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
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>
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.
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.
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
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"
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.
43 static int process_request_key_err(long err_code
)
49 ecryptfs_printk(KERN_WARNING
, "No key\n");
53 ecryptfs_printk(KERN_WARNING
, "Key expired\n");
57 ecryptfs_printk(KERN_WARNING
, "Key revoked\n");
61 ecryptfs_printk(KERN_WARNING
, "Unknown error code: "
62 "[0x%.16x]\n", err_code
);
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
75 * Returns zero on success; non-zero on error
77 int ecryptfs_parse_packet_length(unsigned char *data
, size_t *size
,
86 (*size
) = (unsigned char)data
[0];
88 } else if (data
[0] < 224) {
90 (*size
) = (((unsigned char)(data
[0]) - 192) * 256);
91 (*size
) += ((unsigned char)(data
[1]) + 192);
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 "
100 ecryptfs_printk(KERN_ERR
, "Error parsing packet length\n");
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.
116 * Returns zero on success; non-zero on error.
118 int ecryptfs_write_packet_length(char *dest
, size_t size
,
119 size_t *packet_size_length
)
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;
132 ecryptfs_printk(KERN_WARNING
,
133 "Unsupported packet size: [%d]\n", size
);
139 write_tag_64_packet(char *signature
, struct ecryptfs_session_key
*session_key
,
140 char **packet
, size_t *packet_len
)
144 size_t packet_size_len
;
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 |
156 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
157 + session_key
->encrypted_key_size
);
158 *packet
= kmalloc(data_len
, GFP_KERNEL
);
161 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
165 message
[i
++] = ECRYPTFS_TAG_64_PACKET_TYPE
;
166 rc
= ecryptfs_write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
169 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
170 "header; cannot generate packet length\n");
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
,
180 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
181 "header; cannot generate packet length\n");
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
;
194 parse_tag_65_packet(struct ecryptfs_session_key
*session_key
, u8
*cipher_code
,
195 struct ecryptfs_message
*msg
)
203 u16 expected_checksum
= 0;
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 |
213 message_len
= msg
->data_len
;
215 if (message_len
< 4) {
219 if (data
[i
++] != ECRYPTFS_TAG_65_PACKET_TYPE
) {
220 ecryptfs_printk(KERN_ERR
, "Type should be ECRYPTFS_TAG_65\n");
225 ecryptfs_printk(KERN_ERR
, "Status indicator has non-zero value "
226 "[%d]\n", data
[i
-1]);
230 rc
= ecryptfs_parse_packet_length(&data
[i
], &m_size
, &data_len
);
232 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
237 if (message_len
< (i
+ m_size
)) {
238 ecryptfs_printk(KERN_ERR
, "The message received from ecryptfsd "
239 "is shorter than expected\n");
244 ecryptfs_printk(KERN_ERR
,
245 "The decrypted key is not long enough to "
246 "include a cipher code and checksum\n");
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
);
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
);
280 write_tag_66_packet(char *signature
, u8 cipher_code
,
281 struct ecryptfs_crypt_stat
*crypt_stat
, char **packet
,
288 size_t packet_size_len
;
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 |
300 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
+ crypt_stat
->key_size
);
301 *packet
= kmalloc(data_len
, GFP_KERNEL
);
304 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
308 message
[i
++] = ECRYPTFS_TAG_66_PACKET_TYPE
;
309 rc
= ecryptfs_write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
312 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
313 "header; cannot generate packet length\n");
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,
323 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
324 "header; cannot generate packet length\n");
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);
341 parse_tag_67_packet(struct ecryptfs_key_record
*key_rec
,
342 struct ecryptfs_message
*msg
)
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 |
357 message_len
= msg
->data_len
;
359 /* verify that everything through the encrypted FEK size is present */
360 if (message_len
< 4) {
362 printk(KERN_ERR
"%s: message_len is [%zd]; minimum acceptable "
363 "message length is [%d]\n", __func__
, message_len
, 4);
366 if (data
[i
++] != ECRYPTFS_TAG_67_PACKET_TYPE
) {
368 printk(KERN_ERR
"%s: Type should be ECRYPTFS_TAG_67\n",
374 printk(KERN_ERR
"%s: Status indicator has non zero "
375 "value [%d]\n", __func__
, data
[i
-1]);
379 rc
= ecryptfs_parse_packet_length(&data
[i
], &key_rec
->enc_key_size
,
382 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
387 if (message_len
< (i
+ key_rec
->enc_key_size
)) {
389 printk(KERN_ERR
"%s: message_len [%zd]; max len is [%zd]\n",
390 __func__
, message_len
, (i
+ key_rec
->enc_key_size
));
393 if (key_rec
->enc_key_size
> ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
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
);
401 memcpy(key_rec
->enc_key
, &data
[i
], key_rec
->enc_key_size
);
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
)
411 struct ecryptfs_global_auth_tok
*walker
;
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
);
422 (*global_auth_tok
) = walker
;
428 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
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
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.
445 * Returns zero on no error; non-zero on error
448 ecryptfs_find_auth_tok_for_sig(
449 struct ecryptfs_auth_tok
**auth_tok
,
450 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
453 struct ecryptfs_global_auth_tok
*global_auth_tok
;
457 if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
458 mount_crypt_stat
, sig
)) {
459 struct key
*auth_tok_key
;
461 rc
= ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key
, auth_tok
,
464 (*auth_tok
) = global_auth_tok
->global_auth_tok
;
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.
473 struct ecryptfs_write_tag_70_packet_silly_stack
{
475 size_t max_packet_size
;
476 size_t packet_size_len
;
477 size_t block_aligned_filename_size
;
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
;
496 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
497 * @filename: NULL-terminated filename string
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
506 ecryptfs_write_tag_70_packet(char *dest
, size_t *remaining_bytes
,
508 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
509 char *filename
, size_t filename_size
)
511 struct ecryptfs_write_tag_70_packet_silly_stack
*s
;
514 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
516 printk(KERN_ERR
"%s: Out of memory whilst trying to kmalloc "
517 "[%zd] bytes of kernel memory\n", __func__
, sizeof(*s
));
521 s
->desc
.flags
= CRYPTO_TFM_REQ_MAY_SLEEP
;
523 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(
525 &s
->tfm_mutex
, mount_crypt_stat
->global_default_fn_cipher_name
);
527 printk(KERN_ERR
"Internal error whilst attempting to get "
528 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
529 mount_crypt_stat
->global_default_fn_cipher_name
, rc
);
532 mutex_lock(s
->tfm_mutex
);
533 s
->block_size
= crypto_blkcipher_blocksize(s
->desc
.tfm
);
534 /* Plus one for the \0 separator between the random prefix
535 * and the plaintext filename */
536 s
->num_rand_bytes
= (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
+ 1);
537 s
->block_aligned_filename_size
= (s
->num_rand_bytes
+ filename_size
);
538 if ((s
->block_aligned_filename_size
% s
->block_size
) != 0) {
539 s
->num_rand_bytes
+= (s
->block_size
540 - (s
->block_aligned_filename_size
542 s
->block_aligned_filename_size
= (s
->num_rand_bytes
545 /* Octet 0: Tag 70 identifier
546 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
547 * and block-aligned encrypted filename size)
548 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
549 * Octet N2-N3: Cipher identifier (1 octet)
550 * Octets N3-N4: Block-aligned encrypted filename
551 * - Consists of a minimum number of random characters, a \0
552 * separator, and then the filename */
553 s
