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