2 * eCryptfs: Linux filesystem encryption layer
3 * In-kernel key management code. Includes functions to parse and
4 * write authentication token-related packets with the underlying
7 * Copyright (C) 2004-2006 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
9 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * Trevor S. Highland <trevor.highland@gmail.com>
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
28 #include <linux/string.h>
29 #include <linux/syscalls.h>
30 #include <linux/pagemap.h>
31 #include <linux/key.h>
32 #include <linux/random.h>
33 #include <linux/crypto.h>
34 #include <linux/scatterlist.h>
35 #include <linux/slab.h>
36 #include "ecryptfs_kernel.h"
39 * request_key returned an error instead of a valid key address;
40 * determine the type of error, make appropriate log entries, and
41 * return an error code.
43 static int process_request_key_err(long err_code
)
49 ecryptfs_printk(KERN_WARNING
, "No key\n");
53 ecryptfs_printk(KERN_WARNING
, "Key expired\n");
57 ecryptfs_printk(KERN_WARNING
, "Key revoked\n");
61 ecryptfs_printk(KERN_WARNING
, "Unknown error code: "
62 "[0x%.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 */
104 (*size
) = (unsigned char)data
[0];
106 } else if (data
[0] < 224) {
107 /* Two-byte length */
108 (*size
) = (((unsigned char)(data
[0]) - 192) * 256);
109 (*size
) += ((unsigned char)(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 blkcipher_desc desc
;
606 char iv
[ECRYPTFS_MAX_IV_BYTES
];
607 char hash
[ECRYPTFS_TAG_70_DIGEST_SIZE
];
608 char tmp_hash
[ECRYPTFS_TAG_70_DIGEST_SIZE
];
609 struct hash_desc hash_desc
;
610 struct scatterlist hash_sg
;
614 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
615 * @filename: NULL-terminated filename string
617 * This is the simplest mechanism for achieving filename encryption in
618 * eCryptfs. It encrypts the given filename with the mount-wide
619 * filename encryption key (FNEK) and stores it in a packet to @dest,
620 * which the callee will encode and write directly into the dentry
624 ecryptfs_write_tag_70_packet(char *dest
, size_t *remaining_bytes
,
626 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
627 char *filename
, size_t filename_size
)
629 struct ecryptfs_write_tag_70_packet_silly_stack
*s
;
630 struct key
*auth_tok_key
= NULL
;
633 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
635 printk(KERN_ERR
"%s: Out of memory whilst trying to kmalloc "
636 "[%zd] bytes of kernel memory\n", __func__
, sizeof(*s
));
640 s
->desc
.flags
= CRYPTO_TFM_REQ_MAY_SLEEP
;
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_blkcipher_blocksize(s
->desc
.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
= (1 /* Tag 70 identifier */
683 + 3 /* Max Tag 70 packet size */
684 + ECRYPTFS_SIG_SIZE
/* FNEK sig */
685 + 1 /* Cipher identifier */
686 + s
->block_aligned_filename_size
);
688 (*packet_size
) = s
->max_packet_size
;
691 if (s
->max_packet_size
> (*remaining_bytes
)) {
692 printk(KERN_WARNING
"%s: Require [%zd] bytes to write; only "
693 "[%zd] available\n", __func__
, s
->max_packet_size
,
698 s
->block_aligned_filename
= kzalloc(s
->block_aligned_filename_size
,
700 if (!s
->block_aligned_filename
) {
701 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
702 "kzalloc [%zd] bytes\n", __func__
,
703 s
->block_aligned_filename_size
);
708 dest
[s
->i
++] = ECRYPTFS_TAG_70_PACKET_TYPE
;
709 rc
= ecryptfs_write_packet_length(&dest
[s
->i
],
711 + 1 /* Cipher code */
712 + s
->block_aligned_filename_size
),
713 &s
->packet_size_len
);
715 printk(KERN_ERR
"%s: Error generating tag 70 packet "
716 "header; cannot generate packet length; rc = [%d]\n",
718 goto out_free_unlock
;
720 s
->i
+= s
->packet_size_len
;
721 ecryptfs_from_hex(&dest
[s
->i
],
722 mount_crypt_stat
->global_default_fnek_sig
,
724 s
->i
+= ECRYPTFS_SIG_SIZE
;
725 s
->cipher_code
= ecryptfs_code_for_cipher_string(
726 mount_crypt_stat
->global_default_fn_cipher_name
,
727 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
728 if (s
->cipher_code
== 0) {
729 printk(KERN_WARNING
"%s: Unable to generate code for "
730 "cipher [%s] with key bytes [%zd]\n", __func__
,
731 mount_crypt_stat
->global_default_fn_cipher_name
,
732 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
734 goto out_free_unlock
;
736 dest
[s
->i
++] = s
->cipher_code
;
737 /* TODO: Support other key modules than passphrase for
738 * filename encryption */
739 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
741 printk(KERN_INFO
"%s: Filename encryption only supports "
742 "password tokens\n", __func__
);
743 goto out_free_unlock
;
747 (u8
*)s
->auth_tok
->token
.password
.session_key_encryption_key
,
748 s
->auth_tok
->token
.password
.session_key_encryption_key_bytes
);
749 s
->hash_desc
.flags
= CRYPTO_TFM_REQ_MAY_SLEEP
;
750 s
->hash_desc
.tfm
= crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST
, 0,
752 if (IS_ERR(s
->hash_desc
.tfm
)) {
753 rc
= PTR_ERR(s
->hash_desc
.tfm
);
754 printk(KERN_ERR
"%s: Error attempting to "
755 "allocate hash crypto context; rc = [%d]\n",
757 goto out_free_unlock
;
759 rc
= crypto_hash_init(&s
->hash_desc
);
762 "%s: Error initializing crypto hash; rc = [%d]\n",
764 goto out_release_free_unlock
;
766 rc
= crypto_hash_update(
767 &s
->hash_desc
, &s
->hash_sg
,
768 s
->auth_tok
->token
.password
.session_key_encryption_key_bytes
);
771 "%s: Error updating crypto hash; rc = [%d]\n",
773 goto out_release_free_unlock
;
775 rc
= crypto_hash_final(&s
->hash_desc
, s
->hash
);
778 "%s: Error finalizing crypto hash; rc = [%d]\n",
780 goto out_release_free_unlock
;
782 for (s
->j
= 0; s
->j
< (s
->num_rand_bytes
- 1); s
->j
++) {
783 s
->block_aligned_filename
[s
->j
] =
784 s
->hash
[(s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)];
785 if ((s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)
786 == (ECRYPTFS_TAG_70_DIGEST_SIZE
- 1)) {
787 sg_init_one(&s
->hash_sg
, (u8
*)s
->hash
,
788 ECRYPTFS_TAG_70_DIGEST_SIZE
);
789 rc
= crypto_hash_init(&s
->hash_desc
);
792 "%s: Error initializing crypto hash; "
793 "rc = [%d]\n", __func__
, rc
);
794 goto out_release_free_unlock
;
796 rc
= crypto_hash_update(&s
->hash_desc
, &s
->hash_sg
,
797 ECRYPTFS_TAG_70_DIGEST_SIZE
);
800 "%s: Error updating crypto hash; "
801 "rc = [%d]\n", __func__
, rc
);
802 goto out_release_free_unlock
;
804 rc
= crypto_hash_final(&s
->hash_desc
, s
->tmp_hash
);
807 "%s: Error finalizing crypto hash; "
808 "rc = [%d]\n", __func__
, rc
);
809 goto out_release_free_unlock
;
811 memcpy(s
->hash
, s
->tmp_hash
,
812 ECRYPTFS_TAG_70_DIGEST_SIZE
);
814 if (s
->block_aligned_filename
[s
->j
] == '\0')
815 s
