2 * eCryptfs: Linux filesystem encryption layer
3 * In-kernel key management code. Includes functions to parse and
4 * write authentication token-related packets with the underlying
7 * Copyright (C) 2004-2006 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
9 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * Trevor S. Highland <trevor.highland@gmail.com>
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
28 #include <linux/string.h>
29 #include <linux/syscalls.h>
30 #include <linux/pagemap.h>
31 #include <linux/key.h>
32 #include <linux/random.h>
33 #include <linux/crypto.h>
34 #include <linux/scatterlist.h>
35 #include "ecryptfs_kernel.h"
38 * request_key returned an error instead of a valid key address;
39 * determine the type of error, make appropriate log entries, and
40 * return an error code.
42 int process_request_key_err(long err_code
)
48 ecryptfs_printk(KERN_WARNING
, "No key\n");
52 ecryptfs_printk(KERN_WARNING
, "Key expired\n");
56 ecryptfs_printk(KERN_WARNING
, "Key revoked\n");
60 ecryptfs_printk(KERN_WARNING
, "Unknown error code: "
61 "[0x%.16x]\n", err_code
);
69 * @data: Pointer to memory containing length at offset
70 * @size: This function writes the decoded size to this memory
71 * address; zero on error
72 * @length_size: The number of bytes occupied by the encoded length
74 * Returns Zero on success
76 static int parse_packet_length(unsigned char *data
, size_t *size
,
85 (*size
) = (unsigned char)data
[0];
87 } else if (data
[0] < 224) {
89 (*size
) = (((unsigned char)(data
[0]) - 192) * 256);
90 (*size
) += ((unsigned char)(data
[1]) + 192);
92 } else if (data
[0] == 255) {
93 /* Five-byte length; we're not supposed to see this */
94 ecryptfs_printk(KERN_ERR
, "Five-byte packet length not "
99 ecryptfs_printk(KERN_ERR
, "Error parsing packet length\n");
108 * write_packet_length
109 * @dest: The byte array target into which to write the
110 * length. Must have at least 5 bytes allocated.
111 * @size: The length to write.
112 * @packet_size_length: The number of bytes used to encode the
113 * packet length is written to this address.
115 * Returns zero on success; non-zero on error.
117 static int write_packet_length(char *dest
, size_t size
,
118 size_t *packet_size_length
)
124 (*packet_size_length
) = 1;
125 } else if (size
< 65536) {
126 dest
[0] = (((size
- 192) / 256) + 192);
127 dest
[1] = ((size
- 192) % 256);
128 (*packet_size_length
) = 2;
131 ecryptfs_printk(KERN_WARNING
,
132 "Unsupported packet size: [%d]\n", size
);
138 write_tag_64_packet(char *signature
, struct ecryptfs_session_key
*session_key
,
139 char **packet
, size_t *packet_len
)
143 size_t packet_size_len
;
148 * ***** TAG 64 Packet Format *****
149 * | Content Type | 1 byte |
150 * | Key Identifier Size | 1 or 2 bytes |
151 * | Key Identifier | arbitrary |
152 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
153 * | Encrypted File Encryption Key | arbitrary |
155 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
156 + session_key
->encrypted_key_size
);
157 *packet
= kmalloc(data_len
, GFP_KERNEL
);
160 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
164 message
[i
++] = ECRYPTFS_TAG_64_PACKET_TYPE
;
165 rc
= write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
168 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
169 "header; cannot generate packet length\n");
172 i
+= packet_size_len
;
173 memcpy(&message
[i
], signature
, ECRYPTFS_SIG_SIZE_HEX
);
174 i
+= ECRYPTFS_SIG_SIZE_HEX
;
175 rc
= write_packet_length(&message
[i
], session_key
->encrypted_key_size
,
178 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
179 "header; cannot generate packet length\n");
182 i
+= packet_size_len
;
183 memcpy(&message
[i
], session_key
->encrypted_key
,
184 session_key
->encrypted_key_size
);
185 i
+= session_key
->encrypted_key_size
;
192 parse_tag_65_packet(struct ecryptfs_session_key
*session_key
, u16
*cipher_code
,
193 struct ecryptfs_message
*msg
)
201 u16 expected_checksum
= 0;
205 * ***** TAG 65 Packet Format *****
206 * | Content Type | 1 byte |
207 * | Status Indicator | 1 byte |
208 * | File Encryption Key Size | 1 or 2 bytes |
209 * | File Encryption Key | arbitrary |
211 message_len
= msg
->data_len
;
213 if (message_len
< 4) {
217 if (data
[i
++] != ECRYPTFS_TAG_65_PACKET_TYPE
) {
218 ecryptfs_printk(KERN_ERR
, "Type should be ECRYPTFS_TAG_65\n");
223 ecryptfs_printk(KERN_ERR
, "Status indicator has non-zero value "
224 "[%d]\n", data
[i
-1]);
228 rc
= parse_packet_length(&data
[i
], &m_size
, &data_len
);
230 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
235 if (message_len
< (i
+ m_size
)) {
236 ecryptfs_printk(KERN_ERR
, "The received netlink message is "
237 "shorter than expected\n");
242 ecryptfs_printk(KERN_ERR
,
243 "The decrypted key is not long enough to "
244 "include a cipher code and checksum\n");
248 *cipher_code
= data
[i
++];
249 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
250 session_key
->decrypted_key_size
= m_size
- 3;
251 if (session_key
->decrypted_key_size
> ECRYPTFS_MAX_KEY_BYTES
) {
252 ecryptfs_printk(KERN_ERR
, "key_size [%d] larger than "
253 "the maximum key size [%d]\n",
254 session_key
->decrypted_key_size
,
255 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
);
259 memcpy(session_key
->decrypted_key
, &data
[i
],
260 session_key
->decrypted_key_size
);
261 i
+= session_key
->decrypted_key_size
;
262 expected_checksum
+= (unsigned char)(data
[i
++]) << 8;
263 expected_checksum
+= (unsigned char)(data
[i
++]);
264 for (i
= 0; i
