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 "ecryptfs_kernel.h"
38 * request_key returned an error instead of a valid key address;
39 * determine the type of error, make appropriate log entries, and
40 * return an error code.
42 static int process_request_key_err(long err_code
)
48 ecryptfs_printk(KERN_WARNING
, "No key\n");
52 ecryptfs_printk(KERN_WARNING
, "Key expired\n");
56 ecryptfs_printk(KERN_WARNING
, "Key revoked\n");
60 ecryptfs_printk(KERN_WARNING
, "Unknown error code: "
61 "[0x%.16x]\n", err_code
);
68 * ecryptfs_parse_packet_length
69 * @data: Pointer to memory containing length at offset
70 * @size: This function writes the decoded size to this memory
71 * address; zero on error
72 * @length_size: The number of bytes occupied by the encoded length
74 * Returns zero on success; non-zero on error
76 int ecryptfs_parse_packet_length(unsigned char *data
, size_t *size
,
85 (*size
) = (unsigned char)data
[0];
87 } else if (data
[0] < 224) {
89 (*size
) = (((unsigned char)(data
[0]) - 192) * 256);
90 (*size
) += ((unsigned char)(data
[1]) + 192);
92 } else if (data
[0] == 255) {
93 /* Five-byte length; we're not supposed to see this */
94 ecryptfs_printk(KERN_ERR
, "Five-byte packet length not "
99 ecryptfs_printk(KERN_ERR
, "Error parsing packet length\n");
108 * ecryptfs_write_packet_length
109 * @dest: The byte array target into which to write the length. Must
110 * have at least 5 bytes allocated.
111 * @size: The length to write.
112 * @packet_size_length: The number of bytes used to encode the packet
113 * length is written to this address.
115 * Returns zero on success; non-zero on error.
117 int ecryptfs_write_packet_length(char *dest
, size_t size
,
118 size_t *packet_size_length
)
124 (*packet_size_length
) = 1;
125 } else if (size
< 65536) {
126 dest
[0] = (((size
- 192) / 256) + 192);
127 dest
[1] = ((size
- 192) % 256);
128 (*packet_size_length
) = 2;
131 ecryptfs_printk(KERN_WARNING
,
132 "Unsupported packet size: [%d]\n", size
);
138 write_tag_64_packet(char *signature
, struct ecryptfs_session_key
*session_key
,
139 char **packet
, size_t *packet_len
)
143 size_t packet_size_len
;
148 * ***** TAG 64 Packet Format *****
149 * | Content Type | 1 byte |
150 * | Key Identifier Size | 1 or 2 bytes |
151 * | Key Identifier | arbitrary |
152 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
153 * | Encrypted File Encryption Key | arbitrary |
155 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
156 + session_key
->encrypted_key_size
);
157 *packet
= kmalloc(data_len
, GFP_KERNEL
);
160 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
164 message
[i
++] = ECRYPTFS_TAG_64_PACKET_TYPE
;
165 rc
= ecryptfs_write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
168 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
169 "header; cannot generate packet length\n");
172 i
+= packet_size_len
;
173 memcpy(&message
[i
], signature
, ECRYPTFS_SIG_SIZE_HEX
);
174 i
+= ECRYPTFS_SIG_SIZE_HEX
;
175 rc
= ecryptfs_write_packet_length(&message
[i
],
176 session_key
->encrypted_key_size
,
179 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
180 "header; cannot generate packet length\n");
183 i
+= packet_size_len
;
184 memcpy(&message
[i
], session_key
->encrypted_key
,
185 session_key
->encrypted_key_size
);
186 i
+= session_key
->encrypted_key_size
;
193 parse_tag_65_packet(struct ecryptfs_session_key
*session_key
, u8
*cipher_code
,
194 struct ecryptfs_message
*msg
)
202 u16 expected_checksum
= 0;
206 * ***** TAG 65 Packet Format *****
207 * | Content Type | 1 byte |
208 * | Status Indicator | 1 byte |
209 * | File Encryption Key Size | 1 or 2 bytes |
210 * | File Encryption Key | arbitrary |
212 message_len
= msg
->data_len
;
214 if (message_len
< 4) {
218 if (data
[i
++] != ECRYPTFS_TAG_65_PACKET_TYPE
) {
219 ecryptfs_printk(KERN_ERR
, "Type should be ECRYPTFS_TAG_65\n");
224 ecryptfs_printk(KERN_ERR
, "Status indicator has non-zero value "
225 "[%d]\n", data
[i
-1]);
229 rc
= ecryptfs_parse_packet_length(&data
[i
], &m_size
, &data_len
);
231 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
236 if (message_len
< (i
+ m_size
)) {
237 ecryptfs_printk(KERN_ERR
, "The message received from ecryptfsd "
238 "is shorter than expected\n");
243 ecryptfs_printk(KERN_ERR
,
244 "The decrypted key is not long enough to "
245 "include a cipher code and checksum\n");
249 *cipher_code
= data
[i
++];
250 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
251 session_key
->decrypted_key_size
= m_size
- 3;
252 if (session_key
->decrypted_key_size
> ECRYPTFS_MAX_KEY_BYTES
) {
253 ecryptfs_printk(KERN_ERR
, "key_size [%d] larger than "
254 "the maximum key size [%d]\n",
255 session_key
->decrypted_key_size
,
256 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
);
260 memcpy(session_key
->decrypted_key
, &data
[i
],
261 session_key
->decrypted_key_size
);
262 i
+= session_key
->decrypted_key_size
;
263 expected_checksum
+= (unsigned char)(data
[i
++]) << 8;
264 expected_checksum
+= (unsigned char)(data
[i
++]);
265 for (i
= 0; i
< session_key
->decrypted_key_size
; i
++)
266 checksum
+= session_key
->decrypted_key
[i
];
267 if (expected_checksum
!= checksum
) {
268 ecryptfs_printk(KERN_ERR
, "Invalid checksum for file "
269 "encryption key; expected [%x]; calculated "
270 "[%x]\n", expected_checksum
, checksum
);
279 write_tag_66_packet(char *signature
, u8 cipher_code
,
280 struct ecryptfs_crypt_stat
*crypt_stat
, char **packet
,
287 size_t packet_size_len
;
292 * ***** TAG 66 Packet Format *****
293 * | Content Type | 1 byte |
294 * | Key Identifier Size | 1 or 2 bytes |
295 * | Key Identifier | arbitrary |
296 * | File Encryption Key Size | 1 or 2 bytes |
297 * | File Encryption Key | arbitrary |
299 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
+ crypt_stat
->key_size
);
300 *packet
= kmalloc(data_len
, GFP_KERNEL
);
303 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
307 message
[i
++] = ECRYPTFS_TAG_66_PACKET_TYPE
;
308 rc
= ecryptfs_write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