->block_aligned_filename
[s
->j
] = ECRYPTFS_NON_NULL
;
817 memcpy(&s
->block_aligned_filename
[s
->num_rand_bytes
], filename
,
819 rc
= virt_to_scatterlist(s
->block_aligned_filename
,
820 s
->block_aligned_filename_size
, s
->src_sg
, 2);
822 printk(KERN_ERR
"%s: Internal error whilst attempting to "
823 "convert filename memory to scatterlist; rc = [%d]. "
824 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
825 s
->block_aligned_filename_size
);
826 goto out_release_free_unlock
;
828 rc
= virt_to_scatterlist(&dest
[s
->i
], s
->block_aligned_filename_size
,
831 printk(KERN_ERR
"%s: Internal error whilst attempting to "
832 "convert encrypted filename memory to scatterlist; "
833 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
834 __func__
, rc
, s
->block_aligned_filename_size
);
835 goto out_release_free_unlock
;
837 /* The characters in the first block effectively do the job
838 * of the IV here, so we just use 0's for the IV. Note the
839 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
840 * >= ECRYPTFS_MAX_IV_BYTES. */
841 memset(s
->iv
, 0, ECRYPTFS_MAX_IV_BYTES
);
842 s
->desc
.info
= s
->iv
;
843 rc
= crypto_blkcipher_setkey(
845 s
->auth_tok
->token
.password
.session_key_encryption_key
,
846 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
848 printk(KERN_ERR
"%s: Error setting key for crypto context; "
849 "rc = [%d]. s->auth_tok->token.password.session_key_"
850 "encryption_key = [0x%p]; mount_crypt_stat->"
851 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
853 s
->auth_tok
->token
.password
.session_key_encryption_key
,
854 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
855 goto out_release_free_unlock
;
857 rc
= crypto_blkcipher_encrypt_iv(&s
->desc
, s
->dst_sg
, s
->src_sg
,
858 s
->block_aligned_filename_size
);
860 printk(KERN_ERR
"%s: Error attempting to encrypt filename; "
861 "rc = [%d]\n", __func__
, rc
);
862 goto out_release_free_unlock
;
864 s
->i
+= s
->block_aligned_filename_size
;
865 (*packet_size
) = s
->i
;
866 (*remaining_bytes
) -= (*packet_size
);
867 out_release_free_unlock
:
868 crypto_free_hash(s
->hash_desc
.tfm
);
870 kzfree(s
->block_aligned_filename
);
872 mutex_unlock(s
->tfm_mutex
);
875 up_write(&(auth_tok_key
->sem
));
876 key_put(auth_tok_key
);
882 struct ecryptfs_parse_tag_70_packet_silly_stack
{
884 size_t max_packet_size
;
885 size_t packet_size_len
;
886 size_t parsed_tag_70_packet_size
;
887 size_t block_aligned_filename_size
;
890 struct mutex
*tfm_mutex
;
891 char *decrypted_filename
;
892 struct ecryptfs_auth_tok
*auth_tok
;
893 struct scatterlist src_sg
[2];
894 struct scatterlist dst_sg
[2];
895 struct blkcipher_desc desc
;
896 char fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
+ 1];
897 char iv
[ECRYPTFS_MAX_IV_BYTES
];
898 char cipher_string
[ECRYPTFS_MAX_CIPHER_NAME_SIZE
];
902 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
903 * @filename: This function kmalloc's the memory for the filename
904 * @filename_size: This function sets this to the amount of memory
905 * kmalloc'd for the filename
906 * @packet_size: This function sets this to the the number of octets
907 * in the packet parsed
908 * @mount_crypt_stat: The mount-wide cryptographic context
909 * @data: The memory location containing the start of the tag 70
911 * @max_packet_size: The maximum legal size of the packet to be parsed
914 * Returns zero on success; non-zero otherwise
917 ecryptfs_parse_tag_70_packet(char **filename
, size_t *filename_size
,
919 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
920 char *data
, size_t max_packet_size
)
922 struct ecryptfs_parse_tag_70_packet_silly_stack
*s
;
923 struct key
*auth_tok_key
= NULL
;
927 (*filename_size
) = 0;
929 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
931 printk(KERN_ERR
"%s: Out of memory whilst trying to kmalloc "
932 "[%zd] bytes of kernel memory\n", __func__
, sizeof(*s
));
936 s
->desc
.flags
= CRYPTO_TFM_REQ_MAY_SLEEP
;
937 if (max_packet_size
< (1 + 1 + ECRYPTFS_SIG_SIZE
+ 1 + 1)) {
938 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; it must be "
939 "at least [%d]\n", __func__
, max_packet_size
,
940 (1 + 1 + ECRYPTFS_SIG_SIZE
+ 1 + 1));
944 /* Octet 0: Tag 70 identifier
945 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
946 * and block-aligned encrypted filename size)
947 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
948 * Octet N2-N3: Cipher identifier (1 octet)
949 * Octets N3-N4: Block-aligned encrypted filename
950 * - Consists of a minimum number of random numbers, a \0
951 * separator, and then the filename */
952 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_70_PACKET_TYPE
) {
953 printk(KERN_WARNING
"%s: Invalid packet tag [0x%.2x]; must be "
954 "tag [0x%.2x]\n", __func__
,
955 data
[((*packet_size
) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE
);
959 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)],
960 &s
->parsed_tag_70_packet_size
,
961 &s
->packet_size_len
);
963 printk(KERN_WARNING
"%s: Error parsing packet length; "
964 "rc = [%d]\n", __func__
, rc
);
967 s
->block_aligned_filename_size
= (s
->parsed_tag_70_packet_size
968 - ECRYPTFS_SIG_SIZE
- 1);
969 if ((1 + s
->packet_size_len
+ s
->parsed_tag_70_packet_size
)
971 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; real packet "
972 "size is [%zd]\n", __func__
, max_packet_size
,
973 (1 + s
->packet_size_len
+ 1
974 + s
->block_aligned_filename_size
));
978 (*packet_size
) += s
->packet_size_len
;
979 ecryptfs_to_hex(s
->fnek_sig_hex
, &data
[(*packet_size
)],
981 s
->fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
982 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
983 s
->cipher_code
= data
[(*packet_size
)++];
984 rc
= ecryptfs_cipher_code_to_string(s
->cipher_string
, s
->cipher_code
);
986 printk(KERN_WARNING
"%s: Cipher code [%d] is invalid\n",
987 __func__
, s
->cipher_code
);
990 rc
= ecryptfs_find_auth_tok_for_sig(&auth_tok_key
,
991 &s
->auth_tok
, mount_crypt_stat
,
994 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
995 "fnek sig [%s]; rc = [%d]\n", __func__
, s
->fnek_sig_hex
,
999 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&s
->desc
.tfm
,
1003 printk(KERN_ERR
"Internal error whilst attempting to get "
1004 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1005 s
->cipher_string
, rc
);
1008 mutex_lock(s
->tfm_mutex
);
1009 rc
= virt_to_scatterlist(&data
[(*packet_size
)],
1010 s
->block_aligned_filename_size
, s
->src_sg
, 2);
1012 printk(KERN_ERR
"%s: Internal error whilst attempting to "
1013 "convert encrypted filename memory to scatterlist; "
1014 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1015 __func__
