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 <crypto/hash.h>
29 #include <crypto/skcipher.h>
30 #include <linux/string.h>
31 #include <linux/pagemap.h>
32 #include <linux/key.h>
33 #include <linux/random.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%.16lx]\n", err_code
);
68 static int process_find_global_auth_tok_for_sig_err(int err_code
)
74 ecryptfs_printk(KERN_WARNING
, "Missing auth tok\n");
77 ecryptfs_printk(KERN_WARNING
, "Invalid auth tok\n");
80 rc
= process_request_key_err(err_code
);
87 * ecryptfs_parse_packet_length
88 * @data: Pointer to memory containing length at offset
89 * @size: This function writes the decoded size to this memory
90 * address; zero on error
91 * @length_size: The number of bytes occupied by the encoded length
93 * Returns zero on success; non-zero on error
95 int ecryptfs_parse_packet_length(unsigned char *data
, size_t *size
,
103 /* One-byte length */
106 } else if (data
[0] < 224) {
107 /* Two-byte length */
108 (*size
) = (data
[0] - 192) * 256;
109 (*size
) += data
[1] + 192;
111 } else if (data
[0] == 255) {
112 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
113 ecryptfs_printk(KERN_ERR
, "Five-byte packet length not "
118 ecryptfs_printk(KERN_ERR
, "Error parsing packet length\n");
127 * ecryptfs_write_packet_length
128 * @dest: The byte array target into which to write the length. Must
129 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
130 * @size: The length to write.
131 * @packet_size_length: The number of bytes used to encode the packet
132 * length is written to this address.
134 * Returns zero on success; non-zero on error.
136 int ecryptfs_write_packet_length(char *dest
, size_t size
,
137 size_t *packet_size_length
)
143 (*packet_size_length
) = 1;
144 } else if (size
< 65536) {
145 dest
[0] = (((size
- 192) / 256) + 192);
146 dest
[1] = ((size
- 192) % 256);
147 (*packet_size_length
) = 2;
149 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
151 ecryptfs_printk(KERN_WARNING
,
152 "Unsupported packet size: [%zd]\n", size
);
158 write_tag_64_packet(char *signature
, struct ecryptfs_session_key
*session_key
,
159 char **packet
, size_t *packet_len
)
163 size_t packet_size_len
;
168 * ***** TAG 64 Packet Format *****
169 * | Content Type | 1 byte |
170 * | Key Identifier Size | 1 or 2 bytes |
171 * | Key Identifier | arbitrary |
172 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
173 * | Encrypted File Encryption Key | arbitrary |
175 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
176 + session_key
->encrypted_key_size
);
177 *packet
= kmalloc(data_len
, GFP_KERNEL
);
180 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
184 message
[i
++] = ECRYPTFS_TAG_64_PACKET_TYPE
;
185 rc
= ecryptfs_write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
188 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
189 "header; cannot generate packet length\n");
192 i
+= packet_size_len
;
193 memcpy(&message
[i
], signature
, ECRYPTFS_SIG_SIZE_HEX
);
194 i
+= ECRYPTFS_SIG_SIZE_HEX
;
195 rc
= ecryptfs_write_packet_length(&message
[i
],
196 session_key
->encrypted_key_size
,
199 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
200 "header; cannot generate packet length\n");
203 i
+= packet_size_len
;
204 memcpy(&message
[i
], session_key
->encrypted_key
,
205 session_key
->encrypted_key_size
);
206 i
+= session_key
->encrypted_key_size
;
213 parse_tag_65_packet(struct ecryptfs_session_key
*session_key
, u8
*cipher_code
,
214 struct ecryptfs_message
*msg
)
222 u16 expected_checksum
= 0;
226 * ***** TAG 65 Packet Format *****
227 * | Content Type | 1 byte |
228 * | Status Indicator | 1 byte |
229 * | File Encryption Key Size | 1 or 2 bytes |
230 * | File Encryption Key | arbitrary |
232 message_len
= msg
->data_len
;
234 if (message_len
< 4) {
238 if (data
[i
++] != ECRYPTFS_TAG_65_PACKET_TYPE
) {
239 ecryptfs_printk(KERN_ERR
, "Type should be ECRYPTFS_TAG_65\n");
244 ecryptfs_printk(KERN_ERR
, "Status indicator has non-zero value "
245 "[%d]\n", data
[i
-1]);
249 rc
= ecryptfs_parse_packet_length(&data
[i
], &m_size
, &data_len
);
251 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
256 if (message_len
< (i
+ m_size
)) {
257 ecryptfs_printk(KERN_ERR
, "The message received from ecryptfsd "
258 "is shorter than expected\n");
263 ecryptfs_printk(KERN_ERR
,
264 "The decrypted key is not long enough to "
265 "include a cipher code and checksum\n");
269 *cipher_code
= data
[i
++];
270 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
271 session_key
->decrypted_key_size
= m_size
- 3;
272 if (session_key
->decrypted_key_size
> ECRYPTFS_MAX_KEY_BYTES
) {
273 ecryptfs_printk(KERN_ERR
, "key_size [%d] larger than "
274 "the maximum key size [%d]\n",
275 session_key
->decrypted_key_size
,
276 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
);
280 memcpy(session_key
->decrypted_key
, &data
[i
],
281 session_key
->decrypted_key_size
);
282 i
+= session_key
->decrypted_key_size
;
283 expected_checksum
+= (unsigned char)(data
[i
++]) << 8;
284 expected_checksum
+= (unsigned char)(data
[i
++]);
285 for (i
= 0; i
< session_key
->decrypted_key_size
; i
++)
286 checksum
+= session_key
->decrypted_key
[i
];
287 if (expected_checksum
!= checksum
) {
288 ecryptfs_printk(KERN_ERR
, "Invalid checksum for file "
289 "encryption key; expected [%x]; calculated "
290 "[%x]\n", expected_checksum
, checksum
);
299 write_tag_66_packet(char *signature
, u8 cipher_code
,
300 struct ecryptfs_crypt_stat
*crypt_stat
, char **packet
,
307 size_t packet_size_len
;
312 * ***** TAG 66 Packet Format *****
313 * | Content Type | 1 byte |
314 * | Key Identifier Size | 1 or 2 bytes |
315 * | Key Identifier | arbitrary |
316 * | File Encryption Key Size | 1 or 2 bytes |
317 * | File Encryption Key | arbitrary |
319 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
+ crypt_stat
->key_size
);
320 *packet
= kmalloc(data_len
, GFP_KERNEL
);
323 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
327 message
[i
++] = ECRYPTFS_TAG_66_PACKET_TYPE
;
328 rc
= ecryptfs_write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
331 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
332 "header; cannot generate packet length\n");
335 i
+= packet_size_len
;
336 memcpy(&message
[i
], signature
, ECRYPTFS_SIG_SIZE_HEX
);
337 i
+= ECRYPTFS_SIG_SIZE_HEX
;
338 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
339 rc
= ecryptfs_write_packet_length(&message
[i
], crypt_stat
->key_size
+ 3,
342 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
343 "header; cannot generate packet length\n");
346 i
+= packet_size_len
;
347 message
[i
++] = cipher_code
;
348 memcpy(&message
[i
], crypt_stat
->key
, crypt_stat
->key_size
);
349 i
+= crypt_stat
->key_size
;
350 for (j
= 0; j
< crypt_stat
->key_size
; j
++)
351 checksum
+= crypt_stat
->key
[j
];
352 message
[i
++] = (checksum
/ 256) % 256;
353 message
[i
++] = (checksum
% 256);
360 parse_tag_67_packet(struct ecryptfs_key_record
*key_rec
,
361 struct ecryptfs_message
*msg
)
370 * ***** TAG 65 Packet Format *****
371 * | Content Type | 1 byte |
372 * | Status Indicator | 1 byte |
373 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
374 * | Encrypted File Encryption Key | arbitrary |
376 message_len
= msg
->data_len
;
378 /* verify that everything through the encrypted FEK size is present */
379 if (message_len
< 4) {
381 printk(KERN_ERR
"%s: message_len is [%zd]; minimum acceptable "
382 "message length is [%d]\n", __func__
, message_len
, 4);
385 if (data
[i
++] != ECRYPTFS_TAG_67_PACKET_TYPE
) {
387 printk(KERN_ERR
"%s: Type should be ECRYPTFS_TAG_67\n",
393 printk(KERN_ERR
"%s: Status indicator has non zero "
394 "value [%d]\n", __func__
, data
[i
-1]);
398 rc
= ecryptfs_parse_packet_length(&data
[i
], &key_rec
->enc_key_size
,
401 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
406 if (message_len
< (i
+ key_rec
->enc_key_size
)) {
408 printk(KERN_ERR
"%s: message_len [%zd]; max len is [%zd]\n",
409 __func__
, message_len
, (i
+ key_rec
->enc_key_size
));
412 if (key_rec
->enc_key_size
> ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
414 printk(KERN_ERR
"%s: Encrypted key_size [%zd] larger than "
415 "the maximum key size [%d]\n", __func__
,
416 key_rec
->enc_key_size
,
417 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
);
420 memcpy(key_rec
->enc_key
, &data
[i
], key_rec
->enc_key_size
);
426 * ecryptfs_verify_version
427 * @version: The version number to confirm
429 * Returns zero on good version; non-zero otherwise
431 static int ecryptfs_verify_version(u16 version
)
437 major
= ((version
>> 8) & 0xFF);
438 minor
= (version
& 0xFF);
439 if (major
!= ECRYPTFS_VERSION_MAJOR
) {
440 ecryptfs_printk(KERN_ERR
, "Major version number mismatch. "
441 "Expected [%d]; got [%d]\n",
442 ECRYPTFS_VERSION_MAJOR
, major
);
446 if (minor
!= ECRYPTFS_VERSION_MINOR
) {
447 ecryptfs_printk(KERN_ERR
, "Minor version number mismatch. "
448 "Expected [%d]; got [%d]\n",
449 ECRYPTFS_VERSION_MINOR
, minor
);
458 * ecryptfs_verify_auth_tok_from_key