311 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
312 "header; cannot generate packet length\n");
315 i
+= packet_size_len
;
316 memcpy(&message
[i
], signature
, ECRYPTFS_SIG_SIZE_HEX
);
317 i
+= ECRYPTFS_SIG_SIZE_HEX
;
318 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
319 rc
= ecryptfs_write_packet_length(&message
[i
], crypt_stat
->key_size
+ 3,
322 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
323 "header; cannot generate packet length\n");
326 i
+= packet_size_len
;
327 message
[i
++] = cipher_code
;
328 memcpy(&message
[i
], crypt_stat
->key
, crypt_stat
->key_size
);
329 i
+= crypt_stat
->key_size
;
330 for (j
= 0; j
< crypt_stat
->key_size
; j
++)
331 checksum
+= crypt_stat
->key
[j
];
332 message
[i
++] = (checksum
/ 256) % 256;
333 message
[i
++] = (checksum
% 256);
340 parse_tag_67_packet(struct ecryptfs_key_record
*key_rec
,
341 struct ecryptfs_message
*msg
)
350 * ***** TAG 65 Packet Format *****
351 * | Content Type | 1 byte |
352 * | Status Indicator | 1 byte |
353 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
354 * | Encrypted File Encryption Key | arbitrary |
356 message_len
= msg
->data_len
;
358 /* verify that everything through the encrypted FEK size is present */
359 if (message_len
< 4) {
361 printk(KERN_ERR
"%s: message_len is [%zd]; minimum acceptable "
362 "message length is [%d]\n", __func__
, message_len
, 4);
365 if (data
[i
++] != ECRYPTFS_TAG_67_PACKET_TYPE
) {
367 printk(KERN_ERR
"%s: Type should be ECRYPTFS_TAG_67\n",
373 printk(KERN_ERR
"%s: Status indicator has non zero "
374 "value [%d]\n", __func__
, data
[i
-1]);
378 rc
= ecryptfs_parse_packet_length(&data
[i
], &key_rec
->enc_key_size
,
381 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
386 if (message_len
< (i
+ key_rec
->enc_key_size
)) {
388 printk(KERN_ERR
"%s: message_len [%zd]; max len is [%zd]\n",
389 __func__
, message_len
, (i
+ key_rec
->enc_key_size
));
392 if (key_rec
->enc_key_size
> ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
394 printk(KERN_ERR
"%s: Encrypted key_size [%zd] larger than "
395 "the maximum key size [%d]\n", __func__
,
396 key_rec
->enc_key_size
,
397 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
);
400 memcpy(key_rec
->enc_key
, &data
[i
], key_rec
->enc_key_size
);
406 ecryptfs_find_global_auth_tok_for_sig(
407 struct ecryptfs_global_auth_tok
**global_auth_tok
,
408 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
, char *sig
)
410 struct ecryptfs_global_auth_tok
*walker
;
413 (*global_auth_tok
) = NULL
;
414 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
415 list_for_each_entry(walker
,
416 &mount_crypt_stat
->global_auth_tok_list
,
417 mount_crypt_stat_list
) {
418 if (memcmp(walker
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
) == 0) {
419 rc
= key_validate(walker
->global_auth_tok_key
);
421 (*global_auth_tok
) = walker
;
427 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
432 * ecryptfs_find_auth_tok_for_sig
433 * @auth_tok: Set to the matching auth_tok; NULL if not found
434 * @crypt_stat: inode crypt_stat crypto context
435 * @sig: Sig of auth_tok to find
437 * For now, this function simply looks at the registered auth_tok's
438 * linked off the mount_crypt_stat, so all the auth_toks that can be
439 * used must be registered at mount time. This function could
440 * potentially try a lot harder to find auth_tok's (e.g., by calling
441 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
442 * that static registration of auth_tok's will no longer be necessary.
444 * Returns zero on no error; non-zero on error
447 ecryptfs_find_auth_tok_for_sig(
448 struct ecryptfs_auth_tok
**auth_tok
,
449 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
452 struct ecryptfs_global_auth_tok
*global_auth_tok
;
456 if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
457 mount_crypt_stat
, sig
)) {
458 struct key
*auth_tok_key
;
460 rc
= ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key
, auth_tok
,
463 (*auth_tok
) = global_auth_tok
->global_auth_tok
;
468 * write_tag_70_packet can gobble a lot of stack space. We stuff most
469 * of the function's parameters in a kmalloc'd struct to help reduce
470 * eCryptfs' overall stack usage.
472 struct ecryptfs_write_tag_70_packet_silly_stack
{
474 size_t max_packet_size
;
475 size_t packet_size_len
;
476 size_t block_aligned_filename_size
;
480 size_t num_rand_bytes
;
481 struct mutex
*tfm_mutex
;
482 char *block_aligned_filename
;
483 struct ecryptfs_auth_tok
*auth_tok
;
484 struct scatterlist src_sg
;
485 struct scatterlist dst_sg
;
486 struct blkcipher_desc desc
;
487 char iv
[ECRYPTFS_MAX_IV_BYTES
];
488 char hash
[ECRYPTFS_TAG_70_DIGEST_SIZE
];
489 char tmp_hash
[ECRYPTFS_TAG_70_DIGEST_SIZE
];
490 struct hash_desc hash_desc
;
491 struct scatterlist hash_sg
;
495 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
496 * @filename: NULL-terminated filename string
498 * This is the simplest mechanism for achieving filename encryption in
499 * eCryptfs. It encrypts the given filename with the mount-wide
500 * filename encryption key (FNEK) and stores it in a packet to @dest,
501 * which the callee will encode and write directly into the dentry
505 ecryptfs_write_tag_70_packet(char *dest
, size_t *remaining_bytes
,
507 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
508 char *filename
, size_t filename_size
)
510 struct ecryptfs_write_tag_70_packet_silly_stack
*s
;
513 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
515 printk(KERN_ERR
"%s: Out of memory whilst trying to kmalloc "
516 "[%zd] bytes of kernel memory\n", __func__
, sizeof(*s
));
519 s
->desc
.flags
= CRYPTO_TFM_REQ_MAY_SLEEP
;
521 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(
523 &s
->tfm_mutex
, mount_crypt_stat
->global_default_fn_cipher_name
);
525 printk(KERN_ERR
"Internal error whilst attempting to get "
526 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
527 mount_crypt_stat
->global_default_fn_cipher_name
, rc
);
530 mutex_lock(s
->tfm_mutex
);
531 s
->block_size
= crypto_blkcipher_blocksize(s
->desc
.tfm
);
532 /* Plus one for the \0 separator between the random prefix