->max_packet_size
= (1 /* Tag 70 identifier */
554 + 3 /* Max Tag 70 packet size */
555 + ECRYPTFS_SIG_SIZE
/* FNEK sig */
556 + 1 /* Cipher identifier */
557 + s
->block_aligned_filename_size
);
559 (*packet_size
) = s
->max_packet_size
;
562 if (s
->max_packet_size
> (*remaining_bytes
)) {
563 printk(KERN_WARNING
"%s: Require [%zd] bytes to write; only "
564 "[%zd] available\n", __func__
, s
->max_packet_size
,
569 s
->block_aligned_filename
= kzalloc(s
->block_aligned_filename_size
,
571 if (!s
->block_aligned_filename
) {
572 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
573 "kzalloc [%zd] bytes\n", __func__
,
574 s
->block_aligned_filename_size
);
579 dest
[s
->i
++] = ECRYPTFS_TAG_70_PACKET_TYPE
;
580 rc
= ecryptfs_write_packet_length(&dest
[s
->i
],
582 + 1 /* Cipher code */
583 + s
->block_aligned_filename_size
),
584 &s
->packet_size_len
);
586 printk(KERN_ERR
"%s: Error generating tag 70 packet "
587 "header; cannot generate packet length; rc = [%d]\n",
589 goto out_free_unlock
;
591 s
->i
+= s
->packet_size_len
;
592 ecryptfs_from_hex(&dest
[s
->i
],
593 mount_crypt_stat
->global_default_fnek_sig
,
595 s
->i
+= ECRYPTFS_SIG_SIZE
;
596 s
->cipher_code
= ecryptfs_code_for_cipher_string(
597 mount_crypt_stat
->global_default_fn_cipher_name
,
598 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
599 if (s
->cipher_code
== 0) {
600 printk(KERN_WARNING
"%s: Unable to generate code for "
601 "cipher [%s] with key bytes [%zd]\n", __func__
,
602 mount_crypt_stat
->global_default_fn_cipher_name
,
603 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
605 goto out_free_unlock
;
607 dest
[s
->i
++] = s
->cipher_code
;
608 rc
= ecryptfs_find_auth_tok_for_sig(
609 &s
->auth_tok
, mount_crypt_stat
,
610 mount_crypt_stat
->global_default_fnek_sig
);
612 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
613 "fnek sig [%s]; rc = [%d]\n", __func__
,
614 mount_crypt_stat
->global_default_fnek_sig
, rc
);
615 goto out_free_unlock
;
617 /* TODO: Support other key modules than passphrase for
618 * filename encryption */
619 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
621 printk(KERN_INFO
"%s: Filename encryption only supports "
622 "password tokens\n", __func__
);
623 goto out_free_unlock
;
627 (u8
*)s
->auth_tok
->token
.password
.session_key_encryption_key
,
628 s
->auth_tok
->token
.password
.session_key_encryption_key_bytes
);
629 s
->hash_desc
.flags
= CRYPTO_TFM_REQ_MAY_SLEEP
;
630 s
->hash_desc
.tfm
= crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST
, 0,
632 if (IS_ERR(s
->hash_desc
.tfm
)) {
633 rc
= PTR_ERR(s
->hash_desc
.tfm
);
634 printk(KERN_ERR
"%s: Error attempting to "
635 "allocate hash crypto context; rc = [%d]\n",
637 goto out_free_unlock
;
639 rc
= crypto_hash_init(&s
->hash_desc
);
642 "%s: Error initializing crypto hash; rc = [%d]\n",
644 goto out_release_free_unlock
;
646 rc
= crypto_hash_update(
647 &s
->hash_desc
, &s
->hash_sg
,
648 s
->auth_tok
->token
.password
.session_key_encryption_key_bytes
);
651 "%s: Error updating crypto hash; rc = [%d]\n",
653 goto out_release_free_unlock
;
655 rc
= crypto_hash_final(&s
->hash_desc
, s
->hash
);
658 "%s: Error finalizing crypto hash; rc = [%d]\n",
660 goto out_release_free_unlock
;
662 for (s
->j
= 0; s
->j
< (s
->num_rand_bytes
- 1); s
->j
++) {
663 s
->block_aligned_filename
[s
->j
] =
664 s
->hash
[(s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)];
665 if ((s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)
666 == (ECRYPTFS_TAG_70_DIGEST_SIZE
- 1)) {
667 sg_init_one(&s
->hash_sg
, (u8
*)s
->hash
,
668 ECRYPTFS_TAG_70_DIGEST_SIZE
);
669 rc
= crypto_hash_init(&s
->hash_desc
);
672 "%s: Error initializing crypto hash; "
673 "rc = [%d]\n", __func__
, rc
);
674 goto out_release_free_unlock
;
676 rc
= crypto_hash_update(&s
->hash_desc
, &s
->hash_sg
,
677 ECRYPTFS_TAG_70_DIGEST_SIZE
);
680 "%s: Error updating crypto hash; "
681 "rc = [%d]\n", __func__
, rc
);
682 goto out_release_free_unlock
;
684 rc
= crypto_hash_final(&s
->hash_desc
, s
->tmp_hash
);
687 "%s: Error finalizing crypto hash; "
688 "rc = [%d]\n", __func__
, rc
);
689 goto out_release_free_unlock
;
691 memcpy(s
->hash
, s
->tmp_hash
,
692 ECRYPTFS_TAG_70_DIGEST_SIZE
);
694 if (s
->block_aligned_filename
[s
->j
] == '\0')
695 s
->block_aligned_filename
[s
->j
] = ECRYPTFS_NON_NULL
;
697 memcpy(&s
->block_aligned_filename
[s
->num_rand_bytes
], filename
,
699 rc
= virt_to_scatterlist(s
->block_aligned_filename
,
700 s
->block_aligned_filename_size
, &s
->src_sg
, 1);
702 printk(KERN_ERR
"%s: Internal error whilst attempting to "
703 "convert filename memory to scatterlist; "
704 "expected rc = 1; got rc = [%d]. "
705 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
706 s
->block_aligned_filename_size
);
707 goto out_release_free_unlock
;
709 rc
= virt_to_scatterlist(&dest
[s
->i
], s
->block_aligned_filename_size
,
712 printk(KERN_ERR
"%s: Internal error whilst attempting to "
713 "convert encrypted filename memory to scatterlist; "
714 "expected rc = 1; got rc = [%d]. "
715 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
716 s
->block_aligned_filename_size
);
717 goto out_release_free_unlock
;
719 /* The characters in the first block effectively do the job
720 * of the IV here, so we just use 0's for the IV. Note the
721 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
722 * >= ECRYPTFS_MAX_IV_BYTES. */
723 memset(s
->iv
, 0, ECRYPTFS_MAX_IV_BYTES
);
724 s
->desc
.info
= s
->iv
;
725 rc
= crypto_blkcipher_setkey(
727 s
->auth_tok
->token
.password
.session_key_encryption_key
,
728 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
730 printk(KERN_ERR
"%s: Error setting key for crypto context; "
731 "rc = [%d]. s->auth_tok->token.password.session_key_"
732 "encryption_key = [0x%p]; mount_crypt_stat->"
733 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
735 s
->auth_tok
->token
.password
.session_key_encryption_key
,
736 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
737 goto out_release_free_unlock
;
739 rc
= crypto_blkcipher_encrypt_iv(&s
->desc
, &s
->dst_sg
, &s
->src_sg
,
740 s
->block_aligned_filename_size
);
742 printk(KERN_ERR
"%s: Error attempting to encrypt filename; "
743 "rc = [%d]\n", __func__
, rc
);
744 goto out_release_free_unlock
;
746 s
->i
+= s
->block_aligned_filename_size
;
747 (*packet_size
) = s
->i
;
748 (*remaining_bytes
) -= (*packet_size
);
749 out_release_free_unlock
:
750 crypto_free_hash(s
->hash_desc
.tfm
);
752 kzfree(s
->block_aligned_filename
);
754 mutex_unlock(s
->tfm_mutex
);
760 struct ecryptfs_parse_tag_70_packet_silly_stack
{
762 size_t max_packet_size
;
763 size_t packet_size_len
;
764 size_t parsed_tag_70_packet_size
;
765 size_t block_aligned_filename_size
;
768 struct mutex
*tfm_mutex
;
769 char *decrypted_filename
;
770 struct ecryptfs_auth_tok
*auth_tok
;
771 struct scatterlist src_sg
;
772 struct scatterlist dst_sg
;
773 struct blkcipher_desc desc
;
774 char fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
+ 1];
775 char iv
[ECRYPTFS_MAX_IV_BYTES
];
776 char cipher_string
[ECRYPTFS_MAX_CIPHER_NAME_SIZE
];
780 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
781 * @filename: This function kmalloc's the memory for the filename
782 * @filename_size: This function sets this to the amount of memory
783 * kmalloc'd for the filename
784 * @packet_size: This function sets this to the the number of octets
785 * in the packet parsed
786 * @mount_crypt_stat: The mount-wide cryptographic context
787 * @data: The memory location containing the start of the tag 70
789 * @max_packet_size: The maximum legal size of the packet to be parsed
792 * Returns zero on success; non-zero otherwise
795 ecryptfs_parse_tag_70_packet(char **filename
, size_t *filename_size
,
797 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
798 char *data
, size_t max_packet_size
)
800 struct ecryptfs_parse_tag_70_packet_silly_stack
*s
;
804 (*filename_size
) = 0;
806 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
808 printk(KERN_ERR
"%s: Out of memory whilst trying to kmalloc "
809 "[%zd] bytes of kernel memory\n", __func__
, sizeof(*s
));
813 s
->desc
.flags
= CRYPTO_TFM_REQ_MAY_SLEEP
;
814 if (max_packet_size
< (1 + 1 + ECRYPTFS_SIG_SIZE
+ 1 + 1)) {
815 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; it must be "
816 "at least [%d]\n", __func__
, max_packet_size
,
817 (1 + 1 + ECRYPTFS_SIG_SIZE
+ 1 + 1));
821 /* Octet 0: Tag 70 identifier
