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 if the payload is invalid; or
463 * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
466 ecryptfs_verify_auth_tok_from_key(struct key
*auth_tok_key
,
467 struct ecryptfs_auth_tok
**auth_tok
)
471 (*auth_tok
) = ecryptfs_get_key_payload_data(auth_tok_key
);
472 if (IS_ERR(*auth_tok
)) {
473 rc
= PTR_ERR(*auth_tok
);
478 if (ecryptfs_verify_version((*auth_tok
)->version
)) {
479 printk(KERN_ERR
"Data structure version mismatch. Userspace "
480 "tools must match eCryptfs kernel module with major "
481 "version [%d] and minor version [%d]\n",
482 ECRYPTFS_VERSION_MAJOR
, ECRYPTFS_VERSION_MINOR
);
486 if ((*auth_tok
)->token_type
!= ECRYPTFS_PASSWORD
487 && (*auth_tok
)->token_type
!= ECRYPTFS_PRIVATE_KEY
) {
488 printk(KERN_ERR
"Invalid auth_tok structure "
489 "returned from key query\n");
498 ecryptfs_find_global_auth_tok_for_sig(
499 struct key
**auth_tok_key
,
500 struct ecryptfs_auth_tok
**auth_tok
,
501 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
, char *sig
)
503 struct ecryptfs_global_auth_tok
*walker
;
506 (*auth_tok_key
) = NULL
;
508 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
509 list_for_each_entry(walker
,
510 &mount_crypt_stat
->global_auth_tok_list
,
511 mount_crypt_stat_list
) {
512 if (memcmp(walker
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
))
515 if (walker
->flags
& ECRYPTFS_AUTH_TOK_INVALID
) {
520 rc
= key_validate(walker
->global_auth_tok_key
);
522 if (rc
== -EKEYEXPIRED
)
524 goto out_invalid_auth_tok
;
527 down_write(&(walker
->global_auth_tok_key
->sem
));
528 rc
= ecryptfs_verify_auth_tok_from_key(
529 walker
->global_auth_tok_key
, auth_tok
);
531 goto out_invalid_auth_tok_unlock
;
533 (*auth_tok_key
) = walker
->global_auth_tok_key
;
534 key_get(*auth_tok_key
);
539 out_invalid_auth_tok_unlock
:
540 up_write(&(walker
->global_auth_tok_key
->sem
));
541 out_invalid_auth_tok
:
542 printk(KERN_WARNING
"Invalidating auth tok with sig = [%s]\n", sig
);
543 walker
->flags
|= ECRYPTFS_AUTH_TOK_INVALID
;
544 key_put(walker
->global_auth_tok_key
);
545 walker
->global_auth_tok_key
= NULL
;
547 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
552 * ecryptfs_find_auth_tok_for_sig
553 * @auth_tok: Set to the matching auth_tok; NULL if not found
554 * @crypt_stat: inode crypt_stat crypto context
555 * @sig: Sig of auth_tok to find
557 * For now, this function simply looks at the registered auth_tok's
558 * linked off the mount_crypt_stat, so all the auth_toks that can be
559 * used must be registered at mount time. This function could
560 * potentially try a lot harder to find auth_tok's (e.g., by calling
561 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
562 * that static registration of auth_tok's will no longer be necessary.
564 * Returns zero on no error; non-zero on error
567 ecryptfs_find_auth_tok_for_sig(
568 struct key
**auth_tok_key
,
569 struct ecryptfs_auth_tok
**auth_tok
,
570 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
575 rc
= ecryptfs_find_global_auth_tok_for_sig(auth_tok_key
, auth_tok
,
576 mount_crypt_stat
, sig
);
578 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
579 * mount_crypt_stat structure, we prevent to use auth toks that
580 * are not inserted through the ecryptfs_add_global_auth_tok
583 if (mount_crypt_stat
->flags
584 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY
)
587 rc
= ecryptfs_keyring_auth_tok_for_sig(auth_tok_key
, auth_tok
,
594 * write_tag_70_packet can gobble a lot of stack space. We stuff most
595 * of the function's parameters in a kmalloc'd struct to help reduce
596 * eCryptfs' overall stack usage.
598 struct ecryptfs_write_tag_70_packet_silly_stack
{
600 size_t max_packet_size
;
601 size_t packet_size_len
;
602 size_t block_aligned_filename_size
;
606 size_t num_rand_bytes
;
607 struct mutex
*tfm_mutex
;
608 char *block_aligned_filename
;
609 struct ecryptfs_auth_tok
*auth_tok
;
610 struct scatterlist src_sg
[2];
611 struct scatterlist dst_sg
[2];
612 struct crypto_skcipher
*skcipher_tfm
;
613 struct skcipher_request
*skcipher_req
;
614 char iv
[ECRYPTFS_MAX_IV_BYTES
];
615 char hash
[ECRYPTFS_TAG_70_DIGEST_SIZE
];
616 char tmp_hash
[ECRYPTFS_TAG_70_DIGEST_SIZE
];
617 struct crypto_shash
*hash_tfm
;
618 struct shash_desc
*hash_desc
;
622 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
623 * @filename: NULL-terminated filename string
625 * This is the simplest mechanism for achieving filename encryption in
626 * eCryptfs. It encrypts the given filename with the mount-wide
627 * filename encryption key (FNEK) and stores it in a packet to @dest,
628 * which the callee will encode and write directly into the dentry
632 ecryptfs_write_tag_70_packet(char *dest
, size_t *remaining_bytes
,
634 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
635 char *filename
, size_t filename_size
)
637 struct ecryptfs_write_tag_70_packet_silly_stack
*s
;
638 struct key
*auth_tok_key
= NULL
;
641 s
= kzalloc(sizeof(*s
), GFP_KERNEL
);
646 rc
= ecryptfs_find_auth_tok_for_sig(
648 &s
->auth_tok
, mount_crypt_stat
,
649 mount_crypt_stat
->global_default_fnek_sig
);
651 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
652 "fnek sig [%s]; rc = [%d]\n", __func__
,
653 mount_crypt_stat
->global_default_fnek_sig
, rc
);
656 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(
658 &s
->tfm_mutex
, mount_crypt_stat
->global_default_fn_cipher_name
);
660 printk(KERN_ERR
"Internal error whilst attempting to get "
661 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
662 mount_crypt_stat
->global_default_fn_cipher_name
, rc
);
665 mutex_lock(s
->tfm_mutex
);
666 s
->block_size
= crypto_skcipher_blocksize(s
->skcipher_tfm
);
667 /* Plus one for the \0 separator between the random prefix
668 * and the plaintext filename */
669 s
->num_rand_bytes
= (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
+ 1);
670 s
->block_aligned_filename_size
= (s
->num_rand_bytes
+ filename_size
);
671 if ((s
->block_aligned_filename_size
% s
->block_size
) != 0) {
672 s
->num_rand_bytes
+= (s
->block_size
673 - (s
->block_aligned_filename_size
675 s
->block_aligned_filename_size
= (s
->num_rand_bytes
678 /* Octet 0: Tag 70 identifier
679 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
680 * and block-aligned encrypted filename size)
681 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
682 * Octet N2-N3: Cipher identifier (1 octet)
683 * Octets N3-N4: Block-aligned encrypted filename
684 * - Consists of a minimum number of random characters, a \0
685 * separator, and then the filename */
686 s
->max_packet_size
= (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
687 + s
->block_aligned_filename_size
);
689 (*packet_size
) = s
->max_packet_size
;
692 if (s
->max_packet_size
> (*remaining_bytes
)) {
693 printk(KERN_WARNING
"%s: Require [%zd] bytes to write; only "
694 "[%zd] available\n", __func__
, s
->max_packet_size
,
700 s
->skcipher_req
= skcipher_request_alloc(s
->skcipher_tfm
, GFP_KERNEL
);
701 if (!s
->skcipher_req
) {
702 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
703 "skcipher_request_alloc for %s\n", __func__
,
704 crypto_skcipher_driver_name(s
->skcipher_tfm
));
709 skcipher_request_set_callback(s
->skcipher_req
,
710 CRYPTO_TFM_REQ_MAY_SLEEP
, NULL
, NULL
);
712 s
->block_aligned_filename
= kzalloc(s
->block_aligned_filename_size
,
714 if (!s
->block_aligned_filename
) {
718 dest
[s
->i
++] = ECRYPTFS_TAG_70_PACKET_TYPE
;
719 rc
= ecryptfs_write_packet_length(&dest
[s
->i
],
721 + 1 /* Cipher code */
722 + s
->block_aligned_filename_size
),
723 &s
->packet_size_len
);
725 printk(KERN_ERR
