1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * eCryptfs: Linux filesystem encryption layer
4 * In-kernel key management code. Includes functions to parse and
5 * write authentication token-related packets with the underlying
8 * Copyright (C) 2004-2006 International Business Machines Corp.
9 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
10 * Michael C. Thompson <mcthomps@us.ibm.com>
11 * Trevor S. Highland <trevor.highland@gmail.com>
14 #include <crypto/hash.h>
15 #include <crypto/skcipher.h>
16 #include <linux/string.h>
17 #include <linux/pagemap.h>
18 #include <linux/key.h>
19 #include <linux/random.h>
20 #include <linux/scatterlist.h>
21 #include <linux/slab.h>
22 #include "ecryptfs_kernel.h"
25 * request_key returned an error instead of a valid key address;
26 * determine the type of error, make appropriate log entries, and
27 * return an error code.
29 static int process_request_key_err(long err_code
)
35 ecryptfs_printk(KERN_WARNING
, "No key\n");
39 ecryptfs_printk(KERN_WARNING
, "Key expired\n");
43 ecryptfs_printk(KERN_WARNING
, "Key revoked\n");
47 ecryptfs_printk(KERN_WARNING
, "Unknown error code: "
48 "[0x%.16lx]\n", err_code
);
54 static int process_find_global_auth_tok_for_sig_err(int err_code
)
60 ecryptfs_printk(KERN_WARNING
, "Missing auth tok\n");
63 ecryptfs_printk(KERN_WARNING
, "Invalid auth tok\n");
66 rc
= process_request_key_err(err_code
);
73 * ecryptfs_parse_packet_length
74 * @data: Pointer to memory containing length at offset
75 * @size: This function writes the decoded size to this memory
76 * address; zero on error
77 * @length_size: The number of bytes occupied by the encoded length
79 * Returns zero on success; non-zero on error
81 int ecryptfs_parse_packet_length(unsigned char *data
, size_t *size
,
92 } else if (data
[0] < 224) {
94 (*size
) = (data
[0] - 192) * 256;
95 (*size
) += data
[1] + 192;
97 } else if (data
[0] == 255) {
98 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
99 ecryptfs_printk(KERN_ERR
, "Five-byte packet length not "
104 ecryptfs_printk(KERN_ERR
, "Error parsing packet length\n");
113 * ecryptfs_write_packet_length
114 * @dest: The byte array target into which to write the length. Must
115 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
116 * @size: The length to write.
117 * @packet_size_length: The number of bytes used to encode the packet
118 * length is written to this address.
120 * Returns zero on success; non-zero on error.
122 int ecryptfs_write_packet_length(char *dest
, size_t size
,
123 size_t *packet_size_length
)
129 (*packet_size_length
) = 1;
130 } else if (size
< 65536) {
131 dest
[0] = (((size
- 192) / 256) + 192);
132 dest
[1] = ((size
- 192) % 256);
133 (*packet_size_length
) = 2;
135 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
137 ecryptfs_printk(KERN_WARNING
,
138 "Unsupported packet size: [%zd]\n", size
);
144 write_tag_64_packet(char *signature
, struct ecryptfs_session_key
*session_key
,
145 char **packet
, size_t *packet_len
)
149 size_t packet_size_len
;
154 * ***** TAG 64 Packet Format *****
155 * | Content Type | 1 byte |
156 * | Key Identifier Size | 1 or 2 bytes |
157 * | Key Identifier | arbitrary |
158 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
159 * | Encrypted File Encryption Key | arbitrary |
161 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
162 + session_key
->encrypted_key_size
);
163 *packet
= kmalloc(data_len
, GFP_KERNEL
);
166 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
170 message
[i
++] = ECRYPTFS_TAG_64_PACKET_TYPE
;
171 rc
= ecryptfs_write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
174 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
175 "header; cannot generate packet length\n");
178 i
+= packet_size_len
;
179 memcpy(&message
[i
], signature
, ECRYPTFS_SIG_SIZE_HEX
);
180 i
+= ECRYPTFS_SIG_SIZE_HEX
;
181 rc
= ecryptfs_write_packet_length(&message
[i
],
182 session_key
->encrypted_key_size
,
185 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
186 "header; cannot generate packet length\n");
189 i
+= packet_size_len
;
190 memcpy(&message
[i
], session_key
->encrypted_key
,
191 session_key
->encrypted_key_size
);
192 i
+= session_key
->encrypted_key_size
;
199 parse_tag_65_packet(struct ecryptfs_session_key
*session_key
, u8
*cipher_code
,
200 struct ecryptfs_message
*msg
)
208 u16 expected_checksum
= 0;
212 * ***** TAG 65 Packet Format *****
213 * | Content Type | 1 byte |
214 * | Status Indicator | 1 byte |
215 * | File Encryption Key Size | 1 or 2 bytes |
216 * | File Encryption Key | arbitrary |
218 message_len
= msg
->data_len
;
220 if (message_len
< 4) {
224 if (data
[i
++] != ECRYPTFS_TAG_65_PACKET_TYPE
) {
225 ecryptfs_printk(KERN_ERR
, "Type should be ECRYPTFS_TAG_65\n");
230 ecryptfs_printk(KERN_ERR
, "Status indicator has non-zero value "
231 "[%d]\n", data
[i
-1]);
235 rc
= ecryptfs_parse_packet_length(&data
[i
], &m_size
, &data_len
);
237 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
242 if (message_len
< (i
+ m_size
)) {
243 ecryptfs_printk(KERN_ERR
, "The message received from ecryptfsd "
244 "is shorter than expected\n");
249 ecryptfs_printk(KERN_ERR
,
250 "The decrypted key is not long enough to "
251 "include a cipher code and checksum\n");
255 *cipher_code
= data
[i
++];
256 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
257 session_key
->decrypted_key_size
= m_size
- 3;
258 if (session_key
->decrypted_key_size
> ECRYPTFS_MAX_KEY_BYTES
) {
259 ecryptfs_printk(KERN_ERR
, "key_size [%d] larger than "
260 "the maximum key size [%d]\n",
261 session_key
->decrypted_key_size
,
262 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
);
266 memcpy(session_key
->decrypted_key
, &data
[i
],
267 session_key
->decrypted_key_size
);
268 i
+= session_key
->decrypted_key_size
;
269 expected_checksum
+= (unsigned char)(data
[i
++]) << 8;
270 expected_checksum
+= (unsigned char)(data
[i
++]);
271 for (i
= 0; i
< session_key
->decrypted_key_size
; i
++)
272 checksum
+= session_key
->decrypted_key
[i
];
273 if (expected_checksum
!= checksum
) {
274 ecryptfs_printk(KERN_ERR
, "Invalid checksum for file "
275 "encryption key; expected [%x]; calculated "
276 "[%x]\n", expected_checksum
, checksum
);
285 write_tag_66_packet(char *signature
, u8 cipher_code
,
286 struct ecryptfs_crypt_stat
*crypt_stat
, char **packet
,
293 size_t packet_size_len
;
298 * ***** TAG 66 Packet Format *****
299 * | Content Type | 1 byte |
300 * | Key Identifier Size | 1 or 2 bytes |
301 * | Key Identifier | arbitrary |
302 * | File Encryption Key Size | 1 or 2 bytes |
303 * | File Encryption Key | arbitrary |
305 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
+ crypt_stat
->key_size
);
306 *packet
= kmalloc(data_len
, GFP_KERNEL
);
309 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
313 message
[i
++] = ECRYPTFS_TAG_66_PACKET_TYPE
;
314 rc
= ecryptfs_write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
317 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
318 "header; cannot generate packet length\n");
321 i
+= packet_size_len
;
322 memcpy(&message
[i
], signature
, ECRYPTFS_SIG_SIZE_HEX
);
323 i
+= ECRYPTFS_SIG_SIZE_HEX
;
324 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
325 rc
= ecryptfs_write_packet_length(&message
[i
], crypt_stat
->key_size
+ 3,
328 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
329 "header; cannot generate packet length\n");
332 i
+= packet_size_len
;
333 message
[i
++] = cipher_code
;
334 memcpy(&message
[i
], crypt_stat
->key
, crypt_stat
->key_size
);
335 i
+= crypt_stat
->key_size
;
336 for (j
= 0; j
< crypt_stat
->key_size
; j
++)
337 checksum
+= crypt_stat
->key
[j
];
338 message
[i
++] = (checksum
/ 256) % 256;
339 message
[i
++] = (checksum
% 256);
346 parse_tag_67_packet(struct ecryptfs_key_record
*key_rec
,
347 struct ecryptfs_message
*msg
)
356 * ***** TAG 65 Packet Format *****
357 * | Content Type | 1 byte |
358 * | Status Indicator | 1 byte |
359 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
360 * | Encrypted File Encryption Key | arbitrary |
362 message_len
= msg
->data_len
;
364 /* verify that everything through the encrypted FEK size is present */
365 if (message_len
< 4) {
367 printk(KERN_ERR
"%s: message_len is [%zd]; minimum acceptable "
368 "message length is [%d]\n", __func__
, message_len
, 4);
371 if (data
[i
++] != ECRYPTFS_TAG_67_PACKET_TYPE
) {
373 printk(KERN_ERR
"%s: Type should be ECRYPTFS_TAG_67\n",
379 printk(KERN_ERR
"%s: Status indicator has non zero "
380 "value [%d]\n", __func__
, data
[i
-1]);
384 rc
= ecryptfs_parse_packet_length(&data
[i
], &key_rec
->enc_key_size
,
387 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
392 if (message_len
< (i
+ key_rec
->enc_key_size
)) {
394 printk(KERN_ERR
"%s: message_len [%zd]; max len is [%zd]\n",
395 __func__
, message_len
, (i
+ key_rec
->enc_key_size
));
398 if (key_rec
->enc_key_size
> ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
400 printk(KERN_ERR
"%s: Encrypted key_size [%zd] larger than "
401 "the maximum key size [%d]\n", __func__
,
402 key_rec
->enc_key_size
,
403 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
);
406 memcpy(key_rec
->enc_key
, &data
[i
], key_rec
->enc_key_size
);
412 * ecryptfs_verify_version