822 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
823 * and block-aligned encrypted filename size)
824 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
825 * Octet N2-N3: Cipher identifier (1 octet)
826 * Octets N3-N4: Block-aligned encrypted filename
827 * - Consists of a minimum number of random numbers, a \0
828 * separator, and then the filename */
829 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_70_PACKET_TYPE
) {
830 printk(KERN_WARNING
"%s: Invalid packet tag [0x%.2x]; must be "
831 "tag [0x%.2x]\n", __func__
,
832 data
[((*packet_size
) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE
);
836 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)],
837 &s
->parsed_tag_70_packet_size
,
838 &s
->packet_size_len
);
840 printk(KERN_WARNING
"%s: Error parsing packet length; "
841 "rc = [%d]\n", __func__
, rc
);
844 s
->block_aligned_filename_size
= (s
->parsed_tag_70_packet_size
845 - ECRYPTFS_SIG_SIZE
- 1);
846 if ((1 + s
->packet_size_len
+ s
->parsed_tag_70_packet_size
)
848 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; real packet "
849 "size is [%zd]\n", __func__
, max_packet_size
,
850 (1 + s
->packet_size_len
+ 1
851 + s
->block_aligned_filename_size
));
855 (*packet_size
) += s
->packet_size_len
;
856 ecryptfs_to_hex(s
->fnek_sig_hex
, &data
[(*packet_size
)],
858 s
->fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
859 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
860 s
->cipher_code
= data
[(*packet_size
)++];
861 rc
= ecryptfs_cipher_code_to_string(s
->cipher_string
, s
->cipher_code
);
863 printk(KERN_WARNING
"%s: Cipher code [%d] is invalid\n",
864 __func__
, s
->cipher_code
);
867 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&s
->desc
.tfm
,
871 printk(KERN_ERR
"Internal error whilst attempting to get "
872 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
873 s
->cipher_string
, rc
);
876 mutex_lock(s
->tfm_mutex
);
877 rc
= virt_to_scatterlist(&data
[(*packet_size
)],
878 s
->block_aligned_filename_size
, &s
->src_sg
, 1);
880 printk(KERN_ERR
"%s: Internal error whilst attempting to "
881 "convert encrypted filename memory to scatterlist; "
882 "expected rc = 1; got rc = [%d]. "
883 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
884 s
->block_aligned_filename_size
);
887 (*packet_size
) += s
->block_aligned_filename_size
;
888 s
->decrypted_filename
= kmalloc(s
->block_aligned_filename_size
,
890 if (!s
->decrypted_filename
) {
891 printk(KERN_ERR
"%s: Out of memory whilst attempting to "
892 "kmalloc [%zd] bytes\n", __func__
,
893 s
->block_aligned_filename_size
);
897 rc
= virt_to_scatterlist(s
->decrypted_filename
,
898 s
->block_aligned_filename_size
, &s
->dst_sg
, 1);
900 printk(KERN_ERR
"%s: Internal error whilst attempting to "
901 "convert decrypted filename memory to scatterlist; "
902 "expected rc = 1; got rc = [%d]. "
903 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
904 s
->block_aligned_filename_size
);
905 goto out_free_unlock
;
907 /* The characters in the first block effectively do the job of
908 * the IV here, so we just use 0's for the IV. Note the
909 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
910 * >= ECRYPTFS_MAX_IV_BYTES. */
911 memset(s
->iv
, 0, ECRYPTFS_MAX_IV_BYTES
);
912 s
->desc
.info
= s
->iv
;
913 rc
= ecryptfs_find_auth_tok_for_sig(&s
->auth_tok
, mount_crypt_stat
,
916 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
917 "fnek sig [%s]; rc = [%d]\n", __func__
, s
->fnek_sig_hex
,
919 goto out_free_unlock
;
921 /* TODO: Support other key modules than passphrase for
922 * filename encryption */
923 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
925 printk(KERN_INFO
"%s: Filename encryption only supports "
926 "password tokens\n", __func__
);
927 goto out_free_unlock
;
929 rc
= crypto_blkcipher_setkey(
931 s
->auth_tok
->token
.password
.session_key_encryption_key
,
932 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
934 printk(KERN_ERR
"%s: Error setting key for crypto context; "
935 "rc = [%d]. s->auth_tok->token.password.session_key_"
936 "encryption_key = [0x%p]; mount_crypt_stat->"
937 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
939 s
->auth_tok
->token
.password
.session_key_encryption_key
,
940 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
941 goto out_free_unlock
;
943 rc
= crypto_blkcipher_decrypt_iv(&s
->desc
, &s
->dst_sg
, &s
->src_sg
,
944 s
->block_aligned_filename_size
);
946 printk(KERN_ERR
"%s: Error attempting to decrypt filename; "
947 "rc = [%d]\n", __func__
, rc
);
948 goto out_free_unlock
;
951 while (s
->decrypted_filename
[s
->i
] != '\0'
952 && s
->i
< s
->block_aligned_filename_size
)
954 if (s
->i
== s
->block_aligned_filename_size
) {
955 printk(KERN_WARNING
"%s: Invalid tag 70 packet; could not "
956 "find valid separator between random characters and "
957 "the filename\n", __func__
);
959 goto out_free_unlock
;
962 (*filename_size
) = (s
->block_aligned_filename_size
- s
->i
);
963 if (!((*filename_size
) > 0 && (*filename_size
< PATH_MAX
))) {
964 printk(KERN_WARNING
"%s: Filename size is [%zd], which is "
965 "invalid\n", __func__
, (*filename_size
));
967 goto out_free_unlock
;
969 (*filename
) = kmalloc(((*filename_size
) + 1), GFP_KERNEL
);
971 printk(KERN_ERR
"%s: Out of memory whilst attempting to "
972 "kmalloc [%zd] bytes\n", __func__
,
973 ((*filename_size
) + 1));
975 goto out_free_unlock
;
977 memcpy((*filename
), &s
->decrypted_filename
[s
->i
], (*filename_size
));
978 (*filename
)[(*filename_size
)] = '\0';
980 kfree(s
->decrypted_filename
);
982 mutex_unlock(s
->tfm_mutex
);
986 (*filename_size
) = 0;
994 ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
999 switch (auth_tok
->token_type
) {
1000 case ECRYPTFS_PASSWORD
:
1001 (*sig
) = auth_tok
->token
.password
.signature
;
1003 case ECRYPTFS_PRIVATE_KEY
:
1004 (*sig
) = auth_tok
->token
.private_key
.signature
;
1007 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
1008 auth_tok
->token_type
);
1015 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1016 * @auth_tok: The key authentication token used to decrypt the session key
1017 * @crypt_stat: The cryptographic context
1019 * Returns zero on success; non-zero error otherwise.
1022 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1023 struct ecryptfs_crypt_stat
*crypt_stat
)
1026 struct ecryptfs_msg_ctx
*msg_ctx
;
1027 struct ecryptfs_message
*msg
= NULL
;
1033 rc
= ecryptfs_get_auth_tok_sig(&auth_tok_sig
, auth_tok
);
1035 printk(KERN_ERR
"Unrecognized auth tok type: [%d]\n",
1036 auth_tok
->token_type
);
1039 rc
= write_tag_64_packet(auth_tok_sig
, &(auth_tok
->session_key
),
1040 &payload
, &payload_len
);
1042 ecryptfs_printk(KERN_ERR
, "Failed to write tag 64 packet\n");
1045 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1047 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1051 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1053 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 65 packet "
1054 "from the user space daemon\n");
1058 rc
= parse_tag_65_packet(&(auth_tok
->session_key
),
1061 printk(KERN_ERR
"Failed to parse tag 65 packet; rc = [%d]\n",
1065 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1066 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1067 auth_tok
->session_key
.decrypted_key_size
);
1068 crypt_stat
->key_size
= auth_tok
->session_key
.decrypted_key_size
;
1069 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
, cipher_code
);
1071 ecryptfs_printk(KERN_ERR
, "Cipher code [%d] is invalid\n",
1075 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1076 if (ecryptfs_verbosity
> 0) {
1077 ecryptfs_printk(KERN_DEBUG
, "Decrypted session key:\n");
1078 ecryptfs_dump_hex(crypt_stat
->key
,
1079 crypt_stat
->key_size
);
1087 static void wipe_auth_tok_list(struct list_head
*auth_tok_list_head
)
1089 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1090 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1092 list_for_each_entry_safe(auth_tok_list_item
, auth_tok_list_item_tmp
,
1093 auth_tok_list_head
, list
) {
1094 list_del(&auth_tok_list_item
->list
);
1095 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1096 auth_tok_list_item
);
1100 struct kmem_cache
*ecryptfs_auth_tok_list_item_cache
;
1103 * parse_tag_1_packet
1104 * @crypt_stat: The cryptographic context to modify based on packet contents
1105 * @data: The raw bytes of the packet.