"%s: Error generating tag 70 packet "
726 "header; cannot generate packet length; rc = [%d]\n",
728 goto out_free_unlock
;
730 s
->i
+= s
->packet_size_len
;
731 ecryptfs_from_hex(&dest
[s
->i
],
732 mount_crypt_stat
->global_default_fnek_sig
,
734 s
->i
+= ECRYPTFS_SIG_SIZE
;
735 s
->cipher_code
= ecryptfs_code_for_cipher_string(
736 mount_crypt_stat
->global_default_fn_cipher_name
,
737 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
738 if (s
->cipher_code
== 0) {
739 printk(KERN_WARNING
"%s: Unable to generate code for "
740 "cipher [%s] with key bytes [%zd]\n", __func__
,
741 mount_crypt_stat
->global_default_fn_cipher_name
,
742 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
744 goto out_free_unlock
;
746 dest
[s
->i
++] = s
->cipher_code
;
747 /* TODO: Support other key modules than passphrase for
748 * filename encryption */
749 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
751 printk(KERN_INFO
"%s: Filename encryption only supports "
752 "password tokens\n", __func__
);
753 goto out_free_unlock
;
755 s
->hash_tfm
= crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST
, 0, 0);
756 if (IS_ERR(s
->hash_tfm
)) {
757 rc
= PTR_ERR(s
->hash_tfm
);
758 printk(KERN_ERR
"%s: Error attempting to "
759 "allocate hash crypto context; rc = [%d]\n",
761 goto out_free_unlock
;
764 s
->hash_desc
= kmalloc(sizeof(*s
->hash_desc
) +
765 crypto_shash_descsize(s
->hash_tfm
), GFP_KERNEL
);
768 goto out_release_free_unlock
;
771 s
->hash_desc
->tfm
= s
->hash_tfm
;
773 rc
= crypto_shash_digest(s
->hash_desc
,
774 (u8
*)s
->auth_tok
->token
.password
.session_key_encryption_key
,
775 s
->auth_tok
->token
.password
.session_key_encryption_key_bytes
,
779 "%s: Error computing crypto hash; rc = [%d]\n",
781 goto out_release_free_unlock
;
783 for (s
->j
= 0; s
->j
< (s
->num_rand_bytes
- 1); s
->j
++) {
784 s
->block_aligned_filename
[s
->j
] =
785 s
->hash
[(s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)];
786 if ((s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)
787 == (ECRYPTFS_TAG_70_DIGEST_SIZE
- 1)) {
788 rc
= crypto_shash_digest(s
->hash_desc
, (u8
*)s
->hash
,
789 ECRYPTFS_TAG_70_DIGEST_SIZE
,
793 "%s: Error computing crypto hash; "
794 "rc = [%d]\n", __func__
, rc
);
795 goto out_release_free_unlock
;
797 memcpy(s
->hash
, s
->tmp_hash
,
798 ECRYPTFS_TAG_70_DIGEST_SIZE
);
800 if (s
->block_aligned_filename
[s
->j
] == '\0')
801 s
->block_aligned_filename
[s
->j
] = ECRYPTFS_NON_NULL
;
803 memcpy(&s
->block_aligned_filename
[s
->num_rand_bytes
], filename
,
805 rc
= virt_to_scatterlist(s
->block_aligned_filename
,
806 s
->block_aligned_filename_size
, s
->src_sg
, 2);
808 printk(KERN_ERR
"%s: Internal error whilst attempting to "
809 "convert filename memory to scatterlist; rc = [%d]. "
810 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
811 s
->block_aligned_filename_size
);
812 goto out_release_free_unlock
;
814 rc
= virt_to_scatterlist(&dest
[s
->i
], s
->block_aligned_filename_size
,
817 printk(KERN_ERR
"%s: Internal error whilst attempting to "
818 "convert encrypted filename memory to scatterlist; "
819 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
820 __func__
, rc
, s
->block_aligned_filename_size
);
821 goto out_release_free_unlock
;
823 /* The characters in the first block effectively do the job
824 * of the IV here, so we just use 0's for the IV. Note the
825 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
826 * >= ECRYPTFS_MAX_IV_BYTES. */
827 rc
= crypto_skcipher_setkey(
829 s
->auth_tok
->token
.password
.session_key_encryption_key
,
830 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
832 printk(KERN_ERR
"%s: Error setting key for crypto context; "
833 "rc = [%d]. s->auth_tok->token.password.session_key_"
834 "encryption_key = [0x%p]; mount_crypt_stat->"
835 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
837 s
->auth_tok
->token
.password
.session_key_encryption_key
,
838 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
839 goto out_release_free_unlock
;
841 skcipher_request_set_crypt(s
->skcipher_req
, s
->src_sg
, s
->dst_sg
,
842 s
->block_aligned_filename_size
, s
->iv
);
843 rc
= crypto_skcipher_encrypt(s
->skcipher_req
);
845 printk(KERN_ERR
"%s: Error attempting to encrypt filename; "
846 "rc = [%d]\n", __func__
, rc
);
847 goto out_release_free_unlock
;
849 s
->i
+= s
->block_aligned_filename_size
;
850 (*packet_size
) = s
->i
;
851 (*remaining_bytes
) -= (*packet_size
);
852 out_release_free_unlock
:
853 crypto_free_shash(s
->hash_tfm
);
855 kzfree(s
->block_aligned_filename
);
857 mutex_unlock(s
->tfm_mutex
);
860 up_write(&(auth_tok_key
->sem
));
861 key_put(auth_tok_key
);
863 skcipher_request_free(s
->skcipher_req
);
864 kzfree(s
->hash_desc
);
869 struct ecryptfs_parse_tag_70_packet_silly_stack
{
871 size_t max_packet_size
;
872 size_t packet_size_len
;
873 size_t parsed_tag_70_packet_size
;
874 size_t block_aligned_filename_size
;
877 struct mutex
*tfm_mutex
;
878 char *decrypted_filename
;
879 struct ecryptfs_auth_tok
*auth_tok
;
880 struct scatterlist src_sg
[2];
881 struct scatterlist dst_sg
[2];
882 struct crypto_skcipher
*skcipher_tfm
;
883 struct skcipher_request
*skcipher_req
;
884 char fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
+ 1];
885 char iv
[ECRYPTFS_MAX_IV_BYTES
];
886 char cipher_string
[ECRYPTFS_MAX_CIPHER_NAME_SIZE
+ 1];
890 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
891 * @filename: This function kmalloc's the memory for the filename
892 * @filename_size: This function sets this to the amount of memory
893 * kmalloc'd for the filename
894 * @packet_size: This function sets this to the the number of octets
895 * in the packet parsed
896 * @mount_crypt_stat: The mount-wide cryptographic context
897 * @data: The memory location containing the start of the tag 70
899 * @max_packet_size: The maximum legal size of the packet to be parsed
902 * Returns zero on success; non-zero otherwise
905 ecryptfs_parse_tag_70_packet(char **filename
, size_t *filename_size
,
907 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
908 char *data
, size_t max_packet_size
)
910 struct ecryptfs_parse_tag_70_packet_silly_stack
*s
;
911 struct key
*auth_tok_key
= NULL
;
915 (*filename_size
) = 0;
917 s
= kzalloc(sizeof(*s
), GFP_KERNEL
);
921 if (max_packet_size
< ECRYPTFS_TAG_70_MIN_METADATA_SIZE
) {
922 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; it must be "
923 "at least [%d]\n", __func__
, max_packet_size
,
924 ECRYPTFS_TAG_70_MIN_METADATA_SIZE
);
928 /* Octet 0: Tag 70 identifier
929 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
930 * and block-aligned encrypted filename size)
931 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
932 * Octet N2-N3: Cipher identifier (1 octet)
933 * Octets N3-N4: Block-aligned encrypted filename
934 * - Consists of a minimum number of random numbers, a \0
935 * separator, and then the filename */
936 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_70_PACKET_TYPE
) {
937 printk(KERN_WARNING
"%s: Invalid packet tag [0x%.2x]; must be "
938 "tag [0x%.2x]\n", __func__
,
939 data
[((*packet_size
) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE
);
943 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)],
944 &s
->parsed_tag_70_packet_size
,
945 &s
->packet_size_len
);
947 printk(KERN_WARNING
"%s: Error parsing packet length; "
948 "rc = [%d]\n", __func__
, rc
);
951 s
->block_aligned_filename_size
= (s
->parsed_tag_70_packet_size
952 - ECRYPTFS_SIG_SIZE
- 1);
953 if ((1 + s
->packet_size_len
+ s
->parsed_tag_70_packet_size
)
955 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; real packet "