< session_key
->decrypted_key_size
; i
++)
265 checksum
+= session_key
->decrypted_key
[i
];
266 if (expected_checksum
!= checksum
) {
267 ecryptfs_printk(KERN_ERR
, "Invalid checksum for file "
268 "encryption key; expected [%x]; calculated "
269 "[%x]\n", expected_checksum
, checksum
);
278 write_tag_66_packet(char *signature
, size_t cipher_code
,
279 struct ecryptfs_crypt_stat
*crypt_stat
, char **packet
,
286 size_t packet_size_len
;
291 * ***** TAG 66 Packet Format *****
292 * | Content Type | 1 byte |
293 * | Key Identifier Size | 1 or 2 bytes |
294 * | Key Identifier | arbitrary |
295 * | File Encryption Key Size | 1 or 2 bytes |
296 * | File Encryption Key | arbitrary |
298 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
+ crypt_stat
->key_size
);
299 *packet
= kmalloc(data_len
, GFP_KERNEL
);
302 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
306 message
[i
++] = ECRYPTFS_TAG_66_PACKET_TYPE
;
307 rc
= write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
310 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
311 "header; cannot generate packet length\n");
314 i
+= packet_size_len
;
315 memcpy(&message
[i
], signature
, ECRYPTFS_SIG_SIZE_HEX
);
316 i
+= ECRYPTFS_SIG_SIZE_HEX
;
317 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
318 rc
= write_packet_length(&message
[i
], crypt_stat
->key_size
+ 3,
321 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
322 "header; cannot generate packet length\n");
325 i
+= packet_size_len
;
326 message
[i
++] = cipher_code
;
327 memcpy(&message
[i
], crypt_stat
->key
, crypt_stat
->key_size
);
328 i
+= crypt_stat
->key_size
;
329 for (j
= 0; j
< crypt_stat
->key_size
; j
++)
330 checksum
+= crypt_stat
->key
[j
];
331 message
[i
++] = (checksum
/ 256) % 256;
332 message
[i
++] = (checksum
% 256);
339 parse_tag_67_packet(struct ecryptfs_key_record
*key_rec
,
340 struct ecryptfs_message
*msg
)
349 * ***** TAG 65 Packet Format *****
350 * | Content Type | 1 byte |
351 * | Status Indicator | 1 byte |
352 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
353 * | Encrypted File Encryption Key | arbitrary |
355 message_len
= msg
->data_len
;
357 /* verify that everything through the encrypted FEK size is present */
358 if (message_len
< 4) {
362 if (data
[i
++] != ECRYPTFS_TAG_67_PACKET_TYPE
) {
363 ecryptfs_printk(KERN_ERR
, "Type should be ECRYPTFS_TAG_67\n");
368 ecryptfs_printk(KERN_ERR
, "Status indicator has non zero value"
369 " [%d]\n", data
[i
-1]);
373 rc
= parse_packet_length(&data
[i
], &key_rec
->enc_key_size
, &data_len
);
375 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
380 if (message_len
< (i
+ key_rec
->enc_key_size
)) {
381 ecryptfs_printk(KERN_ERR
, "message_len [%d]; max len is [%d]\n",
382 message_len
, (i
+ key_rec
->enc_key_size
));
386 if (key_rec
->enc_key_size
> ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
387 ecryptfs_printk(KERN_ERR
, "Encrypted key_size [%d] larger than "
388 "the maximum key size [%d]\n",
389 key_rec
->enc_key_size
,
390 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
);
394 memcpy(key_rec
->enc_key
, &data
[i
], key_rec
->enc_key_size
);
400 * decrypt_pki_encrypted_session_key - Decrypt the session key with
401 * the given auth_tok.
403 * Returns Zero on success; non-zero error otherwise.
406 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
407 struct ecryptfs_crypt_stat
*crypt_stat
)
410 struct ecryptfs_msg_ctx
*msg_ctx
;
411 struct ecryptfs_message
*msg
= NULL
;
413 char *netlink_message
;
414 size_t netlink_message_length
;
417 if ((rc
= ecryptfs_get_auth_tok_sig(&auth_tok_sig
, auth_tok
))) {
418 printk(KERN_ERR
"Unrecognized auth tok type: [%d]\n",
419 auth_tok
->token_type
);
422 rc
= write_tag_64_packet(auth_tok_sig
, &(auth_tok
->session_key
),
423 &netlink_message
, &netlink_message_length
);
425 ecryptfs_printk(KERN_ERR
, "Failed to write tag 64 packet");
428 rc
= ecryptfs_send_message(ecryptfs_transport
, netlink_message
,
429 netlink_message_length
, &msg_ctx
);
431 ecryptfs_printk(KERN_ERR
, "Error sending netlink message\n");
434 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
436 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 65 packet "
437 "from the user space daemon\n");
441 rc
= parse_tag_65_packet(&(auth_tok
->session_key
),
444 printk(KERN_ERR
"Failed to parse tag 65 packet; rc = [%d]\n",
448 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
449 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
450 auth_tok
->session_key
.decrypted_key_size
);
451 crypt_stat
->key_size
= auth_tok
->session_key
.decrypted_key_size
;
452 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
, cipher_code
);
454 ecryptfs_printk(KERN_ERR
, "Cipher code [%d] is invalid\n",
458 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
459 if (ecryptfs_verbosity
> 0) {
460 ecryptfs_printk(KERN_DEBUG
, "Decrypted session key:\n");
461 ecryptfs_dump_hex(crypt_stat
->key
,
462 crypt_stat
->key_size
);
470 static void wipe_auth_tok_list(struct list_head
*auth_tok_list_head
)
472 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
473 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
475 list_for_each_entry_safe(auth_tok_list_item
, auth_tok_list_item_tmp
,
476 auth_tok_list_head
, list
) {
477 list_del(&auth_tok_list_item
->list
);
478 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
483 struct kmem_cache
*ecryptfs_auth_tok_list_item_cache
;
487 * @crypt_stat: The cryptographic context to modify based on packet
489 * @data: The raw bytes of the packet.