413 * @version: The version number to confirm
415 * Returns zero on good version; non-zero otherwise
417 static int ecryptfs_verify_version(u16 version
)
423 major
= ((version
>> 8) & 0xFF);
424 minor
= (version
& 0xFF);
425 if (major
!= ECRYPTFS_VERSION_MAJOR
) {
426 ecryptfs_printk(KERN_ERR
, "Major version number mismatch. "
427 "Expected [%d]; got [%d]\n",
428 ECRYPTFS_VERSION_MAJOR
, major
);
432 if (minor
!= ECRYPTFS_VERSION_MINOR
) {
433 ecryptfs_printk(KERN_ERR
, "Minor version number mismatch. "
434 "Expected [%d]; got [%d]\n",
435 ECRYPTFS_VERSION_MINOR
, minor
);
444 * ecryptfs_verify_auth_tok_from_key
445 * @auth_tok_key: key containing the authentication token
446 * @auth_tok: authentication token
448 * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
449 * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
452 ecryptfs_verify_auth_tok_from_key(struct key
*auth_tok_key
,
453 struct ecryptfs_auth_tok
**auth_tok
)
457 (*auth_tok
) = ecryptfs_get_key_payload_data(auth_tok_key
);
458 if (IS_ERR(*auth_tok
)) {
459 rc
= PTR_ERR(*auth_tok
);
464 if (ecryptfs_verify_version((*auth_tok
)->version
)) {
465 printk(KERN_ERR
"Data structure version mismatch. Userspace "
466 "tools must match eCryptfs kernel module with major "
467 "version [%d] and minor version [%d]\n",
468 ECRYPTFS_VERSION_MAJOR
, ECRYPTFS_VERSION_MINOR
);
472 if ((*auth_tok
)->token_type
!= ECRYPTFS_PASSWORD
473 && (*auth_tok
)->token_type
!= ECRYPTFS_PRIVATE_KEY
) {
474 printk(KERN_ERR
"Invalid auth_tok structure "
475 "returned from key query\n");
484 ecryptfs_find_global_auth_tok_for_sig(
485 struct key
**auth_tok_key
,
486 struct ecryptfs_auth_tok
**auth_tok
,
487 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
, char *sig
)
489 struct ecryptfs_global_auth_tok
*walker
;
492 (*auth_tok_key
) = NULL
;
494 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
495 list_for_each_entry(walker
,
496 &mount_crypt_stat
->global_auth_tok_list
,
497 mount_crypt_stat_list
) {
498 if (memcmp(walker
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
))
501 if (walker
->flags
& ECRYPTFS_AUTH_TOK_INVALID
) {
506 rc
= key_validate(walker
->global_auth_tok_key
);
508 if (rc
== -EKEYEXPIRED
)
510 goto out_invalid_auth_tok
;
513 down_write(&(walker
->global_auth_tok_key
->sem
));
514 rc
= ecryptfs_verify_auth_tok_from_key(
515 walker
->global_auth_tok_key
, auth_tok
);
517 goto out_invalid_auth_tok_unlock
;
519 (*auth_tok_key
) = walker
->global_auth_tok_key
;
520 key_get(*auth_tok_key
);
525 out_invalid_auth_tok_unlock
:
526 up_write(&(walker
->global_auth_tok_key
->sem
));
527 out_invalid_auth_tok
:
528 printk(KERN_WARNING
"Invalidating auth tok with sig = [%s]\n", sig
);
529 walker
->flags
|= ECRYPTFS_AUTH_TOK_INVALID
;
530 key_put(walker
->global_auth_tok_key
);
531 walker
->global_auth_tok_key
= NULL
;
533 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
538 * ecryptfs_find_auth_tok_for_sig
539 * @auth_tok_key: key containing the authentication token
540 * @auth_tok: Set to the matching auth_tok; NULL if not found
541 * @mount_crypt_stat: inode crypt_stat crypto context
542 * @sig: Sig of auth_tok to find
544 * For now, this function simply looks at the registered auth_tok's
545 * linked off the mount_crypt_stat, so all the auth_toks that can be
546 * used must be registered at mount time. This function could
547 * potentially try a lot harder to find auth_tok's (e.g., by calling
548 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
549 * that static registration of auth_tok's will no longer be necessary.
551 * Returns zero on no error; non-zero on error
554 ecryptfs_find_auth_tok_for_sig(
555 struct key
**auth_tok_key
,
556 struct ecryptfs_auth_tok
**auth_tok
,
557 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
562 rc
= ecryptfs_find_global_auth_tok_for_sig(auth_tok_key
, auth_tok
,
563 mount_crypt_stat
, sig
);
565 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
566 * mount_crypt_stat structure, we prevent to use auth toks that
567 * are not inserted through the ecryptfs_add_global_auth_tok
570 if (mount_crypt_stat
->flags
571 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY
)
574 rc
= ecryptfs_keyring_auth_tok_for_sig(auth_tok_key
, auth_tok
,
581 * write_tag_70_packet can gobble a lot of stack space. We stuff most
582 * of the function's parameters in a kmalloc'd struct to help reduce
583 * eCryptfs' overall stack usage.
585 struct ecryptfs_write_tag_70_packet_silly_stack
{
587 size_t max_packet_size
;
588 size_t packet_size_len
;
589 size_t block_aligned_filename_size
;
593 size_t num_rand_bytes
;
594 struct mutex
*tfm_mutex
;
595 char *block_aligned_filename
;
596 struct ecryptfs_auth_tok
*auth_tok
;
597 struct scatterlist src_sg
[2];
598 struct scatterlist dst_sg
[2];
599 struct crypto_skcipher
*skcipher_tfm
;
600 struct skcipher_request
*skcipher_req
;
601 char iv
[ECRYPTFS_MAX_IV_BYTES
];
602 char hash
[ECRYPTFS_TAG_70_DIGEST_SIZE
];
603 char tmp_hash
[ECRYPTFS_TAG_70_DIGEST_SIZE
];
604 struct crypto_shash
*hash_tfm
;
605 struct shash_desc
*hash_desc
;
609 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
610 * @filename: NULL-terminated filename string
612 * This is the simplest mechanism for achieving filename encryption in
613 * eCryptfs. It encrypts the given filename with the mount-wide
614 * filename encryption key (FNEK) and stores it in a packet to @dest,
615 * which the callee will encode and write directly into the dentry
619 ecryptfs_write_tag_70_packet(char *dest
, size_t *remaining_bytes
,
621 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
622 char *filename
, size_t filename_size
)
624 struct ecryptfs_write_tag_70_packet_silly_stack
*s
;
625 struct key
*auth_tok_key
= NULL
;
628 s
= kzalloc(sizeof(*s
), GFP_KERNEL
);
633 rc
= ecryptfs_find_auth_tok_for_sig(
635 &s
->auth_tok
, mount_crypt_stat
,
636 mount_crypt_stat
->global_default_fnek_sig
);
638 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
639 "fnek sig [%s]; rc = [%d]\n", __func__
,
640 mount_crypt_stat
->global_default_fnek_sig
, rc
);
643 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(
645 &s
->tfm_mutex
, mount_crypt_stat
->global_default_fn_cipher_name
);
647 printk(KERN_ERR
"Internal error whilst attempting to get "
648 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
649 mount_crypt_stat
->global_default_fn_cipher_name
, rc
);
652 mutex_lock(s
->tfm_mutex
);
653 s
->block_size
= crypto_skcipher_blocksize(s
->skcipher_tfm
);
654 /* Plus one for the \0 separator between the random prefix
655 * and the plaintext filename */
656 s
->num_rand_bytes
= (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
+ 1);
657 s
->block_aligned_filename_size
= (s
->num_rand_bytes
+ filename_size
);
658 if ((s
->block_aligned_filename_size
% s
->block_size
) != 0) {
659 s
->num_rand_bytes
+= (s
->block_size
660 - (s
->block_aligned_filename_size
662 s
->block_aligned_filename_size
= (s
->num_rand_bytes
665 /* Octet 0: Tag 70 identifier
666 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
667 * and block-aligned encrypted filename size)
668 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
669 * Octet N2-N3: Cipher identifier (1 octet)
670 * Octets N3-N4: Block-aligned encrypted filename
671 * - Consists of a minimum number of random characters, a \0
672 * separator, and then the filename */
673 s
->max_packet_size
= (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
674 + s
->block_aligned_filename_size
);
676 (*packet_size
) = s
->max_packet_size
;
679 if (s
->max_packet_size
> (*remaining_bytes
)) {
680 printk(KERN_WARNING
"%s: Require [%zd] bytes to write; only "
681 "[%zd] available\n", __func__
, s
->max_packet_size
,
687 s
->skcipher_req
= skcipher_request_alloc(s
->skcipher_tfm
, GFP_KERNEL
);
688 if (!s
->skcipher_req
) {
689 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
690 "skcipher_request_alloc for %s\n", __func__
,
691 crypto_skcipher_driver_name(s
->skcipher_tfm
));
696 skcipher_request_set_callback(s
->skcipher_req
,
697 CRYPTO_TFM_REQ_MAY_SLEEP
, NULL
, NULL
);
699 s
->block_aligned_filename
= kzalloc(s
->block_aligned_filename_size
,
701 if (!s
->block_aligned_filename
) {
705 dest
[s
->i
++] = ECRYPTFS_TAG_70_PACKET_TYPE
;
706 rc
= ecryptfs_write_packet_length(&dest
[s
->i
],
708 + 1 /* Cipher code */
709 + s
->block_aligned_filename_size
),
710 &s
->packet_size_len
);
712 printk(KERN_ERR
"%s: Error generating tag 70 packet "
713 "header; cannot generate packet length; rc = [%d]\n",
715 goto out_free_unlock
;
717 s
->i
+= s
->packet_size_len
;
718 ecryptfs_from_hex(&dest
[s
->i
],
719 mount_crypt_stat
->global_default_fnek_sig
,
721 s
->i
+= ECRYPTFS_SIG_SIZE
;
722 s
->cipher_code
= ecryptfs_code_for_cipher_string(
723 mount_crypt_stat
->global_default_fn_cipher_name
,
724 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
725 if (s
->cipher_code
== 0) {
726 printk(KERN_WARNING
"%s: Unable to generate code for "
727 "cipher [%s] with key bytes [%zd]\n", __func__
,
728 mount_crypt_stat
->global_default_fn_cipher_name
,
729 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
731 goto out_free_unlock
;
733 dest
[s
->i
++] = s
->cipher_code
;
734 /* TODO: Support other key modules than passphrase for
735 * filename encryption */