, rc
, s
->block_aligned_filename_size
);
1018 (*packet_size
) += s
->block_aligned_filename_size
;
1019 s
->decrypted_filename
= kmalloc(s
->block_aligned_filename_size
,
1021 if (!s
->decrypted_filename
) {
1022 printk(KERN_ERR
"%s: Out of memory whilst attempting to "
1023 "kmalloc [%zd] bytes\n", __func__
,
1024 s
->block_aligned_filename_size
);
1028 rc
= virt_to_scatterlist(s
->decrypted_filename
,
1029 s
->block_aligned_filename_size
, s
->dst_sg
, 2);
1031 printk(KERN_ERR
"%s: Internal error whilst attempting to "
1032 "convert decrypted filename memory to scatterlist; "
1033 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1034 __func__
, rc
, s
->block_aligned_filename_size
);
1035 goto out_free_unlock
;
1037 /* The characters in the first block effectively do the job of
1038 * the IV here, so we just use 0's for the IV. Note the
1039 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1040 * >= ECRYPTFS_MAX_IV_BYTES. */
1041 memset(s
->iv
, 0, ECRYPTFS_MAX_IV_BYTES
);
1042 s
->desc
.info
= s
->iv
;
1043 /* TODO: Support other key modules than passphrase for
1044 * filename encryption */
1045 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
1047 printk(KERN_INFO
"%s: Filename encryption only supports "
1048 "password tokens\n", __func__
);
1049 goto out_free_unlock
;
1051 rc
= crypto_blkcipher_setkey(
1053 s
->auth_tok
->token
.password
.session_key_encryption_key
,
1054 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
1056 printk(KERN_ERR
"%s: Error setting key for crypto context; "
1057 "rc = [%d]. s->auth_tok->token.password.session_key_"
1058 "encryption_key = [0x%p]; mount_crypt_stat->"
1059 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
1061 s
->auth_tok
->token
.password
.session_key_encryption_key
,
1062 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
1063 goto out_free_unlock
;
1065 rc
= crypto_blkcipher_decrypt_iv(&s
->desc
, s
->dst_sg
, s
->src_sg
,
1066 s
->block_aligned_filename_size
);
1068 printk(KERN_ERR
"%s: Error attempting to decrypt filename; "
1069 "rc = [%d]\n", __func__
, rc
);
1070 goto out_free_unlock
;
1073 while (s
->decrypted_filename
[s
->i
] != '\0'
1074 && s
->i
< s
->block_aligned_filename_size
)
1076 if (s
->i
== s
->block_aligned_filename_size
) {
1077 printk(KERN_WARNING
"%s: Invalid tag 70 packet; could not "
1078 "find valid separator between random characters and "
1079 "the filename\n", __func__
);
1081 goto out_free_unlock
;
1084 (*filename_size
) = (s
->block_aligned_filename_size
- s
->i
);
1085 if (!((*filename_size
) > 0 && (*filename_size
< PATH_MAX
))) {
1086 printk(KERN_WARNING
"%s: Filename size is [%zd], which is "
1087 "invalid\n", __func__
, (*filename_size
));
1089 goto out_free_unlock
;
1091 (*filename
) = kmalloc(((*filename_size
) + 1), GFP_KERNEL
);
1093 printk(KERN_ERR
"%s: Out of memory whilst attempting to "
1094 "kmalloc [%zd] bytes\n", __func__
,
1095 ((*filename_size
) + 1));
1097 goto out_free_unlock
;
1099 memcpy((*filename
), &s
->decrypted_filename
[s
->i
], (*filename_size
));
1100 (*filename
)[(*filename_size
)] = '\0';
1102 kfree(s
->decrypted_filename
);
1104 mutex_unlock(s
->tfm_mutex
);
1108 (*filename_size
) = 0;
1112 up_write(&(auth_tok_key
->sem
));
1113 key_put(auth_tok_key
);
1120 ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
1125 switch (auth_tok
->token_type
) {
1126 case ECRYPTFS_PASSWORD
:
1127 (*sig
) = auth_tok
->token
.password
.signature
;
1129 case ECRYPTFS_PRIVATE_KEY
:
1130 (*sig
) = auth_tok
->token
.private_key
.signature
;
1133 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
1134 auth_tok
->token_type
);
1141 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1142 * @auth_tok: The key authentication token used to decrypt the session key
1143 * @crypt_stat: The cryptographic context
1145 * Returns zero on success; non-zero error otherwise.
1148 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1149 struct ecryptfs_crypt_stat
*crypt_stat
)
1152 struct ecryptfs_msg_ctx
*msg_ctx
;
1153 struct ecryptfs_message
*msg
= NULL
;
1159 rc
= ecryptfs_get_auth_tok_sig(&auth_tok_sig
, auth_tok
);
1161 printk(KERN_ERR
"Unrecognized auth tok type: [%d]\n",
1162 auth_tok
->token_type
);
1165 rc
= write_tag_64_packet(auth_tok_sig
, &(auth_tok
->session_key
),
1166 &payload
, &payload_len
);
1168 ecryptfs_printk(KERN_ERR
, "Failed to write tag 64 packet\n");
1171 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1173 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1177 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1179 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 65 packet "
1180 "from the user space daemon\n");
1184 rc
= parse_tag_65_packet(&(auth_tok
->session_key
),
1187 printk(KERN_ERR
"Failed to parse tag 65 packet; rc = [%d]\n",
1191 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1192 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1193 auth_tok
->session_key
.decrypted_key_size
);
1194 crypt_stat
->key_size
= auth_tok
->session_key
.decrypted_key_size
;
1195 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
, cipher_code
);
1197 ecryptfs_printk(KERN_ERR
, "Cipher code [%d] is invalid\n",
1201 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1202 if (ecryptfs_verbosity
> 0) {
1203 ecryptfs_printk(KERN_DEBUG
, "Decrypted session key:\n");
1204 ecryptfs_dump_hex(crypt_stat
->key
,
1205 crypt_stat
->key_size
);
1213 static void wipe_auth_tok_list(struct list_head
*auth_tok_list_head
)
1215 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1216 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1218 list_for_each_entry_safe(auth_tok_list_item
, auth_tok_list_item_tmp
,
1219 auth_tok_list_head
, list
) {
1220 list_del(&auth_tok_list_item
->list
);
1221 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1222 auth_tok_list_item
);
1226 struct kmem_cache
*ecryptfs_auth_tok_list_item_cache
;
1229 * parse_tag_1_packet
1230 * @crypt_stat: The cryptographic context to modify based on packet contents
1231 * @data: The raw bytes of the packet.
1232 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1233 * a new authentication token will be placed at the
1234 * end of this list for this packet.
1235 * @new_auth_tok: Pointer to a pointer to memory that this function
1236 * allocates; sets the memory address of the pointer to
1237 * NULL on error. This object is added to the
1239 * @packet_size: This function writes the size of the parsed packet
1240 * into this memory location; zero on error.
1241 * @max_packet_size: The maximum allowable packet size
1243 * Returns zero on success; non-zero on error.