533 * and the plaintext filename */
534 s
->num_rand_bytes
= (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
+ 1);
535 s
->block_aligned_filename_size
= (s
->num_rand_bytes
+ filename_size
);
536 if ((s
->block_aligned_filename_size
% s
->block_size
) != 0) {
537 s
->num_rand_bytes
+= (s
->block_size
538 - (s
->block_aligned_filename_size
540 s
->block_aligned_filename_size
= (s
->num_rand_bytes
543 /* Octet 0: Tag 70 identifier
544 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
545 * and block-aligned encrypted filename size)
546 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
547 * Octet N2-N3: Cipher identifier (1 octet)
548 * Octets N3-N4: Block-aligned encrypted filename
549 * - Consists of a minimum number of random characters, a \0
550 * separator, and then the filename */
551 s
->max_packet_size
= (1 /* Tag 70 identifier */
552 + 3 /* Max Tag 70 packet size */
553 + ECRYPTFS_SIG_SIZE
/* FNEK sig */
554 + 1 /* Cipher identifier */
555 + s
->block_aligned_filename_size
);
557 (*packet_size
) = s
->max_packet_size
;
560 if (s
->max_packet_size
> (*remaining_bytes
)) {
561 printk(KERN_WARNING
"%s: Require [%zd] bytes to write; only "
562 "[%zd] available\n", __func__
, s
->max_packet_size
,
567 s
->block_aligned_filename
= kzalloc(s
->block_aligned_filename_size
,
569 if (!s
->block_aligned_filename
) {
570 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
571 "kzalloc [%zd] bytes\n", __func__
,
572 s
->block_aligned_filename_size
);
577 dest
[s
->i
++] = ECRYPTFS_TAG_70_PACKET_TYPE
;
578 rc
= ecryptfs_write_packet_length(&dest
[s
->i
],
580 + 1 /* Cipher code */
581 + s
->block_aligned_filename_size
),
582 &s
->packet_size_len
);
584 printk(KERN_ERR
"%s: Error generating tag 70 packet "
585 "header; cannot generate packet length; rc = [%d]\n",
587 goto out_free_unlock
;
589 s
->i
+= s
->packet_size_len
;
590 ecryptfs_from_hex(&dest
[s
->i
],
591 mount_crypt_stat
->global_default_fnek_sig
,
593 s
->i
+= ECRYPTFS_SIG_SIZE
;
594 s
->cipher_code
= ecryptfs_code_for_cipher_string(
595 mount_crypt_stat
->global_default_fn_cipher_name
,
596 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
597 if (s
->cipher_code
== 0) {
598 printk(KERN_WARNING
"%s: Unable to generate code for "
599 "cipher [%s] with key bytes [%zd]\n", __func__
,
600 mount_crypt_stat
->global_default_fn_cipher_name
,
601 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
603 goto out_free_unlock
;
605 dest
[s
->i
++] = s
->cipher_code
;
606 rc
= ecryptfs_find_auth_tok_for_sig(
607 &s
->auth_tok
, mount_crypt_stat
,
608 mount_crypt_stat
->global_default_fnek_sig
);
610 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
611 "fnek sig [%s]; rc = [%d]\n", __func__
,
612 mount_crypt_stat
->global_default_fnek_sig
, rc
);
613 goto out_free_unlock
;
615 /* TODO: Support other key modules than passphrase for
616 * filename encryption */
617 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
619 printk(KERN_INFO
"%s: Filename encryption only supports "
620 "password tokens\n", __func__
);
621 goto out_free_unlock
;
625 (u8
*)s
->auth_tok
->token
.password
.session_key_encryption_key
,
626 s
->auth_tok
->token
.password
.session_key_encryption_key_bytes
);
627 s
->hash_desc
.flags
= CRYPTO_TFM_REQ_MAY_SLEEP
;
628 s
->hash_desc
.tfm
= crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST
, 0,
630 if (IS_ERR(s
->hash_desc
.tfm
)) {
631 rc
= PTR_ERR(s
->hash_desc
.tfm
);
632 printk(KERN_ERR
"%s: Error attempting to "
633 "allocate hash crypto context; rc = [%d]\n",
635 goto out_free_unlock
;
637 rc
= crypto_hash_init(&s
->hash_desc
);
640 "%s: Error initializing crypto hash; rc = [%d]\n",
642 goto out_release_free_unlock
;
644 rc
= crypto_hash_update(
645 &s
->hash_desc
, &s
->hash_sg
,
646 s
->auth_tok
->token
.password
.session_key_encryption_key_bytes
);
649 "%s: Error updating crypto hash; rc = [%d]\n",
651 goto out_release_free_unlock
;
653 rc
= crypto_hash_final(&s
->hash_desc
, s
->hash
);
656 "%s: Error finalizing crypto hash; rc = [%d]\n",
658 goto out_release_free_unlock
;
660 for (s
->j
= 0; s
->j
< (s
->num_rand_bytes
- 1); s
->j
++) {
661 s
->block_aligned_filename
[s
->j
] =
662 s
->hash
[(s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)];
663 if ((s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)
664 == (ECRYPTFS_TAG_70_DIGEST_SIZE
- 1)) {
665 sg_init_one(&s
->hash_sg
, (u8
*)s
->hash
,
666 ECRYPTFS_TAG_70_DIGEST_SIZE
);
667 rc
= crypto_hash_init(&s
->hash_desc
);
670 "%s: Error initializing crypto hash; "
671 "rc = [%d]\n", __func__
, rc
);
672 goto out_release_free_unlock
;
674 rc
= crypto_hash_update(&s
->hash_desc
, &s
->hash_sg
,
675 ECRYPTFS_TAG_70_DIGEST_SIZE
);
678 "%s: Error updating crypto hash; "
679 "rc = [%d]\n", __func__
, rc
);
680 goto out_release_free_unlock
;
682 rc
= crypto_hash_final(&s
->hash_desc
, s
->tmp_hash
);
685 "%s: Error finalizing crypto hash; "
686 "rc = [%d]\n", __func__
, rc
);
687 goto out_release_free_unlock
;
689 memcpy(s
->hash
, s
->tmp_hash
,
690 ECRYPTFS_TAG_70_DIGEST_SIZE
);
692 if (s
->block_aligned_filename
[s
->j
] == '\0')
693 s
->block_aligned_filename
[s
->j
] = ECRYPTFS_NON_NULL
;
695 memcpy(&s
->block_aligned_filename
[s
->num_rand_bytes
], filename
,
697 rc
= virt_to_scatterlist(s
->block_aligned_filename
,
698 s
->block_aligned_filename_size
, &s
->src_sg
, 1);
700 printk(KERN_ERR
"%s: Internal error whilst attempting to "
701 "convert filename memory to scatterlist; "
702 "expected rc = 1; got rc = [%d]. "
703 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
704 s
->block_aligned_filename_size
);
705 goto out_release_free_unlock
;
707 rc
= virt_to_scatterlist(&dest
[s
->i
], s
->block_aligned_filename_size
,
710 printk(KERN_ERR
"%s: Internal error whilst attempting to "
711 "convert encrypted filename memory to scatterlist; "
712 "expected rc = 1; got rc = [%d]. "
713 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
714 s
->block_aligned_filename_size
);
715 goto out_release_free_unlock
;
717 /* The characters in the first block effectively do the job