459 * @auth_tok_key: key containing the authentication token
460 * @auth_tok: authentication token
462 * Returns zero on valid auth tok; -EINVAL otherwise
465 ecryptfs_verify_auth_tok_from_key(struct key
*auth_tok_key
,
466 struct ecryptfs_auth_tok
**auth_tok
)
470 (*auth_tok
) = ecryptfs_get_key_payload_data(auth_tok_key
);
471 if (ecryptfs_verify_version((*auth_tok
)->version
)) {
472 printk(KERN_ERR
"Data structure version mismatch. Userspace "
473 "tools must match eCryptfs kernel module with major "
474 "version [%d] and minor version [%d]\n",
475 ECRYPTFS_VERSION_MAJOR
, ECRYPTFS_VERSION_MINOR
);
479 if ((*auth_tok
)->token_type
!= ECRYPTFS_PASSWORD
480 && (*auth_tok
)->token_type
!= ECRYPTFS_PRIVATE_KEY
) {
481 printk(KERN_ERR
"Invalid auth_tok structure "
482 "returned from key query\n");
491 ecryptfs_find_global_auth_tok_for_sig(
492 struct key
**auth_tok_key
,
493 struct ecryptfs_auth_tok
**auth_tok
,
494 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
, char *sig
)
496 struct ecryptfs_global_auth_tok
*walker
;
499 (*auth_tok_key
) = NULL
;
501 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
502 list_for_each_entry(walker
,
503 &mount_crypt_stat
->global_auth_tok_list
,
504 mount_crypt_stat_list
) {
505 if (memcmp(walker
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
))
508 if (walker
->flags
& ECRYPTFS_AUTH_TOK_INVALID
) {
513 rc
= key_validate(walker
->global_auth_tok_key
);
515 if (rc
== -EKEYEXPIRED
)
517 goto out_invalid_auth_tok
;
520 down_write(&(walker
->global_auth_tok_key
->sem
));
521 rc
= ecryptfs_verify_auth_tok_from_key(
522 walker
->global_auth_tok_key
, auth_tok
);
524 goto out_invalid_auth_tok_unlock
;
526 (*auth_tok_key
) = walker
->global_auth_tok_key
;
527 key_get(*auth_tok_key
);
532 out_invalid_auth_tok_unlock
:
533 up_write(&(walker
->global_auth_tok_key
->sem
));
534 out_invalid_auth_tok
:
535 printk(KERN_WARNING
"Invalidating auth tok with sig = [%s]\n", sig
);
536 walker
->flags
|= ECRYPTFS_AUTH_TOK_INVALID
;
537 key_put(walker
->global_auth_tok_key
);
538 walker
->global_auth_tok_key
= NULL
;
540 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
545 * ecryptfs_find_auth_tok_for_sig
546 * @auth_tok: Set to the matching auth_tok; NULL if not found
547 * @crypt_stat: inode crypt_stat crypto context
548 * @sig: Sig of auth_tok to find
550 * For now, this function simply looks at the registered auth_tok's
551 * linked off the mount_crypt_stat, so all the auth_toks that can be
552 * used must be registered at mount time. This function could
553 * potentially try a lot harder to find auth_tok's (e.g., by calling
554 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
555 * that static registration of auth_tok's will no longer be necessary.
557 * Returns zero on no error; non-zero on error
560 ecryptfs_find_auth_tok_for_sig(
561 struct key
**auth_tok_key
,
562 struct ecryptfs_auth_tok
**auth_tok
,
563 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
568 rc
= ecryptfs_find_global_auth_tok_for_sig(auth_tok_key
, auth_tok
,
569 mount_crypt_stat
, sig
);
571 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
572 * mount_crypt_stat structure, we prevent to use auth toks that
573 * are not inserted through the ecryptfs_add_global_auth_tok
576 if (mount_crypt_stat
->flags
577 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY
)
580 rc
= ecryptfs_keyring_auth_tok_for_sig(auth_tok_key
, auth_tok
,
587 * write_tag_70_packet can gobble a lot of stack space. We stuff most
588 * of the function's parameters in a kmalloc'd struct to help reduce
589 * eCryptfs' overall stack usage.
591 struct ecryptfs_write_tag_70_packet_silly_stack
{
593 size_t max_packet_size
;
594 size_t packet_size_len
;
595 size_t block_aligned_filename_size
;
599 size_t num_rand_bytes
;
600 struct mutex
*tfm_mutex
;
601 char *block_aligned_filename
;
602 struct ecryptfs_auth_tok
*auth_tok
;
603 struct scatterlist src_sg
[2];
604 struct scatterlist dst_sg
[2];
605 struct crypto_skcipher
*skcipher_tfm
;
606 struct skcipher_request
*skcipher_req
;
607 char iv
[ECRYPTFS_MAX_IV_BYTES
];
608 char hash
[ECRYPTFS_TAG_70_DIGEST_SIZE
];
609 char tmp_hash
[ECRYPTFS_TAG_70_DIGEST_SIZE
];
610 struct crypto_shash
*hash_tfm
;
611 struct shash_desc
*hash_desc
;
615 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
616 * @filename: NULL-terminated filename string
618 * This is the simplest mechanism for achieving filename encryption in
619 * eCryptfs. It encrypts the given filename with the mount-wide
620 * filename encryption key (FNEK) and stores it in a packet to @dest,
621 * which the callee will encode and write directly into the dentry
625 ecryptfs_write_tag_70_packet(char *dest
, size_t *remaining_bytes
,
627 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
628 char *filename
, size_t filename_size
)
630 struct ecryptfs_write_tag_70_packet_silly_stack
*s
;
631 struct key
*auth_tok_key
= NULL
;
634 s
= kzalloc(sizeof(*s
), GFP_KERNEL
);
636 printk(KERN_ERR
"%s: Out of memory whilst trying to kmalloc "
637 "[%zd] bytes of kernel memory\n", __func__
, sizeof(*s
));
642 rc
= ecryptfs_find_auth_tok_for_sig(
644 &s
->auth_tok
, mount_crypt_stat
,
645 mount_crypt_stat
->global_default_fnek_sig
);
647 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
648 "fnek sig [%s]; rc = [%d]\n", __func__
,
649 mount_crypt_stat
->global_default_fnek_sig
, rc
);
652 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(
654 &s
->tfm_mutex
, mount_crypt_stat
->global_default_fn_cipher_name
);
656 printk(KERN_ERR
"Internal error whilst attempting to get "
657 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
658 mount_crypt_stat
->global_default_fn_cipher_name
, rc
);
661 mutex_lock(s
->tfm_mutex
);
662 s
->block_size
= crypto_skcipher_blocksize(s
->skcipher_tfm
);
663 /* Plus one for the \0 separator between the random prefix
664 * and the plaintext filename */
665 s
->num_rand_bytes
= (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
+ 1);
666 s
->block_aligned_filename_size
= (s
->num_rand_bytes
+ filename_size
);
667 if ((s
->block_aligned_filename_size
% s
->block_size
) != 0) {
668 s
->num_rand_bytes
+= (s
->block_size
669 - (s
->block_aligned_filename_size
671 s
->block_aligned_filename_size
= (s
->num_rand_bytes
674 /* Octet 0: Tag 70 identifier
675 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
676 * and block-aligned encrypted filename size)
677 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
678 * Octet N2-N3: Cipher identifier (1 octet)
679 * Octets N3-N4: Block-aligned encrypted filename
680 * - Consists of a minimum number of random characters, a \0
681 * separator, and then the filename */
682 s
->max_packet_size
= (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
683 + s
->block_aligned_filename_size
);
685 (*packet_size
) = s
->max_packet_size
;
688 if (s
->max_packet_size
> (*remaining_bytes
)) {
689 printk(KERN_WARNING
"%s: Require [%zd] bytes to write; only "
690 "[%zd] available\n", __func__
, s
->max_packet_size
,
696 s
->skcipher_req
= skcipher_request_alloc(s
->skcipher_tfm
, GFP_KERNEL
);
697 if (!s
->skcipher_req
) {
698 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
699 "skcipher_request_alloc for %s\n", __func__
,
700 crypto_skcipher_driver_name(s
->skcipher_tfm
));
705 skcipher_request_set_callback(s
->skcipher_req
,
706 CRYPTO_TFM_REQ_MAY_SLEEP
, NULL
, NULL
);
708 s
->block_aligned_filename
= kzalloc(s
->block_aligned_filename_size
,
710 if (!s
->block_aligned_filename
) {
711 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
712 "kzalloc [%zd] bytes\n", __func__
,
713 s
->block_aligned_filename_size
);
717 dest
[s
->i
++] = ECRYPTFS_TAG_70_PACKET_TYPE
;
718 rc
= ecryptfs_write_packet_length(&dest
[s
->i
],
720 + 1 /* Cipher code */
721 + s
->block_aligned_filename_size
),
722 &s
->packet_size_len
);
724 printk(KERN_ERR
"%s: Error generating tag 70 packet "
725 "header; cannot generate packet length; rc = [%d]\n",
727 goto out_free_unlock
;
729 s
->i
+= s
->packet_size_len
;
730 ecryptfs_from_hex(&dest
[s
->i
],
731 mount_crypt_stat
->global_default_fnek_sig
,
733 s
->i
+= ECRYPTFS_SIG_SIZE
;
734 s
->cipher_code
= ecryptfs_code_for_cipher_string(
735 mount_crypt_stat
->global_default_fn_cipher_name
,
736 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
737 if (s
->cipher_code
== 0) {
738 printk(KERN_WARNING
"%s: Unable to generate code for "
739 "cipher [%s] with key bytes [%zd]\n", __func__
,
740 mount_crypt_stat
->global_default_fn_cipher_name
,
741 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
743 goto out_free_unlock
;
745 dest
[s
->i
++] = s
->cipher_code
;
746 /* TODO: Support other key modules than passphrase for
747 * filename encryption */
748 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
750 printk(KERN_INFO
"%s: Filename encryption only supports "
751 "password tokens\n", __func__
);
752 goto out_free_unlock
;
754 s
->hash_tfm
= crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST
, 0, 0);
755 if (IS_ERR(s
->hash_tfm
)) {
756 rc
= PTR_ERR(s