1246 parse_tag_1_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1247 unsigned char *data
, struct list_head
*auth_tok_list
,
1248 struct ecryptfs_auth_tok
**new_auth_tok
,
1249 size_t *packet_size
, size_t max_packet_size
)
1252 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1257 (*new_auth_tok
) = NULL
;
1259 * This format is inspired by OpenPGP; see RFC 2440
1262 * Tag 1 identifier (1 byte)
1263 * Max Tag 1 packet size (max 3 bytes)
1265 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1266 * Cipher identifier (1 byte)
1267 * Encrypted key size (arbitrary)
1269 * 12 bytes minimum packet size
1271 if (unlikely(max_packet_size
< 12)) {
1272 printk(KERN_ERR
"Invalid max packet size; must be >=12\n");
1276 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_1_PACKET_TYPE
) {
1277 printk(KERN_ERR
"Enter w/ first byte != 0x%.2x\n",
1278 ECRYPTFS_TAG_1_PACKET_TYPE
);
1282 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1283 * at end of function upon failure */
1284 auth_tok_list_item
=
1285 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
,
1287 if (!auth_tok_list_item
) {
1288 printk(KERN_ERR
"Unable to allocate memory\n");
1292 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1293 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1296 printk(KERN_WARNING
"Error parsing packet length; "
1300 if (unlikely(body_size
< (ECRYPTFS_SIG_SIZE
+ 2))) {
1301 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1305 (*packet_size
) += length_size
;
1306 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1307 printk(KERN_WARNING
"Packet size exceeds max\n");
1311 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1312 printk(KERN_WARNING
"Unknown version number [%d]\n",
1313 data
[(*packet_size
) - 1]);
1317 ecryptfs_to_hex((*new_auth_tok
)->token
.private_key
.signature
,
1318 &data
[(*packet_size
)], ECRYPTFS_SIG_SIZE
);
1319 *packet_size
+= ECRYPTFS_SIG_SIZE
;
1320 /* This byte is skipped because the kernel does not need to
1321 * know which public key encryption algorithm was used */
1323 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1324 body_size
- (ECRYPTFS_SIG_SIZE
+ 2);
1325 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1326 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1327 printk(KERN_WARNING
"Tag 1 packet contains key larger "
1328 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1332 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1333 &data
[(*packet_size
)], (body_size
- (ECRYPTFS_SIG_SIZE
+ 2)));
1334 (*packet_size
) += (*new_auth_tok
)->session_key
.encrypted_key_size
;
1335 (*new_auth_tok
)->session_key
.flags
&=
1336 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1337 (*new_auth_tok
)->session_key
.flags
|=
1338 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1339 (*new_auth_tok
)->token_type
= ECRYPTFS_PRIVATE_KEY
;
1340 (*new_auth_tok
)->flags
= 0;
1341 (*new_auth_tok
)->session_key
.flags
&=
1342 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1343 (*new_auth_tok
)->session_key
.flags
&=
1344 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1345 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1348 (*new_auth_tok
) = NULL
;
1349 memset(auth_tok_list_item
, 0,
1350 sizeof(struct ecryptfs_auth_tok_list_item
));
1351 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1352 auth_tok_list_item
);
1360 * parse_tag_3_packet
1361 * @crypt_stat: The cryptographic context to modify based on packet
1363 * @data: The raw bytes of the packet.
1364 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1365 * a new authentication token will be placed at the end
1366 * of this list for this packet.
1367 * @new_auth_tok: Pointer to a pointer to memory that this function
1368 * allocates; sets the memory address of the pointer to
1369 * NULL on error. This object is added to the
1371 * @packet_size: This function writes the size of the parsed packet
1372 * into this memory location; zero on error.
1373 * @max_packet_size: maximum number of bytes to parse
1375 * Returns zero on success; non-zero on error.
1378 parse_tag_3_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1379 unsigned char *data
, struct list_head
*auth_tok_list
,
1380 struct ecryptfs_auth_tok
**new_auth_tok
,
1381 size_t *packet_size
, size_t max_packet_size
)
1384 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1389 (*new_auth_tok
) = NULL
;
1391 *This format is inspired by OpenPGP; see RFC 2440
1394 * Tag 3 identifier (1 byte)
1395 * Max Tag 3 packet size (max 3 bytes)
1397 * Cipher code (1 byte)
1398 * S2K specifier (1 byte)
1399 * Hash identifier (1 byte)
1400 * Salt (ECRYPTFS_SALT_SIZE)
1401 * Hash iterations (1 byte)
1402 * Encrypted key (arbitrary)
1404 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1406 if (max_packet_size
< (ECRYPTFS_SALT_SIZE
+ 7)) {
1407 printk(KERN_ERR
"Max packet size too large\n");
1411 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_3_PACKET_TYPE
) {
1412 printk(KERN_ERR
"First byte != 0x%.2x; invalid packet\n",
1413 ECRYPTFS_TAG_3_PACKET_TYPE
);
1417 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1418 * at end of function upon failure */
1419 auth_tok_list_item
=
1420 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
, GFP_KERNEL
);
1421 if (!auth_tok_list_item
) {
1422 printk(KERN_ERR
"Unable to allocate memory\n");
1426 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1427 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1430 printk(KERN_WARNING
"Error parsing packet length; rc = [%d]\n",
1434 if (unlikely(body_size
< (ECRYPTFS_SALT_SIZE
+ 5))) {
1435 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1439 (*packet_size
) += length_size
;
1440 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1441 printk(KERN_ERR
"Packet size exceeds max\n");
1445 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1446 (body_size
- (ECRYPTFS_SALT_SIZE
+ 5));
1447 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1448 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1449 printk(KERN_WARNING
"Tag 3 packet contains key larger "
1450 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1454 if (unlikely(data
[(*packet_size
)++] != 0x04)) {
1455 printk(KERN_WARNING
"Unknown version number [%d]\n",
1456 data
[(*packet_size
) - 1]);
1460 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
,
1461 (u16
)data
[(*packet_size
)]);
1464 /* A little extra work to differentiate among the AES key
1465 * sizes; see RFC2440 */
1466 switch(data
[(*packet_size
)++]) {
1467 case RFC2440_CIPHER_AES_192
:
1468 crypt_stat
->key_size
= 24;
1471 crypt_stat
->key_size
=
1472 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1474 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1477 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1478 printk(KERN_WARNING
"Only S2K ID 3 is currently supported\n");
1482 /* TODO: finish the hash mapping */
1483 switch (data
[(*packet_size
)++]) {
1484 case 0x01: /* See RFC2440 for these numbers and their mappings */
1486 memcpy((*new_auth_tok
)->token
.password
.salt
,
1487 &data
[(*packet_size
)], ECRYPTFS_SALT_SIZE
);
1488 (*packet_size
) += ECRYPTFS_SALT_SIZE
;
1489 /* This conversion was taken straight from RFC2440 */
1490 (*new_auth_tok
)->token
.password
.hash_iterations
=
1491 ((u32
) 16 + (data
[(*packet_size
)] & 15))
1492 << ((data
[(*packet_size
)] >> 4) + 6);
1494 /* Friendly reminder:
1495 * (*new_auth_tok)->session_key.encrypted_key_size =
1496 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1497 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1498 &data
[(*packet_size
)],
1499 (*new_auth_tok
)->session_key
.encrypted_key_size
);
1501 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1502 (*new_auth_tok
)->session_key
.flags
&=
1503 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1504 (*new_auth_tok
)->session_key
.flags
|=
1505 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1506 (*new_auth_tok
)->token
.password
.hash_algo
= 0x01; /* MD5 */
1509 ecryptfs_printk(KERN_ERR
, "Unsupported hash algorithm: "
1510 "[%d]\n", data
[(*packet_size
) - 1]);
1514 (*new_auth_tok
)->token_type
= ECRYPTFS_PASSWORD
;
1515 /* TODO: Parametarize; we might actually want userspace to
1516 * decrypt the session key. */
1517 (*new_auth_tok
)->session_key
.flags
&=
1518 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1519 (*new_auth_tok
)->session_key
.flags
&=
1520 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1521 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1524 (*new_auth_tok
) = NULL
;
1525 memset(auth_tok_list_item
, 0,
1526 sizeof(struct ecryptfs_auth_tok_list_item
));
1527 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1528 auth_tok_list_item
);
1536 * parse_tag_11_packet
1537 * @data: The raw bytes of the packet
1538 * @contents: This function writes the data contents of the literal
1539 * packet into this memory location
1540 * @max_contents_bytes: The maximum number of bytes that this function
1541 * is allowed to write into contents
1542 * @tag_11_contents_size: This function writes the size of the parsed
1543 * contents into this memory location; zero on
1545 * @packet_size: This function writes the size of the parsed packet
1546 * into this memory location; zero on error
1547 * @max_packet_size: maximum number of bytes to parse
1549 * Returns zero on success; non-zero on error.