1106 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1107 * a new authentication token will be placed at the
1108 * end of this list for this packet.
1109 * @new_auth_tok: Pointer to a pointer to memory that this function
1110 * allocates; sets the memory address of the pointer to
1111 * NULL on error. This object is added to the
1113 * @packet_size: This function writes the size of the parsed packet
1114 * into this memory location; zero on error.
1115 * @max_packet_size: The maximum allowable packet size
1117 * Returns zero on success; non-zero on error.
1120 parse_tag_1_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1121 unsigned char *data
, struct list_head
*auth_tok_list
,
1122 struct ecryptfs_auth_tok
**new_auth_tok
,
1123 size_t *packet_size
, size_t max_packet_size
)
1126 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1131 (*new_auth_tok
) = NULL
;
1133 * This format is inspired by OpenPGP; see RFC 2440
1136 * Tag 1 identifier (1 byte)
1137 * Max Tag 1 packet size (max 3 bytes)
1139 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1140 * Cipher identifier (1 byte)
1141 * Encrypted key size (arbitrary)
1143 * 12 bytes minimum packet size
1145 if (unlikely(max_packet_size
< 12)) {
1146 printk(KERN_ERR
"Invalid max packet size; must be >=12\n");
1150 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_1_PACKET_TYPE
) {
1151 printk(KERN_ERR
"Enter w/ first byte != 0x%.2x\n",
1152 ECRYPTFS_TAG_1_PACKET_TYPE
);
1156 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1157 * at end of function upon failure */
1158 auth_tok_list_item
=
1159 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
,
1161 if (!auth_tok_list_item
) {
1162 printk(KERN_ERR
"Unable to allocate memory\n");
1166 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1167 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1170 printk(KERN_WARNING
"Error parsing packet length; "
1174 if (unlikely(body_size
< (ECRYPTFS_SIG_SIZE
+ 2))) {
1175 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1179 (*packet_size
) += length_size
;
1180 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1181 printk(KERN_WARNING
"Packet size exceeds max\n");
1185 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1186 printk(KERN_WARNING
"Unknown version number [%d]\n",
1187 data
[(*packet_size
) - 1]);
1191 ecryptfs_to_hex((*new_auth_tok
)->token
.private_key
.signature
,
1192 &data
[(*packet_size
)], ECRYPTFS_SIG_SIZE
);
1193 *packet_size
+= ECRYPTFS_SIG_SIZE
;
1194 /* This byte is skipped because the kernel does not need to
1195 * know which public key encryption algorithm was used */
1197 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1198 body_size
- (ECRYPTFS_SIG_SIZE
+ 2);
1199 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1200 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1201 printk(KERN_WARNING
"Tag 1 packet contains key larger "
1202 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1206 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1207 &data
[(*packet_size
)], (body_size
- (ECRYPTFS_SIG_SIZE
+ 2)));
1208 (*packet_size
) += (*new_auth_tok
)->session_key
.encrypted_key_size
;
1209 (*new_auth_tok
)->session_key
.flags
&=
1210 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1211 (*new_auth_tok
)->session_key
.flags
|=
1212 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1213 (*new_auth_tok
)->token_type
= ECRYPTFS_PRIVATE_KEY
;
1214 (*new_auth_tok
)->flags
= 0;
1215 (*new_auth_tok
)->session_key
.flags
&=
1216 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1217 (*new_auth_tok
)->session_key
.flags
&=
1218 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1219 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1222 (*new_auth_tok
) = NULL
;
1223 memset(auth_tok_list_item
, 0,
1224 sizeof(struct ecryptfs_auth_tok_list_item
));
1225 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1226 auth_tok_list_item
);
1234 * parse_tag_3_packet
1235 * @crypt_stat: The cryptographic context to modify based on packet
1237 * @data: The raw bytes of the packet.
1238 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1239 * a new authentication token will be placed at the end
1240 * of this list for this packet.
1241 * @new_auth_tok: Pointer to a pointer to memory that this function
1242 * allocates; sets the memory address of the pointer to
1243 * NULL on error. This object is added to the
1245 * @packet_size: This function writes the size of the parsed packet
1246 * into this memory location; zero on error.
1247 * @max_packet_size: maximum number of bytes to parse
1249 * Returns zero on success; non-zero on error.
1252 parse_tag_3_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1253 unsigned char *data
, struct list_head
*auth_tok_list
,
1254 struct ecryptfs_auth_tok
**new_auth_tok
,
1255 size_t *packet_size
, size_t max_packet_size
)
1258 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1263 (*new_auth_tok
) = NULL
;
1265 *This format is inspired by OpenPGP; see RFC 2440
1268 * Tag 3 identifier (1 byte)
1269 * Max Tag 3 packet size (max 3 bytes)
1271 * Cipher code (1 byte)
1272 * S2K specifier (1 byte)
1273 * Hash identifier (1 byte)
1274 * Salt (ECRYPTFS_SALT_SIZE)
1275 * Hash iterations (1 byte)
1276 * Encrypted key (arbitrary)
1278 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1280 if (max_packet_size
< (ECRYPTFS_SALT_SIZE
+ 7)) {
1281 printk(KERN_ERR
"Max packet size too large\n");
1285 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_3_PACKET_TYPE
) {
1286 printk(KERN_ERR
"First byte != 0x%.2x; invalid packet\n",
1287 ECRYPTFS_TAG_3_PACKET_TYPE
);
1291 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1292 * at end of function upon failure */
1293 auth_tok_list_item
=
1294 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
, GFP_KERNEL
);
1295 if (!auth_tok_list_item
) {
1296 printk(KERN_ERR
"Unable to allocate memory\n");
1300 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1301 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1304 printk(KERN_WARNING
"Error parsing packet length; rc = [%d]\n",
1308 if (unlikely(body_size
< (ECRYPTFS_SALT_SIZE
+ 5))) {
1309 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1313 (*packet_size
) += length_size
;
1314 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1315 printk(KERN_ERR
"Packet size exceeds max\n");
1319 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1320 (body_size
- (ECRYPTFS_SALT_SIZE
+ 5));
1321 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1322 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1323 printk(KERN_WARNING
"Tag 3 packet contains key larger "
1324 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1328 if (unlikely(data
[(*packet_size
)++] != 0x04)) {
1329 printk(KERN_WARNING
"Unknown version number [%d]\n",
1330 data
[(*packet_size
) - 1]);
1334 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
,
1335 (u16
)data
[(*packet_size
)]);
1338 /* A little extra work to differentiate among the AES key
1339 * sizes; see RFC2440 */
1340 switch(data
[(*packet_size
)++]) {
1341 case RFC2440_CIPHER_AES_192
:
1342 crypt_stat
->key_size
= 24;
1345 crypt_stat
->key_size
=
1346 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1348 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1351 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1352 printk(KERN_WARNING
"Only S2K ID 3 is currently supported\n");
1356 /* TODO: finish the hash mapping */
1357 switch (data
[(*packet_size
)++]) {
1358 case 0x01: /* See RFC2440 for these numbers and their mappings */
1360 memcpy((*new_auth_tok
)->token
.password
.salt
,
1361 &data
[(*packet_size
)], ECRYPTFS_SALT_SIZE
);
1362 (*packet_size
) += ECRYPTFS_SALT_SIZE
;
1363 /* This conversion was taken straight from RFC2440 */
1364 (*new_auth_tok
)->token
.password
.hash_iterations
=
1365 ((u32
) 16 + (data
[(*packet_size
)] & 15))
1366 << ((data
[(*packet_size
)] >> 4) + 6);
1368 /* Friendly reminder:
1369 * (*new_auth_tok)->session_key.encrypted_key_size =
1370 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1371 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1372 &data
[(*packet_size
)],
1373 (*new_auth_tok
)->session_key
.encrypted_key_size
);
1375 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1376 (*new_auth_tok
)->session_key
.flags
&=
1377 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1378 (*new_auth_tok
)->session_key
.flags
|=
1379 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1380 (*new_auth_tok
)->token
.password
.hash_algo
= 0x01; /* MD5 */
1383 ecryptfs_printk(KERN_ERR
, "Unsupported hash algorithm: "
1384 "[%d]\n", data
[(*packet_size
) - 1]);
1388 (*new_auth_tok
)->token_type
= ECRYPTFS_PASSWORD
;
1389 /* TODO: Parametarize; we might actually want userspace to
1390 * decrypt the session key. */
1391 (*new_auth_tok
)->session_key
.flags
&=
1392 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1393 (*new_auth_tok
)->session_key
.flags
&=
1394 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1395 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1398 (*new_auth_tok
) = NULL
;
1399 memset(auth_tok_list_item
, 0,
1400 sizeof(struct ecryptfs_auth_tok_list_item
));
1401 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1402 auth_tok_list_item
);
1410 * parse_tag_11_packet
1411 * @data: The raw bytes of the packet
1412 * @contents: This function writes the data contents of the literal
1413 * packet into this memory location
1414 * @max_contents_bytes: The maximum number of bytes that this function
1415 * is allowed to write into contents
1416 * @tag_11_contents_size: This function writes the size of the parsed
1417 * contents into this memory location; zero on
1419 * @packet_size: This function writes the size of the parsed packet
1420 * into this memory location; zero on error
1421 * @max_packet_size: maximum number of bytes to parse
1423 * Returns zero on success; non-zero on error.
