 ecryptfs_printk(KERN_ERR, "Error writing "
2453 "auth tok signature packet\n");
2454 goto out_free;
2455 }
2456 (*len) += written;
2457 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2458 rc = write_tag_1_packet(dest_base + (*len), &max,
2459 auth_tok_key, auth_tok,
2460 crypt_stat, key_rec, &written);
2461 if (rc) {
2462 ecryptfs_printk(KERN_WARNING, "Error "
2463 "writing tag 1 packet\n");
2464 goto out_free;
2465 }
2466 (*len) += written;
2467 } else {
2468 up_write(&(auth_tok_key->sem));
2469 key_put(auth_tok_key);
2470 ecryptfs_printk(KERN_WARNING, "Unsupported "
2471 "authentication token type\n");
2472 rc = -EINVAL;
2473 goto out_free;
2474 }
2475 }
2476 if (likely(max > 0)) {
2477 dest_base[(*len)] = 0x00;
2478 } else {
2479 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2480 rc = -EIO;
2481 }
2482 out_free:
2483 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2484 out:
2485 if (rc)
2486 (*len) = 0;
2487 mutex_unlock(&crypt_stat->keysig_list_mutex);
2488 return rc;
2489 }
2490
2491 struct kmem_cache *ecryptfs_key_sig_cache;
2492
ecryptfs_add_keysig(struct ecryptfs_crypt_stat * crypt_stat,char * sig)2493 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2494 {
2495 struct ecryptfs_key_sig *new_key_sig;
2496
2497 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2498 if (!new_key_sig)
2499 return -ENOMEM;
2500
2501 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2502 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2503 /* Caller must hold keysig_list_mutex */
2504 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2505
2506 return 0;
2507 }
2508
2509 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2510
2511 int
ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat * mount_crypt_stat,char * sig,u32 global_auth_tok_flags)2512 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2513 char *sig, u32 global_auth_tok_flags)
2514 {
2515 struct ecryptfs_global_auth_tok *new_auth_tok;
2516
2517 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2518 GFP_KERNEL);
2519 if (!new_auth_tok)
2520 return -ENOMEM;
2521
2522 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2523 new_auth_tok->flags = global_auth_tok_flags;
2524 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2525 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2526 list_add(&new_auth_tok->mount_crypt_stat_list,
2527 &mount_crypt_stat->global_auth_tok_list);
2528 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2529 return 0;
2530 }
2531
2532