718 * of the IV here, so we just use 0's for the IV. Note the
719 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
720 * >= ECRYPTFS_MAX_IV_BYTES. */
721 memset(s
->iv
, 0, ECRYPTFS_MAX_IV_BYTES
);
722 s
->desc
.info
= s
->iv
;
723 rc
= crypto_blkcipher_setkey(
725 s
->auth_tok
->token
.password
.session_key_encryption_key
,
726 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
728 printk(KERN_ERR
"%s: Error setting key for crypto context; "
729 "rc = [%d]. s->auth_tok->token.password.session_key_"
730 "encryption_key = [0x%p]; mount_crypt_stat->"
731 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
733 s
->auth_tok
->token
.password
.session_key_encryption_key
,
734 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
735 goto out_release_free_unlock
;
737 rc
= crypto_blkcipher_encrypt_iv(&s
->desc
, &s
->dst_sg
, &s
->src_sg
,
738 s
->block_aligned_filename_size
);
740 printk(KERN_ERR
"%s: Error attempting to encrypt filename; "
741 "rc = [%d]\n", __func__
, rc
);
742 goto out_release_free_unlock
;
744 s
->i
+= s
->block_aligned_filename_size
;
745 (*packet_size
) = s
->i
;
746 (*remaining_bytes
) -= (*packet_size
);
747 out_release_free_unlock
:
748 crypto_free_hash(s
->hash_desc
.tfm
);
750 kzfree(s
->block_aligned_filename
);
752 mutex_unlock(s
->tfm_mutex
);
758 struct ecryptfs_parse_tag_70_packet_silly_stack
{
760 size_t max_packet_size
;
761 size_t packet_size_len
;
762 size_t parsed_tag_70_packet_size
;
763 size_t block_aligned_filename_size
;
766 struct mutex
*tfm_mutex
;
767 char *decrypted_filename
;
768 struct ecryptfs_auth_tok
*auth_tok
;
769 struct scatterlist src_sg
;
770 struct scatterlist dst_sg
;
771 struct blkcipher_desc desc
;
772 char fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
+ 1];
773 char iv
[ECRYPTFS_MAX_IV_BYTES
];
774 char cipher_string
[ECRYPTFS_MAX_CIPHER_NAME_SIZE
];
778 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
779 * @filename: This function kmalloc's the memory for the filename
780 * @filename_size: This function sets this to the amount of memory
781 * kmalloc'd for the filename
782 * @packet_size: This function sets this to the the number of octets
783 * in the packet parsed
784 * @mount_crypt_stat: The mount-wide cryptographic context
785 * @data: The memory location containing the start of the tag 70
787 * @max_packet_size: The maximum legal size of the packet to be parsed
790 * Returns zero on success; non-zero otherwise
793 ecryptfs_parse_tag_70_packet(char **filename
, size_t *filename_size
,
795 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
796 char *data
, size_t max_packet_size
)
798 struct ecryptfs_parse_tag_70_packet_silly_stack
*s
;
802 (*filename_size
) = 0;
804 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
806 printk(KERN_ERR
"%s: Out of memory whilst trying to kmalloc "
807 "[%zd] bytes of kernel memory\n", __func__
, sizeof(*s
));
810 s
->desc
.flags
= CRYPTO_TFM_REQ_MAY_SLEEP
;
811 if (max_packet_size
< (1 + 1 + ECRYPTFS_SIG_SIZE
+ 1 + 1)) {
812 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; it must be "
813 "at least [%d]\n", __func__
, max_packet_size
,
814 (1 + 1 + ECRYPTFS_SIG_SIZE
+ 1 + 1));
818 /* Octet 0: Tag 70 identifier
819 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
820 * and block-aligned encrypted filename size)
821 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
822 * Octet N2-N3: Cipher identifier (1 octet)
823 * Octets N3-N4: Block-aligned encrypted filename
824 * - Consists of a minimum number of random numbers, a \0
825 * separator, and then the filename */
826 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_70_PACKET_TYPE
) {
827 printk(KERN_WARNING
"%s: Invalid packet tag [0x%.2x]; must be "
828 "tag [0x%.2x]\n", __func__
,
829 data
[((*packet_size
) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE
);
833 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)],
834 &s
->parsed_tag_70_packet_size
,
835 &s
->packet_size_len
);
837 printk(KERN_WARNING
"%s: Error parsing packet length; "
838 "rc = [%d]\n", __func__
, rc
);
841 s
->block_aligned_filename_size
= (s
->parsed_tag_70_packet_size
842 - ECRYPTFS_SIG_SIZE
- 1);
843 if ((1 + s
->packet_size_len
+ s
->parsed_tag_70_packet_size
)
845 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; real packet "
846 "size is [%zd]\n", __func__
, max_packet_size
,
847 (1 + s
->packet_size_len
+ 1
848 + s
->block_aligned_filename_size
));
852 (*packet_size
) += s
->packet_size_len
;
853 ecryptfs_to_hex(s
->fnek_sig_hex
, &data
[(*packet_size
)],
855 s
->fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
856 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
857 s
->cipher_code
= data
[(*packet_size
)++];
858 rc
= ecryptfs_cipher_code_to_string(s
->cipher_string
, s
->cipher_code
);
860 printk(KERN_WARNING
"%s: Cipher code [%d] is invalid\n",
861 __func__
, s
->cipher_code
);
864 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&s
->desc
.tfm
,
868 printk(KERN_ERR
"Internal error whilst attempting to get "
869 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
870 s
->cipher_string
, rc
);
873 mutex_lock(s
->tfm_mutex
);
874 rc
= virt_to_scatterlist(&data
[(*packet_size
)],
875 s
->block_aligned_filename_size
, &s
->src_sg
, 1);
877 printk(KERN_ERR
"%s: Internal error whilst attempting to "
878 "convert encrypted filename memory to scatterlist; "
879 "expected rc = 1; got rc = [%d]. "
880 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
881 s
->block_aligned_filename_size
);
884 (*packet_size
) += s
->block_aligned_filename_size
;
885 s
->decrypted_filename
= kmalloc(s
->block_aligned_filename_size
,
887 if (!s
->decrypted_filename
) {
888 printk(KERN_ERR
"%s: Out of memory whilst attempting to "
889 "kmalloc [%zd] bytes\n", __func__
,
890 s
->block_aligned_filename_size
);
894 rc
= virt_to_scatterlist(s
->decrypted_filename
,
895 s
->block_aligned_filename_size
, &s
->dst_sg
, 1);
897 printk(KERN_ERR
"%s: Internal error whilst attempting to "
898 "convert decrypted filename memory to scatterlist; "
899 "expected rc = 1; got rc = [%d]. "