1426 parse_tag_11_packet(unsigned char *data
, unsigned char *contents
,
1427 size_t max_contents_bytes
, size_t *tag_11_contents_size
,
1428 size_t *packet_size
, size_t max_packet_size
)
1435 (*tag_11_contents_size
) = 0;
1436 /* This format is inspired by OpenPGP; see RFC 2440
1439 * Tag 11 identifier (1 byte)
1440 * Max Tag 11 packet size (max 3 bytes)
1441 * Binary format specifier (1 byte)
1442 * Filename length (1 byte)
1443 * Filename ("_CONSOLE") (8 bytes)
1444 * Modification date (4 bytes)
1445 * Literal data (arbitrary)
1447 * We need at least 16 bytes of data for the packet to even be
1450 if (max_packet_size
< 16) {
1451 printk(KERN_ERR
"Maximum packet size too small\n");
1455 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
1456 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1460 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1463 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1466 if (body_size
< 14) {
1467 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1471 (*packet_size
) += length_size
;
1472 (*tag_11_contents_size
) = (body_size
- 14);
1473 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
1474 printk(KERN_ERR
"Packet size exceeds max\n");
1478 if (unlikely((*tag_11_contents_size
) > max_contents_bytes
)) {
1479 printk(KERN_ERR
"Literal data section in tag 11 packet exceeds "
1484 if (data
[(*packet_size
)++] != 0x62) {
1485 printk(KERN_WARNING
"Unrecognizable packet\n");
1489 if (data
[(*packet_size
)++] != 0x08) {
1490 printk(KERN_WARNING
"Unrecognizable packet\n");
1494 (*packet_size
) += 12; /* Ignore filename and modification date */
1495 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
1496 (*packet_size
) += (*tag_11_contents_size
);
1500 (*tag_11_contents_size
) = 0;
1506 * ecryptfs_verify_version
1507 * @version: The version number to confirm
1509 * Returns zero on good version; non-zero otherwise
1511 static int ecryptfs_verify_version(u16 version
)
1514 unsigned char major
;
1515 unsigned char minor
;
1517 major
= ((version
>> 8) & 0xFF);
1518 minor
= (version
& 0xFF);
1519 if (major
!= ECRYPTFS_VERSION_MAJOR
) {
1520 ecryptfs_printk(KERN_ERR
, "Major version number mismatch. "
1521 "Expected [%d]; got [%d]\n",
1522 ECRYPTFS_VERSION_MAJOR
, major
);
1526 if (minor
!= ECRYPTFS_VERSION_MINOR
) {
1527 ecryptfs_printk(KERN_ERR
, "Minor version number mismatch. "
1528 "Expected [%d]; got [%d]\n",
1529 ECRYPTFS_VERSION_MINOR
, minor
);
1537 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
1538 struct ecryptfs_auth_tok
**auth_tok
,
1543 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
1544 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
1545 printk(KERN_ERR
"Could not find key with description: [%s]\n",
1547 rc
= process_request_key_err(PTR_ERR(*auth_tok_key
));
1550 (*auth_tok
) = ecryptfs_get_key_payload_data(*auth_tok_key
);
1551 if (ecryptfs_verify_version((*auth_tok
)->version
)) {
1553 "Data structure version mismatch. "
1554 "Userspace tools must match eCryptfs "
1555 "kernel module with major version [%d] "
1556 "and minor version [%d]\n",
1557 ECRYPTFS_VERSION_MAJOR
,
1558 ECRYPTFS_VERSION_MINOR
);
1562 if ((*auth_tok
)->token_type
!= ECRYPTFS_PASSWORD
1563 && (*auth_tok
)->token_type
!= ECRYPTFS_PRIVATE_KEY
) {
1564 printk(KERN_ERR
"Invalid auth_tok structure "
1565 "returned from key query\n");
1574 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1575 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1576 * @crypt_stat: The cryptographic context
1578 * Returns zero on success; non-zero error otherwise
1581 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1582 struct ecryptfs_crypt_stat
*crypt_stat
)
1584 struct scatterlist dst_sg
[2];
1585 struct scatterlist src_sg
[2];
1586 struct mutex
*tfm_mutex
;
1587 struct blkcipher_desc desc
= {
1588 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1592 if (unlikely(ecryptfs_verbosity
> 0)) {
1594 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1595 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1597 auth_tok
->token
.password
.session_key_encryption_key
,
1598 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1600 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1601 crypt_stat
->cipher
);
1603 printk(KERN_ERR
"Internal error whilst attempting to get "
1604 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1605 crypt_stat
->cipher
, rc
);
1608 rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1609 auth_tok
->session_key
.encrypted_key_size
,
1611 if (rc
< 1 || rc
> 2) {
1612 printk(KERN_ERR
"Internal error whilst attempting to convert "
1613 "auth_tok->session_key.encrypted_key to scatterlist; "
1614 "expected rc = 1; got rc = [%d]. "
1615 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc
,
1616 auth_tok
->session_key
.encrypted_key_size
);
1619 auth_tok
->session_key
.decrypted_key_size
=
1620 auth_tok
->session_key
.encrypted_key_size
;
1621 rc
= virt_to_scatterlist(auth_tok
->session_key
.decrypted_key
,
1622 auth_tok
->session_key
.decrypted_key_size
,
1624 if (rc
< 1 || rc
> 2) {
1625 printk(KERN_ERR
"Internal error whilst attempting to convert "
1626 "auth_tok->session_key.decrypted_key to scatterlist; "
1627 "expected rc = 1; got rc = [%d]\n", rc
);
1630 mutex_lock(tfm_mutex
);
1631 rc
= crypto_blkcipher_setkey(
1632 desc
.tfm
, auth_tok
->token
.password
.session_key_encryption_key
,
1633 crypt_stat
->key_size
);
1634 if (unlikely(rc
< 0)) {
1635 mutex_unlock(tfm_mutex
);
1636 printk(KERN_ERR
"Error setting key for crypto context\n");
1640 rc
= crypto_blkcipher_decrypt(&desc
, dst_sg
, src_sg
,
1641 auth_tok
->session_key
.encrypted_key_size
);
1642 mutex_unlock(tfm_mutex
);
1644 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
1647 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1648 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1649 auth_tok
->session_key
.decrypted_key_size
);
1650 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1651 if (unlikely(ecryptfs_verbosity
> 0)) {
1652 ecryptfs_printk(KERN_DEBUG
, "FEK of size [%d]:\n",
1653 crypt_stat
->key_size
);
1654 ecryptfs_dump_hex(crypt_stat
->key
,
1655 crypt_stat
->key_size
);
1662 * ecryptfs_parse_packet_set
1663 * @crypt_stat: The cryptographic context
1664 * @src: Virtual address of region of memory containing the packets
1665 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1667 * Get crypt_stat to have the file's session key if the requisite key
1668 * is available to decrypt the session key.