->hash_tfm
);
757 printk(KERN_ERR
"%s: Error attempting to "
758 "allocate hash crypto context; rc = [%d]\n",
760 goto out_free_unlock
;
763 s
->hash_desc
= kmalloc(sizeof(*s
->hash_desc
) +
764 crypto_shash_descsize(s
->hash_tfm
), GFP_KERNEL
);
766 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
767 "kmalloc [%zd] bytes\n", __func__
,
768 sizeof(*s
->hash_desc
) +
769 crypto_shash_descsize(s
->hash_tfm
));
771 goto out_release_free_unlock
;
774 s
->hash_desc
->tfm
= s
->hash_tfm
;
775 s
->hash_desc
->flags
= CRYPTO_TFM_REQ_MAY_SLEEP
;
777 rc
= crypto_shash_digest(s
->hash_desc
,
778 (u8
*)s
->auth_tok
->token
.password
.session_key_encryption_key
,
779 s
->auth_tok
->token
.password
.session_key_encryption_key_bytes
,
783 "%s: Error computing crypto hash; rc = [%d]\n",
785 goto out_release_free_unlock
;
787 for (s
->j
= 0; s
->j
< (s
->num_rand_bytes
- 1); s
->j
++) {
788 s
->block_aligned_filename
[s
->j
] =
789 s
->hash
[(s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)];
790 if ((s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)
791 == (ECRYPTFS_TAG_70_DIGEST_SIZE
- 1)) {
792 rc
= crypto_shash_digest(s
->hash_desc
, (u8
*)s
->hash
,
793 ECRYPTFS_TAG_70_DIGEST_SIZE
,
797 "%s: Error computing crypto hash; "
798 "rc = [%d]\n", __func__
, rc
);
799 goto out_release_free_unlock
;
801 memcpy(s
->hash
, s
->tmp_hash
,
802 ECRYPTFS_TAG_70_DIGEST_SIZE
);
804 if (s
->block_aligned_filename
[s
->j
] == '\0')
805 s
->block_aligned_filename
[s
->j
] = ECRYPTFS_NON_NULL
;
807 memcpy(&s
->block_aligned_filename
[s
->num_rand_bytes
], filename
,
809 rc
= virt_to_scatterlist(s
->block_aligned_filename
,
810 s
->block_aligned_filename_size
, s
->src_sg
, 2);
812 printk(KERN_ERR
"%s: Internal error whilst attempting to "
813 "convert filename memory to scatterlist; rc = [%d]. "
814 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
815 s
->block_aligned_filename_size
);
816 goto out_release_free_unlock
;
818 rc
= virt_to_scatterlist(&dest
[s
->i
], s
->block_aligned_filename_size
,
821 printk(KERN_ERR
"%s: Internal error whilst attempting to "
822 "convert encrypted filename memory to scatterlist; "
823 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
824 __func__
, rc
, s
->block_aligned_filename_size
);
825 goto out_release_free_unlock
;
827 /* The characters in the first block effectively do the job
828 * of the IV here, so we just use 0's for the IV. Note the
829 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
830 * >= ECRYPTFS_MAX_IV_BYTES. */
831 rc
= crypto_skcipher_setkey(
833 s
->auth_tok
->token
.password
.session_key_encryption_key
,
834 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
836 printk(KERN_ERR
"%s: Error setting key for crypto context; "
837 "rc = [%d]. s->auth_tok->token.password.session_key_"
838 "encryption_key = [0x%p]; mount_crypt_stat->"
839 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
841 s
->auth_tok
->token
.password
.session_key_encryption_key
,
842 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
843 goto out_release_free_unlock
;
845 skcipher_request_set_crypt(s
->skcipher_req
, s
->src_sg
, s
->dst_sg
,
846 s
->block_aligned_filename_size
, s
->iv
);
847 rc
= crypto_skcipher_encrypt(s
->skcipher_req
);
849 printk(KERN_ERR
"%s: Error attempting to encrypt filename; "
850 "rc = [%d]\n", __func__
, rc
);
851 goto out_release_free_unlock
;
853 s
->i
+= s
->block_aligned_filename_size
;
854 (*packet_size
) = s
->i
;
855 (*remaining_bytes
) -= (*packet_size
);
856 out_release_free_unlock
:
857 crypto_free_shash(s
->hash_tfm
);
859 kzfree(s
->block_aligned_filename
);
861 mutex_unlock(s
->tfm_mutex
);
864 up_write(&(auth_tok_key
->sem
));
865 key_put(auth_tok_key
);
867 skcipher_request_free(s
->skcipher_req
);
868 kzfree(s
->hash_desc
);
873 struct ecryptfs_parse_tag_70_packet_silly_stack
{
875 size_t max_packet_size
;
876 size_t packet_size_len
;
877 size_t parsed_tag_70_packet_size
;
878 size_t block_aligned_filename_size
;
881 struct mutex
*tfm_mutex
;
882 char *decrypted_filename
;
883 struct ecryptfs_auth_tok
*auth_tok
;
884 struct scatterlist src_sg
[2];
885 struct scatterlist dst_sg
[2];
886 struct crypto_skcipher
*skcipher_tfm
;
887 struct skcipher_request
*skcipher_req
;
888 char fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
+ 1];
889 char iv
[ECRYPTFS_MAX_IV_BYTES
];
890 char cipher_string
[ECRYPTFS_MAX_CIPHER_NAME_SIZE
+ 1];
894 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
895 * @filename: This function kmalloc's the memory for the filename
896 * @filename_size: This function sets this to the amount of memory
897 * kmalloc'd for the filename
898 * @packet_size: This function sets this to the the number of octets
899 * in the packet parsed
900 * @mount_crypt_stat: The mount-wide cryptographic context
901 * @data: The memory location containing the start of the tag 70
903 * @max_packet_size: The maximum legal size of the packet to be parsed
906 * Returns zero on success; non-zero otherwise
909 ecryptfs_parse_tag_70_packet(char **filename
, size_t *filename_size
,
911 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
912 char *data
, size_t max_packet_size
)
914 struct ecryptfs_parse_tag_70_packet_silly_stack
*s
;
915 struct key
*auth_tok_key
= NULL
;
919 (*filename_size
) = 0;
921 s
= kzalloc(sizeof(*s
), GFP_KERNEL
);
923 printk(KERN_ERR
"%s: Out of memory whilst trying to kmalloc "
924 "[%zd] bytes of kernel memory\n", __func__
, sizeof(*s
));
928 if (max_packet_size
< ECRYPTFS_TAG_70_MIN_METADATA_SIZE
) {
929 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; it must be "
930 "at least [%d]\n", __func__
, max_packet_size
,
931 ECRYPTFS_TAG_70_MIN_METADATA_SIZE
);
935 /* Octet 0: Tag 70 identifier
936 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
937 * and block-aligned encrypted filename size)
938 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
939 * Octet N2-N3: Cipher identifier (1 octet)
940 * Octets N3-N4: Block-aligned encrypted filename
941 * - Consists of a minimum number of random numbers, a \0
942 * separator, and then the filename */
943 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_70_PACKET_TYPE
) {
944 printk(KERN_WARNING
"%s: Invalid packet tag [0x%.2x]; must be "
945 "tag [0x%.2x]\n", __func__
,
946 data
[((*packet_size
) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE
);
950 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)],
951 &s
->parsed_tag_70_packet_size
,
952 &s
->packet_size_len
);
954 printk(KERN_WARNING
"%s: Error parsing packet length; "
955 "rc = [%d]\n", __func__
, rc
);
958 s
->block_aligned_filename_size
= (s
->parsed_tag_70_packet_size
959 - ECRYPTFS_SIG_SIZE
- 1);
960 if ((1 + s
->packet_size_len
+ s
->parsed_tag_70_packet_size
)
962 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; real packet "
963 "size is [%zd]\n", __func__
, max_packet_size
,
964 (1 + s
->packet_size_len
+ 1
965 + s
->block_aligned_filename_size
));
969 (*packet_size
) += s
->packet_size_len
;
970 ecryptfs_to_hex(s
->fnek_sig_hex
, &data
[(*packet_size
)],
972 s
->fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
973 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
974 s
->cipher_code
= data
[(*packet_size
)++];
975 rc
= ecryptfs_cipher_code_to_string(s
->cipher_string
, s
->cipher_code
);
977 printk(KERN_WARNING
"%s: Cipher code [%d] is invalid\n",
978 __func__
, s
->cipher_code
);
981 rc
= ecryptfs_find_auth_tok_for_sig(&auth_tok_key
,
982 &s
->auth_tok
, mount_crypt_stat
,
985 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
986 "fnek sig [%s]; rc = [%d]\n", __func__
, s
->fnek_sig_hex
,
990 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&s
->skcipher_tfm
,
994 printk(KERN_ERR
"Internal error whilst attempting to get "
995 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
996 s
->cipher_string
, rc
);
999 mutex_lock(s
->tfm_mutex
);
1000 rc
= virt_to_scatterlist(&data
[(*packet_size
)],
1001 s
->block_aligned_filename_size
, s
->src_sg
, 2);
1003 printk(KERN_ERR
"%s: Internal error whilst attempting to "
1004 "convert encrypted filename memory to scatterlist; "
1005 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1006 __func__
, rc
, s
->block_aligned_filename_size
);
1009 (*packet_size
) += s
->block_aligned_filename_size
;
1010 s
->decrypted_filename
= kmalloc(s
->block_aligned_filename_size
,
1012 if (!s
->decrypted_filename
) {
1013 printk(KERN_ERR
"%s: Out of memory whilst attempting to "
1014 "kmalloc [%zd] bytes\n", __func__
,
1015 s
->block_aligned_filename_size
);
1019 rc
= virt_to_scatterlist(s
->decrypted_filename
,
1020 s
->block_aligned_filename_size
, s
->dst_sg
, 2);
1022 printk(KERN_ERR
"%s: Internal error whilst attempting to "
1023 "convert decrypted filename memory to scatterlist; "
1024 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1025 __func__
, rc
, s
->block_aligned_filename_size
);
1026 goto out_free_unlock
;
1029 s
->skcipher_req
= skcipher_request_alloc(s
->skcipher_tfm
, GFP_KERNEL
);
1030 if (!s
->skcipher_req
) {