900 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
901 s
->block_aligned_filename_size
);
902 goto out_free_unlock
;
904 /* The characters in the first block effectively do the job of
905 * the IV here, so we just use 0's for the IV. Note the
906 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
907 * >= ECRYPTFS_MAX_IV_BYTES. */
908 memset(s
->iv
, 0, ECRYPTFS_MAX_IV_BYTES
);
909 s
->desc
.info
= s
->iv
;
910 rc
= ecryptfs_find_auth_tok_for_sig(&s
->auth_tok
, mount_crypt_stat
,
913 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
914 "fnek sig [%s]; rc = [%d]\n", __func__
, s
->fnek_sig_hex
,
916 goto out_free_unlock
;
918 /* TODO: Support other key modules than passphrase for
919 * filename encryption */
920 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
922 printk(KERN_INFO
"%s: Filename encryption only supports "
923 "password tokens\n", __func__
);
924 goto out_free_unlock
;
926 rc
= crypto_blkcipher_setkey(
928 s
->auth_tok
->token
.password
.session_key_encryption_key
,
929 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
931 printk(KERN_ERR
"%s: Error setting key for crypto context; "
932 "rc = [%d]. s->auth_tok->token.password.session_key_"
933 "encryption_key = [0x%p]; mount_crypt_stat->"
934 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
936 s
->auth_tok
->token
.password
.session_key_encryption_key
,
937 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
938 goto out_free_unlock
;
940 rc
= crypto_blkcipher_decrypt_iv(&s
->desc
, &s
->dst_sg
, &s
->src_sg
,
941 s
->block_aligned_filename_size
);
943 printk(KERN_ERR
"%s: Error attempting to decrypt filename; "
944 "rc = [%d]\n", __func__
, rc
);
945 goto out_free_unlock
;
948 while (s
->decrypted_filename
[s
->i
] != '\0'
949 && s
->i
< s
->block_aligned_filename_size
)
951 if (s
->i
== s
->block_aligned_filename_size
) {
952 printk(KERN_WARNING
"%s: Invalid tag 70 packet; could not "
953 "find valid separator between random characters and "
954 "the filename\n", __func__
);
956 goto out_free_unlock
;
959 (*filename_size
) = (s
->block_aligned_filename_size
- s
->i
);
960 if (!((*filename_size
) > 0 && (*filename_size
< PATH_MAX
))) {
961 printk(KERN_WARNING
"%s: Filename size is [%zd], which is "
962 "invalid\n", __func__
, (*filename_size
));
964 goto out_free_unlock
;
966 (*filename
) = kmalloc(((*filename_size
) + 1), GFP_KERNEL
);
968 printk(KERN_ERR
"%s: Out of memory whilst attempting to "
969 "kmalloc [%zd] bytes\n", __func__
,
970 ((*filename_size
) + 1));
972 goto out_free_unlock
;
974 memcpy((*filename
), &s
->decrypted_filename
[s
->i
], (*filename_size
));
975 (*filename
)[(*filename_size
)] = '\0';
977 kfree(s
->decrypted_filename
);
979 mutex_unlock(s
->tfm_mutex
);
983 (*filename_size
) = 0;
991 ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
996 switch (auth_tok
->token_type
) {
997 case ECRYPTFS_PASSWORD
:
998 (*sig
) = auth_tok
->token
.password
.signature
;
1000 case ECRYPTFS_PRIVATE_KEY
:
1001 (*sig
) = auth_tok
->token
.private_key
.signature
;
1004 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
1005 auth_tok
->token_type
);
1012 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1013 * @auth_tok: The key authentication token used to decrypt the session key
1014 * @crypt_stat: The cryptographic context
1016 * Returns zero on success; non-zero error otherwise.
1019 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1020 struct ecryptfs_crypt_stat
*crypt_stat
)
1023 struct ecryptfs_msg_ctx
*msg_ctx
;
1024 struct ecryptfs_message
*msg
= NULL
;
1030 rc
= ecryptfs_get_auth_tok_sig(&auth_tok_sig
, auth_tok
);
1032 printk(KERN_ERR
"Unrecognized auth tok type: [%d]\n",
1033 auth_tok
->token_type
);
1036 rc
= write_tag_64_packet(auth_tok_sig
, &(auth_tok
->session_key
),
1037 &payload
, &payload_len
);
1039 ecryptfs_printk(KERN_ERR
, "Failed to write tag 64 packet\n");
1042 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1044 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1048 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1050 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 65 packet "
1051 "from the user space daemon\n");
1055 rc
= parse_tag_65_packet(&(auth_tok
->session_key
),
1058 printk(KERN_ERR
"Failed to parse tag 65 packet; rc = [%d]\n",
1062 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1063 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1064 auth_tok
->session_key
.decrypted_key_size
);
1065 crypt_stat
->key_size
= auth_tok
->session_key
.decrypted_key_size
;
1066 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
, cipher_code
);
1068 ecryptfs_printk(KERN_ERR
, "Cipher code [%d] is invalid\n",
1072 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1073 if (ecryptfs_verbosity
> 0) {
1074 ecryptfs_printk(KERN_DEBUG
, "Decrypted session key:\n");
1075 ecryptfs_dump_hex(crypt_stat
->key
,
1076 crypt_stat
->key_size
);
1084 static void wipe_auth_tok_list(struct list_head
*auth_tok_list_head
)
1086 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1087 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1089 list_for_each_entry_safe(auth_tok_list_item
, auth_tok_list_item_tmp
,
1090 auth_tok_list_head
, list
) {
1091 list_del(&auth_tok_list_item
->list
);
1092 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1093 auth_tok_list_item
);
1097 struct kmem_cache
*ecryptfs_auth_tok_list_item_cache
;
1100 * parse_tag_1_packet
1101 * @crypt_stat: The cryptographic context to modify based on packet contents
1102 * @data: The raw bytes of the packet.
1103 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1104 * a new authentication token will be placed at the
1105 * end of this list for this packet.
1106 * @new_auth_tok: Pointer to a pointer to memory that this function
1107 * allocates; sets the memory address of the pointer to
1108 * NULL on error. This object is added to the
1110 * @packet_size: This function writes the size of the parsed packet
1111 * into this memory location; zero on error.
1112 * @max_packet_size: The maximum allowable packet size
1114 * Returns zero on success; non-zero on error.