956 "size is [%zd]\n", __func__
, max_packet_size
,
957 (1 + s
->packet_size_len
+ 1
958 + s
->block_aligned_filename_size
));
962 (*packet_size
) += s
->packet_size_len
;
963 ecryptfs_to_hex(s
->fnek_sig_hex
, &data
[(*packet_size
)],
965 s
->fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
966 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
967 s
->cipher_code
= data
[(*packet_size
)++];
968 rc
= ecryptfs_cipher_code_to_string(s
->cipher_string
, s
->cipher_code
);
970 printk(KERN_WARNING
"%s: Cipher code [%d] is invalid\n",
971 __func__
, s
->cipher_code
);
974 rc
= ecryptfs_find_auth_tok_for_sig(&auth_tok_key
,
975 &s
->auth_tok
, mount_crypt_stat
,
978 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
979 "fnek sig [%s]; rc = [%d]\n", __func__
, s
->fnek_sig_hex
,
983 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&s
->skcipher_tfm
,
987 printk(KERN_ERR
"Internal error whilst attempting to get "
988 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
989 s
->cipher_string
, rc
);
992 mutex_lock(s
->tfm_mutex
);
993 rc
= virt_to_scatterlist(&data
[(*packet_size
)],
994 s
->block_aligned_filename_size
, s
->src_sg
, 2);
996 printk(KERN_ERR
"%s: Internal error whilst attempting to "
997 "convert encrypted filename memory to scatterlist; "
998 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
999 __func__
, rc
, s
->block_aligned_filename_size
);
1002 (*packet_size
) += s
->block_aligned_filename_size
;
1003 s
->decrypted_filename
= kmalloc(s
->block_aligned_filename_size
,
1005 if (!s
->decrypted_filename
) {
1009 rc
= virt_to_scatterlist(s
->decrypted_filename
,
1010 s
->block_aligned_filename_size
, s
->dst_sg
, 2);
1012 printk(KERN_ERR
"%s: Internal error whilst attempting to "
1013 "convert decrypted filename memory to scatterlist; "
1014 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1015 __func__
, rc
, s
->block_aligned_filename_size
);
1016 goto out_free_unlock
;
1019 s
->skcipher_req
= skcipher_request_alloc(s
->skcipher_tfm
, GFP_KERNEL
);
1020 if (!s
->skcipher_req
) {
1021 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
1022 "skcipher_request_alloc for %s\n", __func__
,
1023 crypto_skcipher_driver_name(s
->skcipher_tfm
));
1025 goto out_free_unlock
;
1028 skcipher_request_set_callback(s
->skcipher_req
,
1029 CRYPTO_TFM_REQ_MAY_SLEEP
, NULL
, NULL
);
1031 /* The characters in the first block effectively do the job of
1032 * the IV here, so we just use 0's for the IV. Note the
1033 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1034 * >= ECRYPTFS_MAX_IV_BYTES. */
1035 /* TODO: Support other key modules than passphrase for
1036 * filename encryption */
1037 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
1039 printk(KERN_INFO
"%s: Filename encryption only supports "
1040 "password tokens\n", __func__
);
1041 goto out_free_unlock
;
1043 rc
= crypto_skcipher_setkey(
1045 s
->auth_tok
->token
.password
.session_key_encryption_key
,
1046 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
1048 printk(KERN_ERR
"%s: Error setting key for crypto context; "
1049 "rc = [%d]. s->auth_tok->token.password.session_key_"
1050 "encryption_key = [0x%p]; mount_crypt_stat->"
1051 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
1053 s
->auth_tok
->token
.password
.session_key_encryption_key
,
1054 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
1055 goto out_free_unlock
;
1057 skcipher_request_set_crypt(s
->skcipher_req
, s
->src_sg
, s
->dst_sg
,
1058 s
->block_aligned_filename_size
, s
->iv
);
1059 rc
= crypto_skcipher_decrypt(s
->skcipher_req
);
1061 printk(KERN_ERR
"%s: Error attempting to decrypt filename; "
1062 "rc = [%d]\n", __func__
, rc
);
1063 goto out_free_unlock
;
1065 while (s
->decrypted_filename
[s
->i
] != '\0'
1066 && s
->i
< s
->block_aligned_filename_size
)
1068 if (s
->i
== s
->block_aligned_filename_size
) {
1069 printk(KERN_WARNING
"%s: Invalid tag 70 packet; could not "
1070 "find valid separator between random characters and "
1071 "the filename\n", __func__
);
1073 goto out_free_unlock
;
1076 (*filename_size
) = (s
->block_aligned_filename_size
- s
->i
);
1077 if (!((*filename_size
) > 0 && (*filename_size
< PATH_MAX
))) {
1078 printk(KERN_WARNING
"%s: Filename size is [%zd], which is "
1079 "invalid\n", __func__
, (*filename_size
));
1081 goto out_free_unlock
;
1083 (*filename
) = kmalloc(((*filename_size
) + 1), GFP_KERNEL
);
1086 goto out_free_unlock
;
1088 memcpy((*filename
), &s
->decrypted_filename
[s
->i
], (*filename_size
));
1089 (*filename
)[(*filename_size
)] = '\0';
1091 kfree(s
->decrypted_filename
);
1093 mutex_unlock(s
->tfm_mutex
);
1097 (*filename_size
) = 0;
1101 up_write(&(auth_tok_key
->sem
));
1102 key_put(auth_tok_key
);
1104 skcipher_request_free(s
->skcipher_req
);
1110 ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
1115 switch (auth_tok
->token_type
) {
1116 case ECRYPTFS_PASSWORD
:
1117 (*sig
) = auth_tok
->token
.password
.signature
;
1119 case ECRYPTFS_PRIVATE_KEY
:
1120 (*sig
) = auth_tok
->token
.private_key
.signature
;
1123 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
1124 auth_tok
->token_type
);
1131 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1132 * @auth_tok: The key authentication token used to decrypt the session key
1133 * @crypt_stat: The cryptographic context
1135 * Returns zero on success; non-zero error otherwise.
1138 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1139 struct ecryptfs_crypt_stat
*crypt_stat
)
1142 struct ecryptfs_msg_ctx
*msg_ctx
;
1143 struct ecryptfs_message
*msg
= NULL
;
1145 char *payload
= NULL
;
1146 size_t payload_len
= 0;
1149 rc
= ecryptfs_get_auth_tok_sig(&auth_tok_sig
, auth_tok
);
1151 printk(KERN_ERR
"Unrecognized auth tok type: [%d]\n",
1152 auth_tok
->token_type
);
1155 rc
= write_tag_64_packet(auth_tok_sig
, &(auth_tok
->session_key
),
1156 &payload
, &payload_len
);
1158 ecryptfs_printk(KERN_ERR
, "Failed to write tag 64 packet\n");
1161 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1163 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1164 "ecryptfsd: %d\n", rc
);
1167 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1169 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 65 packet "
1170 "from the user space daemon\n");
1174 rc
= parse_tag_65_packet(&(auth_tok
->session_key
),
1177 printk(KERN_ERR
"Failed to parse tag 65 packet; rc = [%d]\n",
1181 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1182 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1183 auth_tok
->session_key
.decrypted_key_size
);
1184 crypt_stat
->key_size
= auth_tok
->session_key
.decrypted_key_size
;
1185 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
, cipher_code
);
1187 ecryptfs_printk(KERN_ERR
, "Cipher code [%d] is invalid\n",
1191 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1192 if (ecryptfs_verbosity
> 0) {
1193 ecryptfs_printk(KERN_DEBUG
, "Decrypted session key:\n");
1194 ecryptfs_dump_hex(crypt_stat
->key
,
1195 crypt_stat
->key_size
);
1203 static void wipe_auth_tok_list(struct list_head
*auth_tok_list_head
)
1205 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1206 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1208 list_for_each_entry_safe(auth_tok_list_item
, auth_tok_list_item_tmp
,
1209 auth_tok_list_head
, list
) {
1210 list_del(&auth_tok_list_item
->list
);
1211 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1212 auth_tok_list_item
);
1216 struct kmem_cache
*ecryptfs_auth_tok_list_item_cache
;
1219 * parse_tag_1_packet
1220 * @crypt_stat: The cryptographic context to modify based on packet contents
1221 * @data: The raw bytes of the packet.