1031 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
1032 "skcipher_request_alloc for %s\n", __func__
,
1033 crypto_skcipher_driver_name(s
->skcipher_tfm
));
1035 goto out_free_unlock
;
1038 skcipher_request_set_callback(s
->skcipher_req
,
1039 CRYPTO_TFM_REQ_MAY_SLEEP
, NULL
, NULL
);
1041 /* The characters in the first block effectively do the job of
1042 * the IV here, so we just use 0's for the IV. Note the
1043 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1044 * >= ECRYPTFS_MAX_IV_BYTES. */
1045 /* TODO: Support other key modules than passphrase for
1046 * filename encryption */
1047 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
1049 printk(KERN_INFO
"%s: Filename encryption only supports "
1050 "password tokens\n", __func__
);
1051 goto out_free_unlock
;
1053 rc
= crypto_skcipher_setkey(
1055 s
->auth_tok
->token
.password
.session_key_encryption_key
,
1056 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
1058 printk(KERN_ERR
"%s: Error setting key for crypto context; "
1059 "rc = [%d]. s->auth_tok->token.password.session_key_"
1060 "encryption_key = [0x%p]; mount_crypt_stat->"
1061 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
1063 s
->auth_tok
->token
.password
.session_key_encryption_key
,
1064 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
1065 goto out_free_unlock
;
1067 skcipher_request_set_crypt(s
->skcipher_req
, s
->src_sg
, s
->dst_sg
,
1068 s
->block_aligned_filename_size
, s
->iv
);
1069 rc
= crypto_skcipher_decrypt(s
->skcipher_req
);
1071 printk(KERN_ERR
"%s: Error attempting to decrypt filename; "
1072 "rc = [%d]\n", __func__
, rc
);
1073 goto out_free_unlock
;
1075 while (s
->decrypted_filename
[s
->i
] != '\0'
1076 && s
->i
< s
->block_aligned_filename_size
)
1078 if (s
->i
== s
->block_aligned_filename_size
) {
1079 printk(KERN_WARNING
"%s: Invalid tag 70 packet; could not "
1080 "find valid separator between random characters and "
1081 "the filename\n", __func__
);
1083 goto out_free_unlock
;
1086 (*filename_size
) = (s
->block_aligned_filename_size
- s
->i
);
1087 if (!((*filename_size
) > 0 && (*filename_size
< PATH_MAX
))) {
1088 printk(KERN_WARNING
"%s: Filename size is [%zd], which is "
1089 "invalid\n", __func__
, (*filename_size
));
1091 goto out_free_unlock
;
1093 (*filename
) = kmalloc(((*filename_size
) + 1), GFP_KERNEL
);
1095 printk(KERN_ERR
"%s: Out of memory whilst attempting to "
1096 "kmalloc [%zd] bytes\n", __func__
,
1097 ((*filename_size
) + 1));
1099 goto out_free_unlock
;
1101 memcpy((*filename
), &s
->decrypted_filename
[s
->i
], (*filename_size
));
1102 (*filename
)[(*filename_size
)] = '\0';
1104 kfree(s
->decrypted_filename
);
1106 mutex_unlock(s
->tfm_mutex
);
1110 (*filename_size
) = 0;
1114 up_write(&(auth_tok_key
->sem
));
1115 key_put(auth_tok_key
);
1117 skcipher_request_free(s
->skcipher_req
);
1123 ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
1128 switch (auth_tok
->token_type
) {
1129 case ECRYPTFS_PASSWORD
:
1130 (*sig
) = auth_tok
->token
.password
.signature
;
1132 case ECRYPTFS_PRIVATE_KEY
:
1133 (*sig
) = auth_tok
->token
.private_key
.signature
;
1136 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
1137 auth_tok
->token_type
);
1144 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1145 * @auth_tok: The key authentication token used to decrypt the session key
1146 * @crypt_stat: The cryptographic context
1148 * Returns zero on success; non-zero error otherwise.
1151 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1152 struct ecryptfs_crypt_stat
*crypt_stat
)
1155 struct ecryptfs_msg_ctx
*msg_ctx
;
1156 struct ecryptfs_message
*msg
= NULL
;
1158 char *payload
= NULL
;
1159 size_t payload_len
= 0;
1162 rc
= ecryptfs_get_auth_tok_sig(&auth_tok_sig
, auth_tok
);
1164 printk(KERN_ERR
"Unrecognized auth tok type: [%d]\n",
1165 auth_tok
->token_type
);
1168 rc
= write_tag_64_packet(auth_tok_sig
, &(auth_tok
->session_key
),
1169 &payload
, &payload_len
);
1171 ecryptfs_printk(KERN_ERR
, "Failed to write tag 64 packet\n");
1174 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1176 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1177 "ecryptfsd: %d\n", rc
);
1180 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1182 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 65 packet "
1183 "from the user space daemon\n");
1187 rc
= parse_tag_65_packet(&(auth_tok
->session_key
),
1190 printk(KERN_ERR
"Failed to parse tag 65 packet; rc = [%d]\n",
1194 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1195 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1196 auth_tok
->session_key
.decrypted_key_size
);
1197 crypt_stat
->key_size
= auth_tok
->session_key
.decrypted_key_size
;
1198 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
, cipher_code
);
1200 ecryptfs_printk(KERN_ERR
, "Cipher code [%d] is invalid\n",
1204 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1205 if (ecryptfs_verbosity
> 0) {
1206 ecryptfs_printk(KERN_DEBUG
, "Decrypted session key:\n");
1207 ecryptfs_dump_hex(crypt_stat
->key
,
1208 crypt_stat
->key_size
);
1216 static void wipe_auth_tok_list(struct list_head
*auth_tok_list_head
)
1218 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1219 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1221 list_for_each_entry_safe(auth_tok_list_item
, auth_tok_list_item_tmp
,
1222 auth_tok_list_head
, list
) {
1223 list_del(&auth_tok_list_item
->list
);
1224 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1225 auth_tok_list_item
);
1229 struct kmem_cache
*ecryptfs_auth_tok_list_item_cache
;
1232 * parse_tag_1_packet
1233 * @crypt_stat: The cryptographic context to modify based on packet contents
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
1237 * end 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: The maximum allowable packet size
1246 * Returns zero on success; non-zero on error.
1249 parse_tag_1_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 1 identifier (1 byte)
1266 * Max Tag 1 packet size (max 3 bytes)
1268 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1269 * Cipher identifier (1 byte)
1270 * Encrypted key size (arbitrary)
1272 * 12 bytes minimum packet size
1274 if (unlikely(max_packet_size
< 12)) {
1275 printk(KERN_ERR
"Invalid max packet size; must be >=12\n");
1279 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_1_PACKET_TYPE
) {
1280 printk(KERN_ERR
"Enter w/ first byte != 0x%.2x\n",
1281 ECRYPTFS_TAG_1_PACKET_TYPE
);
1285 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1286 * at end of function upon failure */
1287 auth_tok_list_item
=
1288 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
,
1290 if (!auth_tok_list_item
) {
1291 printk(KERN_ERR
"Unable to allocate memory\n");
1295 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1296 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1299 printk(KERN_WARNING
"Error parsing packet length; "
1303 if (unlikely(body_size
< (ECRYPTFS_SIG_SIZE
+ 2))) {
1304 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1308 (*packet_size
) += length_size
;
1309 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1310 printk(KERN_WARNING
"Packet size exceeds max\n");
1314 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1315 printk(KERN_WARNING
"Unknown version number [%d]\n",
1316 data
[(*packet_size
) - 1]);
1320 ecryptfs_to_hex((*new_auth_tok
)->token
.private_key
.signature
,
1321 &data
[(*packet_size
)], ECRYPTFS_SIG_SIZE
);
1322 *packet_size
+= ECRYPTFS_SIG_SIZE
;
1323 /* This byte is skipped because the kernel does not need to
1324 * know which public key encryption algorithm was used */
1326 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1327 body_size
- (ECRYPTFS_SIG_SIZE
+ 2);
1328 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1329 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1330 printk(KERN_WARNING
"Tag 1 packet contains key larger "
1331 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1335 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1336 &data
[(*packet_size
)], (body_size
- (ECRYPTFS_SIG_SIZE
+ 2)));
1337 (*packet_size
) += (*new_auth_tok
)->session_key
.encrypted_key_size
;
1338 (*new_auth_tok
)->session_key
.flags
&=
1339 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1340 (*new_auth_tok
)->session_key
.flags
|=
1341 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1342 (*new_auth_tok
)->token_type
= ECRYPTFS_PRIVATE_KEY
;
1343 (*new_auth_tok
)->flags
= 0;
1344 (*new_auth_tok
)->session_key
.flags
&=
1345 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1346 (*new_auth_tok
)->session_key
.flags
&=
1347 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1348 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1351 (*new_auth_tok
) = NULL
;
1352 memset(auth_tok_list_item
, 0,
1353 sizeof(struct ecryptfs_auth_tok_list_item
));
1354 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1355 auth_tok_list_item
);
1363 * parse_tag_3_packet
1364 * @crypt_stat: The cryptographic context to modify based on packet
1366 * @data: The raw bytes of the packet.