736 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
738 printk(KERN_INFO
"%s: Filename encryption only supports "
739 "password tokens\n", __func__
);
740 goto out_free_unlock
;
742 s
->hash_tfm
= crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST
, 0, 0);
743 if (IS_ERR(s
->hash_tfm
)) {
744 rc
= PTR_ERR(s
->hash_tfm
);
745 printk(KERN_ERR
"%s: Error attempting to "
746 "allocate hash crypto context; rc = [%d]\n",
748 goto out_free_unlock
;
751 s
->hash_desc
= kmalloc(sizeof(*s
->hash_desc
) +
752 crypto_shash_descsize(s
->hash_tfm
), GFP_KERNEL
);
755 goto out_release_free_unlock
;
758 s
->hash_desc
->tfm
= s
->hash_tfm
;
760 rc
= crypto_shash_digest(s
->hash_desc
,
761 (u8
*)s
->auth_tok
->token
.password
.session_key_encryption_key
,
762 s
->auth_tok
->token
.password
.session_key_encryption_key_bytes
,
766 "%s: Error computing crypto hash; rc = [%d]\n",
768 goto out_release_free_unlock
;
770 for (s
->j
= 0; s
->j
< (s
->num_rand_bytes
- 1); s
->j
++) {
771 s
->block_aligned_filename
[s
->j
] =
772 s
->hash
[(s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)];
773 if ((s
->j
% ECRYPTFS_TAG_70_DIGEST_SIZE
)
774 == (ECRYPTFS_TAG_70_DIGEST_SIZE
- 1)) {
775 rc
= crypto_shash_digest(s
->hash_desc
, (u8
*)s
->hash
,
776 ECRYPTFS_TAG_70_DIGEST_SIZE
,
780 "%s: Error computing crypto hash; "
781 "rc = [%d]\n", __func__
, rc
);
782 goto out_release_free_unlock
;
784 memcpy(s
->hash
, s
->tmp_hash
,
785 ECRYPTFS_TAG_70_DIGEST_SIZE
);
787 if (s
->block_aligned_filename
[s
->j
] == '\0')
788 s
->block_aligned_filename
[s
->j
] = ECRYPTFS_NON_NULL
;
790 memcpy(&s
->block_aligned_filename
[s
->num_rand_bytes
], filename
,
792 rc
= virt_to_scatterlist(s
->block_aligned_filename
,
793 s
->block_aligned_filename_size
, s
->src_sg
, 2);
795 printk(KERN_ERR
"%s: Internal error whilst attempting to "
796 "convert filename memory to scatterlist; rc = [%d]. "
797 "block_aligned_filename_size = [%zd]\n", __func__
, rc
,
798 s
->block_aligned_filename_size
);
799 goto out_release_free_unlock
;
801 rc
= virt_to_scatterlist(&dest
[s
->i
], s
->block_aligned_filename_size
,
804 printk(KERN_ERR
"%s: Internal error whilst attempting to "
805 "convert encrypted filename memory to scatterlist; "
806 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
807 __func__
, rc
, s
->block_aligned_filename_size
);
808 goto out_release_free_unlock
;
810 /* The characters in the first block effectively do the job
811 * of the IV here, so we just use 0's for the IV. Note the
812 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
813 * >= ECRYPTFS_MAX_IV_BYTES. */
814 rc
= crypto_skcipher_setkey(
816 s
->auth_tok
->token
.password
.session_key_encryption_key
,
817 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
819 printk(KERN_ERR
"%s: Error setting key for crypto context; "
820 "rc = [%d]. s->auth_tok->token.password.session_key_"
821 "encryption_key = [0x%p]; mount_crypt_stat->"
822 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
824 s
->auth_tok
->token
.password
.session_key_encryption_key
,
825 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
826 goto out_release_free_unlock
;
828 skcipher_request_set_crypt(s
->skcipher_req
, s
->src_sg
, s
->dst_sg
,
829 s
->block_aligned_filename_size
, s
->iv
);
830 rc
= crypto_skcipher_encrypt(s
->skcipher_req
);
832 printk(KERN_ERR
"%s: Error attempting to encrypt filename; "
833 "rc = [%d]\n", __func__
, rc
);
834 goto out_release_free_unlock
;
836 s
->i
+= s
->block_aligned_filename_size
;
837 (*packet_size
) = s
->i
;
838 (*remaining_bytes
) -= (*packet_size
);
839 out_release_free_unlock
:
840 crypto_free_shash(s
->hash_tfm
);
842 kfree_sensitive(s
->block_aligned_filename
);
844 mutex_unlock(s
->tfm_mutex
);
847 up_write(&(auth_tok_key
->sem
));
848 key_put(auth_tok_key
);
850 skcipher_request_free(s
->skcipher_req
);
851 kfree_sensitive(s
->hash_desc
);
856 struct ecryptfs_parse_tag_70_packet_silly_stack
{
858 size_t max_packet_size
;
859 size_t packet_size_len
;
860 size_t parsed_tag_70_packet_size
;
861 size_t block_aligned_filename_size
;
864 struct mutex
*tfm_mutex
;
865 char *decrypted_filename
;
866 struct ecryptfs_auth_tok
*auth_tok
;
867 struct scatterlist src_sg
[2];
868 struct scatterlist dst_sg
[2];
869 struct crypto_skcipher
*skcipher_tfm
;
870 struct skcipher_request
*skcipher_req
;
871 char fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
+ 1];
872 char iv
[ECRYPTFS_MAX_IV_BYTES
];
873 char cipher_string
[ECRYPTFS_MAX_CIPHER_NAME_SIZE
+ 1];
877 * ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
878 * @filename: This function kmalloc's the memory for the filename
879 * @filename_size: This function sets this to the amount of memory
880 * kmalloc'd for the filename
881 * @packet_size: This function sets this to the the number of octets
882 * in the packet parsed
883 * @mount_crypt_stat: The mount-wide cryptographic context
884 * @data: The memory location containing the start of the tag 70
886 * @max_packet_size: The maximum legal size of the packet to be parsed
889 * Returns zero on success; non-zero otherwise
892 ecryptfs_parse_tag_70_packet(char **filename
, size_t *filename_size
,
894 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
895 char *data
, size_t max_packet_size
)
897 struct ecryptfs_parse_tag_70_packet_silly_stack
*s
;
898 struct key
*auth_tok_key
= NULL
;
902 (*filename_size
) = 0;
904 s
= kzalloc(sizeof(*s
), GFP_KERNEL
);
908 if (max_packet_size
< ECRYPTFS_TAG_70_MIN_METADATA_SIZE
) {
909 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; it must be "
910 "at least [%d]\n", __func__
, max_packet_size
,
911 ECRYPTFS_TAG_70_MIN_METADATA_SIZE
);
915 /* Octet 0: Tag 70 identifier
916 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
917 * and block-aligned encrypted filename size)
918 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
919 * Octet N2-N3: Cipher identifier (1 octet)
920 * Octets N3-N4: Block-aligned encrypted filename
921 * - Consists of a minimum number of random numbers, a \0
922 * separator, and then the filename */
923 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_70_PACKET_TYPE
) {
924 printk(KERN_WARNING
"%s: Invalid packet tag [0x%.2x]; must be "
925 "tag [0x%.2x]\n", __func__
,
926 data
[((*packet_size
) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE
);
930 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)],
931 &s
->parsed_tag_70_packet_size
,
932 &s
->packet_size_len
);
934 printk(KERN_WARNING
"%s: Error parsing packet length; "
935 "rc = [%d]\n", __func__
, rc
);
938 s
->block_aligned_filename_size
= (s
->parsed_tag_70_packet_size
939 - ECRYPTFS_SIG_SIZE
- 1);
940 if ((1 + s
->packet_size_len
+ s
->parsed_tag_70_packet_size
)
942 printk(KERN_WARNING
"%s: max_packet_size is [%zd]; real packet "
943 "size is [%zd]\n", __func__
, max_packet_size
,
944 (1 + s
->packet_size_len
+ 1
945 + s
->block_aligned_filename_size
));
949 (*packet_size
) += s
->packet_size_len
;
950 ecryptfs_to_hex(s
->fnek_sig_hex
, &data
[(*packet_size
)],
952 s
->fnek_sig_hex
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
953 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
954 s
->cipher_code
= data
[(*packet_size
)++];
955 rc
= ecryptfs_cipher_code_to_string(s
->cipher_string
, s
->cipher_code
);
957 printk(KERN_WARNING
"%s: Cipher code [%d] is invalid\n",
958 __func__
, s
->cipher_code
);
961 rc
= ecryptfs_find_auth_tok_for_sig(&auth_tok_key
,
962 &s
->auth_tok
, mount_crypt_stat
,
965 printk(KERN_ERR
"%s: Error attempting to find auth tok for "
966 "fnek sig [%s]; rc = [%d]\n", __func__
, s
->fnek_sig_hex
,
970 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&s
->skcipher_tfm
,
974 printk(KERN_ERR
"Internal error whilst attempting to get "
975 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
976 s
->cipher_string
, rc
);
979 mutex_lock(s
->tfm_mutex
);
980 rc
= virt_to_scatterlist(&data
[(*packet_size
)],
981 s
->block_aligned_filename_size
, s
->src_sg
, 2);
983 printk(KERN_ERR
"%s: Internal error whilst attempting to "
984 "convert encrypted filename memory to scatterlist; "
985 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
986 __func__
, rc
, s
->block_aligned_filename_size
);
989 (*packet_size
) += s
->block_aligned_filename_size
;
990 s
->decrypted_filename
= kmalloc(s
->block_aligned_filename_size
,
992 if (!s
->decrypted_filename
) {
996 rc
= virt_to_scatterlist(s
->decrypted_filename
,
997 s
->block_aligned_filename_size
, s
->dst_sg
, 2);
999 printk(KERN_ERR
"%s: Internal error whilst attempting to "
1000 "convert decrypted filename memory to scatterlist; "
1001 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1002 __func__
, rc
, s
->block_aligned_filename_size
);
1003 goto out_free_unlock
;
1006 s
->skcipher_req
= skcipher_request_alloc(s
->skcipher_tfm
, GFP_KERNEL
);
1007 if (!s
->skcipher_req
) {
1008 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
1009 "skcipher_request_alloc for %s\n", __func__
,
1010 crypto_skcipher_driver_name(s
->skcipher_tfm
));
1012 goto out_free_unlock
;
1015 skcipher_request_set_callback(s
->skcipher_req
,
1016 CRYPTO_TFM_REQ_MAY_SLEEP
, NULL
, NULL
);
1018 /* The characters in the first block effectively do the job of
1019 * the IV here, so we just use 0's for the IV. Note the