1222 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1223 * a new authentication token will be placed at the
1224 * end of this list for this packet.
1225 * @new_auth_tok: Pointer to a pointer to memory that this function
1226 * allocates; sets the memory address of the pointer to
1227 * NULL on error. This object is added to the
1229 * @packet_size: This function writes the size of the parsed packet
1230 * into this memory location; zero on error.
1231 * @max_packet_size: The maximum allowable packet size
1233 * Returns zero on success; non-zero on error.
1236 parse_tag_1_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1237 unsigned char *data
, struct list_head
*auth_tok_list
,
1238 struct ecryptfs_auth_tok
**new_auth_tok
,
1239 size_t *packet_size
, size_t max_packet_size
)
1242 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1247 (*new_auth_tok
) = NULL
;
1249 * This format is inspired by OpenPGP; see RFC 2440
1252 * Tag 1 identifier (1 byte)
1253 * Max Tag 1 packet size (max 3 bytes)
1255 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1256 * Cipher identifier (1 byte)
1257 * Encrypted key size (arbitrary)
1259 * 12 bytes minimum packet size
1261 if (unlikely(max_packet_size
< 12)) {
1262 printk(KERN_ERR
"Invalid max packet size; must be >=12\n");
1266 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_1_PACKET_TYPE
) {
1267 printk(KERN_ERR
"Enter w/ first byte != 0x%.2x\n",
1268 ECRYPTFS_TAG_1_PACKET_TYPE
);
1272 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1273 * at end of function upon failure */
1274 auth_tok_list_item
=
1275 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
,
1277 if (!auth_tok_list_item
) {
1278 printk(KERN_ERR
"Unable to allocate memory\n");
1282 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1283 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1286 printk(KERN_WARNING
"Error parsing packet length; "
1290 if (unlikely(body_size
< (ECRYPTFS_SIG_SIZE
+ 2))) {
1291 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1295 (*packet_size
) += length_size
;
1296 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1297 printk(KERN_WARNING
"Packet size exceeds max\n");
1301 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1302 printk(KERN_WARNING
"Unknown version number [%d]\n",
1303 data
[(*packet_size
) - 1]);
1307 ecryptfs_to_hex((*new_auth_tok
)->token
.private_key
.signature
,
1308 &data
[(*packet_size
)], ECRYPTFS_SIG_SIZE
);
1309 *packet_size
+= ECRYPTFS_SIG_SIZE
;
1310 /* This byte is skipped because the kernel does not need to
1311 * know which public key encryption algorithm was used */
1313 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1314 body_size
- (ECRYPTFS_SIG_SIZE
+ 2);
1315 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1316 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1317 printk(KERN_WARNING
"Tag 1 packet contains key larger "
1318 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1322 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1323 &data
[(*packet_size
)], (body_size
- (ECRYPTFS_SIG_SIZE
+ 2)));
1324 (*packet_size
) += (*new_auth_tok
)->session_key
.encrypted_key_size
;
1325 (*new_auth_tok
)->session_key
.flags
&=
1326 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1327 (*new_auth_tok
)->session_key
.flags
|=
1328 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1329 (*new_auth_tok
)->token_type
= ECRYPTFS_PRIVATE_KEY
;
1330 (*new_auth_tok
)->flags
= 0;
1331 (*new_auth_tok
)->session_key
.flags
&=
1332 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1333 (*new_auth_tok
)->session_key
.flags
&=
1334 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1335 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1338 (*new_auth_tok
) = NULL
;
1339 memset(auth_tok_list_item
, 0,
1340 sizeof(struct ecryptfs_auth_tok_list_item
));
1341 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1342 auth_tok_list_item
);
1350 * parse_tag_3_packet
1351 * @crypt_stat: The cryptographic context to modify based on packet
1353 * @data: The raw bytes of the packet.
1354 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1355 * a new authentication token will be placed at the end
1356 * of this list for this packet.
1357 * @new_auth_tok: Pointer to a pointer to memory that this function
1358 * allocates; sets the memory address of the pointer to
1359 * NULL on error. This object is added to the
1361 * @packet_size: This function writes the size of the parsed packet
1362 * into this memory location; zero on error.
1363 * @max_packet_size: maximum number of bytes to parse
1365 * Returns zero on success; non-zero on error.
1368 parse_tag_3_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1369 unsigned char *data
, struct list_head
*auth_tok_list
,
1370 struct ecryptfs_auth_tok
**new_auth_tok
,
1371 size_t *packet_size
, size_t max_packet_size
)
1374 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1379 (*new_auth_tok
) = NULL
;
1381 *This format is inspired by OpenPGP; see RFC 2440
1384 * Tag 3 identifier (1 byte)
1385 * Max Tag 3 packet size (max 3 bytes)
1387 * Cipher code (1 byte)
1388 * S2K specifier (1 byte)
1389 * Hash identifier (1 byte)
1390 * Salt (ECRYPTFS_SALT_SIZE)
1391 * Hash iterations (1 byte)
1392 * Encrypted key (arbitrary)
1394 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1396 if (max_packet_size
< (ECRYPTFS_SALT_SIZE
+ 7)) {
1397 printk(KERN_ERR
"Max packet size too large\n");
1401 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_3_PACKET_TYPE
) {
1402 printk(KERN_ERR
"First byte != 0x%.2x; invalid packet\n",
1403 ECRYPTFS_TAG_3_PACKET_TYPE
);
1407 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1408 * at end of function upon failure */
1409 auth_tok_list_item
=
1410 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
, GFP_KERNEL
);
1411 if (!auth_tok_list_item
) {
1412 printk(KERN_ERR
"Unable to allocate memory\n");
1416 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1417 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1420 printk(KERN_WARNING
"Error parsing packet length; rc = [%d]\n",
1424 if (unlikely(body_size
< (ECRYPTFS_SALT_SIZE
+ 5))) {
1425 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1429 (*packet_size
) += length_size
;
1430 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1431 printk(KERN_ERR
"Packet size exceeds max\n");
1435 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1436 (body_size
- (ECRYPTFS_SALT_SIZE
+ 5));
1437 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1438 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1439 printk(KERN_WARNING
"Tag 3 packet contains key larger "
1440 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1444 if (unlikely(data
[(*packet_size
)++] != 0x04)) {
1445 printk(KERN_WARNING
"Unknown version number [%d]\n",
1446 data
[(*packet_size
) - 1]);
1450 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
,
1451 (u16
)data
[(*packet_size
)]);
1454 /* A little extra work to differentiate among the AES key
1455 * sizes; see RFC2440 */
1456 switch(data
[(*packet_size
)++]) {
1457 case RFC2440_CIPHER_AES_192
:
1458 crypt_stat
->key_size
= 24;
1461 crypt_stat
->key_size
=
1462 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1464 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1467 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1468 printk(KERN_WARNING
"Only S2K ID 3 is currently supported\n");
1472 /* TODO: finish the hash mapping */
1473 switch (data
[(*packet_size
)++]) {
1474 case 0x01: /* See RFC2440 for these numbers and their mappings */
1476 memcpy((*new_auth_tok
)->token
.password
.salt
,
1477 &data
[(*packet_size
)], ECRYPTFS_SALT_SIZE
);
1478 (*packet_size
) += ECRYPTFS_SALT_SIZE
;
1479 /* This conversion was taken straight from RFC2440 */
1480 (*new_auth_tok
)->token
.password
.hash_iterations
=
1481 ((u32
) 16 + (data
[(*packet_size
)] & 15))
1482 << ((data
[(*packet_size
)] >> 4) + 6);
1484 /* Friendly reminder:
1485 * (*new_auth_tok)->session_key.encrypted_key_size =
1486 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1487 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1488 &data
[(*packet_size
)],
1489 (*new_auth_tok
)->session_key
.encrypted_key_size
);
1491 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1492 (*new_auth_tok
)->session_key
.flags
&=
1493 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1494 (*new_auth_tok
)->session_key
.flags
|=
1495 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1496 (*new_auth_tok
)->token
.password
.hash_algo
= 0x01; /* MD5 */
1499 ecryptfs_printk(KERN_ERR
, "Unsupported hash algorithm: "
1500 "[%d]\n", data
[(*packet_size
) - 1]);
1504 (*new_auth_tok
)->token_type
= ECRYPTFS_PASSWORD
;
1505 /* TODO: Parametarize; we might actually want userspace to
1506 * decrypt the session key. */
1507 (*new_auth_tok
)->session_key
.flags
&=
1508 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1509 (*new_auth_tok
)->session_key
.flags
&=
1510 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1511 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1514 (*new_auth_tok
) = NULL
;
1515 memset(auth_tok_list_item
, 0,
1516 sizeof(struct ecryptfs_auth_tok_list_item
));
1517 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1518 auth_tok_list_item
);
1526 * parse_tag_11_packet
1527 * @data: The raw bytes of the packet
1528 * @contents: This function writes the data contents of the literal
1529 * packet into this memory location
1530 * @max_contents_bytes: The maximum number of bytes that this function
1531 * is allowed to write into contents
1532 * @tag_11_contents_size: This function writes the size of the parsed
1533 * contents into this memory location; zero on
1535 * @packet_size: This function writes the size of the parsed packet
1536 * into this memory location; zero on error
1537 * @max_packet_size: maximum number of bytes to parse
1539 * Returns zero on success; non-zero on error.