1367 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1368 * a new authentication token will be placed at the end
1369 * of this list for this packet.
1370 * @new_auth_tok: Pointer to a pointer to memory that this function
1371 * allocates; sets the memory address of the pointer to
1372 * NULL on error. This object is added to the
1374 * @packet_size: This function writes the size of the parsed packet
1375 * into this memory location; zero on error.
1376 * @max_packet_size: maximum number of bytes to parse
1378 * Returns zero on success; non-zero on error.
1381 parse_tag_3_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1382 unsigned char *data
, struct list_head
*auth_tok_list
,
1383 struct ecryptfs_auth_tok
**new_auth_tok
,
1384 size_t *packet_size
, size_t max_packet_size
)
1387 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1392 (*new_auth_tok
) = NULL
;
1394 *This format is inspired by OpenPGP; see RFC 2440
1397 * Tag 3 identifier (1 byte)
1398 * Max Tag 3 packet size (max 3 bytes)
1400 * Cipher code (1 byte)
1401 * S2K specifier (1 byte)
1402 * Hash identifier (1 byte)
1403 * Salt (ECRYPTFS_SALT_SIZE)
1404 * Hash iterations (1 byte)
1405 * Encrypted key (arbitrary)
1407 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1409 if (max_packet_size
< (ECRYPTFS_SALT_SIZE
+ 7)) {
1410 printk(KERN_ERR
"Max packet size too large\n");
1414 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_3_PACKET_TYPE
) {
1415 printk(KERN_ERR
"First byte != 0x%.2x; invalid packet\n",
1416 ECRYPTFS_TAG_3_PACKET_TYPE
);
1420 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1421 * at end of function upon failure */
1422 auth_tok_list_item
=
1423 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
, GFP_KERNEL
);
1424 if (!auth_tok_list_item
) {
1425 printk(KERN_ERR
"Unable to allocate memory\n");
1429 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1430 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1433 printk(KERN_WARNING
"Error parsing packet length; rc = [%d]\n",
1437 if (unlikely(body_size
< (ECRYPTFS_SALT_SIZE
+ 5))) {
1438 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1442 (*packet_size
) += length_size
;
1443 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1444 printk(KERN_ERR
"Packet size exceeds max\n");
1448 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1449 (body_size
- (ECRYPTFS_SALT_SIZE
+ 5));
1450 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1451 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1452 printk(KERN_WARNING
"Tag 3 packet contains key larger "
1453 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1457 if (unlikely(data
[(*packet_size
)++] != 0x04)) {
1458 printk(KERN_WARNING
"Unknown version number [%d]\n",
1459 data
[(*packet_size
) - 1]);
1463 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
,
1464 (u16
)data
[(*packet_size
)]);
1467 /* A little extra work to differentiate among the AES key
1468 * sizes; see RFC2440 */
1469 switch(data
[(*packet_size
)++]) {
1470 case RFC2440_CIPHER_AES_192
:
1471 crypt_stat
->key_size
= 24;
1474 crypt_stat
->key_size
=
1475 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1477 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1480 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1481 printk(KERN_WARNING
"Only S2K ID 3 is currently supported\n");
1485 /* TODO: finish the hash mapping */
1486 switch (data
[(*packet_size
)++]) {
1487 case 0x01: /* See RFC2440 for these numbers and their mappings */
1489 memcpy((*new_auth_tok
)->token
.password
.salt
,
1490 &data
[(*packet_size
)], ECRYPTFS_SALT_SIZE
);
1491 (*packet_size
) += ECRYPTFS_SALT_SIZE
;
1492 /* This conversion was taken straight from RFC2440 */
1493 (*new_auth_tok
)->token
.password
.hash_iterations
=
1494 ((u32
) 16 + (data
[(*packet_size
)] & 15))
1495 << ((data
[(*packet_size
)] >> 4) + 6);
1497 /* Friendly reminder:
1498 * (*new_auth_tok)->session_key.encrypted_key_size =
1499 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1500 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1501 &data
[(*packet_size
)],
1502 (*new_auth_tok
)->session_key
.encrypted_key_size
);
1504 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1505 (*new_auth_tok
)->session_key
.flags
&=
1506 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1507 (*new_auth_tok
)->session_key
.flags
|=
1508 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1509 (*new_auth_tok
)->token
.password
.hash_algo
= 0x01; /* MD5 */
1512 ecryptfs_printk(KERN_ERR
, "Unsupported hash algorithm: "
1513 "[%d]\n", data
[(*packet_size
) - 1]);
1517 (*new_auth_tok
)->token_type
= ECRYPTFS_PASSWORD
;
1518 /* TODO: Parametarize; we might actually want userspace to
1519 * decrypt the session key. */
1520 (*new_auth_tok
)->session_key
.flags
&=
1521 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1522 (*new_auth_tok
)->session_key
.flags
&=
1523 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1524 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1527 (*new_auth_tok
) = NULL
;
1528 memset(auth_tok_list_item
, 0,
1529 sizeof(struct ecryptfs_auth_tok_list_item
));
1530 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1531 auth_tok_list_item
);
1539 * parse_tag_11_packet
1540 * @data: The raw bytes of the packet
1541 * @contents: This function writes the data contents of the literal
1542 * packet into this memory location
1543 * @max_contents_bytes: The maximum number of bytes that this function
1544 * is allowed to write into contents
1545 * @tag_11_contents_size: This function writes the size of the parsed
1546 * contents into this memory location; zero on
1548 * @packet_size: This function writes the size of the parsed packet
1549 * into this memory location; zero on error
1550 * @max_packet_size: maximum number of bytes to parse
1552 * Returns zero on success; non-zero on error.
1555 parse_tag_11_packet(unsigned char *data
, unsigned char *contents
,
1556 size_t max_contents_bytes
, size_t *tag_11_contents_size
,
1557 size_t *packet_size
, size_t max_packet_size
)
1564 (*tag_11_contents_size
) = 0;
1565 /* This format is inspired by OpenPGP; see RFC 2440
1568 * Tag 11 identifier (1 byte)
1569 * Max Tag 11 packet size (max 3 bytes)
1570 * Binary format specifier (1 byte)
1571 * Filename length (1 byte)
1572 * Filename ("_CONSOLE") (8 bytes)
1573 * Modification date (4 bytes)
1574 * Literal data (arbitrary)
1576 * We need at least 16 bytes of data for the packet to even be
1579 if (max_packet_size
< 16) {
1580 printk(KERN_ERR
"Maximum packet size too small\n");
1584 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
1585 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1589 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1592 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1595 if (body_size
< 14) {
1596 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1600 (*packet_size
) += length_size
;
1601 (*tag_11_contents_size
) = (body_size
- 14);
1602 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
1603 printk(KERN_ERR
"Packet size exceeds max\n");
1607 if (unlikely((*tag_11_contents_size
) > max_contents_bytes
)) {
1608 printk(KERN_ERR
"Literal data section in tag 11 packet exceeds "
1613 if (data
[(*packet_size
)++] != 0x62) {
1614 printk(KERN_WARNING
"Unrecognizable packet\n");
1618 if (data
[(*packet_size
)++] != 0x08) {
1619 printk(KERN_WARNING
"Unrecognizable packet\n");
1623 (*packet_size
) += 12; /* Ignore filename and modification date */
1624 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
1625 (*packet_size
) += (*tag_11_contents_size
);
1629 (*tag_11_contents_size
) = 0;
1634 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
1635 struct ecryptfs_auth_tok
**auth_tok
,
1640 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
1641 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
1642 (*auth_tok_key
) = ecryptfs_get_encrypted_key(sig
);
1643 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
1644 printk(KERN_ERR
"Could not find key with description: [%s]\n",
1646 rc
= process_request_key_err(PTR_ERR(*auth_tok_key
));
1647 (*auth_tok_key
) = NULL
;
1651 down_write(&(*auth_tok_key
)->sem
);
1652 rc
= ecryptfs_verify_auth_tok_from_key(*auth_tok_key
, auth_tok
);
1654 up_write(&(*auth_tok_key
)->sem
);
1655 key_put(*auth_tok_key
);
1656 (*auth_tok_key
) = NULL
;
1664 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1665 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1666 * @crypt_stat: The cryptographic context
1668 * Returns zero on success; non-zero error otherwise
1671 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1672 struct ecryptfs_crypt_stat
*crypt_stat
)
1674 struct scatterlist dst_sg
[2];
1675 struct scatterlist src_sg
[2];
1676 struct mutex
*tfm_mutex
;
1677 struct crypto_skcipher
*tfm
;
1678 struct skcipher_request
*req
= NULL
;
1681 if (unlikely(ecryptfs_verbosity
> 0)) {
1683 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1684 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1686 auth_tok
->token
.password
.session_key_encryption_key
,
1687 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1689 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm
, &tfm_mutex
,
1690 crypt_stat
->cipher
);
1692 printk(KERN_ERR
"Internal error whilst attempting to get "
1693 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1694 crypt_stat
->cipher
, rc
);
1697 rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1698 auth_tok
->session_key
.encrypted_key_size
,
1700 if (rc
< 1 || rc
> 2) {
1701 printk(KERN_ERR
"Internal error whilst attempting to convert "
1702 "auth_tok->session_key.encrypted_key to scatterlist; "
1703 "expected rc = 1; got rc = [%d]. "
1704 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc
,
1705 auth_tok
->session_key
.encrypted_key_size
);
1708 auth_tok
->session_key
.decrypted_key_size
=
1709 auth_tok
->session_key
.encrypted_key_size
;
1710 rc
= virt_to_scatterlist(auth_tok
->session_key
.decrypted_key
,
1711 auth_tok
->session_key
.decrypted_key_size
,
1713 if (rc
< 1 || rc
> 2) {
1714 printk(KERN_ERR
"Internal error whilst attempting to convert "
1715 "auth_tok->session_key.decrypted_key to scatterlist; "
1716 "expected rc = 1; got rc = [%d]\n", rc
);
1719 mutex_lock(tfm_mutex
);
1720 req
= skcipher_request_alloc(tfm
, GFP_KERNEL
);
1722 mutex_unlock(tfm_mutex
);
1723 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
1724 "skcipher_request_alloc for %s\n", __func__
,
1725 crypto_skcipher_driver_name(tfm
));
1730 skcipher_request_set_callback(req
, CRYPTO_TFM_REQ_MAY_SLEEP
,
1732 rc
= crypto_skcipher_setkey(
1733 tfm
, auth_tok
->token
.password
.session_key_encryption_key
,
1734 crypt_stat
->key_size
);
1735 if (unlikely(rc
< 0)) {
1736 mutex_unlock(tfm_mutex
);
1737 printk(KERN_ERR
"Error setting key for crypto context\n");
1741 skcipher_request_set_crypt(req
, src_sg
, dst_sg
,
1742 auth_tok
->session_key
.encrypted_key_size
,
1744 rc
= crypto_skcipher_decrypt(req
);
1745 mutex_unlock(tfm_mutex
);
1747 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
1750 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1751 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1752 auth_tok
->session_key
.decrypted_key_size
);
1753 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1754 if (unlikely(ecryptfs_verbosity
> 0)) {
1755 ecryptfs_printk(KERN_DEBUG
, "FEK of size [%zd]:\n",
1756 crypt_stat
->key_size
);
1757 ecryptfs_dump_hex(crypt_stat
->key
,
1758 crypt_stat
->key_size
);
1761 skcipher_request_free(req
);
1766 * ecryptfs_parse_packet_set
1767 * @crypt_stat: The cryptographic context
1768 * @src: Virtual address of region of memory containing the packets
1769 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1771 * Get crypt_stat to have the file's session key if the requisite key
1772 * is available to decrypt the session key.