1670 * Returns Zero if a valid authentication token was retrieved and
1671 * processed; negative value for file not encrypted or for error
1674 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1676 struct dentry
*ecryptfs_dentry
)
1679 size_t found_auth_tok
;
1680 size_t next_packet_is_auth_tok_packet
;
1681 struct list_head auth_tok_list
;
1682 struct ecryptfs_auth_tok
*matching_auth_tok
;
1683 struct ecryptfs_auth_tok
*candidate_auth_tok
;
1684 char *candidate_auth_tok_sig
;
1686 struct ecryptfs_auth_tok
*new_auth_tok
;
1687 unsigned char sig_tmp_space
[ECRYPTFS_SIG_SIZE
];
1688 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1689 size_t tag_11_contents_size
;
1690 size_t tag_11_packet_size
;
1693 INIT_LIST_HEAD(&auth_tok_list
);
1694 /* Parse the header to find as many packets as we can; these will be
1695 * added the our &auth_tok_list */
1696 next_packet_is_auth_tok_packet
= 1;
1697 while (next_packet_is_auth_tok_packet
) {
1698 size_t max_packet_size
= ((PAGE_CACHE_SIZE
- 8) - i
);
1701 case ECRYPTFS_TAG_3_PACKET_TYPE
:
1702 rc
= parse_tag_3_packet(crypt_stat
,
1703 (unsigned char *)&src
[i
],
1704 &auth_tok_list
, &new_auth_tok
,
1705 &packet_size
, max_packet_size
);
1707 ecryptfs_printk(KERN_ERR
, "Error parsing "
1713 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1716 &tag_11_contents_size
,
1717 &tag_11_packet_size
,
1720 ecryptfs_printk(KERN_ERR
, "No valid "
1721 "(ecryptfs-specific) literal "
1722 "packet containing "
1723 "authentication token "
1724 "signature found after "
1729 i
+= tag_11_packet_size
;
1730 if (ECRYPTFS_SIG_SIZE
!= tag_11_contents_size
) {
1731 ecryptfs_printk(KERN_ERR
, "Expected "
1732 "signature of size [%d]; "
1735 tag_11_contents_size
);
1739 ecryptfs_to_hex(new_auth_tok
->token
.password
.signature
,
1740 sig_tmp_space
, tag_11_contents_size
);
1741 new_auth_tok
->token
.password
.signature
[
1742 ECRYPTFS_PASSWORD_SIG_SIZE
] = '\0';
1743 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1745 case ECRYPTFS_TAG_1_PACKET_TYPE
:
1746 rc
= parse_tag_1_packet(crypt_stat
,
1747 (unsigned char *)&src
[i
],
1748 &auth_tok_list
, &new_auth_tok
,
1749 &packet_size
, max_packet_size
);
1751 ecryptfs_printk(KERN_ERR
, "Error parsing "
1757 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1759 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1760 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1761 "(Tag 11 not allowed by itself)\n");
1766 ecryptfs_printk(KERN_DEBUG
, "No packet at offset "
1767 "[%d] of the file header; hex value of "
1768 "character is [0x%.2x]\n", i
, src
[i
]);
1769 next_packet_is_auth_tok_packet
= 0;
1772 if (list_empty(&auth_tok_list
)) {
1773 printk(KERN_ERR
"The lower file appears to be a non-encrypted "
1774 "eCryptfs file; this is not supported in this version "
1775 "of the eCryptfs kernel module\n");
1779 /* auth_tok_list contains the set of authentication tokens
1780 * parsed from the metadata. We need to find a matching
1781 * authentication token that has the secret component(s)
1782 * necessary to decrypt the EFEK in the auth_tok parsed from
1783 * the metadata. There may be several potential matches, but
1784 * just one will be sufficient to decrypt to get the FEK. */
1785 find_next_matching_auth_tok
:
1787 list_for_each_entry(auth_tok_list_item
, &auth_tok_list
, list
) {
1788 candidate_auth_tok
= &auth_tok_list_item
->auth_tok
;
1789 if (unlikely(ecryptfs_verbosity
> 0)) {
1790 ecryptfs_printk(KERN_DEBUG
,
1791 "Considering cadidate auth tok:\n");
1792 ecryptfs_dump_auth_tok(candidate_auth_tok
);
1794 rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1795 candidate_auth_tok
);
1798 "Unrecognized candidate auth tok type: [%d]\n",
1799 candidate_auth_tok
->token_type
);
1803 ecryptfs_find_auth_tok_for_sig(&matching_auth_tok
,
1804 crypt_stat
->mount_crypt_stat
,
1805 candidate_auth_tok_sig
);
1806 if (matching_auth_tok
) {
1808 goto found_matching_auth_tok
;
1811 if (!found_auth_tok
) {
1812 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1813 "authentication token\n");
1817 found_matching_auth_tok
:
1818 if (candidate_auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1819 memcpy(&(candidate_auth_tok
->token
.private_key
),
1820 &(matching_auth_tok
->token
.private_key
),
1821 sizeof(struct ecryptfs_private_key
));
1822 rc
= decrypt_pki_encrypted_session_key(candidate_auth_tok
,
1824 } else if (candidate_auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1825 memcpy(&(candidate_auth_tok
->token
.password
),
1826 &(matching_auth_tok
->token
.password
),
1827 sizeof(struct ecryptfs_password
));
1828 rc
= decrypt_passphrase_encrypted_session_key(
1829 candidate_auth_tok
, crypt_stat
);
1832 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1834 ecryptfs_printk(KERN_WARNING
, "Error decrypting the "
1835 "session key for authentication token with sig "
1836 "[%.*s]; rc = [%d]. Removing auth tok "
1837 "candidate from the list and searching for "
1838 "the next match.\n", candidate_auth_tok_sig
,
1839 ECRYPTFS_SIG_SIZE_HEX
, rc
);
1840 list_for_each_entry_safe(auth_tok_list_item
,
1841 auth_tok_list_item_tmp
,
1842 &auth_tok_list
, list
) {
1843 if (candidate_auth_tok
1844 == &auth_tok_list_item
->auth_tok
) {
1845 list_del(&auth_tok_list_item
->list
);
1847 ecryptfs_auth_tok_list_item_cache
,
1848 auth_tok_list_item
);
1849 goto find_next_matching_auth_tok
;
1854 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1856 ecryptfs_printk(KERN_ERR
, "Error computing "
1860 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1862 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1863 "context for cipher [%s]; rc = [%d]\n",
1864 crypt_stat
->cipher
, rc
);
1867 wipe_auth_tok_list(&auth_tok_list
);
1873 pki_encrypt_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1874 struct ecryptfs_crypt_stat
*crypt_stat
,
1875 struct ecryptfs_key_record
*key_rec
)
1877 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1878 char *payload
= NULL
;
1880 struct ecryptfs_message
*msg
;
1883 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1884 ecryptfs_code_for_cipher_string(
1886 crypt_stat
->key_size
),
1887 crypt_stat
, &payload
, &payload_len
);
1889 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
1892 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1894 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1898 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1900 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
1901 "from the user space daemon\n");
1905 rc
= parse_tag_67_packet(key_rec
, msg
);
1907 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
1914 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1915 * @dest: Buffer into which to write the packet
1916 * @remaining_bytes: Maximum number of bytes that can be writtn
1917 * @auth_tok: The authentication token used for generating the tag 1 packet
1918 * @crypt_stat: The cryptographic context
1919 * @key_rec: The key record struct for the tag 1 packet
1920 * @packet_size: This function will write the number of bytes that end
1921 * up constituting the packet; set to zero on error
1923 * Returns zero on success; non-zero on error.