490 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
491 * a new authentication token will be placed at the end
492 * of this list for this packet.
493 * @new_auth_tok: Pointer to a pointer to memory that this function
494 * allocates; sets the memory address of the pointer to
495 * NULL on error. This object is added to the
497 * @packet_size: This function writes the size of the parsed packet
498 * into this memory location; zero on error.
500 * Returns zero on success; non-zero on error.
503 parse_tag_1_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
504 unsigned char *data
, struct list_head
*auth_tok_list
,
505 struct ecryptfs_auth_tok
**new_auth_tok
,
506 size_t *packet_size
, size_t max_packet_size
)
509 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
514 (*new_auth_tok
) = NULL
;
516 * This format is inspired by OpenPGP; see RFC 2440
519 * Tag 1 identifier (1 byte)
520 * Max Tag 1 packet size (max 3 bytes)
522 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
523 * Cipher identifier (1 byte)
524 * Encrypted key size (arbitrary)
526 * 12 bytes minimum packet size
528 if (unlikely(max_packet_size
< 12)) {
529 printk(KERN_ERR
"Invalid max packet size; must be >=12\n");
533 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_1_PACKET_TYPE
) {
534 printk(KERN_ERR
"Enter w/ first byte != 0x%.2x\n",
535 ECRYPTFS_TAG_1_PACKET_TYPE
);
539 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
540 * at end of function upon failure */
542 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
,
544 if (!auth_tok_list_item
) {
545 printk(KERN_ERR
"Unable to allocate memory\n");
549 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
550 if ((rc
= parse_packet_length(&data
[(*packet_size
)], &body_size
,
552 printk(KERN_WARNING
"Error parsing packet length; "
556 if (unlikely(body_size
< (ECRYPTFS_SIG_SIZE
+ 2))) {
557 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
561 (*packet_size
) += length_size
;
562 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
563 printk(KERN_WARNING
"Packet size exceeds max\n");
567 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
568 printk(KERN_WARNING
"Unknown version number [%d]\n",
569 data
[(*packet_size
) - 1]);
573 ecryptfs_to_hex((*new_auth_tok
)->token
.private_key
.signature
,
574 &data
[(*packet_size
)], ECRYPTFS_SIG_SIZE
);
575 *packet_size
+= ECRYPTFS_SIG_SIZE
;
576 /* This byte is skipped because the kernel does not need to
577 * know which public key encryption algorithm was used */
579 (*new_auth_tok
)->session_key
.encrypted_key_size
=
580 body_size
- (ECRYPTFS_SIG_SIZE
+ 2);
581 if ((*new_auth_tok
)->session_key
.encrypted_key_size
582 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
583 printk(KERN_WARNING
"Tag 1 packet contains key larger "
584 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
588 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
589 &data
[(*packet_size
)], (body_size
- (ECRYPTFS_SIG_SIZE
+ 2)));
590 (*packet_size
) += (*new_auth_tok
)->session_key
.encrypted_key_size
;
591 (*new_auth_tok
)->session_key
.flags
&=
592 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
593 (*new_auth_tok
)->session_key
.flags
|=
594 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
595 (*new_auth_tok
)->token_type
= ECRYPTFS_PRIVATE_KEY
;
596 (*new_auth_tok
)->flags
= 0;
597 (*new_auth_tok
)->session_key
.flags
&=
598 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
599 (*new_auth_tok
)->session_key
.flags
&=
600 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
601 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
604 (*new_auth_tok
) = NULL
;
605 memset(auth_tok_list_item
, 0,
606 sizeof(struct ecryptfs_auth_tok_list_item
));
607 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
617 * @crypt_stat: The cryptographic context to modify based on packet
619 * @data: The raw bytes of the packet.
620 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
621 * a new authentication token will be placed at the end
622 * of this list for this packet.
623 * @new_auth_tok: Pointer to a pointer to memory that this function
624 * allocates; sets the memory address of the pointer to
625 * NULL on error. This object is added to the
627 * @packet_size: This function writes the size of the parsed packet
628 * into this memory location; zero on error.
629 * @max_packet_size: maximum number of bytes to parse
631 * Returns zero on success; non-zero on error.