1774 * Returns Zero if a valid authentication token was retrieved and
1775 * processed; negative value for file not encrypted or for error
1778 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1780 struct dentry
*ecryptfs_dentry
)
1783 size_t found_auth_tok
;
1784 size_t next_packet_is_auth_tok_packet
;
1785 struct list_head auth_tok_list
;
1786 struct ecryptfs_auth_tok
*matching_auth_tok
;
1787 struct ecryptfs_auth_tok
*candidate_auth_tok
;
1788 char *candidate_auth_tok_sig
;
1790 struct ecryptfs_auth_tok
*new_auth_tok
;
1791 unsigned char sig_tmp_space
[ECRYPTFS_SIG_SIZE
];
1792 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1793 size_t tag_11_contents_size
;
1794 size_t tag_11_packet_size
;
1795 struct key
*auth_tok_key
= NULL
;
1798 INIT_LIST_HEAD(&auth_tok_list
);
1799 /* Parse the header to find as many packets as we can; these will be
1800 * added the our &auth_tok_list */
1801 next_packet_is_auth_tok_packet
= 1;
1802 while (next_packet_is_auth_tok_packet
) {
1803 size_t max_packet_size
= ((PAGE_CACHE_SIZE
- 8) - i
);
1806 case ECRYPTFS_TAG_3_PACKET_TYPE
:
1807 rc
= parse_tag_3_packet(crypt_stat
,
1808 (unsigned char *)&src
[i
],
1809 &auth_tok_list
, &new_auth_tok
,
1810 &packet_size
, max_packet_size
);
1812 ecryptfs_printk(KERN_ERR
, "Error parsing "
1818 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1821 &tag_11_contents_size
,
1822 &tag_11_packet_size
,
1825 ecryptfs_printk(KERN_ERR
, "No valid "
1826 "(ecryptfs-specific) literal "
1827 "packet containing "
1828 "authentication token "
1829 "signature found after "
1834 i
+= tag_11_packet_size
;
1835 if (ECRYPTFS_SIG_SIZE
!= tag_11_contents_size
) {
1836 ecryptfs_printk(KERN_ERR
, "Expected "
1837 "signature of size [%d]; "
1838 "read size [%zd]\n",
1840 tag_11_contents_size
);
1844 ecryptfs_to_hex(new_auth_tok
->token
.password
.signature
,
1845 sig_tmp_space
, tag_11_contents_size
);
1846 new_auth_tok
->token
.password
.signature
[
1847 ECRYPTFS_PASSWORD_SIG_SIZE
] = '\0';
1848 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1850 case ECRYPTFS_TAG_1_PACKET_TYPE
:
1851 rc
= parse_tag_1_packet(crypt_stat
,
1852 (unsigned char *)&src
[i
],
1853 &auth_tok_list
, &new_auth_tok
,
1854 &packet_size
, max_packet_size
);
1856 ecryptfs_printk(KERN_ERR
, "Error parsing "
1862 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1864 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1865 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1866 "(Tag 11 not allowed by itself)\n");
1870 ecryptfs_printk(KERN_DEBUG
, "No packet at offset [%zd] "
1871 "of the file header; hex value of "
1872 "character is [0x%.2x]\n", i
, src
[i
]);
1873 next_packet_is_auth_tok_packet
= 0;
1876 if (list_empty(&auth_tok_list
)) {
1877 printk(KERN_ERR
"The lower file appears to be a non-encrypted "
1878 "eCryptfs file; this is not supported in this version "
1879 "of the eCryptfs kernel module\n");
1883 /* auth_tok_list contains the set of authentication tokens
1884 * parsed from the metadata. We need to find a matching
1885 * authentication token that has the secret component(s)
1886 * necessary to decrypt the EFEK in the auth_tok parsed from
1887 * the metadata. There may be several potential matches, but
1888 * just one will be sufficient to decrypt to get the FEK. */
1889 find_next_matching_auth_tok
:
1891 list_for_each_entry(auth_tok_list_item
, &auth_tok_list
, list
) {
1892 candidate_auth_tok
= &auth_tok_list_item
->auth_tok
;
1893 if (unlikely(ecryptfs_verbosity
> 0)) {
1894 ecryptfs_printk(KERN_DEBUG
,
1895 "Considering cadidate auth tok:\n");
1896 ecryptfs_dump_auth_tok(candidate_auth_tok
);
1898 rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1899 candidate_auth_tok
);
1902 "Unrecognized candidate auth tok type: [%d]\n",
1903 candidate_auth_tok
->token_type
);
1907 rc
= ecryptfs_find_auth_tok_for_sig(&auth_tok_key
,
1909 crypt_stat
->mount_crypt_stat
,
1910 candidate_auth_tok_sig
);
1913 goto found_matching_auth_tok
;
1916 if (!found_auth_tok
) {
1917 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1918 "authentication token\n");
1922 found_matching_auth_tok
:
1923 if (candidate_auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1924 memcpy(&(candidate_auth_tok
->token
.private_key
),
1925 &(matching_auth_tok
->token
.private_key
),
1926 sizeof(struct ecryptfs_private_key
));
1927 up_write(&(auth_tok_key
->sem
));
1928 key_put(auth_tok_key
);
1929 rc
= decrypt_pki_encrypted_session_key(candidate_auth_tok
,
1931 } else if (candidate_auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1932 memcpy(&(candidate_auth_tok
->token
.password
),
1933 &(matching_auth_tok
->token
.password
),
1934 sizeof(struct ecryptfs_password
));
1935 up_write(&(auth_tok_key
->sem
));
1936 key_put(auth_tok_key
);
1937 rc
= decrypt_passphrase_encrypted_session_key(
1938 candidate_auth_tok
, crypt_stat
);
1940 up_write(&(auth_tok_key
->sem
));
1941 key_put(auth_tok_key
);
1945 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1947 ecryptfs_printk(KERN_WARNING
, "Error decrypting the "
1948 "session key for authentication token with sig "
1949 "[%.*s]; rc = [%d]. Removing auth tok "
1950 "candidate from the list and searching for "
1951 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX
,
1952 candidate_auth_tok_sig
, rc
);
1953 list_for_each_entry_safe(auth_tok_list_item
,
1954 auth_tok_list_item_tmp
,
1955 &auth_tok_list
, list
) {
1956 if (candidate_auth_tok
1957 == &auth_tok_list_item
->auth_tok
) {
1958 list_del(&auth_tok_list_item
->list
);
1960 ecryptfs_auth_tok_list_item_cache
,
1961 auth_tok_list_item
);
1962 goto find_next_matching_auth_tok
;
1967 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1969 ecryptfs_printk(KERN_ERR
, "Error computing "
1973 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1975 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1976 "context for cipher [%s]; rc = [%d]\n",
1977 crypt_stat
->cipher
, rc
);
1980 wipe_auth_tok_list(&auth_tok_list
);
1986 pki_encrypt_session_key(struct key
*auth_tok_key
,
1987 struct ecryptfs_auth_tok
*auth_tok
,
1988 struct ecryptfs_crypt_stat
*crypt_stat
,
1989 struct ecryptfs_key_record
*key_rec
)
1991 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1992 char *payload
= NULL
;
1993 size_t payload_len
= 0;
1994 struct ecryptfs_message
*msg
;
1997 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1998 ecryptfs_code_for_cipher_string(
2000 crypt_stat
->key_size
),
2001 crypt_stat
, &payload
, &payload_len
);
2002 up_write(&(auth_tok_key
->sem
));
2003 key_put(auth_tok_key
);
2005 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
2008 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
2010 ecryptfs_printk(KERN_ERR
, "Error sending message to "
2011 "ecryptfsd: %d\n", rc
);
2014 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
2016 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
2017 "from the user space daemon\n");
2021 rc
= parse_tag_67_packet(key_rec
, msg
);
2023 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
2030 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2031 * @dest: Buffer into which to write the packet
2032 * @remaining_bytes: Maximum number of bytes that can be writtn
2033 * @auth_tok_key: The authentication token key to unlock and put when done with
2035 * @auth_tok: The authentication token used for generating the tag 1 packet
2036 * @crypt_stat: The cryptographic context
2037 * @key_rec: The key record struct for the tag 1 packet
2038 * @packet_size: This function will write the number of bytes that end
2039 * up constituting the packet; set to zero on error
2041 * Returns zero on success; non-zero on error.