1542 parse_tag_11_packet(unsigned char *data
, unsigned char *contents
,
1543 size_t max_contents_bytes
, size_t *tag_11_contents_size
,
1544 size_t *packet_size
, size_t max_packet_size
)
1551 (*tag_11_contents_size
) = 0;
1552 /* This format is inspired by OpenPGP; see RFC 2440
1555 * Tag 11 identifier (1 byte)
1556 * Max Tag 11 packet size (max 3 bytes)
1557 * Binary format specifier (1 byte)
1558 * Filename length (1 byte)
1559 * Filename ("_CONSOLE") (8 bytes)
1560 * Modification date (4 bytes)
1561 * Literal data (arbitrary)
1563 * We need at least 16 bytes of data for the packet to even be
1566 if (max_packet_size
< 16) {
1567 printk(KERN_ERR
"Maximum packet size too small\n");
1571 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
1572 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1576 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1579 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1582 if (body_size
< 14) {
1583 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1587 (*packet_size
) += length_size
;
1588 (*tag_11_contents_size
) = (body_size
- 14);
1589 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
1590 printk(KERN_ERR
"Packet size exceeds max\n");
1594 if (unlikely((*tag_11_contents_size
) > max_contents_bytes
)) {
1595 printk(KERN_ERR
"Literal data section in tag 11 packet exceeds "
1600 if (data
[(*packet_size
)++] != 0x62) {
1601 printk(KERN_WARNING
"Unrecognizable packet\n");
1605 if (data
[(*packet_size
)++] != 0x08) {
1606 printk(KERN_WARNING
"Unrecognizable packet\n");
1610 (*packet_size
) += 12; /* Ignore filename and modification date */
1611 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
1612 (*packet_size
) += (*tag_11_contents_size
);
1616 (*tag_11_contents_size
) = 0;
1621 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
1622 struct ecryptfs_auth_tok
**auth_tok
,
1627 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
1628 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
1629 (*auth_tok_key
) = ecryptfs_get_encrypted_key(sig
);
1630 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
1631 printk(KERN_ERR
"Could not find key with description: [%s]\n",
1633 rc
= process_request_key_err(PTR_ERR(*auth_tok_key
));
1634 (*auth_tok_key
) = NULL
;
1638 down_write(&(*auth_tok_key
)->sem
);
1639 rc
= ecryptfs_verify_auth_tok_from_key(*auth_tok_key
, auth_tok
);
1641 up_write(&(*auth_tok_key
)->sem
);
1642 key_put(*auth_tok_key
);
1643 (*auth_tok_key
) = NULL
;
1651 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1652 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1653 * @crypt_stat: The cryptographic context
1655 * Returns zero on success; non-zero error otherwise
1658 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1659 struct ecryptfs_crypt_stat
*crypt_stat
)
1661 struct scatterlist dst_sg
[2];
1662 struct scatterlist src_sg
[2];
1663 struct mutex
*tfm_mutex
;
1664 struct crypto_skcipher
*tfm
;
1665 struct skcipher_request
*req
= NULL
;
1668 if (unlikely(ecryptfs_verbosity
> 0)) {
1670 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1671 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1673 auth_tok
->token
.password
.session_key_encryption_key
,
1674 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1676 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm
, &tfm_mutex
,
1677 crypt_stat
->cipher
);
1679 printk(KERN_ERR
"Internal error whilst attempting to get "
1680 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1681 crypt_stat
->cipher
, rc
);
1684 rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1685 auth_tok
->session_key
.encrypted_key_size
,
1687 if (rc
< 1 || rc
> 2) {
1688 printk(KERN_ERR
"Internal error whilst attempting to convert "
1689 "auth_tok->session_key.encrypted_key to scatterlist; "
1690 "expected rc = 1; got rc = [%d]. "
1691 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc
,
1692 auth_tok
->session_key
.encrypted_key_size
);
1695 auth_tok
->session_key
.decrypted_key_size
=
1696 auth_tok
->session_key
.encrypted_key_size
;
1697 rc
= virt_to_scatterlist(auth_tok
->session_key
.decrypted_key
,
1698 auth_tok
->session_key
.decrypted_key_size
,
1700 if (rc
< 1 || rc
> 2) {
1701 printk(KERN_ERR
"Internal error whilst attempting to convert "
1702 "auth_tok->session_key.decrypted_key to scatterlist; "
1703 "expected rc = 1; got rc = [%d]\n", rc
);
1706 mutex_lock(tfm_mutex
);
1707 req
= skcipher_request_alloc(tfm
, GFP_KERNEL
);
1709 mutex_unlock(tfm_mutex
);
1710 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
1711 "skcipher_request_alloc for %s\n", __func__
,
1712 crypto_skcipher_driver_name(tfm
));
1717 skcipher_request_set_callback(req
, CRYPTO_TFM_REQ_MAY_SLEEP
,
1719 rc
= crypto_skcipher_setkey(
1720 tfm
, auth_tok
->token
.password
.session_key_encryption_key
,
1721 crypt_stat
->key_size
);
1722 if (unlikely(rc
< 0)) {
1723 mutex_unlock(tfm_mutex
);
1724 printk(KERN_ERR
"Error setting key for crypto context\n");
1728 skcipher_request_set_crypt(req
, src_sg
, dst_sg
,
1729 auth_tok
->session_key
.encrypted_key_size
,
1731 rc
= crypto_skcipher_decrypt(req
);
1732 mutex_unlock(tfm_mutex
);
1734 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
1737 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1738 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1739 auth_tok
->session_key
.decrypted_key_size
);
1740 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1741 if (unlikely(ecryptfs_verbosity
> 0)) {
1742 ecryptfs_printk(KERN_DEBUG
, "FEK of size [%zd]:\n",
1743 crypt_stat
->key_size
);
1744 ecryptfs_dump_hex(crypt_stat
->key
,
1745 crypt_stat
->key_size
);
1748 skcipher_request_free(req
);
1753 * ecryptfs_parse_packet_set
1754 * @crypt_stat: The cryptographic context
1755 * @src: Virtual address of region of memory containing the packets
1756 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1758 * Get crypt_stat to have the file's session key if the requisite key
1759 * is available to decrypt the session key.