634 parse_tag_3_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
635 unsigned char *data
, struct list_head
*auth_tok_list
,
636 struct ecryptfs_auth_tok
**new_auth_tok
,
637 size_t *packet_size
, size_t max_packet_size
)
640 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
645 (*new_auth_tok
) = NULL
;
647 *This format is inspired by OpenPGP; see RFC 2440
650 * Tag 3 identifier (1 byte)
651 * Max Tag 3 packet size (max 3 bytes)
653 * Cipher code (1 byte)
654 * S2K specifier (1 byte)
655 * Hash identifier (1 byte)
656 * Salt (ECRYPTFS_SALT_SIZE)
657 * Hash iterations (1 byte)
658 * Encrypted key (arbitrary)
660 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
662 if (max_packet_size
< (ECRYPTFS_SALT_SIZE
+ 7)) {
663 printk(KERN_ERR
"Max packet size too large\n");
667 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_3_PACKET_TYPE
) {
668 printk(KERN_ERR
"First byte != 0x%.2x; invalid packet\n",
669 ECRYPTFS_TAG_3_PACKET_TYPE
);
673 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
674 * at end of function upon failure */
676 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
, GFP_KERNEL
);
677 if (!auth_tok_list_item
) {
678 printk(KERN_ERR
"Unable to allocate memory\n");
682 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
683 if ((rc
= parse_packet_length(&data
[(*packet_size
)], &body_size
,
685 printk(KERN_WARNING
"Error parsing packet length; rc = [%d]\n",
689 if (unlikely(body_size
< (ECRYPTFS_SALT_SIZE
+ 5))) {
690 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
694 (*packet_size
) += length_size
;
695 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
696 printk(KERN_ERR
"Packet size exceeds max\n");
700 (*new_auth_tok
)->session_key
.encrypted_key_size
=
701 (body_size
- (ECRYPTFS_SALT_SIZE
+ 5));
702 if (unlikely(data
[(*packet_size
)++] != 0x04)) {
703 printk(KERN_WARNING
"Unknown version number [%d]\n",
704 data
[(*packet_size
) - 1]);
708 ecryptfs_cipher_code_to_string(crypt_stat
->cipher
,
709 (u16
)data
[(*packet_size
)]);
710 /* A little extra work to differentiate among the AES key
711 * sizes; see RFC2440 */
712 switch(data
[(*packet_size
)++]) {
713 case RFC2440_CIPHER_AES_192
:
714 crypt_stat
->key_size
= 24;
717 crypt_stat
->key_size
=
718 (*new_auth_tok
)->session_key
.encrypted_key_size
;
720 ecryptfs_init_crypt_ctx(crypt_stat
);
721 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
722 printk(KERN_WARNING
"Only S2K ID 3 is currently supported\n");
726 /* TODO: finish the hash mapping */
727 switch (data
[(*packet_size
)++]) {
728 case 0x01: /* See RFC2440 for these numbers and their mappings */
730 memcpy((*new_auth_tok
)->token
.password
.salt
,
731 &data
[(*packet_size
)], ECRYPTFS_SALT_SIZE
);
732 (*packet_size
) += ECRYPTFS_SALT_SIZE
;
733 /* This conversion was taken straight from RFC2440 */
734 (*new_auth_tok
)->token
.password
.hash_iterations
=
735 ((u32
) 16 + (data
[(*packet_size
)] & 15))
736 << ((data
[(*packet_size
)] >> 4) + 6);
738 /* Friendly reminder:
739 * (*new_auth_tok)->session_key.encrypted_key_size =
740 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
741 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
742 &data
[(*packet_size
)],
743 (*new_auth_tok
)->session_key
.encrypted_key_size
);
745 (*new_auth_tok
)->session_key
.encrypted_key_size
;
746 (*new_auth_tok
)->session_key
.flags
&=
747 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
748 (*new_auth_tok
)->session_key
.flags
|=
749 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
750 (*new_auth_tok
)->token
.password
.hash_algo
= 0x01; /* MD5 */
753 ecryptfs_printk(KERN_ERR
, "Unsupported hash algorithm: "
754 "[%d]\n", data
[(*packet_size
) - 1]);
758 (*new_auth_tok
)->token_type
= ECRYPTFS_PASSWORD
;
759 /* TODO: Parametarize; we might actually want userspace to
760 * decrypt the session key. */
761 (*new_auth_tok
)->session_key
.flags
&=
762 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
763 (*new_auth_tok
)->session_key
.flags
&=
764 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
765 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
768 (*new_auth_tok
) = NULL
;
769 memset(auth_tok_list_item
, 0,
770 sizeof(struct ecryptfs_auth_tok_list_item
));
771 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
780 * parse_tag_11_packet
781 * @data: The raw bytes of the packet
782 * @contents: This function writes the data contents of the literal
783 * packet into this memory location
784 * @max_contents_bytes: The maximum number of bytes that this function
785 * is allowed to write into contents
786 * @tag_11_contents_size: This function writes the size of the parsed
787 * contents into this memory location; zero on
789 * @packet_size: This function writes the size of the parsed packet
790 * into this memory location; zero on error
791 * @max_packet_size: maximum number of bytes to parse
793 * Returns zero on success; non-zero on error.