1020 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1021 * >= ECRYPTFS_MAX_IV_BYTES. */
1022 /* TODO: Support other key modules than passphrase for
1023 * filename encryption */
1024 if (s
->auth_tok
->token_type
!= ECRYPTFS_PASSWORD
) {
1026 printk(KERN_INFO
"%s: Filename encryption only supports "
1027 "password tokens\n", __func__
);
1028 goto out_free_unlock
;
1030 rc
= crypto_skcipher_setkey(
1032 s
->auth_tok
->token
.password
.session_key_encryption_key
,
1033 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
1035 printk(KERN_ERR
"%s: Error setting key for crypto context; "
1036 "rc = [%d]. s->auth_tok->token.password.session_key_"
1037 "encryption_key = [0x%p]; mount_crypt_stat->"
1038 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__
,
1040 s
->auth_tok
->token
.password
.session_key_encryption_key
,
1041 mount_crypt_stat
->global_default_fn_cipher_key_bytes
);
1042 goto out_free_unlock
;
1044 skcipher_request_set_crypt(s
->skcipher_req
, s
->src_sg
, s
->dst_sg
,
1045 s
->block_aligned_filename_size
, s
->iv
);
1046 rc
= crypto_skcipher_decrypt(s
->skcipher_req
);
1048 printk(KERN_ERR
"%s: Error attempting to decrypt filename; "
1049 "rc = [%d]\n", __func__
, rc
);
1050 goto out_free_unlock
;
1053 while (s
->i
< s
->block_aligned_filename_size
&&
1054 s
->decrypted_filename
[s
->i
] != '\0')
1056 if (s
->i
== s
->block_aligned_filename_size
) {
1057 printk(KERN_WARNING
"%s: Invalid tag 70 packet; could not "
1058 "find valid separator between random characters and "
1059 "the filename\n", __func__
);
1061 goto out_free_unlock
;
1064 (*filename_size
) = (s
->block_aligned_filename_size
- s
->i
);
1065 if (!((*filename_size
) > 0 && (*filename_size
< PATH_MAX
))) {
1066 printk(KERN_WARNING
"%s: Filename size is [%zd], which is "
1067 "invalid\n", __func__
, (*filename_size
));
1069 goto out_free_unlock
;
1071 (*filename
) = kmalloc(((*filename_size
) + 1), GFP_KERNEL
);
1074 goto out_free_unlock
;
1076 memcpy((*filename
), &s
->decrypted_filename
[s
->i
], (*filename_size
));
1077 (*filename
)[(*filename_size
)] = '\0';
1079 kfree(s
->decrypted_filename
);
1081 mutex_unlock(s
->tfm_mutex
);
1085 (*filename_size
) = 0;
1089 up_write(&(auth_tok_key
->sem
));
1090 key_put(auth_tok_key
);
1092 skcipher_request_free(s
->skcipher_req
);
1098 ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
1103 switch (auth_tok
->token_type
) {
1104 case ECRYPTFS_PASSWORD
:
1105 (*sig
) = auth_tok
->token
.password
.signature
;
1107 case ECRYPTFS_PRIVATE_KEY
:
1108 (*sig
) = auth_tok
->token
.private_key
.signature
;
1111 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
1112 auth_tok
->token_type
);
1119 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1120 * @auth_tok: The key authentication token used to decrypt the session key
1121 * @crypt_stat: The cryptographic context
1123 * Returns zero on success; non-zero error otherwise.
1126 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1127 struct ecryptfs_crypt_stat
*crypt_stat
)
1130 struct ecryptfs_msg_ctx
*msg_ctx
;
1131 struct ecryptfs_message
*msg
= NULL
;
1133 char *payload
= NULL
;
1134 size_t payload_len
= 0;
1137 rc
= ecryptfs_get_auth_tok_sig(&auth_tok_sig
, auth_tok
);
1139 printk(KERN_ERR
"Unrecognized auth tok type: [%d]\n",
1140 auth_tok
->token_type
);
1143 rc
= write_tag_64_packet(auth_tok_sig
, &(auth_tok
->session_key
),
1144 &payload
, &payload_len
);
1146 ecryptfs_printk(KERN_ERR
, "Failed to write tag 64 packet\n");
1149 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1151 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1152 "ecryptfsd: %d\n", rc
);
1155 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1157 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 65 packet "
1158 "from the user space daemon\n");
1162 rc
= parse_tag_65_packet(&(auth_tok
->session_key
),
1165 printk(KERN_ERR
"Failed to parse tag 65 packet; rc = [%d]\n",
1169 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1170 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1171 auth_tok
->session_key
.decrypted_key_size
);
1172 crypt_stat
->key_size
= auth_tok
->session_key
.decrypted_key_size
;
1173 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
, cipher_code
);
1175 ecryptfs_printk(KERN_ERR
, "Cipher code [%d] is invalid\n",
1179 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1180 if (ecryptfs_verbosity
> 0) {
1181 ecryptfs_printk(KERN_DEBUG
, "Decrypted session key:\n");
1182 ecryptfs_dump_hex(crypt_stat
->key
,
1183 crypt_stat
->key_size
);
1191 static void wipe_auth_tok_list(struct list_head
*auth_tok_list_head
)
1193 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1194 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1196 list_for_each_entry_safe(auth_tok_list_item
, auth_tok_list_item_tmp
,
1197 auth_tok_list_head
, list
) {
1198 list_del(&auth_tok_list_item
->list
);
1199 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1200 auth_tok_list_item
);
1204 struct kmem_cache
*ecryptfs_auth_tok_list_item_cache
;
1207 * parse_tag_1_packet
1208 * @crypt_stat: The cryptographic context to modify based on packet contents
1209 * @data: The raw bytes of the packet.
1210 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1211 * a new authentication token will be placed at the
1212 * end of this list for this packet.
1213 * @new_auth_tok: Pointer to a pointer to memory that this function
1214 * allocates; sets the memory address of the pointer to
1215 * NULL on error. This object is added to the
1217 * @packet_size: This function writes the size of the parsed packet
1218 * into this memory location; zero on error.
1219 * @max_packet_size: The maximum allowable packet size
1221 * Returns zero on success; non-zero on error.
1224 parse_tag_1_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1225 unsigned char *data
, struct list_head
*auth_tok_list
,
1226 struct ecryptfs_auth_tok
**new_auth_tok
,
1227 size_t *packet_size
, size_t max_packet_size
)
1230 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1235 (*new_auth_tok
) = NULL
;
1237 * This format is inspired by OpenPGP; see RFC 2440
1240 * Tag 1 identifier (1 byte)
1241 * Max Tag 1 packet size (max 3 bytes)
1243 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1244 * Cipher identifier (1 byte)
1245 * Encrypted key size (arbitrary)
1247 * 12 bytes minimum packet size
1249 if (unlikely(max_packet_size
< 12)) {
1250 printk(KERN_ERR
"Invalid max packet size; must be >=12\n");
1254 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_1_PACKET_TYPE
) {
1255 printk(KERN_ERR
"Enter w/ first byte != 0x%.2x\n",
1256 ECRYPTFS_TAG_1_PACKET_TYPE
);
1260 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1261 * at end of function upon failure */
1262 auth_tok_list_item
=
1263 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
,
1265 if (!auth_tok_list_item
) {
1266 printk(KERN_ERR
"Unable to allocate memory\n");
1270 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1271 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1274 printk(KERN_WARNING
"Error parsing packet length; "
1278 if (unlikely(body_size
< (ECRYPTFS_SIG_SIZE
+ 2))) {
1279 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1283 (*packet_size
) += length_size
;
1284 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1285 printk(KERN_WARNING
"Packet size exceeds max\n");
1289 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1290 printk(KERN_WARNING
"Unknown version number [%d]\n",
1291 data
[(*packet_size
) - 1]);
1295 ecryptfs_to_hex((*new_auth_tok
)->token
.private_key
.signature
,
1296 &data
[(*packet_size
)], ECRYPTFS_SIG_SIZE
);
1297 *packet_size
+= ECRYPTFS_SIG_SIZE
;
1298 /* This byte is skipped because the kernel does not need to
1299 * know which public key encryption algorithm was used */
1301 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1302 body_size
- (ECRYPTFS_SIG_SIZE
+ 2);
1303 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1304 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1305 printk(KERN_WARNING
"Tag 1 packet contains key larger "
1306 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1310 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1311 &data
[(*packet_size
)], (body_size
- (ECRYPTFS_SIG_SIZE
+ 2)));
1312 (*packet_size
) += (*new_auth_tok
)->session_key
.encrypted_key_size
;
1313 (*new_auth_tok
)->session_key
.flags
&=
1314 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1315 (*new_auth_tok
)->session_key
.flags
|=
1316 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1317 (*new_auth_tok
)->token_type
= ECRYPTFS_PRIVATE_KEY
;
1318 (*new_auth_tok
)->flags
= 0;
1319 (*new_auth_tok
)->session_key
.flags
&=
1320 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1321 (*new_auth_tok
)->session_key
.flags
&=
1322 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1323 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1326 (*new_auth_tok
) = NULL
;
1327 memset(auth_tok_list_item
, 0,
1328 sizeof(struct ecryptfs_auth_tok_list_item
));
1329 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1330 auth_tok_list_item
);
1338 * parse_tag_3_packet
1339 * @crypt_stat: The cryptographic context to modify based on packet
1341 * @data: The raw bytes of the packet.