1117 parse_tag_1_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1118 unsigned char *data
, struct list_head
*auth_tok_list
,
1119 struct ecryptfs_auth_tok
**new_auth_tok
,
1120 size_t *packet_size
, size_t max_packet_size
)
1123 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1128 (*new_auth_tok
) = NULL
;
1130 * This format is inspired by OpenPGP; see RFC 2440
1133 * Tag 1 identifier (1 byte)
1134 * Max Tag 1 packet size (max 3 bytes)
1136 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1137 * Cipher identifier (1 byte)
1138 * Encrypted key size (arbitrary)
1140 * 12 bytes minimum packet size
1142 if (unlikely(max_packet_size
< 12)) {
1143 printk(KERN_ERR
"Invalid max packet size; must be >=12\n");
1147 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_1_PACKET_TYPE
) {
1148 printk(KERN_ERR
"Enter w/ first byte != 0x%.2x\n",
1149 ECRYPTFS_TAG_1_PACKET_TYPE
);
1153 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1154 * at end of function upon failure */
1155 auth_tok_list_item
=
1156 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
,
1158 if (!auth_tok_list_item
) {
1159 printk(KERN_ERR
"Unable to allocate memory\n");
1163 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1164 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1167 printk(KERN_WARNING
"Error parsing packet length; "
1171 if (unlikely(body_size
< (ECRYPTFS_SIG_SIZE
+ 2))) {
1172 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1176 (*packet_size
) += length_size
;
1177 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1178 printk(KERN_WARNING
"Packet size exceeds max\n");
1182 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1183 printk(KERN_WARNING
"Unknown version number [%d]\n",
1184 data
[(*packet_size
) - 1]);
1188 ecryptfs_to_hex((*new_auth_tok
)->token
.private_key
.signature
,
1189 &data
[(*packet_size
)], ECRYPTFS_SIG_SIZE
);
1190 *packet_size
+= ECRYPTFS_SIG_SIZE
;
1191 /* This byte is skipped because the kernel does not need to
1192 * know which public key encryption algorithm was used */
1194 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1195 body_size
- (ECRYPTFS_SIG_SIZE
+ 2);
1196 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1197 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1198 printk(KERN_WARNING
"Tag 1 packet contains key larger "
1199 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1203 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1204 &data
[(*packet_size
)], (body_size
- (ECRYPTFS_SIG_SIZE
+ 2)));
1205 (*packet_size
) += (*new_auth_tok
)->session_key
.encrypted_key_size
;
1206 (*new_auth_tok
)->session_key
.flags
&=
1207 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1208 (*new_auth_tok
)->session_key
.flags
|=
1209 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1210 (*new_auth_tok
)->token_type
= ECRYPTFS_PRIVATE_KEY
;
1211 (*new_auth_tok
)->flags
= 0;
1212 (*new_auth_tok
)->session_key
.flags
&=
1213 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1214 (*new_auth_tok
)->session_key
.flags
&=
1215 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1216 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1219 (*new_auth_tok
) = NULL
;
1220 memset(auth_tok_list_item
, 0,
1221 sizeof(struct ecryptfs_auth_tok_list_item
));
1222 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1223 auth_tok_list_item
);
1231 * parse_tag_3_packet
1232 * @crypt_stat: The cryptographic context to modify based on packet
1234 * @data: The raw bytes of the packet.
1235 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1236 * a new authentication token will be placed at the end
1237 * of this list for this packet.
1238 * @new_auth_tok: Pointer to a pointer to memory that this function
1239 * allocates; sets the memory address of the pointer to
1240 * NULL on error. This object is added to the
1242 * @packet_size: This function writes the size of the parsed packet
1243 * into this memory location; zero on error.
1244 * @max_packet_size: maximum number of bytes to parse
1246 * Returns zero on success; non-zero on error.
1249 parse_tag_3_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1250 unsigned char *data
, struct list_head
*auth_tok_list
,
1251 struct ecryptfs_auth_tok
**new_auth_tok
,
1252 size_t *packet_size
, size_t max_packet_size
)
1255 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1260 (*new_auth_tok
) = NULL
;
1262 *This format is inspired by OpenPGP; see RFC 2440
1265 * Tag 3 identifier (1 byte)
1266 * Max Tag 3 packet size (max 3 bytes)
1268 * Cipher code (1 byte)
1269 * S2K specifier (1 byte)
1270 * Hash identifier (1 byte)
1271 * Salt (ECRYPTFS_SALT_SIZE)
1272 * Hash iterations (1 byte)
1273 * Encrypted key (arbitrary)
1275 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1277 if (max_packet_size
< (ECRYPTFS_SALT_SIZE
+ 7)) {
1278 printk(KERN_ERR
"Max packet size too large\n");
1282 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_3_PACKET_TYPE
) {
1283 printk(KERN_ERR
"First byte != 0x%.2x; invalid packet\n",
1284 ECRYPTFS_TAG_3_PACKET_TYPE
);
1288 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1289 * at end of function upon failure */
1290 auth_tok_list_item
=
1291 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
, GFP_KERNEL
);
1292 if (!auth_tok_list_item
) {
1293 printk(KERN_ERR
"Unable to allocate memory\n");
1297 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1298 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1301 printk(KERN_WARNING
"Error parsing packet length; rc = [%d]\n",
1305 if (unlikely(body_size
< (ECRYPTFS_SALT_SIZE
+ 5))) {
1306 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1310 (*packet_size
) += length_size
;
1311 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1312 printk(KERN_ERR
"Packet size exceeds max\n");
1316 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1317 (body_size
- (ECRYPTFS_SALT_SIZE
+ 5));
1318 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1319 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1320 printk(KERN_WARNING
"Tag 3 packet contains key larger "
1321 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1325 if (unlikely(data
[(*packet_size
)++] != 0x04)) {
1326 printk(KERN_WARNING
"Unknown version number [%d]\n",
1327 data
[(*packet_size
) - 1]);
1331 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
,
1332 (u16
)data
[(*packet_size
)]);
1335 /* A little extra work to differentiate among the AES key
1336 * sizes; see RFC2440 */
1337 switch(data
[(*packet_size
)++]) {
1338 case RFC2440_CIPHER_AES_192
:
1339 crypt_stat
->key_size
= 24;
1342 crypt_stat
->key_size
=
1343 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1345 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1348 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1349 printk(KERN_WARNING
"Only S2K ID 3 is currently supported\n");
1353 /* TODO: finish the hash mapping */
1354 switch (data
[(*packet_size
)++]) {
1355 case 0x01: /* See RFC2440 for these numbers and their mappings */
1357 memcpy((*new_auth_tok
)->token
.password
.salt
,
1358 &data
[(*packet_size
)], ECRYPTFS_SALT_SIZE
);
1359 (*packet_size
) += ECRYPTFS_SALT_SIZE
;
1360 /* This conversion was taken straight from RFC2440 */
1361 (*new_auth_tok
)->token
.password
.hash_iterations
=
1362 ((u32
) 16 + (data
[(*packet_size
)] & 15))
1363 << ((data
[(*packet_size
)] >> 4) + 6);
1365 /* Friendly reminder:
1366 * (*new_auth_tok)->session_key.encrypted_key_size =
1367 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1368 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1369 &data
[(*packet_size
)],
1370 (*new_auth_tok
)->session_key
.encrypted_key_size
);
1372 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1373 (*new_auth_tok
)->session_key
.flags
&=
1374 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1375 (*new_auth_tok
)->session_key
.flags
|=
1376 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1377 (*new_auth_tok
)->token
.password
.hash_algo
= 0x01; /* MD5 */
1380 ecryptfs_printk(KERN_ERR
, "Unsupported hash algorithm: "
1381 "[%d]\n", data
[(*packet_size
) - 1]);
1385 (*new_auth_tok
)->token_type
= ECRYPTFS_PASSWORD
;
1386 /* TODO: Parametarize; we might actually want userspace to
1387 * decrypt the session key. */
1388 (*new_auth_tok
)->session_key
.flags
&=
1389 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1390 (*new_auth_tok
)->session_key
.flags
&=
1391 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1392 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1395 (*new_auth_tok
) = NULL
;
1396 memset(auth_tok_list_item
, 0,
1397 sizeof(struct ecryptfs_auth_tok_list_item
));
1398 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1399 auth_tok_list_item
);
1407 * parse_tag_11_packet
1408 * @data: The raw bytes of the packet
1409 * @contents: This function writes the data contents of the literal
1410 * packet into this memory location
1411 * @max_contents_bytes: The maximum number of bytes that this function
1412 * is allowed to write into contents
1413 * @tag_11_contents_size: This function writes the size of the parsed
1414 * contents into this memory location; zero on
1416 * @packet_size: This function writes the size of the parsed packet
1417 * into this memory location; zero on error
1418 * @max_packet_size: maximum number of bytes to parse
1420 * Returns zero on success; non-zero on error.