796 parse_tag_11_packet(unsigned char *data
, unsigned char *contents
,
797 size_t max_contents_bytes
, size_t *tag_11_contents_size
,
798 size_t *packet_size
, size_t max_packet_size
)
805 (*tag_11_contents_size
) = 0;
806 /* This format is inspired by OpenPGP; see RFC 2440
809 * Tag 11 identifier (1 byte)
810 * Max Tag 11 packet size (max 3 bytes)
811 * Binary format specifier (1 byte)
812 * Filename length (1 byte)
813 * Filename ("_CONSOLE") (8 bytes)
814 * Modification date (4 bytes)
815 * Literal data (arbitrary)
817 * We need at least 16 bytes of data for the packet to even be
820 if (max_packet_size
< 16) {
821 printk(KERN_ERR
"Maximum packet size too small\n");
825 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
826 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
830 if ((rc
= parse_packet_length(&data
[(*packet_size
)], &body_size
,
832 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
835 if (body_size
< 14) {
836 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
840 (*packet_size
) += length_size
;
841 (*tag_11_contents_size
) = (body_size
- 14);
842 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
843 printk(KERN_ERR
"Packet size exceeds max\n");
847 if (data
[(*packet_size
)++] != 0x62) {
848 printk(KERN_WARNING
"Unrecognizable packet\n");
852 if (data
[(*packet_size
)++] != 0x08) {
853 printk(KERN_WARNING
"Unrecognizable packet\n");
857 (*packet_size
) += 12; /* Ignore filename and modification date */
858 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
859 (*packet_size
) += (*tag_11_contents_size
);
863 (*tag_11_contents_size
) = 0;
869 ecryptfs_find_global_auth_tok_for_sig(
870 struct ecryptfs_global_auth_tok
**global_auth_tok
,
871 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
, char *sig
)
873 struct ecryptfs_global_auth_tok
*walker
;
876 (*global_auth_tok
) = NULL
;
877 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
878 list_for_each_entry(walker
,
879 &mount_crypt_stat
->global_auth_tok_list
,
880 mount_crypt_stat_list
) {
881 if (memcmp(walker
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
) == 0) {
882 (*global_auth_tok
) = walker
;
888 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
893 * ecryptfs_verify_version
894 * @version: The version number to confirm
896 * Returns zero on good version; non-zero otherwise
898 static int ecryptfs_verify_version(u16 version
)
904 major
= ((version
>> 8) & 0xFF);
905 minor
= (version
& 0xFF);
906 if (major
!= ECRYPTFS_VERSION_MAJOR
) {
907 ecryptfs_printk(KERN_ERR
, "Major version number mismatch. "
908 "Expected [%d]; got [%d]\n",
909 ECRYPTFS_VERSION_MAJOR
, major
);
913 if (minor
!= ECRYPTFS_VERSION_MINOR
) {
914 ecryptfs_printk(KERN_ERR
, "Minor version number mismatch. "
915 "Expected [%d]; got [%d]\n",
916 ECRYPTFS_VERSION_MINOR
, minor
);
924 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
925 struct ecryptfs_auth_tok
**auth_tok
,
930 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
931 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
932 printk(KERN_ERR
"Could not find key with description: [%s]\n",
934 process_request_key_err(PTR_ERR(*auth_tok_key
));
938 (*auth_tok
) = ecryptfs_get_key_payload_data(*auth_tok_key
);
939 if (ecryptfs_verify_version((*auth_tok
)->version
)) {
941 "Data structure version mismatch. "
942 "Userspace tools must match eCryptfs "
943 "kernel module with major version [%d] "
944 "and minor version [%d]\n",
945 ECRYPTFS_VERSION_MAJOR
,
946 ECRYPTFS_VERSION_MINOR
);
950 if ((*auth_tok
)->token_type
!= ECRYPTFS_PASSWORD
951 && (*auth_tok
)->token_type
!= ECRYPTFS_PRIVATE_KEY
) {
952 printk(KERN_ERR
"Invalid auth_tok structure "
953 "returned from key query\n");
962 * ecryptfs_find_auth_tok_for_sig
963 * @auth_tok: Set to the matching auth_tok; NULL if not found
964 * @crypt_stat: inode crypt_stat crypto context
965 * @sig: Sig of auth_tok to find
967 * For now, this function simply looks at the registered auth_tok's
968 * linked off the mount_crypt_stat, so all the auth_toks that can be
969 * used must be registered at mount time. This function could
970 * potentially try a lot harder to find auth_tok's (e.g., by calling
971 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
972 * that static registration of auth_tok's will no longer be necessary.
974 * Returns zero on no error; non-zero on error
977 ecryptfs_find_auth_tok_for_sig(
978 struct ecryptfs_auth_tok
**auth_tok
,
979 struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
981 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
982 crypt_stat
->mount_crypt_stat
;
983 struct ecryptfs_global_auth_tok
*global_auth_tok
;
987 if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
988 mount_crypt_stat
, sig
)) {
989 struct key
*auth_tok_key
;
991 rc
= ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key
, auth_tok
,
994 (*auth_tok
) = global_auth_tok
->global_auth_tok
;
999 * decrypt_passphrase_encrypted_session_key - Decrypt the session key
1000 * with the given auth_tok.
1002 * Returns Zero on success; non-zero error otherwise.