1342 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1343 * a new authentication token will be placed at the end
1344 * of this list for this packet.
1345 * @new_auth_tok: Pointer to a pointer to memory that this function
1346 * allocates; sets the memory address of the pointer to
1347 * NULL on error. This object is added to the
1349 * @packet_size: This function writes the size of the parsed packet
1350 * into this memory location; zero on error.
1351 * @max_packet_size: maximum number of bytes to parse
1353 * Returns zero on success; non-zero on error.
1356 parse_tag_3_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
1357 unsigned char *data
, struct list_head
*auth_tok_list
,
1358 struct ecryptfs_auth_tok
**new_auth_tok
,
1359 size_t *packet_size
, size_t max_packet_size
)
1362 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1367 (*new_auth_tok
) = NULL
;
1369 *This format is inspired by OpenPGP; see RFC 2440
1372 * Tag 3 identifier (1 byte)
1373 * Max Tag 3 packet size (max 3 bytes)
1375 * Cipher code (1 byte)
1376 * S2K specifier (1 byte)
1377 * Hash identifier (1 byte)
1378 * Salt (ECRYPTFS_SALT_SIZE)
1379 * Hash iterations (1 byte)
1380 * Encrypted key (arbitrary)
1382 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1384 if (max_packet_size
< (ECRYPTFS_SALT_SIZE
+ 7)) {
1385 printk(KERN_ERR
"Max packet size too large\n");
1389 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_3_PACKET_TYPE
) {
1390 printk(KERN_ERR
"First byte != 0x%.2x; invalid packet\n",
1391 ECRYPTFS_TAG_3_PACKET_TYPE
);
1395 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1396 * at end of function upon failure */
1397 auth_tok_list_item
=
1398 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
, GFP_KERNEL
);
1399 if (!auth_tok_list_item
) {
1400 printk(KERN_ERR
"Unable to allocate memory\n");
1404 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
1405 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1408 printk(KERN_WARNING
"Error parsing packet length; rc = [%d]\n",
1412 if (unlikely(body_size
< (ECRYPTFS_SALT_SIZE
+ 5))) {
1413 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1417 (*packet_size
) += length_size
;
1418 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
1419 printk(KERN_ERR
"Packet size exceeds max\n");
1423 (*new_auth_tok
)->session_key
.encrypted_key_size
=
1424 (body_size
- (ECRYPTFS_SALT_SIZE
+ 5));
1425 if ((*new_auth_tok
)->session_key
.encrypted_key_size
1426 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
1427 printk(KERN_WARNING
"Tag 3 packet contains key larger "
1428 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1432 if (unlikely(data
[(*packet_size
)++] != 0x04)) {
1433 printk(KERN_WARNING
"Unknown version number [%d]\n",
1434 data
[(*packet_size
) - 1]);
1438 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
,
1439 (u16
)data
[(*packet_size
)]);
1442 /* A little extra work to differentiate among the AES key
1443 * sizes; see RFC2440 */
1444 switch(data
[(*packet_size
)++]) {
1445 case RFC2440_CIPHER_AES_192
:
1446 crypt_stat
->key_size
= 24;
1449 crypt_stat
->key_size
=
1450 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1452 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1455 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
1456 printk(KERN_WARNING
"Only S2K ID 3 is currently supported\n");
1460 /* TODO: finish the hash mapping */
1461 switch (data
[(*packet_size
)++]) {
1462 case 0x01: /* See RFC2440 for these numbers and their mappings */
1464 memcpy((*new_auth_tok
)->token
.password
.salt
,
1465 &data
[(*packet_size
)], ECRYPTFS_SALT_SIZE
);
1466 (*packet_size
) += ECRYPTFS_SALT_SIZE
;
1467 /* This conversion was taken straight from RFC2440 */
1468 (*new_auth_tok
)->token
.password
.hash_iterations
=
1469 ((u32
) 16 + (data
[(*packet_size
)] & 15))
1470 << ((data
[(*packet_size
)] >> 4) + 6);
1472 /* Friendly reminder:
1473 * (*new_auth_tok)->session_key.encrypted_key_size =
1474 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1475 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
1476 &data
[(*packet_size
)],
1477 (*new_auth_tok
)->session_key
.encrypted_key_size
);
1479 (*new_auth_tok
)->session_key
.encrypted_key_size
;
1480 (*new_auth_tok
)->session_key
.flags
&=
1481 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1482 (*new_auth_tok
)->session_key
.flags
|=
1483 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
1484 (*new_auth_tok
)->token
.password
.hash_algo
= 0x01; /* MD5 */
1487 ecryptfs_printk(KERN_ERR
, "Unsupported hash algorithm: "
1488 "[%d]\n", data
[(*packet_size
) - 1]);
1492 (*new_auth_tok
)->token_type
= ECRYPTFS_PASSWORD
;
1493 /* TODO: Parametarize; we might actually want userspace to
1494 * decrypt the session key. */
1495 (*new_auth_tok
)->session_key
.flags
&=
1496 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
1497 (*new_auth_tok
)->session_key
.flags
&=
1498 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
1499 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
1502 (*new_auth_tok
) = NULL
;
1503 memset(auth_tok_list_item
, 0,
1504 sizeof(struct ecryptfs_auth_tok_list_item
));
1505 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
1506 auth_tok_list_item
);
1514 * parse_tag_11_packet
1515 * @data: The raw bytes of the packet
1516 * @contents: This function writes the data contents of the literal
1517 * packet into this memory location
1518 * @max_contents_bytes: The maximum number of bytes that this function
1519 * is allowed to write into contents
1520 * @tag_11_contents_size: This function writes the size of the parsed
1521 * contents into this memory location; zero on
1523 * @packet_size: This function writes the size of the parsed packet
1524 * into this memory location; zero on error
1525 * @max_packet_size: maximum number of bytes to parse
1527 * Returns zero on success; non-zero on error.
1530 parse_tag_11_packet(unsigned char *data
, unsigned char *contents
,
1531 size_t max_contents_bytes
, size_t *tag_11_contents_size
,
1532 size_t *packet_size
, size_t max_packet_size
)
1539 (*tag_11_contents_size
) = 0;
1540 /* This format is inspired by OpenPGP; see RFC 2440
1543 * Tag 11 identifier (1 byte)
1544 * Max Tag 11 packet size (max 3 bytes)
1545 * Binary format specifier (1 byte)
1546 * Filename length (1 byte)
1547 * Filename ("_CONSOLE") (8 bytes)
1548 * Modification date (4 bytes)
1549 * Literal data (arbitrary)
1551 * We need at least 16 bytes of data for the packet to even be
1554 if (max_packet_size
< 16) {
1555 printk(KERN_ERR
"Maximum packet size too small\n");
1559 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
1560 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1564 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
1567 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
1570 if (body_size
< 14) {
1571 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
1575 (*packet_size
) += length_size
;
1576 (*tag_11_contents_size
) = (body_size
- 14);
1577 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
1578 printk(KERN_ERR
"Packet size exceeds max\n");
1582 if (unlikely((*tag_11_contents_size
) > max_contents_bytes
)) {
1583 printk(KERN_ERR
"Literal data section in tag 11 packet exceeds "
1588 if (data
[(*packet_size
)++] != 0x62) {
1589 printk(KERN_WARNING
"Unrecognizable packet\n");
1593 if (data
[(*packet_size
)++] != 0x08) {
1594 printk(KERN_WARNING
"Unrecognizable packet\n");
1598 (*packet_size
) += 12; /* Ignore filename and modification date */
1599 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
1600 (*packet_size
) += (*tag_11_contents_size
);
1604 (*tag_11_contents_size
) = 0;
1609 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
1610 struct ecryptfs_auth_tok
**auth_tok
,
1615 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
1616 if (IS_ERR(*auth_tok_key
)) {
1617 (*auth_tok_key
) = ecryptfs_get_encrypted_key(sig
);
1618 if (IS_ERR(*auth_tok_key
)) {
1619 printk(KERN_ERR
"Could not find key with description: [%s]\n",
1621 rc
= process_request_key_err(PTR_ERR(*auth_tok_key
));
1622 (*auth_tok_key
) = NULL
;
1626 down_write(&(*auth_tok_key
)->sem
);
1627 rc
= ecryptfs_verify_auth_tok_from_key(*auth_tok_key
, auth_tok
);
1629 up_write(&(*auth_tok_key
)->sem
);
1630 key_put(*auth_tok_key
);
1631 (*auth_tok_key
) = NULL
;
1639 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1640 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1641 * @crypt_stat: The cryptographic context
1643 * Returns zero on success; non-zero error otherwise
1646 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1647 struct ecryptfs_crypt_stat
*crypt_stat
)
1649 struct scatterlist dst_sg
[2];
1650 struct scatterlist src_sg
[2];
1651 struct mutex
*tfm_mutex
;
1652 struct crypto_skcipher
*tfm
;
1653 struct skcipher_request
*req
= NULL
;
1656 if (unlikely(ecryptfs_verbosity
> 0)) {
1658 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1659 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1661 auth_tok
->token
.password
.session_key_encryption_key
,
1662 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1664 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm
, &tfm_mutex
,
1665 crypt_stat
->cipher
);
1667 printk(KERN_ERR
"Internal error whilst attempting to get "
1668 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1669 crypt_stat
->cipher
, rc
);
1672 rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1673 auth_tok
->session_key
.encrypted_key_size
,
1675 if (rc
< 1 || rc
> 2) {
1676 printk(KERN_ERR
"Internal error whilst attempting to convert "
1677 "auth_tok->session_key.encrypted_key to scatterlist; "
1678 "expected rc = 1; got rc = [%d]. "
1679 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc
,
1680 auth_tok