2044 write_tag_1_packet(char *dest
, size_t *remaining_bytes
,
2045 struct key
*auth_tok_key
, struct ecryptfs_auth_tok
*auth_tok
,
2046 struct ecryptfs_crypt_stat
*crypt_stat
,
2047 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
2050 size_t encrypted_session_key_valid
= 0;
2051 size_t packet_size_length
;
2052 size_t max_packet_size
;
2056 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
2058 encrypted_session_key_valid
= 0;
2059 for (i
= 0; i
< crypt_stat
->key_size
; i
++)
2060 encrypted_session_key_valid
|=
2061 auth_tok
->session_key
.encrypted_key
[i
];
2062 if (encrypted_session_key_valid
) {
2063 memcpy(key_rec
->enc_key
,
2064 auth_tok
->session_key
.encrypted_key
,
2065 auth_tok
->session_key
.encrypted_key_size
);
2066 up_write(&(auth_tok_key
->sem
));
2067 key_put(auth_tok_key
);
2068 goto encrypted_session_key_set
;
2070 if (auth_tok
->session_key
.encrypted_key_size
== 0)
2071 auth_tok
->session_key
.encrypted_key_size
=
2072 auth_tok
->token
.private_key
.key_size
;
2073 rc
= pki_encrypt_session_key(auth_tok_key
, auth_tok
, crypt_stat
,
2076 printk(KERN_ERR
"Failed to encrypt session key via a key "
2077 "module; rc = [%d]\n", rc
);
2080 if (ecryptfs_verbosity
> 0) {
2081 ecryptfs_printk(KERN_DEBUG
, "Encrypted key:\n");
2082 ecryptfs_dump_hex(key_rec
->enc_key
, key_rec
->enc_key_size
);
2084 encrypted_session_key_set
:
2085 /* This format is inspired by OpenPGP; see RFC 2440
2087 max_packet_size
= (1 /* Tag 1 identifier */
2088 + 3 /* Max Tag 1 packet size */
2090 + ECRYPTFS_SIG_SIZE
/* Key identifier */
2091 + 1 /* Cipher identifier */
2092 + key_rec
->enc_key_size
); /* Encrypted key size */
2093 if (max_packet_size
> (*remaining_bytes
)) {
2094 printk(KERN_ERR
"Packet length larger than maximum allowable; "
2095 "need up to [%td] bytes, but there are only [%td] "
2096 "available\n", max_packet_size
, (*remaining_bytes
));
2100 dest
[(*packet_size
)++] = ECRYPTFS_TAG_1_PACKET_TYPE
;
2101 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
2102 (max_packet_size
- 4),
2103 &packet_size_length
);
2105 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
2106 "header; cannot generate packet length\n");
2109 (*packet_size
) += packet_size_length
;
2110 dest
[(*packet_size
)++] = 0x03; /* version 3 */
2111 memcpy(&dest
[(*packet_size
)], key_rec
->sig
, ECRYPTFS_SIG_SIZE
);
2112 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
2113 dest
[(*packet_size
)++] = RFC2440_CIPHER_RSA
;
2114 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
2115 key_rec
->enc_key_size
);
2116 (*packet_size
) += key_rec
->enc_key_size
;
2121 (*remaining_bytes
) -= (*packet_size
);
2126 * write_tag_11_packet
2127 * @dest: Target into which Tag 11 packet is to be written
2128 * @remaining_bytes: Maximum packet length
2129 * @contents: Byte array of contents to copy in
2130 * @contents_length: Number of bytes in contents
2131 * @packet_length: Length of the Tag 11 packet written; zero on error
2133 * Returns zero on success; non-zero on error.
2136 write_tag_11_packet(char *dest
, size_t *remaining_bytes
, char *contents
,
2137 size_t contents_length
, size_t *packet_length
)
2139 size_t packet_size_length
;
2140 size_t max_packet_size
;
2143 (*packet_length
) = 0;
2144 /* This format is inspired by OpenPGP; see RFC 2440
2146 max_packet_size
= (1 /* Tag 11 identifier */
2147 + 3 /* Max Tag 11 packet size */
2148 + 1 /* Binary format specifier */
2149 + 1 /* Filename length */
2150 + 8 /* Filename ("_CONSOLE") */
2151 + 4 /* Modification date */
2152 + contents_length
); /* Literal data */
2153 if (max_packet_size
> (*remaining_bytes
)) {
2154 printk(KERN_ERR
"Packet length larger than maximum allowable; "
2155 "need up to [%td] bytes, but there are only [%td] "
2156 "available\n", max_packet_size
, (*remaining_bytes
));
2160 dest
[(*packet_length
)++] = ECRYPTFS_TAG_11_PACKET_TYPE
;
2161 rc
= ecryptfs_write_packet_length(&dest
[(*packet_length
)],
2162 (max_packet_size
- 4),
2163 &packet_size_length
);
2165 printk(KERN_ERR
"Error generating tag 11 packet header; cannot "
2166 "generate packet length. rc = [%d]\n", rc
);
2169 (*packet_length
) += packet_size_length
;
2170 dest
[(*packet_length
)++] = 0x62; /* binary data format specifier */
2171 dest
[(*packet_length
)++] = 8;
2172 memcpy(&dest
[(*packet_length
)], "_CONSOLE", 8);
2173 (*packet_length
) += 8;
2174 memset(&dest
[(*packet_length
)], 0x00, 4);
2175 (*packet_length
) += 4;
2176 memcpy(&dest
[(*packet_length
)], contents
, contents_length
);
2177 (*packet_length
) += contents_length
;
2180 (*packet_length
) = 0;
2182 (*remaining_bytes
) -= (*packet_length
);
2187 * write_tag_3_packet
2188 * @dest: Buffer into which to write the packet
2189 * @remaining_bytes: Maximum number of bytes that can be written
2190 * @auth_tok: Authentication token
2191 * @crypt_stat: The cryptographic context
2192 * @key_rec: encrypted key
2193 * @packet_size: This function will write the number of bytes that end
2194 * up constituting the packet; set to zero on error
2196 * Returns zero on success; non-zero on error.
2199 write_tag_3_packet(char *dest
, size_t *remaining_bytes
,
2200 struct ecryptfs_auth_tok
*auth_tok
,
2201 struct ecryptfs_crypt_stat
*crypt_stat
,
2202 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
2205 size_t encrypted_session_key_valid
= 0;
2206 char session_key_encryption_key
[ECRYPTFS_MAX_KEY_BYTES
];
2207 struct scatterlist dst_sg
[2];
2208 struct scatterlist src_sg
[2];
2209 struct mutex
*tfm_mutex
= NULL
;
2211 size_t packet_size_length
;
2212 size_t max_packet_size
;
2213 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2214 crypt_stat
->mount_crypt_stat
;
2215 struct crypto_skcipher
*tfm
;
2216 struct skcipher_request
*req
;
2220 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
2222 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm
, &tfm_mutex
,
2223 crypt_stat
->cipher
);
2225 printk(KERN_ERR
"Internal error whilst attempting to get "
2226 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2227 crypt_stat
->cipher
, rc
);
2230 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
2231 printk(KERN_WARNING
"No key size specified at mount; "
2232 "defaulting to [%d]\n",
2233 crypto_skcipher_default_keysize(tfm
));
2234 mount_crypt_stat
->global_default_cipher_key_size
=
2235 crypto_skcipher_default_keysize(tfm
);
2237 if (crypt_stat
->key_size
== 0)
2238 crypt_stat
->key_size
=
2239 mount_crypt_stat
->global_default_cipher_key_size
;
2240 if (auth_tok
->session_key
.encrypted_key_size
== 0)
2241 auth_tok
->session_key
.encrypted_key_size
=
2242 crypt_stat
->key_size
;
2243 if (crypt_stat
->key_size
== 24
2244 && strcmp("aes", crypt_stat
->cipher
) == 0) {
2245 memset((crypt_stat
->key
+ 24), 0, 8);
2246 auth_tok
->session_key
.encrypted_key_size
= 32;
2248 auth_tok
->session_key
.encrypted_key_size
= crypt_stat
->key_size
;
2249 key_rec
->enc_key_size
=
2250 auth_tok
->session_key
.encrypted_key_size
;
2251 encrypted_session_key_valid
= 0;
2252 for (i
= 0; i
< auth_tok
->session_key
.encrypted_key_size
; i
++)
2253 encrypted_session_key_valid
|=
2254 auth_tok
->session_key
.encrypted_key
[i
];
2255 if (encrypted_session_key_valid
) {
2256 ecryptfs_printk(KERN_DEBUG
, "encrypted_session_key_valid != 0; "
2257 "using auth_tok->session_key.encrypted_key, "
2258 "where key_rec->enc_key_size = [%zd]\n",
2259 key_rec
->enc_key_size
);
2260 memcpy(key_rec
->enc_key
,
2261 auth_tok
->session_key
.encrypted_key
,
2262 key_rec
->enc_key_size
);
2263 goto encrypted_session_key_set
;
2265 if (auth_tok
->token
.password
.flags
&
2266 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET
) {
2267 ecryptfs_printk(KERN_DEBUG
, "Using previously generated "
2268 "session key encryption key of size [%d]\n",
2269 auth_tok
->token
.password
.