1005 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1006 struct ecryptfs_crypt_stat
*crypt_stat
)
1008 struct scatterlist dst_sg
;
1009 struct scatterlist src_sg
;
1010 struct mutex
*tfm_mutex
= NULL
;
1011 struct blkcipher_desc desc
= {
1012 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1016 if (unlikely(ecryptfs_verbosity
> 0)) {
1018 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1019 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1021 auth_tok
->token
.password
.session_key_encryption_key
,
1022 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1024 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1025 crypt_stat
->cipher
);
1027 printk(KERN_ERR
"Internal error whilst attempting to get "
1028 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1029 crypt_stat
->cipher
, rc
);
1032 if ((rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1033 auth_tok
->session_key
.encrypted_key_size
,
1034 &src_sg
, 1)) != 1) {
1035 printk(KERN_ERR
"Internal error whilst attempting to convert "
1036 "auth_tok->session_key.encrypted_key to scatterlist; "
1037 "expected rc = 1; got rc = [%d]. "
1038 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc
,
1039 auth_tok
->session_key
.encrypted_key_size
);
1042 auth_tok
->session_key
.decrypted_key_size
=
1043 auth_tok
->session_key
.encrypted_key_size
;
1044 if ((rc
= virt_to_scatterlist(auth_tok
->session_key
.decrypted_key
,
1045 auth_tok
->session_key
.decrypted_key_size
,
1046 &dst_sg
, 1)) != 1) {
1047 printk(KERN_ERR
"Internal error whilst attempting to convert "
1048 "auth_tok->session_key.decrypted_key to scatterlist; "
1049 "expected rc = 1; got rc = [%d]\n", rc
);
1052 mutex_lock(tfm_mutex
);
1053 rc
= crypto_blkcipher_setkey(
1054 desc
.tfm
, auth_tok
->token
.password
.session_key_encryption_key
,
1055 crypt_stat
->key_size
);
1056 if (unlikely(rc
< 0)) {
1057 mutex_unlock(tfm_mutex
);
1058 printk(KERN_ERR
"Error setting key for crypto context\n");
1062 rc
= crypto_blkcipher_decrypt(&desc
, &dst_sg
, &src_sg
,
1063 auth_tok
->session_key
.encrypted_key_size
);
1064 mutex_unlock(tfm_mutex
);
1066 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
1069 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1070 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1071 auth_tok
->session_key
.decrypted_key_size
);
1072 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1073 if (unlikely(ecryptfs_verbosity
> 0)) {
1074 ecryptfs_printk(KERN_DEBUG
, "FEK of size [%d]:\n",
1075 crypt_stat
->key_size
);
1076 ecryptfs_dump_hex(crypt_stat
->key
,
1077 crypt_stat
->key_size
);
1083 int ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
1088 switch (auth_tok
->token_type
) {
1089 case ECRYPTFS_PASSWORD
:
1090 (*sig
) = auth_tok
->token
.password
.signature
;
1092 case ECRYPTFS_PRIVATE_KEY
:
1093 (*sig
) = auth_tok
->token
.private_key
.signature
;
1096 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
1097 auth_tok
->token_type
);
1104 * ecryptfs_parse_packet_set
1105 * @dest: The header page in memory
1106 * @version: Version of file format, to guide parsing behavior
1108 * Get crypt_stat to have the file's session key if the requisite key
1109 * is available to decrypt the session key.
1111 * Returns Zero if a valid authentication token was retrieved and
1112 * processed; negative value for file not encrypted or for error
1115 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1117 struct dentry
*ecryptfs_dentry
)
1120 size_t found_auth_tok
;
1121 size_t next_packet_is_auth_tok_packet
;
1122 struct list_head auth_tok_list
;
1123 struct ecryptfs_auth_tok
*matching_auth_tok
= NULL
;
1124 struct ecryptfs_auth_tok
*candidate_auth_tok
= NULL
;
1125 char *candidate_auth_tok_sig
;
1127 struct ecryptfs_auth_tok
*new_auth_tok
;
1128 unsigned char sig_tmp_space
[ECRYPTFS_SIG_SIZE
];
1129 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1130 size_t tag_11_contents_size
;
1131 size_t tag_11_packet_size
;
1134 INIT_LIST_HEAD(&auth_tok_list
);
1135 /* Parse the header to find as many packets as we can; these will be
1136 * added the our &auth_tok_list */
1137 next_packet_is_auth_tok_packet
= 1;
1138 while (next_packet_is_auth_tok_packet
) {
1139 size_t max_packet_size
= ((PAGE_CACHE_SIZE
- 8) - i
);
1142 case ECRYPTFS_TAG_3_PACKET_TYPE
:
1143 rc
= parse_tag_3_packet(crypt_stat
,
1144 (unsigned char *)&src
[i
],
1145 &auth_tok_list
, &new_auth_tok
,
1146 &packet_size
, max_packet_size
);
1148 ecryptfs_printk(KERN_ERR
, "Error parsing "
1154 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1157 &tag_11_contents_size
,
1158 &tag_11_packet_size
,
1161 ecryptfs_printk(KERN_ERR
, "No valid "
1162 "(ecryptfs-specific) literal "
1163 "packet containing "
1164 "authentication token "
1165 "signature found after "
1170 i
+= tag_11_packet_size
;
1171 if (ECRYPTFS_SIG_SIZE
!= tag_11_contents_size
) {
1172 ecryptfs_printk(KERN_ERR
, "Expected "
1173 "signature of size [%d]; "
1176 tag_11_contents_size
);
1180 ecryptfs_to_hex(new_auth_tok
->token
.password
.signature
,
1181 sig_tmp_space
, tag_11_contents_size
);
1182 new_auth_tok
->token
.password
.signature
[
1183 ECRYPTFS_PASSWORD_SIG_SIZE
] = '\0';