->session_key
.encrypted_key_size
);
1683 auth_tok
->session_key
.decrypted_key_size
=
1684 auth_tok
->session_key
.encrypted_key_size
;
1685 rc
= virt_to_scatterlist(auth_tok
->session_key
.decrypted_key
,
1686 auth_tok
->session_key
.decrypted_key_size
,
1688 if (rc
< 1 || rc
> 2) {
1689 printk(KERN_ERR
"Internal error whilst attempting to convert "
1690 "auth_tok->session_key.decrypted_key to scatterlist; "
1691 "expected rc = 1; got rc = [%d]\n", rc
);
1694 mutex_lock(tfm_mutex
);
1695 req
= skcipher_request_alloc(tfm
, GFP_KERNEL
);
1697 mutex_unlock(tfm_mutex
);
1698 printk(KERN_ERR
"%s: Out of kernel memory whilst attempting to "
1699 "skcipher_request_alloc for %s\n", __func__
,
1700 crypto_skcipher_driver_name(tfm
));
1705 skcipher_request_set_callback(req
, CRYPTO_TFM_REQ_MAY_SLEEP
,
1707 rc
= crypto_skcipher_setkey(
1708 tfm
, auth_tok
->token
.password
.session_key_encryption_key
,
1709 crypt_stat
->key_size
);
1710 if (unlikely(rc
< 0)) {
1711 mutex_unlock(tfm_mutex
);
1712 printk(KERN_ERR
"Error setting key for crypto context\n");
1716 skcipher_request_set_crypt(req
, src_sg
, dst_sg
,
1717 auth_tok
->session_key
.encrypted_key_size
,
1719 rc
= crypto_skcipher_decrypt(req
);
1720 mutex_unlock(tfm_mutex
);
1722 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
1725 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1726 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1727 auth_tok
->session_key
.decrypted_key_size
);
1728 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1729 if (unlikely(ecryptfs_verbosity
> 0)) {
1730 ecryptfs_printk(KERN_DEBUG
, "FEK of size [%zd]:\n",
1731 crypt_stat
->key_size
);
1732 ecryptfs_dump_hex(crypt_stat
->key
,
1733 crypt_stat
->key_size
);
1736 skcipher_request_free(req
);
1741 * ecryptfs_parse_packet_set
1742 * @crypt_stat: The cryptographic context
1743 * @src: Virtual address of region of memory containing the packets
1744 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1746 * Get crypt_stat to have the file's session key if the requisite key
1747 * is available to decrypt the session key.
1749 * Returns Zero if a valid authentication token was retrieved and
1750 * processed; negative value for file not encrypted or for error
1753 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1755 struct dentry
*ecryptfs_dentry
)
1758 size_t found_auth_tok
;
1759 size_t next_packet_is_auth_tok_packet
;
1760 struct list_head auth_tok_list
;
1761 struct ecryptfs_auth_tok
*matching_auth_tok
;
1762 struct ecryptfs_auth_tok
*candidate_auth_tok
;
1763 char *candidate_auth_tok_sig
;
1765 struct ecryptfs_auth_tok
*new_auth_tok
;
1766 unsigned char sig_tmp_space
[ECRYPTFS_SIG_SIZE
];
1767 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1768 size_t tag_11_contents_size
;
1769 size_t tag_11_packet_size
;
1770 struct key
*auth_tok_key
= NULL
;
1773 INIT_LIST_HEAD(&auth_tok_list
);
1774 /* Parse the header to find as many packets as we can; these will be
1775 * added the our &auth_tok_list */
1776 next_packet_is_auth_tok_packet
= 1;
1777 while (next_packet_is_auth_tok_packet
) {
1778 size_t max_packet_size
= ((PAGE_SIZE
- 8) - i
);
1781 case ECRYPTFS_TAG_3_PACKET_TYPE
:
1782 rc
= parse_tag_3_packet(crypt_stat
,
1783 (unsigned char *)&src
[i
],
1784 &auth_tok_list
, &new_auth_tok
,
1785 &packet_size
, max_packet_size
);
1787 ecryptfs_printk(KERN_ERR
, "Error parsing "
1793 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1796 &tag_11_contents_size
,
1797 &tag_11_packet_size
,
1800 ecryptfs_printk(KERN_ERR
, "No valid "
1801 "(ecryptfs-specific) literal "
1802 "packet containing "
1803 "authentication token "
1804 "signature found after "
1809 i
+= tag_11_packet_size
;
1810 if (ECRYPTFS_SIG_SIZE
!= tag_11_contents_size
) {
1811 ecryptfs_printk(KERN_ERR
, "Expected "
1812 "signature of size [%d]; "
1813 "read size [%zd]\n",
1815 tag_11_contents_size
);
1819 ecryptfs_to_hex(new_auth_tok
->token
.password
.signature
,
1820 sig_tmp_space
, tag_11_contents_size
);
1821 new_auth_tok
->token
.password
.signature
[
1822 ECRYPTFS_PASSWORD_SIG_SIZE
] = '\0';
1823 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1825 case ECRYPTFS_TAG_1_PACKET_TYPE
:
1826 rc
= parse_tag_1_packet(crypt_stat
,
1827 (unsigned char *)&src
[i
],
1828 &auth_tok_list
, &new_auth_tok
,
1829 &packet_size
, max_packet_size
);
1831 ecryptfs_printk(KERN_ERR
, "Error parsing "
1837 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1839 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1840 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1841 "(Tag 11 not allowed by itself)\n");
1845 ecryptfs_printk(KERN_DEBUG
, "No packet at offset [%zd] "
1846 "of the file header; hex value of "
1847 "character is [0x%.2x]\n", i
, src
[i
]);
1848 next_packet_is_auth_tok_packet
= 0;
1851 if (list_empty(&auth_tok_list
)) {
1852 printk(KERN_ERR
"The lower file appears to be a non-encrypted "
1853 "eCryptfs file; this is not supported in this version "
1854 "of the eCryptfs kernel module\n");
1858 /* auth_tok_list contains the set of authentication tokens
1859 * parsed from the metadata. We need to find a matching
1860 * authentication token that has the secret component(s)
1861 * necessary to decrypt the EFEK in the auth_tok parsed from
1862 * the metadata. There may be several potential matches, but
1863 * just one will be sufficient to decrypt to get the FEK. */
1864 find_next_matching_auth_tok
:
1866 list_for_each_entry(auth_tok_list_item
, &auth_tok_list
, list
) {
1867 candidate_auth_tok
= &auth_tok_list_item
->auth_tok
;
1868 if (unlikely(ecryptfs_verbosity
> 0)) {
1869 ecryptfs_printk(KERN_DEBUG
,
1870 "Considering candidate auth tok:\n");
1871 ecryptfs_dump_auth_tok(candidate_auth_tok
);
1873 rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1874 candidate_auth_tok
);
1877 "Unrecognized candidate auth tok type: [%d]\n",
1878 candidate_auth_tok
->token_type
);
1882 rc
= ecryptfs_find_auth_tok_for_sig(&auth_tok_key
,
1884 crypt_stat
->mount_crypt_stat
,
1885 candidate_auth_tok_sig
);
1888 goto found_matching_auth_tok
;
1891 if (!found_auth_tok
) {
1892 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1893 "authentication token\n");
1897 found_matching_auth_tok
:
1898 if (candidate_auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1899 memcpy(&(candidate_auth_tok
->token
.private_key
),
1900 &(matching_auth_tok
->token
.private_key
),
1901 sizeof(struct ecryptfs_private_key
));
1902 up_write(&(auth_tok_key
->sem
));
1903 key_put(auth_tok_key
);
1904 rc
= decrypt_pki_encrypted_session_key(candidate_auth_tok
,
1906 } else if (candidate_auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1907 memcpy(&(candidate_auth_tok
->token
.password
),
1908 &(matching_auth_tok
->token
.password
),
1909 sizeof(struct ecryptfs_password
));
1910 up_write(&(auth_tok_key
->sem
));
1911 key_put(auth_tok_key
);
1912 rc
= decrypt_passphrase_encrypted_session_key(
1913 candidate_auth_tok
, crypt_stat
);
1915 up_write(&(auth_tok_key
->sem
));
1916 key_put(auth_tok_key
);
1920 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1922 ecryptfs_printk(KERN_WARNING
, "Error decrypting the "
1923 "session key for authentication token with sig "
1924 "[%.*s]; rc = [%d]. Removing auth tok "
1925 "candidate from the list and searching for "
1926 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX
,
1927 candidate_auth_tok_sig
, rc
);
1928 list_for_each_entry_safe(auth_tok_list_item
,
1929 auth_tok_list_item_tmp
,
1930 &auth_tok_list
, list
) {
1931 if (candidate_auth_tok
1932 == &auth_tok_list_item
->auth_tok
) {
1933 list_del(&auth_tok_list_item
->list
);
1935 ecryptfs_auth_tok_list_item_cache
,
1936 auth_tok_list_item
);
1937 goto find_next_matching_auth_tok
;
1942 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1944 ecryptfs_printk(KERN_ERR
, "Error computing "
1948 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1950 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1951 "context for cipher [%s]; rc = [%d]\n",
1952 crypt_stat
->cipher
, rc
);
1955 wipe_auth_tok_list(&auth_tok_list
);
1961 pki_encrypt_session_key(struct key
*auth_tok_key
,
1962 struct ecryptfs_auth_tok
*auth_tok
,
1963 struct ecryptfs_crypt_stat
*crypt_stat
,
1964 struct ecryptfs_key_record
*key_rec
)
1966 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1967 char *payload
= NULL
;
1968 size_t payload_len
= 0;
1969 struct ecryptfs_message
*msg
;
1972 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1973 ecryptfs_code_for_cipher_string(
1975 crypt_stat
->key_size
),
1976 crypt_stat
, &payload
, &payload_len
);
1977 up_write(&(auth_tok_key
->sem
));
1978 key_put(auth_tok_key
);
1980 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
1983 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1985 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1986 "ecryptfsd: %d\n", rc
);
1989 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1991 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
1992 "from the user space daemon\n");
1996 rc
= parse_tag_67_packet(key_rec
, msg
);
1998 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
2005 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2006 * @dest: Buffer into which to write the packet
2007 * @remaining_bytes: Maximum number of bytes that can be writtn
2008 * @auth_tok_key: The authentication token key to unlock and put when done with
2010 * @auth_tok: The authentication token used for generating the tag 1 packet
2011 * @crypt_stat: The cryptographic context
2012 * @key_rec: The key record struct for the tag 1 packet
2013 * @packet_size: This function will write the number of bytes that end
2014 * up constituting the packet; set to zero on error
2016 * Returns zero on success; non-zero on error.