1761 * Returns Zero if a valid authentication token was retrieved and
1762 * processed; negative value for file not encrypted or for error
1765 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1767 struct dentry
*ecryptfs_dentry
)
1770 size_t found_auth_tok
;
1771 size_t next_packet_is_auth_tok_packet
;
1772 struct list_head auth_tok_list
;
1773 struct ecryptfs_auth_tok
*matching_auth_tok
;
1774 struct ecryptfs_auth_tok
*candidate_auth_tok
;
1775 char *candidate_auth_tok_sig
;
1777 struct ecryptfs_auth_tok
*new_auth_tok
;
1778 unsigned char sig_tmp_space
[ECRYPTFS_SIG_SIZE
];
1779 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1780 size_t tag_11_contents_size
;
1781 size_t tag_11_packet_size
;
1782 struct key
*auth_tok_key
= NULL
;
1785 INIT_LIST_HEAD(&auth_tok_list
);
1786 /* Parse the header to find as many packets as we can; these will be
1787 * added the our &auth_tok_list */
1788 next_packet_is_auth_tok_packet
= 1;
1789 while (next_packet_is_auth_tok_packet
) {
1790 size_t max_packet_size
= ((PAGE_SIZE
- 8) - i
);
1793 case ECRYPTFS_TAG_3_PACKET_TYPE
:
1794 rc
= parse_tag_3_packet(crypt_stat
,
1795 (unsigned char *)&src
[i
],
1796 &auth_tok_list
, &new_auth_tok
,
1797 &packet_size
, max_packet_size
);
1799 ecryptfs_printk(KERN_ERR
, "Error parsing "
1805 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1808 &tag_11_contents_size
,
1809 &tag_11_packet_size
,
1812 ecryptfs_printk(KERN_ERR
, "No valid "
1813 "(ecryptfs-specific) literal "
1814 "packet containing "
1815 "authentication token "
1816 "signature found after "
1821 i
+= tag_11_packet_size
;
1822 if (ECRYPTFS_SIG_SIZE
!= tag_11_contents_size
) {
1823 ecryptfs_printk(KERN_ERR
, "Expected "
1824 "signature of size [%d]; "
1825 "read size [%zd]\n",
1827 tag_11_contents_size
);
1831 ecryptfs_to_hex(new_auth_tok
->token
.password
.signature
,
1832 sig_tmp_space
, tag_11_contents_size
);
1833 new_auth_tok
->token
.password
.signature
[
1834 ECRYPTFS_PASSWORD_SIG_SIZE
] = '\0';
1835 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1837 case ECRYPTFS_TAG_1_PACKET_TYPE
:
1838 rc
= parse_tag_1_packet(crypt_stat
,
1839 (unsigned char *)&src
[i
],
1840 &auth_tok_list
, &new_auth_tok
,
1841 &packet_size
, max_packet_size
);
1843 ecryptfs_printk(KERN_ERR
, "Error parsing "
1849 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1851 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1852 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1853 "(Tag 11 not allowed by itself)\n");
1857 ecryptfs_printk(KERN_DEBUG
, "No packet at offset [%zd] "
1858 "of the file header; hex value of "
1859 "character is [0x%.2x]\n", i
, src
[i
]);
1860 next_packet_is_auth_tok_packet
= 0;
1863 if (list_empty(&auth_tok_list
)) {
1864 printk(KERN_ERR
"The lower file appears to be a non-encrypted "
1865 "eCryptfs file; this is not supported in this version "
1866 "of the eCryptfs kernel module\n");
1870 /* auth_tok_list contains the set of authentication tokens
1871 * parsed from the metadata. We need to find a matching
1872 * authentication token that has the secret component(s)
1873 * necessary to decrypt the EFEK in the auth_tok parsed from
1874 * the metadata. There may be several potential matches, but
1875 * just one will be sufficient to decrypt to get the FEK. */
1876 find_next_matching_auth_tok
:
1878 list_for_each_entry(auth_tok_list_item
, &auth_tok_list
, list
) {
1879 candidate_auth_tok
= &auth_tok_list_item
->auth_tok
;
1880 if (unlikely(ecryptfs_verbosity
> 0)) {
1881 ecryptfs_printk(KERN_DEBUG
,
1882 "Considering candidate auth tok:\n");
1883 ecryptfs_dump_auth_tok(candidate_auth_tok
);
1885 rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1886 candidate_auth_tok
);
1889 "Unrecognized candidate auth tok type: [%d]\n",
1890 candidate_auth_tok
->token_type
);
1894 rc
= ecryptfs_find_auth_tok_for_sig(&auth_tok_key
,
1896 crypt_stat
->mount_crypt_stat
,
1897 candidate_auth_tok_sig
);
1900 goto found_matching_auth_tok
;
1903 if (!found_auth_tok
) {
1904 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1905 "authentication token\n");
1909 found_matching_auth_tok
:
1910 if (candidate_auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1911 memcpy(&(candidate_auth_tok
->token
.private_key
),
1912 &(matching_auth_tok
->token
.private_key
),
1913 sizeof(struct ecryptfs_private_key
));
1914 up_write(&(auth_tok_key
->sem
));
1915 key_put(auth_tok_key
);
1916 rc
= decrypt_pki_encrypted_session_key(candidate_auth_tok
,
1918 } else if (candidate_auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1919 memcpy(&(candidate_auth_tok
->token
.password
),
1920 &(matching_auth_tok
->token
.password
),
1921 sizeof(struct ecryptfs_password
));
1922 up_write(&(auth_tok_key
->sem
));
1923 key_put(auth_tok_key
);
1924 rc
= decrypt_passphrase_encrypted_session_key(
1925 candidate_auth_tok
, crypt_stat
);
1927 up_write(&(auth_tok_key
->sem
));
1928 key_put(auth_tok_key
);
1932 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1934 ecryptfs_printk(KERN_WARNING
, "Error decrypting the "
1935 "session key for authentication token with sig "
1936 "[%.*s]; rc = [%d]. Removing auth tok "
1937 "candidate from the list and searching for "
1938 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX
,
1939 candidate_auth_tok_sig
, rc
);
1940 list_for_each_entry_safe(auth_tok_list_item
,
1941 auth_tok_list_item_tmp
,
1942 &auth_tok_list
, list
) {
1943 if (candidate_auth_tok
1944 == &auth_tok_list_item
->auth_tok
) {
1945 list_del(&auth_tok_list_item
->list
);
1947 ecryptfs_auth_tok_list_item_cache
,
1948 auth_tok_list_item
);
1949 goto find_next_matching_auth_tok
;
1954 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1956 ecryptfs_printk(KERN_ERR
, "Error computing "
1960 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1962 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1963 "context for cipher [%s]; rc = [%d]\n",
1964 crypt_stat
->cipher
, rc
);
1967 wipe_auth_tok_list(&auth_tok_list
);
1973 pki_encrypt_session_key(struct key
*auth_tok_key
,
1974 struct ecryptfs_auth_tok
*auth_tok
,
1975 struct ecryptfs_crypt_stat
*crypt_stat
,
1976 struct ecryptfs_key_record
*key_rec
)
1978 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1979 char *payload
= NULL
;
1980 size_t payload_len
= 0;
1981 struct ecryptfs_message
*msg
;
1984 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1985 ecryptfs_code_for_cipher_string(
1987 crypt_stat
->key_size
),
1988 crypt_stat
, &payload
, &payload_len
);
1989 up_write(&(auth_tok_key
->sem
));
1990 key_put(auth_tok_key
);
1992 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
1995 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1997 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1998 "ecryptfsd: %d\n", rc
);
2001 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
2003 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
2004 "from the user space daemon\n");
2008 rc
= parse_tag_67_packet(key_rec
, msg
);
2010 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
2017 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2018 * @dest: Buffer into which to write the packet
2019 * @remaining_bytes: Maximum number of bytes that can be writtn
2020 * @auth_tok_key: The authentication token key to unlock and put when done with
2022 * @auth_tok: The authentication token used for generating the tag 1 packet
2023 * @crypt_stat: The cryptographic context
2024 * @key_rec: The key record struct for the tag 1 packet
2025 * @packet_size: This function will write the number of bytes that end
2026 * up constituting the packet; set to zero on error
2028 * Returns zero on success; non-zero on error.