1184 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1186 case ECRYPTFS_TAG_1_PACKET_TYPE
:
1187 rc
= parse_tag_1_packet(crypt_stat
,
1188 (unsigned char *)&src
[i
],
1189 &auth_tok_list
, &new_auth_tok
,
1190 &packet_size
, max_packet_size
);
1192 ecryptfs_printk(KERN_ERR
, "Error parsing "
1198 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1200 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1201 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1202 "(Tag 11 not allowed by itself)\n");
1207 ecryptfs_printk(KERN_DEBUG
, "No packet at offset "
1208 "[%d] of the file header; hex value of "
1209 "character is [0x%.2x]\n", i
, src
[i
]);
1210 next_packet_is_auth_tok_packet
= 0;
1213 if (list_empty(&auth_tok_list
)) {
1214 printk(KERN_ERR
"The lower file appears to be a non-encrypted "
1215 "eCryptfs file; this is not supported in this version "
1216 "of the eCryptfs kernel module\n");
1220 /* auth_tok_list contains the set of authentication tokens
1221 * parsed from the metadata. We need to find a matching
1222 * authentication token that has the secret component(s)
1223 * necessary to decrypt the EFEK in the auth_tok parsed from
1224 * the metadata. There may be several potential matches, but
1225 * just one will be sufficient to decrypt to get the FEK. */
1226 find_next_matching_auth_tok
:
1228 list_for_each_entry(auth_tok_list_item
, &auth_tok_list
, list
) {
1229 candidate_auth_tok
= &auth_tok_list_item
->auth_tok
;
1230 if (unlikely(ecryptfs_verbosity
> 0)) {
1231 ecryptfs_printk(KERN_DEBUG
,
1232 "Considering cadidate auth tok:\n");
1233 ecryptfs_dump_auth_tok(candidate_auth_tok
);
1235 if ((rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1236 candidate_auth_tok
))) {
1238 "Unrecognized candidate auth tok type: [%d]\n",
1239 candidate_auth_tok
->token_type
);
1243 if ((rc
= ecryptfs_find_auth_tok_for_sig(
1244 &matching_auth_tok
, crypt_stat
,
1245 candidate_auth_tok_sig
)))
1247 if (matching_auth_tok
) {
1249 goto found_matching_auth_tok
;
1252 if (!found_auth_tok
) {
1253 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1254 "authentication token\n");
1258 found_matching_auth_tok
:
1259 if (candidate_auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1260 memcpy(&(candidate_auth_tok
->token
.private_key
),
1261 &(matching_auth_tok
->token
.private_key
),
1262 sizeof(struct ecryptfs_private_key
));
1263 rc
= decrypt_pki_encrypted_session_key(candidate_auth_tok
,
1265 } else if (candidate_auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1266 memcpy(&(candidate_auth_tok
->token
.password
),
1267 &(matching_auth_tok
->token
.password
),
1268 sizeof(struct ecryptfs_password
));
1269 rc
= decrypt_passphrase_encrypted_session_key(
1270 candidate_auth_tok
, crypt_stat
);
1273 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1275 ecryptfs_printk(KERN_WARNING
, "Error decrypting the "
1276 "session key for authentication token with sig "
1277 "[%.*s]; rc = [%d]. Removing auth tok "
1278 "candidate from the list and searching for "
1279 "the next match.\n", candidate_auth_tok_sig
,
1280 ECRYPTFS_SIG_SIZE_HEX
, rc
);
1281 list_for_each_entry_safe(auth_tok_list_item
,
1282 auth_tok_list_item_tmp
,
1283 &auth_tok_list
, list
) {
1284 if (candidate_auth_tok
1285 == &auth_tok_list_item
->auth_tok
) {
1286 list_del(&auth_tok_list_item
->list
);
1288 ecryptfs_auth_tok_list_item_cache
,
1289 auth_tok_list_item
);
1290 goto find_next_matching_auth_tok
;
1295 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1297 ecryptfs_printk(KERN_ERR
, "Error computing "
1301 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1303 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1304 "context for cipher [%s]; rc = [%d]\n",
1305 crypt_stat
->cipher
, rc
);
1308 wipe_auth_tok_list(&auth_tok_list
);
1314 pki_encrypt_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1315 struct ecryptfs_crypt_stat
*crypt_stat
,
1316 struct ecryptfs_key_record
*key_rec
)
1318 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1319 char *netlink_payload
;
1320 size_t netlink_payload_length
;
1321 struct ecryptfs_message
*msg
;
1324 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1325 ecryptfs_code_for_cipher_string(crypt_stat
),
1326 crypt_stat
, &netlink_payload
,
1327 &netlink_payload_length
);
1329 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
1332 rc
= ecryptfs_send_message(ecryptfs_transport
, netlink_payload
,
1333 netlink_payload_length
, &msg_ctx
);
1335 ecryptfs_printk(KERN_ERR
, "Error sending netlink message\n");
1338 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1340 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
1341 "from the user space daemon\n");
1345 rc
= parse_tag_67_packet(key_rec
, msg
);
1347 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
1350 if (netlink_payload
)
1351 kfree(netlink_payload
);
1355 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1356 * @dest: Buffer into which to write the packet
1357 * @max: Maximum number of bytes that can be writtn
1358 * @packet_size: This function will write the number of bytes that end
1359 * up constituting the packet; set to zero on error
1361 * Returns zero on success; non-zero on error.