1926 write_tag_1_packet(char *dest
, size_t *remaining_bytes
,
1927 struct ecryptfs_auth_tok
*auth_tok
,
1928 struct ecryptfs_crypt_stat
*crypt_stat
,
1929 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1932 size_t encrypted_session_key_valid
= 0;
1933 size_t packet_size_length
;
1934 size_t max_packet_size
;
1938 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
1940 encrypted_session_key_valid
= 0;
1941 for (i
= 0; i
< crypt_stat
->key_size
; i
++)
1942 encrypted_session_key_valid
|=
1943 auth_tok
->session_key
.encrypted_key
[i
];
1944 if (encrypted_session_key_valid
) {
1945 memcpy(key_rec
->enc_key
,
1946 auth_tok
->session_key
.encrypted_key
,
1947 auth_tok
->session_key
.encrypted_key_size
);
1948 goto encrypted_session_key_set
;
1950 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1951 auth_tok
->session_key
.encrypted_key_size
=
1952 auth_tok
->token
.private_key
.key_size
;
1953 rc
= pki_encrypt_session_key(auth_tok
, crypt_stat
, key_rec
);
1955 printk(KERN_ERR
"Failed to encrypt session key via a key "
1956 "module; rc = [%d]\n", rc
);
1959 if (ecryptfs_verbosity
> 0) {
1960 ecryptfs_printk(KERN_DEBUG
, "Encrypted key:\n");
1961 ecryptfs_dump_hex(key_rec
->enc_key
, key_rec
->enc_key_size
);
1963 encrypted_session_key_set
:
1964 /* This format is inspired by OpenPGP; see RFC 2440
1966 max_packet_size
= (1 /* Tag 1 identifier */
1967 + 3 /* Max Tag 1 packet size */
1969 + ECRYPTFS_SIG_SIZE
/* Key identifier */
1970 + 1 /* Cipher identifier */
1971 + key_rec
->enc_key_size
); /* Encrypted key size */
1972 if (max_packet_size
> (*remaining_bytes
)) {
1973 printk(KERN_ERR
"Packet length larger than maximum allowable; "
1974 "need up to [%td] bytes, but there are only [%td] "
1975 "available\n", max_packet_size
, (*remaining_bytes
));
1979 dest
[(*packet_size
)++] = ECRYPTFS_TAG_1_PACKET_TYPE
;
1980 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
1981 (max_packet_size
- 4),
1982 &packet_size_length
);
1984 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
1985 "header; cannot generate packet length\n");
1988 (*packet_size
) += packet_size_length
;
1989 dest
[(*packet_size
)++] = 0x03; /* version 3 */
1990 memcpy(&dest
[(*packet_size
)], key_rec
->sig
, ECRYPTFS_SIG_SIZE
);
1991 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
1992 dest
[(*packet_size
)++] = RFC2440_CIPHER_RSA
;
1993 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1994 key_rec
->enc_key_size
);
1995 (*packet_size
) += key_rec
->enc_key_size
;
2000 (*remaining_bytes
) -= (*packet_size
);
2005 * write_tag_11_packet
2006 * @dest: Target into which Tag 11 packet is to be written
2007 * @remaining_bytes: Maximum packet length
2008 * @contents: Byte array of contents to copy in
2009 * @contents_length: Number of bytes in contents
2010 * @packet_length: Length of the Tag 11 packet written; zero on error
2012 * Returns zero on success; non-zero on error.
2015 write_tag_11_packet(char *dest
, size_t *remaining_bytes
, char *contents
,
2016 size_t contents_length
, size_t *packet_length
)
2018 size_t packet_size_length
;
2019 size_t max_packet_size
;
2022 (*packet_length
) = 0;
2023 /* This format is inspired by OpenPGP; see RFC 2440
2025 max_packet_size
= (1 /* Tag 11 identifier */
2026 + 3 /* Max Tag 11 packet size */
2027 + 1 /* Binary format specifier */
2028 + 1 /* Filename length */
2029 + 8 /* Filename ("_CONSOLE") */
2030 + 4 /* Modification date */
2031 + contents_length
); /* Literal data */
2032 if (max_packet_size
> (*remaining_bytes
)) {
2033 printk(KERN_ERR
"Packet length larger than maximum allowable; "
2034 "need up to [%td] bytes, but there are only [%td] "
2035 "available\n", max_packet_size
, (*remaining_bytes
));
2039 dest
[(*packet_length
)++] = ECRYPTFS_TAG_11_PACKET_TYPE
;
2040 rc
= ecryptfs_write_packet_length(&dest
[(*packet_length
)],
2041 (max_packet_size
- 4),
2042 &packet_size_length
);
2044 printk(KERN_ERR
"Error generating tag 11 packet header; cannot "
2045 "generate packet length. rc = [%d]\n", rc
);
2048 (*packet_length
) += packet_size_length
;
2049 dest
[(*packet_length
)++] = 0x62; /* binary data format specifier */
2050 dest
[(*packet_length
)++] = 8;
2051 memcpy(&dest
[(*packet_length
)], "_CONSOLE", 8);
2052 (*packet_length
) += 8;
2053 memset(&dest
[(*packet_length
)], 0x00, 4);
2054 (*packet_length
) += 4;
2055 memcpy(&dest
[(*packet_length
)], contents
, contents_length
);
2056 (*packet_length
) += contents_length
;
2059 (*packet_length
) = 0;
2061 (*remaining_bytes
) -= (*packet_length
);
2066 * write_tag_3_packet
2067 * @dest: Buffer into which to write the packet
2068 * @remaining_bytes: Maximum number of bytes that can be written
2069 * @auth_tok: Authentication token
2070 * @crypt_stat: The cryptographic context
2071 * @key_rec: encrypted key
2072 * @packet_size: This function will write the number of bytes that end
2073 * up constituting the packet; set to zero on error
2075 * Returns zero on success; non-zero on error.
2078 write_tag_3_packet(char *dest
, size_t *remaining_bytes
,
2079 struct ecryptfs_auth_tok
*auth_tok
,
2080 struct ecryptfs_crypt_stat
*crypt_stat
,
2081 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
2084 size_t encrypted_session_key_valid
= 0;
2085 char session_key_encryption_key
[ECRYPTFS_MAX_KEY_BYTES
];
2086 struct scatterlist dst_sg
[2];
2087 struct scatterlist src_sg
[2];
2088 struct mutex
*tfm_mutex
= NULL
;
2090 size_t packet_size_length
;
2091 size_t max_packet_size
;
2092 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2093 crypt_stat
->mount_crypt_stat
;
2094 struct blkcipher_desc desc
= {
2096 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
2101 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
2103 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
2104 crypt_stat
->cipher
);
2106 printk(KERN_ERR
"Internal error whilst attempting to get "
2107 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2108 crypt_stat
->cipher
, rc
);
2111 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
2112 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(desc
.tfm
);
2114 printk(KERN_WARNING
"No key size specified at mount; "
2115 "defaulting to [%d]\n", alg
->max_keysize
);
2116 mount_crypt_stat
->global_default_cipher_key_size
=
2119 if (crypt_stat
->key_size
== 0)
2120 crypt_stat
->key_size
=
2121 mount_crypt_stat
->global_default_cipher_key_size
;
2122 if (auth_tok
->session_key
.encrypted_key_size
== 0)
2123 auth_tok
->session_key
.encrypted_key_size
=
2124 crypt_stat
->key_size
;
2125 if (crypt_stat
->key_size
== 24
2126 && strcmp("aes", crypt_stat
->cipher
) == 0) {
2127 memset((crypt_stat
->key
+ 24), 0, 8);
2128 auth_tok
->session_key
.encrypted_key_size
= 32;
2130 auth_tok
->session_key
.encrypted_key_size
= crypt_stat
->key_size
;
2131 key_rec
->enc_key_size
=
2132 auth_tok
->session_key
.encrypted_key_size
;
2133 encrypted_session_key_valid
= 0;
2134 for (i
= 0; i
< auth_tok
->session_key
.encrypted_key_size
; i
++)
2135 encrypted_session_key_valid
|=
2136 auth_tok
->session_key
.encrypted_key
[i
];
2137 if (encrypted_session_key_valid
) {
2138 ecryptfs_printk(KERN_DEBUG
, "encrypted_session_key_valid != 0; "
2139 "using auth_tok->session_key.encrypted_key, "
2140 "where key_rec->enc_key_size = [%d]\n",
2141 key_rec
->enc_key_size
);
2142 memcpy(key_rec
->enc_key
,
2143 auth_tok
->session_key
.encrypted_key
,
2144 key_rec
->enc_key_size
);
2145 goto encrypted_session_key_set
;
2147 if (auth_tok
->token
.password
.flags
&
2148 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET
) {
2149 ecryptfs_printk(KERN_DEBUG
, "Using previously generated "
2150 "session key encryption key of size [%d]\n",
2151 auth_tok
->token
.password
.