1552 parse_tag_11_packet(unsigned char *data
, unsigned char *contents
,
1553 size_t max_contents_bytes
, size_t *tag_11_contents_size
,
1554 size_t *packet_size
, size_t max_packet_size
)
1561 (*tag_11_contents_size
) = 0;
1562 /* This format is inspired by OpenPGP; see RFC 2440
1565 * Tag 11 identifier (1 byte)
1566 * Max Tag 11 packet size (max 3 bytes)
1567 * Binary format specifier (1 byte)
1568 * Filename length (1 byte)
1569 * Filename ("_CONSOLE") (8 bytes)
1570 * Modification date (4 bytes)
1571 * Literal data (arbitrary)
1573 * We need at least 16 bytes of data for the packet to even be
1576 if (max_packet_size
< 16) {
1577 printk(KERN_ERR
"Maximum packet size too small\n");
1581 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
1582 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1586 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1589 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1592 if (body_size
< 14) {
1593 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1597 (*packet_size
) += length_size
;
1598 (*tag_11_contents_size
) = (body_size
- 14);
1599 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
1600 printk(KERN_ERR
"Packet size exceeds max\n");
1604 if (unlikely((*tag_11_contents_size
) > max_contents_bytes
)) {
1605 printk(KERN_ERR
"Literal data section in tag 11 packet exceeds "
1610 if (data
[(*packet_size
)++] != 0x62) {
1611 printk(KERN_WARNING
"Unrecognizable packet\n");
1615 if (data
[(*packet_size
)++] != 0x08) {
1616 printk(KERN_WARNING
"Unrecognizable packet\n");
1620 (*packet_size
) += 12; /* Ignore filename and modification date */
1621 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
1622 (*packet_size
) += (*tag_11_contents_size
);
1626 (*tag_11_contents_size
) = 0;
1631 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
1632 struct ecryptfs_auth_tok
**auth_tok
,
1637 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
1638 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
1639 (*auth_tok_key
) = ecryptfs_get_encrypted_key(sig
);
1640 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
1641 printk(KERN_ERR
"Could not find key with description: [%s]\n",
1643 rc
= process_request_key_err(PTR_ERR(*auth_tok_key
));
1644 (*auth_tok_key
) = NULL
;
1648 down_write(&(*auth_tok_key
)->sem
);
1649 rc
= ecryptfs_verify_auth_tok_from_key(*auth_tok_key
, auth_tok
);
1651 up_write(&(*auth_tok_key
)->sem
);
1652 key_put(*auth_tok_key
);
1653 (*auth_tok_key
) = NULL
;
1661 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1662 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1663 * @crypt_stat: The cryptographic context
1665 * Returns zero on success; non-zero error otherwise
1668 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1669 struct ecryptfs_crypt_stat
*crypt_stat
)
1671 struct scatterlist dst_sg
[2];
1672 struct scatterlist src_sg
[2];
1673 struct mutex
*tfm_mutex
;
1674 struct blkcipher_desc desc
= {
1675 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1679 if (unlikely(ecryptfs_verbosity
> 0)) {
1681 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1682 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1684 auth_tok
->token
.password
.session_key_encryption_key
,
1685 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1687 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1688 crypt_stat
->cipher
);
1690 printk(KERN_ERR
"Internal error whilst attempting to get "
1691 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1692 crypt_stat
->cipher
, rc
);
1695 rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1696 auth_tok
->session_key
.encrypted_key_size
,
1698 if (rc
< 1 || rc
> 2) {
1699 printk(KERN_ERR
"Internal error whilst attempting to convert "
1700 "auth_tok->session_key.encrypted_key to scatterlist; "
1701 "expected rc = 1; got rc = [%d]. "
1702 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc
,
1703 auth_tok
->session_key
.encrypted_key_size
);
1706 auth_tok
->session_key
.decrypted_key_size
=
1707 auth_tok
->session_key
.encrypted_key_size
;
1708 rc
= virt_to_scatterlist(auth_tok
->session_key
.decrypted_key
,
1709 auth_tok
->session_key
.decrypted_key_size
,
1711 if (rc
< 1 || rc
> 2) {
1712 printk(KERN_ERR
"Internal error whilst attempting to convert "
1713 "auth_tok->session_key.decrypted_key to scatterlist; "
1714 "expected rc = 1; got rc = [%d]\n", rc
);
1717 mutex_lock(tfm_mutex
);
1718 rc
= crypto_blkcipher_setkey(
1719 desc
.tfm
, auth_tok
->token
.password
.session_key_encryption_key
,
1720 crypt_stat
->key_size
);
1721 if (unlikely(rc
< 0)) {
1722 mutex_unlock(tfm_mutex
);
1723 printk(KERN_ERR
"Error setting key for crypto context\n");
1727 rc
= crypto_blkcipher_decrypt(&desc
, dst_sg
, src_sg
,
1728 auth_tok
->session_key
.encrypted_key_size
);
1729 mutex_unlock(tfm_mutex
);
1731 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
1734 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1735 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1736 auth_tok
->session_key
.decrypted_key_size
);
1737 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1738 if (unlikely(ecryptfs_verbosity
> 0)) {
1739 ecryptfs_printk(KERN_DEBUG
, "FEK of size [%zd]:\n",
1740 crypt_stat
->key_size
);
1741 ecryptfs_dump_hex(crypt_stat
->key
,
1742 crypt_stat
->key_size
);
1749 * ecryptfs_parse_packet_set
1750 * @crypt_stat: The cryptographic context
1751 * @src: Virtual address of region of memory containing the packets
1752 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1754 * Get crypt_stat to have the file's session key if the requisite key
1755 * is available to decrypt the session key.