2031 write_tag_1_packet(char *dest
, size_t *remaining_bytes
,
2032 struct key
*auth_tok_key
, struct ecryptfs_auth_tok
*auth_tok
,
2033 struct ecryptfs_crypt_stat
*crypt_stat
,
2034 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
2037 size_t encrypted_session_key_valid
= 0;
2038 size_t packet_size_length
;
2039 size_t max_packet_size
;
2043 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
2045 encrypted_session_key_valid
= 0;
2046 for (i
= 0; i
< crypt_stat
->key_size
; i
++)
2047 encrypted_session_key_valid
|=
2048 auth_tok
->session_key
.encrypted_key
[i
];
2049 if (encrypted_session_key_valid
) {
2050 memcpy(key_rec
->enc_key
,
2051 auth_tok
->session_key
.encrypted_key
,
2052 auth_tok
->session_key
.encrypted_key_size
);
2053 up_write(&(auth_tok_key
->sem
));
2054 key_put(auth_tok_key
);
2055 goto encrypted_session_key_set
;
2057 if (auth_tok
->session_key
.encrypted_key_size
== 0)
2058 auth_tok
->session_key
.encrypted_key_size
=
2059 auth_tok
->token
.private_key
.key_size
;
2060 rc
= pki_encrypt_session_key(auth_tok_key
, auth_tok
, crypt_stat
,
2063 printk(KERN_ERR
"Failed to encrypt session key via a key "
2064 "module; rc = [%d]\n", rc
);
2067 if (ecryptfs_verbosity
> 0) {
2068 ecryptfs_printk(KERN_DEBUG
, "Encrypted key:\n");
2069 ecryptfs_dump_hex(key_rec
->enc_key
, key_rec
->enc_key_size
);
2071 encrypted_session_key_set
:
2072 /* This format is inspired by OpenPGP; see RFC 2440
2074 max_packet_size
= (1 /* Tag 1 identifier */
2075 + 3 /* Max Tag 1 packet size */
2077 + ECRYPTFS_SIG_SIZE
/* Key identifier */
2078 + 1 /* Cipher identifier */
2079 + key_rec
->enc_key_size
); /* Encrypted key size */
2080 if (max_packet_size
> (*remaining_bytes
)) {
2081 printk(KERN_ERR
"Packet length larger than maximum allowable; "
2082 "need up to [%td] bytes, but there are only [%td] "
2083 "available\n", max_packet_size
, (*remaining_bytes
));
2087 dest
[(*packet_size
)++] = ECRYPTFS_TAG_1_PACKET_TYPE
;
2088 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
2089 (max_packet_size
- 4),
2090 &packet_size_length
);
2092 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
2093 "header; cannot generate packet length\n");
2096 (*packet_size
) += packet_size_length
;
2097 dest
[(*packet_size
)++] = 0x03; /* version 3 */
2098 memcpy(&dest
[(*packet_size
)], key_rec
->sig
, ECRYPTFS_SIG_SIZE
);
2099 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
2100 dest
[(*packet_size
)++] = RFC2440_CIPHER_RSA
;
2101 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
2102 key_rec
->enc_key_size
);
2103 (*packet_size
) += key_rec
->enc_key_size
;
2108 (*remaining_bytes
) -= (*packet_size
);
2113 * write_tag_11_packet
2114 * @dest: Target into which Tag 11 packet is to be written
2115 * @remaining_bytes: Maximum packet length
2116 * @contents: Byte array of contents to copy in
2117 * @contents_length: Number of bytes in contents
2118 * @packet_length: Length of the Tag 11 packet written; zero on error
2120 * Returns zero on success; non-zero on error.
2123 write_tag_11_packet(char *dest
, size_t *remaining_bytes
, char *contents
,
2124 size_t contents_length
, size_t *packet_length
)
2126 size_t packet_size_length
;
2127 size_t max_packet_size
;
2130 (*packet_length
) = 0;
2131 /* This format is inspired by OpenPGP; see RFC 2440
2133 max_packet_size
= (1 /* Tag 11 identifier */
2134 + 3 /* Max Tag 11 packet size */
2135 + 1 /* Binary format specifier */
2136 + 1 /* Filename length */
2137 + 8 /* Filename ("_CONSOLE") */
2138 + 4 /* Modification date */
2139 + contents_length
); /* Literal data */
2140 if (max_packet_size
> (*remaining_bytes
)) {
2141 printk(KERN_ERR
"Packet length larger than maximum allowable; "
2142 "need up to [%td] bytes, but there are only [%td] "
2143 "available\n", max_packet_size
, (*remaining_bytes
));
2147 dest
[(*packet_length
)++] = ECRYPTFS_TAG_11_PACKET_TYPE
;
2148 rc
= ecryptfs_write_packet_length(&dest
[(*packet_length
)],
2149 (max_packet_size
- 4),
2150 &packet_size_length
);
2152 printk(KERN_ERR
"Error generating tag 11 packet header; cannot "
2153 "generate packet length. rc = [%d]\n", rc
);
2156 (*packet_length
) += packet_size_length
;
2157 dest
[(*packet_length
)++] = 0x62; /* binary data format specifier */
2158 dest
[(*packet_length
)++] = 8;
2159 memcpy(&dest
[(*packet_length
)], "_CONSOLE", 8);
2160 (*packet_length
) += 8;
2161 memset(&dest
[(*packet_length
)], 0x00, 4);
2162 (*packet_length
) += 4;
2163 memcpy(&dest
[(*packet_length
)], contents
, contents_length
);
2164 (*packet_length
) += contents_length
;
2167 (*packet_length
) = 0;
2169 (*remaining_bytes
) -= (*packet_length
);
2174 * write_tag_3_packet
2175 * @dest: Buffer into which to write the packet
2176 * @remaining_bytes: Maximum number of bytes that can be written
2177 * @auth_tok: Authentication token
2178 * @crypt_stat: The cryptographic context
2179 * @key_rec: encrypted key
2180 * @packet_size: This function will write the number of bytes that end
2181 * up constituting the packet; set to zero on error
2183 * Returns zero on success; non-zero on error.
2186 write_tag_3_packet(char *dest
, size_t *remaining_bytes
,
2187 struct ecryptfs_auth_tok
*auth_tok
,
2188 struct ecryptfs_crypt_stat
*crypt_stat
,
2189 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
2192 size_t encrypted_session_key_valid
= 0;
2193 char session_key_encryption_key
[ECRYPTFS_MAX_KEY_BYTES
];
2194 struct scatterlist dst_sg
[2];
2195 struct scatterlist src_sg
[2];
2196 struct mutex
*tfm_mutex
= NULL
;
2198 size_t packet_size_length
;
2199 size_t max_packet_size
;
2200 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2201 crypt_stat
->mount_crypt_stat
;
2202 struct crypto_skcipher
*tfm
;
2203 struct skcipher_request
*req
;
2207 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
2209 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm
, &tfm_mutex
,
2210 crypt_stat
->cipher
);
2212 printk(KERN_ERR
"Internal error whilst attempting to get "
2213 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2214 crypt_stat
->cipher
, rc
);
2217 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
2218 printk(KERN_WARNING
"No key size specified at mount; "
2219 "defaulting to [%d]\n",
2220 crypto_skcipher_default_keysize(tfm
));
2221 mount_crypt_stat
->global_default_cipher_key_size
=
2222 crypto_skcipher_default_keysize(tfm
);
2224 if (crypt_stat
->key_size
== 0)
2225 crypt_stat
->key_size
=
2226 mount_crypt_stat
->global_default_cipher_key_size
;
2227 if (auth_tok
->session_key
.encrypted_key_size
== 0)
2228 auth_tok
->session_key
.encrypted_key_size
=
2229 crypt_stat
->key_size
;
2230 if (crypt_stat
->key_size
== 24
2231 && strcmp("aes", crypt_stat
->cipher
) == 0) {
2232 memset((crypt_stat
->key
+ 24), 0, 8);
2233 auth_tok
->session_key
.encrypted_key_size
= 32;
2235 auth_tok
->session_key
.encrypted_key_size
= crypt_stat
->key_size
;
2236 key_rec
->enc_key_size
=
2237 auth_tok
->session_key
.encrypted_key_size
;
2238 encrypted_session_key_valid
= 0;
2239 for (i
= 0; i
< auth_tok
->session_key
.encrypted_key_size
; i
++)
2240 encrypted_session_key_valid
|=
2241 auth_tok
->session_key
.encrypted_key
[i
];
2242 if (encrypted_session_key_valid
) {
2243 ecryptfs_printk(KERN_DEBUG
, "encrypted_session_key_valid != 0; "
2244 "using auth_tok->session_key.encrypted_key, "
2245 "where key_rec->enc_key_size = [%zd]\n",
2246 key_rec
->enc_key_size
);
2247 memcpy(key_rec
->enc_key
,
2248 auth_tok
->session_key
.encrypted_key
,
2249 key_rec
->enc_key_size
);
2250 goto encrypted_session_key_set
;
2252 if (auth_tok
->token
.password
.flags
&
2253 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET
) {
2254 ecryptfs_printk(KERN_DEBUG
, "Using previously generated "
2255 "session key encryption key of size [%d]\n",
2256 auth_tok
->token
.password
.