2019 write_tag_1_packet(char *dest
, size_t *remaining_bytes
,
2020 struct key
*auth_tok_key
, struct ecryptfs_auth_tok
*auth_tok
,
2021 struct ecryptfs_crypt_stat
*crypt_stat
,
2022 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
2025 size_t encrypted_session_key_valid
= 0;
2026 size_t packet_size_length
;
2027 size_t max_packet_size
;
2031 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
2033 encrypted_session_key_valid
= 0;
2034 for (i
= 0; i
< crypt_stat
->key_size
; i
++)
2035 encrypted_session_key_valid
|=
2036 auth_tok
->session_key
.encrypted_key
[i
];
2037 if (encrypted_session_key_valid
) {
2038 memcpy(key_rec
->enc_key
,
2039 auth_tok
->session_key
.encrypted_key
,
2040 auth_tok
->session_key
.encrypted_key_size
);
2041 up_write(&(auth_tok_key
->sem
));
2042 key_put(auth_tok_key
);
2043 goto encrypted_session_key_set
;
2045 if (auth_tok
->session_key
.encrypted_key_size
== 0)
2046 auth_tok
->session_key
.encrypted_key_size
=
2047 auth_tok
->token
.private_key
.key_size
;
2048 rc
= pki_encrypt_session_key(auth_tok_key
, auth_tok
, crypt_stat
,
2051 printk(KERN_ERR
"Failed to encrypt session key via a key "
2052 "module; rc = [%d]\n", rc
);
2055 if (ecryptfs_verbosity
> 0) {
2056 ecryptfs_printk(KERN_DEBUG
, "Encrypted key:\n");
2057 ecryptfs_dump_hex(key_rec
->enc_key
, key_rec
->enc_key_size
);
2059 encrypted_session_key_set
:
2060 /* This format is inspired by OpenPGP; see RFC 2440
2062 max_packet_size
= (1 /* Tag 1 identifier */
2063 + 3 /* Max Tag 1 packet size */
2065 + ECRYPTFS_SIG_SIZE
/* Key identifier */
2066 + 1 /* Cipher identifier */
2067 + key_rec
->enc_key_size
); /* Encrypted key size */
2068 if (max_packet_size
> (*remaining_bytes
)) {
2069 printk(KERN_ERR
"Packet length larger than maximum allowable; "
2070 "need up to [%td] bytes, but there are only [%td] "
2071 "available\n", max_packet_size
, (*remaining_bytes
));
2075 dest
[(*packet_size
)++] = ECRYPTFS_TAG_1_PACKET_TYPE
;
2076 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
2077 (max_packet_size
- 4),
2078 &packet_size_length
);
2080 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
2081 "header; cannot generate packet length\n");
2084 (*packet_size
) += packet_size_length
;
2085 dest
[(*packet_size
)++] = 0x03; /* version 3 */
2086 memcpy(&dest
[(*packet_size
)], key_rec
->sig
, ECRYPTFS_SIG_SIZE
);
2087 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
2088 dest
[(*packet_size
)++] = RFC2440_CIPHER_RSA
;
2089 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
2090 key_rec
->enc_key_size
);
2091 (*packet_size
) += key_rec
->enc_key_size
;
2096 (*remaining_bytes
) -= (*packet_size
);
2101 * write_tag_11_packet
2102 * @dest: Target into which Tag 11 packet is to be written
2103 * @remaining_bytes: Maximum packet length
2104 * @contents: Byte array of contents to copy in
2105 * @contents_length: Number of bytes in contents
2106 * @packet_length: Length of the Tag 11 packet written; zero on error
2108 * Returns zero on success; non-zero on error.
2111 write_tag_11_packet(char *dest
, size_t *remaining_bytes
, char *contents
,
2112 size_t contents_length
, size_t *packet_length
)
2114 size_t packet_size_length
;
2115 size_t max_packet_size
;
2118 (*packet_length
) = 0;
2119 /* This format is inspired by OpenPGP; see RFC 2440
2121 max_packet_size
= (1 /* Tag 11 identifier */
2122 + 3 /* Max Tag 11 packet size */
2123 + 1 /* Binary format specifier */
2124 + 1 /* Filename length */
2125 + 8 /* Filename ("_CONSOLE") */
2126 + 4 /* Modification date */
2127 + contents_length
); /* Literal data */
2128 if (max_packet_size
> (*remaining_bytes
)) {
2129 printk(KERN_ERR
"Packet length larger than maximum allowable; "
2130 "need up to [%td] bytes, but there are only [%td] "
2131 "available\n", max_packet_size
, (*remaining_bytes
));
2135 dest
[(*packet_length
)++] = ECRYPTFS_TAG_11_PACKET_TYPE
;
2136 rc
= ecryptfs_write_packet_length(&dest
[(*packet_length
)],
2137 (max_packet_size
- 4),
2138 &packet_size_length
);
2140 printk(KERN_ERR
"Error generating tag 11 packet header; cannot "
2141 "generate packet length. rc = [%d]\n", rc
);
2144 (*packet_length
) += packet_size_length
;
2145 dest
[(*packet_length
)++] = 0x62; /* binary data format specifier */
2146 dest
[(*packet_length
)++] = 8;
2147 memcpy(&dest
[(*packet_length
)], "_CONSOLE", 8);
2148 (*packet_length
) += 8;
2149 memset(&dest
[(*packet_length
)], 0x00, 4);
2150 (*packet_length
) += 4;
2151 memcpy(&dest
[(*packet_length
)], contents
, contents_length
);
2152 (*packet_length
) += contents_length
;
2155 (*packet_length
) = 0;
2157 (*remaining_bytes
) -= (*packet_length
);
2162 * write_tag_3_packet
2163 * @dest: Buffer into which to write the packet
2164 * @remaining_bytes: Maximum number of bytes that can be written
2165 * @auth_tok: Authentication token
2166 * @crypt_stat: The cryptographic context
2167 * @key_rec: encrypted key
2168 * @packet_size: This function will write the number of bytes that end
2169 * up constituting the packet; set to zero on error
2171 * Returns zero on success; non-zero on error.
2174 write_tag_3_packet(char *dest
, size_t *remaining_bytes
,
2175 struct ecryptfs_auth_tok
*auth_tok
,
2176 struct ecryptfs_crypt_stat
*crypt_stat
,
2177 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
2180 size_t encrypted_session_key_valid
= 0;
2181 char session_key_encryption_key
[ECRYPTFS_MAX_KEY_BYTES
];
2182 struct scatterlist dst_sg
[2];
2183 struct scatterlist src_sg
[2];
2184 struct mutex
*tfm_mutex
= NULL
;
2186 size_t packet_size_length
;
2187 size_t max_packet_size
;
2188 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2189 crypt_stat
->mount_crypt_stat
;
2190 struct crypto_skcipher
*tfm
;
2191 struct skcipher_request
*req
;
2195 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
2197 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm
, &tfm_mutex
,
2198 crypt_stat
->cipher
);
2200 printk(KERN_ERR
"Internal error whilst attempting to get "
2201 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2202 crypt_stat
->cipher
, rc
);
2205 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
2206 printk(KERN_WARNING
"No key size specified at mount; "
2207 "defaulting to [%d]\n",
2208 crypto_skcipher_max_keysize(tfm
));
2209 mount_crypt_stat
->global_default_cipher_key_size
=
2210 crypto_skcipher_max_keysize(tfm
);
2212 if (crypt_stat
->key_size
== 0)
2213 crypt_stat
->key_size
=
2214 mount_crypt_stat
->global_default_cipher_key_size
;
2215 if (auth_tok
->session_key
.encrypted_key_size
== 0)
2216 auth_tok
->session_key
.encrypted_key_size
=
2217 crypt_stat
->key_size
;
2218 if (crypt_stat
->key_size
== 24
2219 && strcmp("aes", crypt_stat
->cipher
) == 0) {
2220 memset((crypt_stat
->key
+ 24), 0, 8);
2221 auth_tok
->session_key
.encrypted_key_size
= 32;
2223 auth_tok
->session_key
.encrypted_key_size
= crypt_stat
->key_size
;
2224 key_rec
->enc_key_size
=
2225 auth_tok
->session_key
.encrypted_key_size
;
2226 encrypted_session_key_valid
= 0;
2227 for (i
= 0; i
< auth_tok
->session_key
.encrypted_key_size
; i
++)
2228 encrypted_session_key_valid
|=
2229 auth_tok
->session_key
.encrypted_key
[i
];
2230 if (encrypted_session_key_valid
) {
2231 ecryptfs_printk(KERN_DEBUG
, "encrypted_session_key_valid != 0; "
2232 "using auth_tok->session_key.encrypted_key, "
2233 "where key_rec->enc_key_size = [%zd]\n",
2234 key_rec
->enc_key_size
);
2235 memcpy(key_rec
->enc_key
,
2236 auth_tok
->session_key
.encrypted_key
,
2237 key_rec
->enc_key_size
);
2238 goto encrypted_session_key_set
;
2240 if (auth_tok
->token
.password
.flags
&
2241 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET
) {
2242 ecryptfs_printk(KERN_DEBUG
, "Using previously generated "
2243 "session key encryption key of size [%d]\n",
2244 auth_tok
->token
.password
.