1757 * Returns Zero if a valid authentication token was retrieved and
1758 * processed; negative value for file not encrypted or for error
1761 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1763 struct dentry
*ecryptfs_dentry
)
1766 size_t found_auth_tok
;
1767 size_t next_packet_is_auth_tok_packet
;
1768 struct list_head auth_tok_list
;
1769 struct ecryptfs_auth_tok
*matching_auth_tok
;
1770 struct ecryptfs_auth_tok
*candidate_auth_tok
;
1771 char *candidate_auth_tok_sig
;
1773 struct ecryptfs_auth_tok
*new_auth_tok
;
1774 unsigned char sig_tmp_space
[ECRYPTFS_SIG_SIZE
];
1775 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1776 size_t tag_11_contents_size
;
1777 size_t tag_11_packet_size
;
1778 struct key
*auth_tok_key
= NULL
;
1781 INIT_LIST_HEAD(&auth_tok_list
);
1782 /* Parse the header to find as many packets as we can; these will be
1783 * added the our &auth_tok_list */
1784 next_packet_is_auth_tok_packet
= 1;
1785 while (next_packet_is_auth_tok_packet
) {
1786 size_t max_packet_size
= ((PAGE_CACHE_SIZE
- 8) - i
);
1789 case ECRYPTFS_TAG_3_PACKET_TYPE
:
1790 rc
= parse_tag_3_packet(crypt_stat
,
1791 (unsigned char *)&src
[i
],
1792 &auth_tok_list
, &new_auth_tok
,
1793 &packet_size
, max_packet_size
);
1795 ecryptfs_printk(KERN_ERR
, "Error parsing "
1801 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1804 &tag_11_contents_size
,
1805 &tag_11_packet_size
,
1808 ecryptfs_printk(KERN_ERR
, "No valid "
1809 "(ecryptfs-specific) literal "
1810 "packet containing "
1811 "authentication token "
1812 "signature found after "
1817 i
+= tag_11_packet_size
;
1818 if (ECRYPTFS_SIG_SIZE
!= tag_11_contents_size
) {
1819 ecryptfs_printk(KERN_ERR
, "Expected "
1820 "signature of size [%d]; "
1821 "read size [%zd]\n",
1823 tag_11_contents_size
);
1827 ecryptfs_to_hex(new_auth_tok
->token
.password
.signature
,
1828 sig_tmp_space
, tag_11_contents_size
);
1829 new_auth_tok
->token
.password
.signature
[
1830 ECRYPTFS_PASSWORD_SIG_SIZE
] = '\0';
1831 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1833 case ECRYPTFS_TAG_1_PACKET_TYPE
:
1834 rc
= parse_tag_1_packet(crypt_stat
,
1835 (unsigned char *)&src
[i
],
1836 &auth_tok_list
, &new_auth_tok
,
1837 &packet_size
, max_packet_size
);
1839 ecryptfs_printk(KERN_ERR
, "Error parsing "
1845 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1847 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1848 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1849 "(Tag 11 not allowed by itself)\n");
1854 ecryptfs_printk(KERN_DEBUG
, "No packet at offset [%zd] "
1855 "of the file header; hex value of "
1856 "character is [0x%.2x]\n", i
, src
[i
]);
1857 next_packet_is_auth_tok_packet
= 0;
1860 if (list_empty(&auth_tok_list
)) {
1861 printk(KERN_ERR
"The lower file appears to be a non-encrypted "
1862 "eCryptfs file; this is not supported in this version "
1863 "of the eCryptfs kernel module\n");
1867 /* auth_tok_list contains the set of authentication tokens
1868 * parsed from the metadata. We need to find a matching
1869 * authentication token that has the secret component(s)
1870 * necessary to decrypt the EFEK in the auth_tok parsed from
1871 * the metadata. There may be several potential matches, but
1872 * just one will be sufficient to decrypt to get the FEK. */
1873 find_next_matching_auth_tok
:
1875 list_for_each_entry(auth_tok_list_item
, &auth_tok_list
, list
) {
1876 candidate_auth_tok
= &auth_tok_list_item
->auth_tok
;
1877 if (unlikely(ecryptfs_verbosity
> 0)) {
1878 ecryptfs_printk(KERN_DEBUG
,
1879 "Considering cadidate auth tok:\n");
1880 ecryptfs_dump_auth_tok(candidate_auth_tok
);
1882 rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1883 candidate_auth_tok
);
1886 "Unrecognized candidate auth tok type: [%d]\n",
1887 candidate_auth_tok
->token_type
);
1891 rc
= ecryptfs_find_auth_tok_for_sig(&auth_tok_key
,
1893 crypt_stat
->mount_crypt_stat
,
1894 candidate_auth_tok_sig
);
1897 goto found_matching_auth_tok
;
1900 if (!found_auth_tok
) {
1901 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1902 "authentication token\n");
1906 found_matching_auth_tok
:
1907 if (candidate_auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1908 memcpy(&(candidate_auth_tok
->token
.private_key
),
1909 &(matching_auth_tok
->token
.private_key
),
1910 sizeof(struct ecryptfs_private_key
));
1911 up_write(&(auth_tok_key
->sem
));
1912 key_put(auth_tok_key
);
1913 rc
= decrypt_pki_encrypted_session_key(candidate_auth_tok
,
1915 } else if (candidate_auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1916 memcpy(&(candidate_auth_tok
->token
.password
),
1917 &(matching_auth_tok
->token
.password
),
1918 sizeof(struct ecryptfs_password
));
1919 up_write(&(auth_tok_key
->sem
));
1920 key_put(auth_tok_key
);
1921 rc
= decrypt_passphrase_encrypted_session_key(
1922 candidate_auth_tok
, crypt_stat
);
1924 up_write(&(auth_tok_key
->sem
));
1925 key_put(auth_tok_key
);
1929 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1931 ecryptfs_printk(KERN_WARNING
, "Error decrypting the "
1932 "session key for authentication token with sig "
1933 "[%.*s]; rc = [%d]. Removing auth tok "
1934 "candidate from the list and searching for "
1935 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX
,
1936 candidate_auth_tok_sig
, rc
);
1937 list_for_each_entry_safe(auth_tok_list_item
,
1938 auth_tok_list_item_tmp
,
1939 &auth_tok_list
, list
) {
1940 if (candidate_auth_tok
1941 == &auth_tok_list_item
->auth_tok
) {
1942 list_del(&auth_tok_list_item
->list
);
1944 ecryptfs_auth_tok_list_item_cache
,
1945 auth_tok_list_item
);
1946 goto find_next_matching_auth_tok
;
1951 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1953 ecryptfs_printk(KERN_ERR
, "Error computing "
1957 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1959 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1960 "context for cipher [%s]; rc = [%d]\n",
1961 crypt_stat
->cipher
, rc
);
1964 wipe_auth_tok_list(&auth_tok_list
);
1970 pki_encrypt_session_key(struct key
*auth_tok_key
,
1971 struct ecryptfs_auth_tok
*auth_tok
,
1972 struct ecryptfs_crypt_stat
*crypt_stat
,
1973 struct ecryptfs_key_record
*key_rec
)
1975 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1976 char *payload
= NULL
;
1977 size_t payload_len
= 0;
1978 struct ecryptfs_message
*msg
;
1981 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1982 ecryptfs_code_for_cipher_string(
1984 crypt_stat
->key_size
),
1985 crypt_stat
, &payload
, &payload_len
);
1986 up_write(&(auth_tok_key
->sem
));
1987 key_put(auth_tok_key
);
1989 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
1992 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1994 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1998 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
2000 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
2001 "from the user space daemon\n");
2005 rc
= parse_tag_67_packet(key_rec
, msg
);
2007 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
2014 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2015 * @dest: Buffer into which to write the packet
2016 * @remaining_bytes: Maximum number of bytes that can be writtn
2017 * @auth_tok_key: The authentication token key to unlock and put when done with
2019 * @auth_tok: The authentication token used for generating the tag 1 packet
2020 * @crypt_stat: The cryptographic context
2021 * @key_rec: The key record struct for the tag 1 packet
2022 * @packet_size: This function will write the number of bytes that end
2023 * up constituting the packet; set to zero on error
2025 * Returns zero on success; non-zero on error.