1423 parse_tag_11_packet(unsigned char *data
, unsigned char *contents
,
1424 size_t max_contents_bytes
, size_t *tag_11_contents_size
,
1425 size_t *packet_size
, size_t max_packet_size
)
1432 (*tag_11_contents_size
) = 0;
1433 /* This format is inspired by OpenPGP; see RFC 2440
1436 * Tag 11 identifier (1 byte)
1437 * Max Tag 11 packet size (max 3 bytes)
1438 * Binary format specifier (1 byte)
1439 * Filename length (1 byte)
1440 * Filename ("_CONSOLE") (8 bytes)
1441 * Modification date (4 bytes)
1442 * Literal data (arbitrary)
1444 * We need at least 16 bytes of data for the packet to even be
1447 if (max_packet_size
< 16) {
1448 printk(KERN_ERR
"Maximum packet size too small\n");
1452 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
1453 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1457 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1460 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1463 if (body_size
< 14) {
1464 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1468 (*packet_size
) += length_size
;
1469 (*tag_11_contents_size
) = (body_size
- 14);
1470 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
1471 printk(KERN_ERR
"Packet size exceeds max\n");
1475 if (unlikely((*tag_11_contents_size
) > max_contents_bytes
)) {
1476 printk(KERN_ERR
"Literal data section in tag 11 packet exceeds "
1481 if (data
[(*packet_size
)++] != 0x62) {
1482 printk(KERN_WARNING
"Unrecognizable packet\n");
1486 if (data
[(*packet_size
)++] != 0x08) {
1487 printk(KERN_WARNING
"Unrecognizable packet\n");
1491 (*packet_size
) += 12; /* Ignore filename and modification date */
1492 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
1493 (*packet_size
) += (*tag_11_contents_size
);
1497 (*tag_11_contents_size
) = 0;
1503 * ecryptfs_verify_version
1504 * @version: The version number to confirm
1506 * Returns zero on good version; non-zero otherwise
1508 static int ecryptfs_verify_version(u16 version
)
1511 unsigned char major
;
1512 unsigned char minor
;
1514 major
= ((version
>> 8) & 0xFF);
1515 minor
= (version
& 0xFF);
1516 if (major
!= ECRYPTFS_VERSION_MAJOR
) {
1517 ecryptfs_printk(KERN_ERR
, "Major version number mismatch. "
1518 "Expected [%d]; got [%d]\n",
1519 ECRYPTFS_VERSION_MAJOR
, major
);
1523 if (minor
!= ECRYPTFS_VERSION_MINOR
) {
1524 ecryptfs_printk(KERN_ERR
, "Minor version number mismatch. "
1525 "Expected [%d]; got [%d]\n",
1526 ECRYPTFS_VERSION_MINOR
, minor
);
1534 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
1535 struct ecryptfs_auth_tok
**auth_tok
,
1540 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
1541 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
1542 printk(KERN_ERR
"Could not find key with description: [%s]\n",
1544 rc
= process_request_key_err(PTR_ERR(*auth_tok_key
));
1545 (*auth_tok_key
) = NULL
;
1548 (*auth_tok
) = ecryptfs_get_key_payload_data(*auth_tok_key
);
1549 if (ecryptfs_verify_version((*auth_tok
)->version
)) {
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
);
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");
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
1576 * Returns zero on success; non-zero error otherwise
1579 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1580 struct ecryptfs_crypt_stat
*crypt_stat
)
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
1590 if (unlikely(ecryptfs_verbosity
> 0)) {
1592 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1593 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1595 auth_tok
->token
.password
.session_key_encryption_key
,
1596 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1598 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1599 crypt_stat
->cipher
);
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
);
1606 rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1607 auth_tok
->session_key
.encrypted_key_size
,
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
);
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
,
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
);
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");
1638 rc
= crypto_blkcipher_decrypt(&desc
, dst_sg
, src_sg
,
1639 auth_tok
->session_key
.encrypted_key_size
);
1640 mutex_unlock(tfm_mutex
);
1642 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
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
);
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
1665 * Get crypt_stat to have the file's session key if the requisite key
1666 * is available to decrypt the session key.