2152 session_key_encryption_key_bytes
);
2153 memcpy(session_key_encryption_key
,
2154 auth_tok
->token
.password
.session_key_encryption_key
,
2155 crypt_stat
->key_size
);
2156 ecryptfs_printk(KERN_DEBUG
,
2157 "Cached session key " "encryption key: \n");
2158 if (ecryptfs_verbosity
> 0)
2159 ecryptfs_dump_hex(session_key_encryption_key
, 16);
2161 if (unlikely(ecryptfs_verbosity
> 0)) {
2162 ecryptfs_printk(KERN_DEBUG
, "Session key encryption key:\n");
2163 ecryptfs_dump_hex(session_key_encryption_key
, 16);
2165 rc
= virt_to_scatterlist(crypt_stat
->key
, key_rec
->enc_key_size
,
2167 if (rc
< 1 || rc
> 2) {
2168 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
2169 "for crypt_stat session key; expected rc = 1; "
2170 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
2171 rc
, key_rec
->enc_key_size
);
2175 rc
= virt_to_scatterlist(key_rec
->enc_key
, key_rec
->enc_key_size
,
2177 if (rc
< 1 || rc
> 2) {
2178 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
2179 "for crypt_stat encrypted session key; "
2180 "expected rc = 1; got rc = [%d]. "
2181 "key_rec->enc_key_size = [%d]\n", rc
,
2182 key_rec
->enc_key_size
);
2186 mutex_lock(tfm_mutex
);
2187 rc
= crypto_blkcipher_setkey(desc
.tfm
, session_key_encryption_key
,
2188 crypt_stat
->key_size
);
2190 mutex_unlock(tfm_mutex
);
2191 ecryptfs_printk(KERN_ERR
, "Error setting key for crypto "
2192 "context; rc = [%d]\n", rc
);
2196 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%d] bytes of the key\n",
2197 crypt_stat
->key_size
);
2198 rc
= crypto_blkcipher_encrypt(&desc
, dst_sg
, src_sg
,
2199 (*key_rec
).enc_key_size
);
2200 mutex_unlock(tfm_mutex
);
2202 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
2205 ecryptfs_printk(KERN_DEBUG
, "This should be the encrypted key:\n");
2206 if (ecryptfs_verbosity
> 0) {
2207 ecryptfs_printk(KERN_DEBUG
, "EFEK of size [%d]:\n",
2208 key_rec
->enc_key_size
);
2209 ecryptfs_dump_hex(key_rec
->enc_key
,
2210 key_rec
->enc_key_size
);
2212 encrypted_session_key_set
:
2213 /* This format is inspired by OpenPGP; see RFC 2440
2215 max_packet_size
= (1 /* Tag 3 identifier */
2216 + 3 /* Max Tag 3 packet size */
2218 + 1 /* Cipher code */
2219 + 1 /* S2K specifier */
2220 + 1 /* Hash identifier */
2221 + ECRYPTFS_SALT_SIZE
/* Salt */
2222 + 1 /* Hash iterations */
2223 + key_rec
->enc_key_size
); /* Encrypted key size */
2224 if (max_packet_size
> (*remaining_bytes
)) {
2225 printk(KERN_ERR
"Packet too large; need up to [%td] bytes, but "
2226 "there are only [%td] available\n", max_packet_size
,
2227 (*remaining_bytes
));
2231 dest
[(*packet_size
)++] = ECRYPTFS_TAG_3_PACKET_TYPE
;
2232 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2233 * to get the number of octets in the actual Tag 3 packet */
2234 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
2235 (max_packet_size
- 4),
2236 &packet_size_length
);
2238 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
2239 "generate packet length. rc = [%d]\n", rc
);
2242 (*packet_size
) += packet_size_length
;
2243 dest
[(*packet_size
)++] = 0x04; /* version 4 */
2244 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2245 * specified with strings */
2246 cipher_code
= ecryptfs_code_for_cipher_string(crypt_stat
->cipher
,
2247 crypt_stat
->key_size
);
2248 if (cipher_code
== 0) {
2249 ecryptfs_printk(KERN_WARNING
, "Unable to generate code for "
2250 "cipher [%s]\n", crypt_stat
->cipher
);
2254 dest
[(*packet_size
)++] = cipher_code
;
2255 dest
[(*packet_size
)++] = 0x03; /* S2K */
2256 dest
[(*packet_size
)++] = 0x01; /* MD5 (TODO: parameterize) */
2257 memcpy(&dest
[(*packet_size
)], auth_tok
->token
.password
.salt
,
2258 ECRYPTFS_SALT_SIZE
);
2259 (*packet_size
) += ECRYPTFS_SALT_SIZE
; /* salt */
2260 dest
[(*packet_size
)++] = 0x60; /* hash iterations (65536) */
2261 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
2262 key_rec
->enc_key_size
);
2263 (*packet_size
) += key_rec
->enc_key_size
;
2268 (*remaining_bytes
) -= (*packet_size
);
2272 struct kmem_cache
*ecryptfs_key_record_cache
;
2275 * ecryptfs_generate_key_packet_set
2276 * @dest_base: Virtual address from which to write the key record set
2277 * @crypt_stat: The cryptographic context from which the
2278 * authentication tokens will be retrieved
2279 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2280 * for the global parameters
2281 * @len: The amount written
2282 * @max: The maximum amount of data allowed to be written
2284 * Generates a key packet set and writes it to the virtual address
2287 * Returns zero on success; non-zero on error.
2290 ecryptfs_generate_key_packet_set(char *dest_base
,
2291 struct ecryptfs_crypt_stat
*crypt_stat
,
2292 struct dentry
*ecryptfs_dentry
, size_t *len
,
2295 struct ecryptfs_auth_tok
*auth_tok
;
2296 struct ecryptfs_global_auth_tok
*global_auth_tok
;
2297 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2298 &ecryptfs_superblock_to_private(
2299 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
2301 struct ecryptfs_key_record
*key_rec
;
2302 struct ecryptfs_key_sig
*key_sig
;
2306 mutex_lock(&crypt_stat
->keysig_list_mutex
);
2307 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
2312 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
2314 memset(key_rec
, 0, sizeof(*key_rec
));
2315 rc
= ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
2319 printk(KERN_ERR
"Error attempting to get the global "
2320 "auth_tok; rc = [%d]\n", rc
);
2323 if (global_auth_tok
->flags
& ECRYPTFS_AUTH_TOK_INVALID
) {
2325 "Skipping invalid auth tok with sig = [%s]\n",
2326 global_auth_tok
->sig
);
2329 auth_tok
= global_auth_tok
->global_auth_tok
;
2330 if (auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
2331 rc
= write_tag_3_packet((dest_base
+ (*len
)),
2333 crypt_stat
, key_rec
,
2336 ecryptfs_printk(KERN_WARNING
, "Error "
2337 "writing tag 3 packet\n");
2341 /* Write auth tok signature packet */
2342 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
2344 ECRYPTFS_SIG_SIZE
, &written
);
2346 ecryptfs_printk(KERN_ERR
, "Error writing "
2347 "auth tok signature packet\n");
2351 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
2352 rc
= write_tag_1_packet(dest_base
+ (*len
),
2354 crypt_stat
, key_rec
, &written
);
2356 ecryptfs_printk(KERN_WARNING
, "Error "
2357 "writing tag 1 packet\n");
2362 ecryptfs_printk(KERN_WARNING
, "Unsupported "
2363 "authentication token type\n");
2368 if (likely(max
> 0)) {
2369 dest_base
[(*len
)] = 0x00;
2371 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
2375 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
2379 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
2383 struct kmem_cache
*ecryptfs_key_sig_cache
;
2385 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
2387 struct ecryptfs_key_sig
*new_key_sig
;
2389 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
2392 "Error allocating from ecryptfs_key_sig_cache\n");
2395 memcpy(new_key_sig
->keysig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
2396 /* Caller must hold keysig_list_mutex */
2397 list_add(&new_key_sig
->crypt_stat_list
, &crypt_stat
->keysig_list
);
2402 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
2405 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
2406 char *sig
, u32 global_auth_tok_flags
)
2408 struct ecryptfs_global_auth_tok
*new_auth_tok
;
2411 new_auth_tok
= kmem_cache_zalloc(ecryptfs_global_auth_tok_cache
,
2413 if (!new_auth_tok
) {
2415 printk(KERN_ERR
"Error allocating from "
2416 "ecryptfs_global_auth_tok_cache\n");
2419 memcpy(new_auth_tok
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
2420 new_auth_tok
->flags
= global_auth_tok_flags
;
2421 new_auth_tok
->sig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
2422 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
2423 list_add(&new_auth_tok
->mount_crypt_stat_list
,
2424 &mount_crypt_stat
->global_auth_tok_list
);
2425 mount_crypt_stat
->num_global_auth_toks
++;
2426 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);