2028 write_tag_1_packet(char *dest
, size_t *remaining_bytes
,
2029 struct key
*auth_tok_key
, struct ecryptfs_auth_tok
*auth_tok
,
2030 struct ecryptfs_crypt_stat
*crypt_stat
,
2031 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
2034 size_t encrypted_session_key_valid
= 0;
2035 size_t packet_size_length
;
2036 size_t max_packet_size
;
2040 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
2042 encrypted_session_key_valid
= 0;
2043 for (i
= 0; i
< crypt_stat
->key_size
; i
++)
2044 encrypted_session_key_valid
|=
2045 auth_tok
->session_key
.encrypted_key
[i
];
2046 if (encrypted_session_key_valid
) {
2047 memcpy(key_rec
->enc_key
,
2048 auth_tok
->session_key
.encrypted_key
,
2049 auth_tok
->session_key
.encrypted_key_size
);
2050 up_write(&(auth_tok_key
->sem
));
2051 key_put(auth_tok_key
);
2052 goto encrypted_session_key_set
;
2054 if (auth_tok
->session_key
.encrypted_key_size
== 0)
2055 auth_tok
->session_key
.encrypted_key_size
=
2056 auth_tok
->token
.private_key
.key_size
;
2057 rc
= pki_encrypt_session_key(auth_tok_key
, auth_tok
, crypt_stat
,
2060 printk(KERN_ERR
"Failed to encrypt session key via a key "
2061 "module; rc = [%d]\n", rc
);
2064 if (ecryptfs_verbosity
> 0) {
2065 ecryptfs_printk(KERN_DEBUG
, "Encrypted key:\n");
2066 ecryptfs_dump_hex(key_rec
->enc_key
, key_rec
->enc_key_size
);
2068 encrypted_session_key_set
:
2069 /* This format is inspired by OpenPGP; see RFC 2440
2071 max_packet_size
= (1 /* Tag 1 identifier */
2072 + 3 /* Max Tag 1 packet size */
2074 + ECRYPTFS_SIG_SIZE
/* Key identifier */
2075 + 1 /* Cipher identifier */
2076 + key_rec
->enc_key_size
); /* Encrypted key size */
2077 if (max_packet_size
> (*remaining_bytes
)) {
2078 printk(KERN_ERR
"Packet length larger than maximum allowable; "
2079 "need up to [%td] bytes, but there are only [%td] "
2080 "available\n", max_packet_size
, (*remaining_bytes
));
2084 dest
[(*packet_size
)++] = ECRYPTFS_TAG_1_PACKET_TYPE
;
2085 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
2086 (max_packet_size
- 4),
2087 &packet_size_length
);
2089 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
2090 "header; cannot generate packet length\n");
2093 (*packet_size
) += packet_size_length
;
2094 dest
[(*packet_size
)++] = 0x03; /* version 3 */
2095 memcpy(&dest
[(*packet_size
)], key_rec
->sig
, ECRYPTFS_SIG_SIZE
);
2096 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
2097 dest
[(*packet_size
)++] = RFC2440_CIPHER_RSA
;
2098 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
2099 key_rec
->enc_key_size
);
2100 (*packet_size
) += key_rec
->enc_key_size
;
2105 (*remaining_bytes
) -= (*packet_size
);
2110 * write_tag_11_packet
2111 * @dest: Target into which Tag 11 packet is to be written
2112 * @remaining_bytes: Maximum packet length
2113 * @contents: Byte array of contents to copy in
2114 * @contents_length: Number of bytes in contents
2115 * @packet_length: Length of the Tag 11 packet written; zero on error
2117 * Returns zero on success; non-zero on error.
2120 write_tag_11_packet(char *dest
, size_t *remaining_bytes
, char *contents
,
2121 size_t contents_length
, size_t *packet_length
)
2123 size_t packet_size_length
;
2124 size_t max_packet_size
;
2127 (*packet_length
) = 0;
2128 /* This format is inspired by OpenPGP; see RFC 2440
2130 max_packet_size
= (1 /* Tag 11 identifier */
2131 + 3 /* Max Tag 11 packet size */
2132 + 1 /* Binary format specifier */
2133 + 1 /* Filename length */
2134 + 8 /* Filename ("_CONSOLE") */
2135 + 4 /* Modification date */
2136 + contents_length
); /* Literal data */
2137 if (max_packet_size
> (*remaining_bytes
)) {
2138 printk(KERN_ERR
"Packet length larger than maximum allowable; "
2139 "need up to [%td] bytes, but there are only [%td] "
2140 "available\n", max_packet_size
, (*remaining_bytes
));
2144 dest
[(*packet_length
)++] = ECRYPTFS_TAG_11_PACKET_TYPE
;
2145 rc
= ecryptfs_write_packet_length(&dest
[(*packet_length
)],
2146 (max_packet_size
- 4),
2147 &packet_size_length
);
2149 printk(KERN_ERR
"Error generating tag 11 packet header; cannot "
2150 "generate packet length. rc = [%d]\n", rc
);
2153 (*packet_length
) += packet_size_length
;
2154 dest
[(*packet_length
)++] = 0x62; /* binary data format specifier */
2155 dest
[(*packet_length
)++] = 8;
2156 memcpy(&dest
[(*packet_length
)], "_CONSOLE", 8);
2157 (*packet_length
) += 8;
2158 memset(&dest
[(*packet_length
)], 0x00, 4);
2159 (*packet_length
) += 4;
2160 memcpy(&dest
[(*packet_length
)], contents
, contents_length
);
2161 (*packet_length
) += contents_length
;
2164 (*packet_length
) = 0;
2166 (*remaining_bytes
) -= (*packet_length
);
2171 * write_tag_3_packet
2172 * @dest: Buffer into which to write the packet
2173 * @remaining_bytes: Maximum number of bytes that can be written
2174 * @auth_tok: Authentication token
2175 * @crypt_stat: The cryptographic context
2176 * @key_rec: encrypted key
2177 * @packet_size: This function will write the number of bytes that end
2178 * up constituting the packet; set to zero on error
2180 * Returns zero on success; non-zero on error.