2270 session_key_encryption_key_bytes
);
2271 memcpy(session_key_encryption_key
,
2272 auth_tok
->token
.password
.session_key_encryption_key
,
2273 crypt_stat
->key_size
);
2274 ecryptfs_printk(KERN_DEBUG
,
2275 "Cached session key encryption key:\n");
2276 if (ecryptfs_verbosity
> 0)
2277 ecryptfs_dump_hex(session_key_encryption_key
, 16);
2279 if (unlikely(ecryptfs_verbosity
> 0)) {
2280 ecryptfs_printk(KERN_DEBUG
, "Session key encryption key:\n");
2281 ecryptfs_dump_hex(session_key_encryption_key
, 16);
2283 rc
= virt_to_scatterlist(crypt_stat
->key
, key_rec
->enc_key_size
,
2285 if (rc
< 1 || rc
> 2) {
2286 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
2287 "for crypt_stat session key; expected rc = 1; "
2288 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2289 rc
, key_rec
->enc_key_size
);
2293 rc
= virt_to_scatterlist(key_rec
->enc_key
, key_rec
->enc_key_size
,
2295 if (rc
< 1 || rc
> 2) {
2296 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
2297 "for crypt_stat encrypted session key; "
2298 "expected rc = 1; got rc = [%d]. "
2299 "key_rec->enc_key_size = [%zd]\n", rc
,
2300 key_rec
->enc_key_size
);
2304 mutex_lock(tfm_mutex
);
2305 rc
= crypto_skcipher_setkey(tfm
, session_key_encryption_key
,
2306 crypt_stat
->key_size
);
2308 mutex_unlock(tfm_mutex
);
2309 ecryptfs_printk(KERN_ERR
, "Error setting key for crypto "
2310 "context; rc = [%d]\n", rc
);
2314 req
= skcipher_request_alloc(tfm
, GFP_KERNEL
);
2316 mutex_unlock(tfm_mutex
);
2317 ecryptfs_printk(KERN_ERR
, "Out of kernel memory whilst "
2318 "attempting to skcipher_request_alloc for "
2319 "%s\n", crypto_skcipher_driver_name(tfm
));
2324 skcipher_request_set_callback(req
, CRYPTO_TFM_REQ_MAY_SLEEP
,
2328 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%zd] bytes of the key\n",
2329 crypt_stat
->key_size
);
2330 skcipher_request_set_crypt(req
, src_sg
, dst_sg
,
2331 (*key_rec
).enc_key_size
, NULL
);
2332 rc
= crypto_skcipher_encrypt(req
);
2333 mutex_unlock(tfm_mutex
);
2334 skcipher_request_free(req
);
2336 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
2339 ecryptfs_printk(KERN_DEBUG
, "This should be the encrypted key:\n");
2340 if (ecryptfs_verbosity
> 0) {
2341 ecryptfs_printk(KERN_DEBUG
, "EFEK of size [%zd]:\n",
2342 key_rec
->enc_key_size
);
2343 ecryptfs_dump_hex(key_rec
->enc_key
,
2344 key_rec
->enc_key_size
);
2346 encrypted_session_key_set
:
2347 /* This format is inspired by OpenPGP; see RFC 2440
2349 max_packet_size
= (1 /* Tag 3 identifier */
2350 + 3 /* Max Tag 3 packet size */
2352 + 1 /* Cipher code */
2353 + 1 /* S2K specifier */
2354 + 1 /* Hash identifier */
2355 + ECRYPTFS_SALT_SIZE
/* Salt */
2356 + 1 /* Hash iterations */
2357 + key_rec
->enc_key_size
); /* Encrypted key size */
2358 if (max_packet_size
> (*remaining_bytes
)) {
2359 printk(KERN_ERR
"Packet too large; need up to [%td] bytes, but "
2360 "there are only [%td] available\n", max_packet_size
,
2361 (*remaining_bytes
));
2365 dest
[(*packet_size
)++] = ECRYPTFS_TAG_3_PACKET_TYPE
;
2366 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2367 * to get the number of octets in the actual Tag 3 packet */
2368 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
2369 (max_packet_size
- 4),
2370 &packet_size_length
);
2372 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
2373 "generate packet length. rc = [%d]\n", rc
);
2376 (*packet_size
) += packet_size_length
;
2377 dest
[(*packet_size
)++] = 0x04; /* version 4 */
2378 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2379 * specified with strings */
2380 cipher_code
= ecryptfs_code_for_cipher_string(crypt_stat
->cipher
,
2381 crypt_stat
->key_size
);
2382 if (cipher_code
== 0) {
2383 ecryptfs_printk(KERN_WARNING
, "Unable to generate code for "
2384 "cipher [%s]\n", crypt_stat
->cipher
);
2388 dest
[(*packet_size
)++] = cipher_code
;
2389 dest
[(*packet_size
)++] = 0x03; /* S2K */
2390 dest
[(*packet_size
)++] = 0x01; /* MD5 (TODO: parameterize) */
2391 memcpy(&dest
[(*packet_size
)], auth_tok
->token
.password
.salt
,
2392 ECRYPTFS_SALT_SIZE
);
2393 (*packet_size
) += ECRYPTFS_SALT_SIZE
; /* salt */
2394 dest
[(*packet_size
)++] = 0x60; /* hash iterations (65536) */
2395 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
2396 key_rec
->enc_key_size
);
2397 (*packet_size
) += key_rec
->enc_key_size
;
2402 (*remaining_bytes
) -= (*packet_size
);
2406 struct kmem_cache
*ecryptfs_key_record_cache
;
2409 * ecryptfs_generate_key_packet_set
2410 * @dest_base: Virtual address from which to write the key record set
2411 * @crypt_stat: The cryptographic context from which the
2412 * authentication tokens will be retrieved
2413 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2414 * for the global parameters
2415 * @len: The amount written
2416 * @max: The maximum amount of data allowed to be written
2418 * Generates a key packet set and writes it to the virtual address
2421 * Returns zero on success; non-zero on error.
2424 ecryptfs_generate_key_packet_set(char *dest_base
,
2425 struct ecryptfs_crypt_stat
*crypt_stat
,
2426 struct dentry
*ecryptfs_dentry
, size_t *len
,
2429 struct ecryptfs_auth_tok
*auth_tok
;
2430 struct key
*auth_tok_key
= NULL
;
2431 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2432 &ecryptfs_superblock_to_private(
2433 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
2435 struct ecryptfs_key_record
*key_rec
;
2436 struct ecryptfs_key_sig
*key_sig
;
2440 mutex_lock(&crypt_stat
->keysig_list_mutex
);
2441 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
2446 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
2448 memset(key_rec
, 0, sizeof(*key_rec
));
2449 rc
= ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key
,
2454 printk(KERN_WARNING
"Unable to retrieve auth tok with "
2455 "sig = [%s]\n", key_sig
->keysig
);
2456 rc
= process_find_global_auth_tok_for_sig_err(rc
);
2459 if (auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
2460 rc
= write_tag_3_packet((dest_base
+ (*len
)),
2462 crypt_stat
, key_rec
,
2464 up_write(&(auth_tok_key
->sem
));
2465 key_put(auth_tok_key
);
2467 ecryptfs_printk(KERN_WARNING
, "Error "
2468 "writing tag 3 packet\n");
2472 /* Write auth tok signature packet */
2473 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
2475 ECRYPTFS_SIG_SIZE
, &written
);
2477 ecryptfs_printk(KERN_ERR
, "Error writing "
2478 "auth tok signature packet\n");
2482 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
2483 rc
= write_tag_1_packet(dest_base
+ (*len
), &max
,
2484 auth_tok_key
, auth_tok
,
2485 crypt_stat
, key_rec
, &written
);
2487 ecryptfs_printk(KERN_WARNING
, "Error "
2488 "writing tag 1 packet\n");
2493 up_write(&(auth_tok_key
->sem
));
2494 key_put(auth_tok_key
);
2495 ecryptfs_printk(KERN_WARNING
, "Unsupported "
2496 "authentication token type\n");
2501 if (likely(max
> 0)) {
2502 dest_base
[(*len
)] = 0x00;
2504 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
2508 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
2512 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
2516 struct kmem_cache
*ecryptfs_key_sig_cache
;
2518 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
2520 struct ecryptfs_key_sig
*new_key_sig
;
2522 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
2525 "Error allocating from ecryptfs_key_sig_cache\n");
2528 memcpy(new_key_sig
->keysig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
2529 new_key_sig
->keysig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
2530 /* Caller must hold keysig_list_mutex */
2531 list_add(&new_key_sig
->crypt_stat_list
, &crypt_stat
->keysig_list
);
2536 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
2539 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
2540 char *sig
, u32 global_auth_tok_flags
)
2542 struct ecryptfs_global_auth_tok
*new_auth_tok
;
2545 new_auth_tok
= kmem_cache_zalloc(ecryptfs_global_auth_tok_cache
,
2547 if (!new_auth_tok
) {
2549 printk(KERN_ERR
"Error allocating from "
2550 "ecryptfs_global_auth_tok_cache\n");
2553 memcpy(new_auth_tok
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
2554 new_auth_tok
->flags
= global_auth_tok_flags
;
2555 new_auth_tok
->sig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
2556 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
2557 list_add(&new_auth_tok
->mount_crypt_stat_list
,
2558 &mount_crypt_stat
->global_auth_tok_list
);
2559 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);