1668 * Returns Zero if a valid authentication token was retrieved and
1669 * processed; negative value for file not encrypted or for error
1672 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1674 struct dentry
*ecryptfs_dentry
)
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
;
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
;
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
);
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
);
1705 ecryptfs_printk(KERN_ERR
, "Error parsing "
1711 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1714 &tag_11_contents_size
,
1715 &tag_11_packet_size
,
1718 ecryptfs_printk(KERN_ERR
, "No valid "
1719 "(ecryptfs-specific) literal "
1720 "packet containing "
1721 "authentication token "
1722 "signature found after "
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]; "
1733 tag_11_contents_size
);
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
;
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
);
1749 ecryptfs_printk(KERN_ERR
, "Error parsing "
1755 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1757 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1758 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1759 "(Tag 11 not allowed by itself)\n");
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;
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");
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
:
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
);
1792 rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1793 candidate_auth_tok
);
1796 "Unrecognized candidate auth tok type: [%d]\n",
1797 candidate_auth_tok
->token_type
);
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
) {
1806 goto found_matching_auth_tok
;
1809 if (!found_auth_tok
) {
1810 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1811 "authentication token\n");
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
,
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
);
1830 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
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
);
1845 ecryptfs_auth_tok_list_item_cache
,
1846 auth_tok_list_item
);
1847 goto find_next_matching_auth_tok
;
1852 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1854 ecryptfs_printk(KERN_ERR
, "Error computing "
1858 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1860 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1861 "context for cipher [%s]; rc = [%d]\n",
1862 crypt_stat
->cipher
, rc
);
1865 wipe_auth_tok_list(&auth_tok_list
);
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
)
1875 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1876 char *payload
= NULL
;
1878 struct ecryptfs_message
*msg
;
1881 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1882 ecryptfs_code_for_cipher_string(
1884 crypt_stat
->key_size
),
1885 crypt_stat
, &payload
, &payload_len
);
1887 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
1890 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1892 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1896 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1898 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
1899 "from the user space daemon\n");
1903 rc
= parse_tag_67_packet(key_rec
, msg
);
1905 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
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
1921 * Returns zero on success; non-zero on error.
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
)
1930 size_t encrypted_session_key_valid
= 0;
1931 size_t packet_size_length
;
1932 size_t max_packet_size
;
1936 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
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
;
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
);
1953 printk(KERN_ERR
"Failed to encrypt session key via a key "
1954 "module; rc = [%d]\n", rc
);
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
);
1961 encrypted_session_key_set
:
1962 /* This format is inspired by OpenPGP; see RFC 2440
1964 max_packet_size
= (1 /* Tag 1 identifier */
1965 + 3 /* Max Tag 1 packet size */
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
));
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
);
1982 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
1983 "header; cannot generate packet length\n");
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
;
1998 (*remaining_bytes
) -= (*packet_size
);
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
2010 * Returns zero on success; non-zero on error.
2013 write_tag_11_packet(char *dest
, size_t *remaining_bytes
, char *contents
,
2014 size_t contents_length
, size_t *packet_length
)
2016 size_t packet_size_length
;
2017 size_t max_packet_size
;
2020 (*packet_length
) = 0;
2021 /* This format is inspired by OpenPGP; see RFC 2440
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
));
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
);
2042 printk(KERN_ERR
"Error generating tag 11 packet header; cannot "
2043 "generate packet length. rc = [%d]\n", rc
);
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
;
2057 (*packet_length
) = 0;
2059 (*remaining_bytes
) -= (*packet_length
);
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
2073 * Returns zero on success; non-zero on error.
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
)
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
;
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
= {
2094 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
2099 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
2101 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
2102 crypt_stat
->cipher
);
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
);
2109 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
2110 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(desc
.tfm
);
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
=
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;
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
;
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);
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);
2163 rc
= virt_to_scatterlist(crypt_stat
->key
, key_rec
->enc_key_size
,
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
);
2173 rc
= virt_to_scatterlist(key_rec
->enc_key
, key_rec
->enc_key_size
,
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
);
2184 mutex_lock(tfm_mutex
);
2185 rc
= crypto_blkcipher_setkey(desc
.tfm
, session_key_encryption_key
,
2186 crypt_stat
->key_size
);
2188 mutex_unlock(tfm_mutex
);
2189 ecryptfs_printk(KERN_ERR
, "Error setting key for crypto "
2190 "context; rc = [%d]\n", rc
);
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
);
2200 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
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
);
2210 encrypted_session_key_set
:
2211 /* This format is inspired by OpenPGP; see RFC 2440
2213 max_packet_size
= (1 /* Tag 3 identifier */
2214 + 3 /* Max Tag 3 packet size */
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
));
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
);
2236 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
2237 "generate packet length. rc = [%d]\n", rc
);
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
);
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
;
2266 (*remaining_bytes
) -= (*packet_size
);
2270 struct kmem_cache
*ecryptfs_key_record_cache
;
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
2282 * Generates a key packet set and writes it to the virtual address
2285 * Returns zero on success; non-zero on error.
2288 ecryptfs_generate_key_packet_set(char *dest_base
,
2289 struct ecryptfs_crypt_stat
*crypt_stat
,
2290 struct dentry
*ecryptfs_dentry
, size_t *len
,
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
;
2299 struct ecryptfs_key_record
*key_rec
;
2300 struct ecryptfs_key_sig
*key_sig
;
2304 mutex_lock(&crypt_stat
->keysig_list_mutex
);
2305 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
2310 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
2312 memset(key_rec
, 0, sizeof(*key_rec
));
2313 rc
= ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
2317 printk(KERN_ERR
"Error attempting to get the global "
2318 "auth_tok; rc = [%d]\n", rc
);
2321 if (global_auth_tok
->flags
& ECRYPTFS_AUTH_TOK_INVALID
) {
2323 "Skipping invalid auth tok with sig = [%s]\n",
2324 global_auth_tok
->sig
);
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
)),
2331 crypt_stat
, key_rec
,
2334 ecryptfs_printk(KERN_WARNING
, "Error "
2335 "writing tag 3 packet\n");
2339 /* Write auth tok signature packet */
2340 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
2342 ECRYPTFS_SIG_SIZE
, &written
);
2344 ecryptfs_printk(KERN_ERR
, "Error writing "
2345 "auth tok signature packet\n");
2349 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
2350 rc
= write_tag_1_packet(dest_base
+ (*len
),
2352 crypt_stat
, key_rec
, &written
);
2354 ecryptfs_printk(KERN_WARNING
, "Error "
2355 "writing tag 1 packet\n");
2360 ecryptfs_printk(KERN_WARNING
, "Unsupported "
2361 "authentication token type\n");
2366 if (likely(max
> 0)) {
2367 dest_base
[(*len
)] = 0x00;
2369 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
2373 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
2377 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
2381 struct kmem_cache
*ecryptfs_key_sig_cache
;
2383 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
2385 struct ecryptfs_key_sig
*new_key_sig
;
2387 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
2390 "Error allocating from ecryptfs_key_sig_cache\n");
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
);
2400 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
2403 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
2404 char *sig
, u32 global_auth_tok_flags
)
2406 struct ecryptfs_global_auth_tok
*new_auth_tok
;
2409 new_auth_tok
= kmem_cache_zalloc(ecryptfs_global_auth_tok_cache
,
2411 if (!new_auth_tok
) {
2413 printk(KERN_ERR
"Error allocating from "
2414 "ecryptfs_global_auth_tok_cache\n");
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
);