2183 write_tag_3_packet(char *dest
, size_t *remaining_bytes
,
2184 struct ecryptfs_auth_tok
*auth_tok
,
2185 struct ecryptfs_crypt_stat
*crypt_stat
,
2186 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
2189 size_t encrypted_session_key_valid
= 0;
2190 char session_key_encryption_key
[ECRYPTFS_MAX_KEY_BYTES
];
2191 struct scatterlist dst_sg
[2];
2192 struct scatterlist src_sg
[2];
2193 struct mutex
*tfm_mutex
= NULL
;
2195 size_t packet_size_length
;
2196 size_t max_packet_size
;
2197 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2198 crypt_stat
->mount_crypt_stat
;
2199 struct blkcipher_desc desc
= {
2201 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
2206 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
2208 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
2209 crypt_stat
->cipher
);
2211 printk(KERN_ERR
"Internal error whilst attempting to get "
2212 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2213 crypt_stat
->cipher
, rc
);
2216 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
2217 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(desc
.tfm
);
2219 printk(KERN_WARNING
"No key size specified at mount; "
2220 "defaulting to [%d]\n", alg
->max_keysize
);
2221 mount_crypt_stat
->global_default_cipher_key_size
=
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_blkcipher_setkey(desc
.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 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%zd] bytes of the key\n",
2302 crypt_stat
->key_size
);
2303 rc
= crypto_blkcipher_encrypt(&desc
, dst_sg
, src_sg
,
2304 (*key_rec
).enc_key_size
);
2305 mutex_unlock(tfm_mutex
);
2307 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
2310 ecryptfs_printk(KERN_DEBUG
, "This should be the encrypted key:\n");
2311 if (ecryptfs_verbosity
> 0) {
2312 ecryptfs_printk(KERN_DEBUG
, "EFEK of size [%zd]:\n",
2313 key_rec
->enc_key_size
);
2314 ecryptfs_dump_hex(key_rec
->enc_key
,
2315 key_rec
->enc_key_size
);
2317 encrypted_session_key_set
:
2318 /* This format is inspired by OpenPGP; see RFC 2440
2320 max_packet_size
= (1 /* Tag 3 identifier */
2321 + 3 /* Max Tag 3 packet size */
2323 + 1 /* Cipher code */
2324 + 1 /* S2K specifier */
2325 + 1 /* Hash identifier */
2326 + ECRYPTFS_SALT_SIZE
/* Salt */
2327 + 1 /* Hash iterations */
2328 + key_rec
->enc_key_size
); /* Encrypted key size */
2329 if (max_packet_size
> (*remaining_bytes
)) {
2330 printk(KERN_ERR
"Packet too large; need up to [%td] bytes, but "
2331 "there are only [%td] available\n", max_packet_size
,
2332 (*remaining_bytes
));
2336 dest
[(*packet_size
)++] = ECRYPTFS_TAG_3_PACKET_TYPE
;
2337 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2338 * to get the number of octets in the actual Tag 3 packet */
2339 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
2340 (max_packet_size
- 4),
2341 &packet_size_length
);
2343 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
2344 "generate packet length. rc = [%d]\n", rc
);
2347 (*packet_size
) += packet_size_length
;
2348 dest
[(*packet_size
)++] = 0x04; /* version 4 */
2349 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2350 * specified with strings */
2351 cipher_code
= ecryptfs_code_for_cipher_string(crypt_stat
->cipher
,
2352 crypt_stat
->key_size
);
2353 if (cipher_code
== 0) {
2354 ecryptfs_printk(KERN_WARNING
, "Unable to generate code for "
2355 "cipher [%s]\n", crypt_stat
->cipher
);
2359 dest
[(*packet_size
)++] = cipher_code
;
2360 dest
[(*packet_size
)++] = 0x03; /* S2K */
2361 dest
[(*packet_size
)++] = 0x01; /* MD5 (TODO: parameterize) */
2362 memcpy(&dest
[(*packet_size
)], auth_tok
->token
.password
.salt
,
2363 ECRYPTFS_SALT_SIZE
);
2364 (*packet_size
) += ECRYPTFS_SALT_SIZE
; /* salt */
2365 dest
[(*packet_size
)++] = 0x60; /* hash iterations (65536) */
2366 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
2367 key_rec
->enc_key_size
);
2368 (*packet_size
) += key_rec
->enc_key_size
;
2373 (*remaining_bytes
) -= (*packet_size
);
2377 struct kmem_cache
*ecryptfs_key_record_cache
;
2380 * ecryptfs_generate_key_packet_set
2381 * @dest_base: Virtual address from which to write the key record set
2382 * @crypt_stat: The cryptographic context from which the
2383 * authentication tokens will be retrieved
2384 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2385 * for the global parameters
2386 * @len: The amount written
2387 * @max: The maximum amount of data allowed to be written
2389 * Generates a key packet set and writes it to the virtual address
2392 * Returns zero on success; non-zero on error.
2395 ecryptfs_generate_key_packet_set(char *dest_base
,
2396 struct ecryptfs_crypt_stat
*crypt_stat
,
2397 struct dentry
*ecryptfs_dentry
, size_t *len
,
2400 struct ecryptfs_auth_tok
*auth_tok
;
2401 struct key
*auth_tok_key
= NULL
;
2402 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2403 &ecryptfs_superblock_to_private(
2404 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
2406 struct ecryptfs_key_record
*key_rec
;
2407 struct ecryptfs_key_sig
*key_sig
;
2411 mutex_lock(&crypt_stat
->keysig_list_mutex
);
2412 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
2417 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
2419 memset(key_rec
, 0, sizeof(*key_rec
));
2420 rc
= ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key
,
2425 printk(KERN_WARNING
"Unable to retrieve auth tok with "
2426 "sig = [%s]\n", key_sig
->keysig
);
2427 rc
= process_find_global_auth_tok_for_sig_err(rc
);
2430 if (auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
2431 rc
= write_tag_3_packet((dest_base
+ (*len
)),
2433 crypt_stat
, key_rec
,
2435 up_write(&(auth_tok_key
->sem
));
2436 key_put(auth_tok_key
);
2438 ecryptfs_printk(KERN_WARNING
, "Error "
2439 "writing tag 3 packet\n");
2443 /* Write auth tok signature packet */
2444 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
2446 ECRYPTFS_SIG_SIZE
, &written
);
2448 ecryptfs_printk(KERN_ERR
, "Error writing "
2449 "auth tok signature packet\n");
2453 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
2454 rc
= write_tag_1_packet(dest_base
+ (*len
), &max
,
2455 auth_tok_key
, auth_tok
,
2456 crypt_stat
, key_rec
, &written
);
2458 ecryptfs_printk(KERN_WARNING
, "Error "
2459 "writing tag 1 packet\n");
2464 up_write(&(auth_tok_key
->sem
));
2465 key_put(auth_tok_key
);
2466 ecryptfs_printk(KERN_WARNING
, "Unsupported "
2467 "authentication token type\n");
2472 if (likely(max
> 0)) {
2473 dest_base
[(*len
)] = 0x00;
2475 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
2479 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
2483 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
2487 struct kmem_cache
*ecryptfs_key_sig_cache
;
2489 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
2491 struct ecryptfs_key_sig
*new_key_sig
;
2493 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
2496 "Error allocating from ecryptfs_key_sig_cache\n");
2499 memcpy(new_key_sig
->keysig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
2500 new_key_sig
->keysig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
2501 /* Caller must hold keysig_list_mutex */
2502 list_add(&new_key_sig
->crypt_stat_list
, &crypt_stat
->keysig_list
);
2507 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
2510 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
2511 char *sig
, u32 global_auth_tok_flags
)
2513 struct ecryptfs_global_auth_tok
*new_auth_tok
;
2516 new_auth_tok
= kmem_cache_zalloc(ecryptfs_global_auth_tok_cache
,
2518 if (!new_auth_tok
) {
2520 printk(KERN_ERR
"Error allocating from "
2521 "ecryptfs_global_auth_tok_cache\n");
2524 memcpy(new_auth_tok
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
2525 new_auth_tok
->flags
= global_auth_tok_flags
;
2526 new_auth_tok
->sig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
2527 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
2528 list_add(&new_auth_tok
->mount_crypt_stat_list
,
2529 &mount_crypt_stat
->global_auth_tok_list
);
2530 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);