2257 session_key_encryption_key_bytes
);
2258 memcpy(session_key_encryption_key
,
2259 auth_tok
->token
.password
.session_key_encryption_key
,
2260 crypt_stat
->key_size
);
2261 ecryptfs_printk(KERN_DEBUG
,
2262 "Cached session key encryption key:\n");
2263 if (ecryptfs_verbosity
> 0)
2264 ecryptfs_dump_hex(session_key_encryption_key
, 16);
2266 if (unlikely(ecryptfs_verbosity
> 0)) {
2267 ecryptfs_printk(KERN_DEBUG
, "Session key encryption key:\n");
2268 ecryptfs_dump_hex(session_key_encryption_key
, 16);
2270 rc
= virt_to_scatterlist(crypt_stat
->key
, key_rec
->enc_key_size
,
2272 if (rc
< 1 || rc
> 2) {
2273 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
2274 "for crypt_stat session key; expected rc = 1; "
2275 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2276 rc
, key_rec
->enc_key_size
);
2280 rc
= virt_to_scatterlist(key_rec
->enc_key
, key_rec
->enc_key_size
,
2282 if (rc
< 1 || rc
> 2) {
2283 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
2284 "for crypt_stat encrypted session key; "
2285 "expected rc = 1; got rc = [%d]. "
2286 "key_rec->enc_key_size = [%zd]\n", rc
,
2287 key_rec
->enc_key_size
);
2291 mutex_lock(tfm_mutex
);
2292 rc
= crypto_skcipher_setkey(tfm
, session_key_encryption_key
,
2293 crypt_stat
->key_size
);
2295 mutex_unlock(tfm_mutex
);
2296 ecryptfs_printk(KERN_ERR
, "Error setting key for crypto "
2297 "context; rc = [%d]\n", rc
);
2301 req
= skcipher_request_alloc(tfm
, GFP_KERNEL
);
2303 mutex_unlock(tfm_mutex
);
2304 ecryptfs_printk(KERN_ERR
, "Out of kernel memory whilst "
2305 "attempting to skcipher_request_alloc for "
2306 "%s\n", crypto_skcipher_driver_name(tfm
));
2311 skcipher_request_set_callback(req
, CRYPTO_TFM_REQ_MAY_SLEEP
,
2315 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%zd] bytes of the key\n",
2316 crypt_stat
->key_size
);
2317 skcipher_request_set_crypt(req
, src_sg
, dst_sg
,
2318 (*key_rec
).enc_key_size
, NULL
);
2319 rc
= crypto_skcipher_encrypt(req
);
2320 mutex_unlock(tfm_mutex
);
2321 skcipher_request_free(req
);
2323 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
2326 ecryptfs_printk(KERN_DEBUG
, "This should be the encrypted key:\n");
2327 if (ecryptfs_verbosity
> 0) {
2328 ecryptfs_printk(KERN_DEBUG
, "EFEK of size [%zd]:\n",
2329 key_rec
->enc_key_size
);
2330 ecryptfs_dump_hex(key_rec
->enc_key
,
2331 key_rec
->enc_key_size
);
2333 encrypted_session_key_set
:
2334 /* This format is inspired by OpenPGP; see RFC 2440
2336 max_packet_size
= (1 /* Tag 3 identifier */
2337 + 3 /* Max Tag 3 packet size */
2339 + 1 /* Cipher code */
2340 + 1 /* S2K specifier */
2341 + 1 /* Hash identifier */
2342 + ECRYPTFS_SALT_SIZE
/* Salt */
2343 + 1 /* Hash iterations */
2344 + key_rec
->enc_key_size
); /* Encrypted key size */
2345 if (max_packet_size
> (*remaining_bytes
)) {
2346 printk(KERN_ERR
"Packet too large; need up to [%td] bytes, but "
2347 "there are only [%td] available\n", max_packet_size
,
2348 (*remaining_bytes
));
2352 dest
[(*packet_size
)++] = ECRYPTFS_TAG_3_PACKET_TYPE
;
2353 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2354 * to get the number of octets in the actual Tag 3 packet */
2355 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
2356 (max_packet_size
- 4),
2357 &packet_size_length
);
2359 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
2360 "generate packet length. rc = [%d]\n", rc
);
2363 (*packet_size
) += packet_size_length
;
2364 dest
[(*packet_size
)++] = 0x04; /* version 4 */
2365 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2366 * specified with strings */
2367 cipher_code
= ecryptfs_code_for_cipher_string(crypt_stat
->cipher
,
2368 crypt_stat
->key_size
);
2369 if (cipher_code
== 0) {
2370 ecryptfs_printk(KERN_WARNING
, "Unable to generate code for "
2371 "cipher [%s]\n", crypt_stat
->cipher
);
2375 dest
[(*packet_size
)++] = cipher_code
;
2376 dest
[(*packet_size
)++] = 0x03; /* S2K */
2377 dest
[(*packet_size
)++] = 0x01; /* MD5 (TODO: parameterize) */
2378 memcpy(&dest
[(*packet_size
)], auth_tok
->token
.password
.salt
,
2379 ECRYPTFS_SALT_SIZE
);
2380 (*packet_size
) += ECRYPTFS_SALT_SIZE
; /* salt */
2381 dest
[(*packet_size
)++] = 0x60; /* hash iterations (65536) */
2382 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
2383 key_rec
->enc_key_size
);
2384 (*packet_size
) += key_rec
->enc_key_size
;
2389 (*remaining_bytes
) -= (*packet_size
);
2393 struct kmem_cache
*ecryptfs_key_record_cache
;
2396 * ecryptfs_generate_key_packet_set
2397 * @dest_base: Virtual address from which to write the key record set
2398 * @crypt_stat: The cryptographic context from which the
2399 * authentication tokens will be retrieved
2400 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2401 * for the global parameters
2402 * @len: The amount written
2403 * @max: The maximum amount of data allowed to be written
2405 * Generates a key packet set and writes it to the virtual address
2408 * Returns zero on success; non-zero on error.
2411 ecryptfs_generate_key_packet_set(char *dest_base
,
2412 struct ecryptfs_crypt_stat
*crypt_stat
,
2413 struct dentry
*ecryptfs_dentry
, size_t *len
,
2416 struct ecryptfs_auth_tok
*auth_tok
;
2417 struct key
*auth_tok_key
= NULL
;
2418 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2419 &ecryptfs_superblock_to_private(
2420 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
2422 struct ecryptfs_key_record
*key_rec
;
2423 struct ecryptfs_key_sig
*key_sig
;
2427 mutex_lock(&crypt_stat
->keysig_list_mutex
);
2428 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
2433 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
2435 memset(key_rec
, 0, sizeof(*key_rec
));
2436 rc
= ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key
,
2441 printk(KERN_WARNING
"Unable to retrieve auth tok with "
2442 "sig = [%s]\n", key_sig
->keysig
);
2443 rc
= process_find_global_auth_tok_for_sig_err(rc
);
2446 if (auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
2447 rc
= write_tag_3_packet((dest_base
+ (*len
)),
2449 crypt_stat
, key_rec
,
2451 up_write(&(auth_tok_key
->sem
));
2452 key_put(auth_tok_key
);
2454 ecryptfs_printk(KERN_WARNING
, "Error "
2455 "writing tag 3 packet\n");
2459 /* Write auth tok signature packet */
2460 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
2462 ECRYPTFS_SIG_SIZE
, &written
);
2464 ecryptfs_printk(KERN_ERR
, "Error writing "
2465 "auth tok signature packet\n");
2469 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
2470 rc
= write_tag_1_packet(dest_base
+ (*len
), &max
,
2471 auth_tok_key
, auth_tok
,
2472 crypt_stat
, key_rec
, &written
);
2474 ecryptfs_printk(KERN_WARNING
, "Error "
2475 "writing tag 1 packet\n");
2480 up_write(&(auth_tok_key
->sem
));
2481 key_put(auth_tok_key
);
2482 ecryptfs_printk(KERN_WARNING
, "Unsupported "
2483 "authentication token type\n");
2488 if (likely(max
> 0)) {
2489 dest_base
[(*len
)] = 0x00;
2491 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
2495 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
2499 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
2503 struct kmem_cache
*ecryptfs_key_sig_cache
;
2505 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
2507 struct ecryptfs_key_sig
*new_key_sig
;
2509 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
2513 memcpy(new_key_sig
->keysig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
2514 new_key_sig
->keysig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
2515 /* Caller must hold keysig_list_mutex */
2516 list_add(&new_key_sig
->crypt_stat_list
, &crypt_stat
->keysig_list
);
2521 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
2524 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
2525 char *sig
, u32 global_auth_tok_flags
)
2527 struct ecryptfs_global_auth_tok
*new_auth_tok
;
2529 new_auth_tok
= kmem_cache_zalloc(ecryptfs_global_auth_tok_cache
,
2534 memcpy(new_auth_tok
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
2535 new_auth_tok
->flags
= global_auth_tok_flags
;
2536 new_auth_tok
->sig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
2537 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
2538 list_add(&new_auth_tok
->mount_crypt_stat_list
,
2539 &mount_crypt_stat
->global_auth_tok_list
);
2540 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);