2245 session_key_encryption_key_bytes
);
2246 memcpy(session_key_encryption_key
,
2247 auth_tok
->token
.password
.session_key_encryption_key
,
2248 crypt_stat
->key_size
);
2249 ecryptfs_printk(KERN_DEBUG
,
2250 "Cached session key encryption key:\n");
2251 if (ecryptfs_verbosity
> 0)
2252 ecryptfs_dump_hex(session_key_encryption_key
, 16);
2254 if (unlikely(ecryptfs_verbosity
> 0)) {
2255 ecryptfs_printk(KERN_DEBUG
, "Session key encryption key:\n");
2256 ecryptfs_dump_hex(session_key_encryption_key
, 16);
2258 rc
= virt_to_scatterlist(crypt_stat
->key
, key_rec
->enc_key_size
,
2260 if (rc
< 1 || rc
> 2) {
2261 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
2262 "for crypt_stat session key; expected rc = 1; "
2263 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2264 rc
, key_rec
->enc_key_size
);
2268 rc
= virt_to_scatterlist(key_rec
->enc_key
, key_rec
->enc_key_size
,
2270 if (rc
< 1 || rc
> 2) {
2271 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
2272 "for crypt_stat encrypted session key; "
2273 "expected rc = 1; got rc = [%d]. "
2274 "key_rec->enc_key_size = [%zd]\n", rc
,
2275 key_rec
->enc_key_size
);
2279 mutex_lock(tfm_mutex
);
2280 rc
= crypto_skcipher_setkey(tfm
, session_key_encryption_key
,
2281 crypt_stat
->key_size
);
2283 mutex_unlock(tfm_mutex
);
2284 ecryptfs_printk(KERN_ERR
, "Error setting key for crypto "
2285 "context; rc = [%d]\n", rc
);
2289 req
= skcipher_request_alloc(tfm
, GFP_KERNEL
);
2291 mutex_unlock(tfm_mutex
);
2292 ecryptfs_printk(KERN_ERR
, "Out of kernel memory whilst "
2293 "attempting to skcipher_request_alloc for "
2294 "%s\n", crypto_skcipher_driver_name(tfm
));
2299 skcipher_request_set_callback(req
, CRYPTO_TFM_REQ_MAY_SLEEP
,
2303 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%zd] bytes of the key\n",
2304 crypt_stat
->key_size
);
2305 skcipher_request_set_crypt(req
, src_sg
, dst_sg
,
2306 (*key_rec
).enc_key_size
, NULL
);
2307 rc
= crypto_skcipher_encrypt(req
);
2308 mutex_unlock(tfm_mutex
);
2309 skcipher_request_free(req
);
2311 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
2314 ecryptfs_printk(KERN_DEBUG
, "This should be the encrypted key:\n");
2315 if (ecryptfs_verbosity
> 0) {
2316 ecryptfs_printk(KERN_DEBUG
, "EFEK of size [%zd]:\n",
2317 key_rec
->enc_key_size
);
2318 ecryptfs_dump_hex(key_rec
->enc_key
,
2319 key_rec
->enc_key_size
);
2321 encrypted_session_key_set
:
2322 /* This format is inspired by OpenPGP; see RFC 2440
2324 max_packet_size
= (1 /* Tag 3 identifier */
2325 + 3 /* Max Tag 3 packet size */
2327 + 1 /* Cipher code */
2328 + 1 /* S2K specifier */
2329 + 1 /* Hash identifier */
2330 + ECRYPTFS_SALT_SIZE
/* Salt */
2331 + 1 /* Hash iterations */
2332 + key_rec
->enc_key_size
); /* Encrypted key size */
2333 if (max_packet_size
> (*remaining_bytes
)) {
2334 printk(KERN_ERR
"Packet too large; need up to [%td] bytes, but "
2335 "there are only [%td] available\n", max_packet_size
,
2336 (*remaining_bytes
));
2340 dest
[(*packet_size
)++] = ECRYPTFS_TAG_3_PACKET_TYPE
;
2341 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2342 * to get the number of octets in the actual Tag 3 packet */
2343 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
2344 (max_packet_size
- 4),
2345 &packet_size_length
);
2347 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
2348 "generate packet length. rc = [%d]\n", rc
);
2351 (*packet_size
) += packet_size_length
;
2352 dest
[(*packet_size
)++] = 0x04; /* version 4 */
2353 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2354 * specified with strings */
2355 cipher_code
= ecryptfs_code_for_cipher_string(crypt_stat
->cipher
,
2356 crypt_stat
->key_size
);
2357 if (cipher_code
== 0) {
2358 ecryptfs_printk(KERN_WARNING
, "Unable to generate code for "
2359 "cipher [%s]\n", crypt_stat
->cipher
);
2363 dest
[(*packet_size
)++] = cipher_code
;
2364 dest
[(*packet_size
)++] = 0x03; /* S2K */
2365 dest
[(*packet_size
)++] = 0x01; /* MD5 (TODO: parameterize) */
2366 memcpy(&dest
[(*packet_size
)], auth_tok
->token
.password
.salt
,
2367 ECRYPTFS_SALT_SIZE
);
2368 (*packet_size
) += ECRYPTFS_SALT_SIZE
; /* salt */
2369 dest
[(*packet_size
)++] = 0x60; /* hash iterations (65536) */
2370 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
2371 key_rec
->enc_key_size
);
2372 (*packet_size
) += key_rec
->enc_key_size
;
2377 (*remaining_bytes
) -= (*packet_size
);
2381 struct kmem_cache
*ecryptfs_key_record_cache
;
2384 * ecryptfs_generate_key_packet_set
2385 * @dest_base: Virtual address from which to write the key record set
2386 * @crypt_stat: The cryptographic context from which the
2387 * authentication tokens will be retrieved
2388 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2389 * for the global parameters
2390 * @len: The amount written
2391 * @max: The maximum amount of data allowed to be written
2393 * Generates a key packet set and writes it to the virtual address
2396 * Returns zero on success; non-zero on error.
2399 ecryptfs_generate_key_packet_set(char *dest_base
,
2400 struct ecryptfs_crypt_stat
*crypt_stat
,
2401 struct dentry
*ecryptfs_dentry
, size_t *len
,
2404 struct ecryptfs_auth_tok
*auth_tok
;
2405 struct key
*auth_tok_key
= NULL
;
2406 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
2407 &ecryptfs_superblock_to_private(
2408 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
2410 struct ecryptfs_key_record
*key_rec
;
2411 struct ecryptfs_key_sig
*key_sig
;
2415 mutex_lock(&crypt_stat
->keysig_list_mutex
);
2416 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
2421 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
2423 memset(key_rec
, 0, sizeof(*key_rec
));
2424 rc
= ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key
,
2429 printk(KERN_WARNING
"Unable to retrieve auth tok with "
2430 "sig = [%s]\n", key_sig
->keysig
);
2431 rc
= process_find_global_auth_tok_for_sig_err(rc
);
2434 if (auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
2435 rc
= write_tag_3_packet((dest_base
+ (*len
)),
2437 crypt_stat
, key_rec
,
2439 up_write(&(auth_tok_key
->sem
));
2440 key_put(auth_tok_key
);
2442 ecryptfs_printk(KERN_WARNING
, "Error "
2443 "writing tag 3 packet\n");
2447 /* Write auth tok signature packet */
2448 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
2450 ECRYPTFS_SIG_SIZE
, &written
);
2452 ecryptfs_printk(KERN_ERR
, "Error writing "
2453 "auth tok signature packet\n");
2457 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
2458 rc
= write_tag_1_packet(dest_base
+ (*len
), &max
,
2459 auth_tok_key
, auth_tok
,
2460 crypt_stat
, key_rec
, &written
);
2462 ecryptfs_printk(KERN_WARNING
, "Error "
2463 "writing tag 1 packet\n");
2468 up_write(&(auth_tok_key
->sem
));
2469 key_put(auth_tok_key
);
2470 ecryptfs_printk(KERN_WARNING
, "Unsupported "
2471 "authentication token type\n");
2476 if (likely(max
> 0)) {
2477 dest_base
[(*len
)] = 0x00;
2479 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
2483 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
2487 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
2491 struct kmem_cache
*ecryptfs_key_sig_cache
;
2493 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
2495 struct ecryptfs_key_sig
*new_key_sig
;
2497 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
2501 memcpy(new_key_sig
->keysig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
2502 new_key_sig
->keysig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
2503 /* Caller must hold keysig_list_mutex */
2504 list_add(&new_key_sig
->crypt_stat_list
, &crypt_stat
->keysig_list
);
2509 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
2512 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
2513 char *sig
, u32 global_auth_tok_flags
)
2515 struct ecryptfs_global_auth_tok
*new_auth_tok
;
2517 new_auth_tok
= kmem_cache_zalloc(ecryptfs_global_auth_tok_cache
,
2522 memcpy(new_auth_tok
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
2523 new_auth_tok
->flags
= global_auth_tok_flags
;
2524 new_auth_tok
->sig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
2525 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
2526 list_add(&new_auth_tok
->mount_crypt_stat_list
,
2527 &mount_crypt_stat
->global_auth_tok_list
);
2528 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);