1364 write_tag_1_packet(char *dest
, size_t *remaining_bytes
,
1365 struct ecryptfs_auth_tok
*auth_tok
,
1366 struct ecryptfs_crypt_stat
*crypt_stat
,
1367 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1370 size_t encrypted_session_key_valid
= 0;
1371 size_t packet_size_length
;
1372 size_t max_packet_size
;
1376 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
1378 encrypted_session_key_valid
= 0;
1379 for (i
= 0; i
< crypt_stat
->key_size
; i
++)
1380 encrypted_session_key_valid
|=
1381 auth_tok
->session_key
.encrypted_key
[i
];
1382 if (encrypted_session_key_valid
) {
1383 memcpy(key_rec
->enc_key
,
1384 auth_tok
->session_key
.encrypted_key
,
1385 auth_tok
->session_key
.encrypted_key_size
);
1386 goto encrypted_session_key_set
;
1388 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1389 auth_tok
->session_key
.encrypted_key_size
=
1390 auth_tok
->token
.private_key
.key_size
;
1391 rc
= pki_encrypt_session_key(auth_tok
, crypt_stat
, key_rec
);
1393 ecryptfs_printk(KERN_ERR
, "Failed to encrypt session key "
1397 if (ecryptfs_verbosity
> 0) {
1398 ecryptfs_printk(KERN_DEBUG
, "Encrypted key:\n");
1399 ecryptfs_dump_hex(key_rec
->enc_key
, key_rec
->enc_key_size
);
1401 encrypted_session_key_set
:
1402 /* This format is inspired by OpenPGP; see RFC 2440
1404 max_packet_size
= (1 /* Tag 1 identifier */
1405 + 3 /* Max Tag 1 packet size */
1407 + ECRYPTFS_SIG_SIZE
/* Key identifier */
1408 + 1 /* Cipher identifier */
1409 + key_rec
->enc_key_size
); /* Encrypted key size */
1410 if (max_packet_size
> (*remaining_bytes
)) {
1411 printk(KERN_ERR
"Packet length larger than maximum allowable; "
1412 "need up to [%td] bytes, but there are only [%td] "
1413 "available\n", max_packet_size
, (*remaining_bytes
));
1417 dest
[(*packet_size
)++] = ECRYPTFS_TAG_1_PACKET_TYPE
;
1418 rc
= write_packet_length(&dest
[(*packet_size
)], (max_packet_size
- 4),
1419 &packet_size_length
);
1421 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
1422 "header; cannot generate packet length\n");
1425 (*packet_size
) += packet_size_length
;
1426 dest
[(*packet_size
)++] = 0x03; /* version 3 */
1427 memcpy(&dest
[(*packet_size
)], key_rec
->sig
, ECRYPTFS_SIG_SIZE
);
1428 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
1429 dest
[(*packet_size
)++] = RFC2440_CIPHER_RSA
;
1430 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1431 key_rec
->enc_key_size
);
1432 (*packet_size
) += key_rec
->enc_key_size
;
1437 (*remaining_bytes
) -= (*packet_size
);
1442 * write_tag_11_packet
1443 * @dest: Target into which Tag 11 packet is to be written
1444 * @max: Maximum packet length
1445 * @contents: Byte array of contents to copy in
1446 * @contents_length: Number of bytes in contents
1447 * @packet_length: Length of the Tag 11 packet written; zero on error
1449 * Returns zero on success; non-zero on error.
1452 write_tag_11_packet(char *dest
, size_t *remaining_bytes
, char *contents
,
1453 size_t contents_length
, size_t *packet_length
)
1455 size_t packet_size_length
;
1456 size_t max_packet_size
;
1459 (*packet_length
) = 0;
1460 /* This format is inspired by OpenPGP; see RFC 2440
1462 max_packet_size
= (1 /* Tag 11 identifier */
1463 + 3 /* Max Tag 11 packet size */
1464 + 1 /* Binary format specifier */
1465 + 1 /* Filename length */
1466 + 8 /* Filename ("_CONSOLE") */
1467 + 4 /* Modification date */
1468 + contents_length
); /* Literal data */
1469 if (max_packet_size
> (*remaining_bytes
)) {
1470 printk(KERN_ERR
"Packet length larger than maximum allowable; "
1471 "need up to [%td] bytes, but there are only [%td] "
1472 "available\n", max_packet_size
, (*remaining_bytes
));
1476 dest
[(*packet_length
)++] = ECRYPTFS_TAG_11_PACKET_TYPE
;
1477 rc
= write_packet_length(&dest
[(*packet_length
)],
1478 (max_packet_size
- 4), &packet_size_length
);
1480 printk(KERN_ERR
"Error generating tag 11 packet header; cannot "
1481 "generate packet length. rc = [%d]\n", rc
);
1484 (*packet_length
) += packet_size_length
;
1485 dest
[(*packet_length
)++] = 0x62; /* binary data format specifier */
1486 dest
[(*packet_length
)++] = 8;
1487 memcpy(&dest
[(*packet_length
)], "_CONSOLE", 8);
1488 (*packet_length
) += 8;
1489 memset(&dest
[(*packet_length
)], 0x00, 4);
1490 (*packet_length
) += 4;
1491 memcpy(&dest
[(*packet_length
)], contents
, contents_length
);
1492 (*packet_length
) += contents_length
;
1495 (*packet_length
) = 0;
1497 (*remaining_bytes
) -= (*packet_length
);
1502 * write_tag_3_packet
1503 * @dest: Buffer into which to write the packet
1504 * @max: Maximum number of bytes that can be written
1505 * @auth_tok: Authentication token
1506 * @crypt_stat: The cryptographic context
1507 * @key_rec: encrypted key
1508 * @packet_size: This function will write the number of bytes that end
1509 * up constituting the packet; set to zero on error
1511 * Returns zero on success; non-zero on error.
1514 write_tag_3_packet(char *dest
, size_t *remaining_bytes
,
1515 struct ecryptfs_auth_tok
*auth_tok
,
1516 struct ecryptfs_crypt_stat
*crypt_stat
,
1517 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1520 size_t encrypted_session_key_valid
= 0;
1521 char session_key_encryption_key
[ECRYPTFS_MAX_KEY_BYTES
];
1522 struct scatterlist dst_sg
;
1523 struct scatterlist src_sg
;
1524 struct mutex
*tfm_mutex
= NULL
;
1526 size_t packet_size_length
;
1527 size_t max_packet_size
;
1528 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1529 crypt_stat
->mount_crypt_stat
;
1530 struct blkcipher_desc desc
= {
1532 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1537 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
1539 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1540 crypt_stat
->cipher
);
1542 printk(KERN_ERR
"Internal error whilst attempting to get "
1543 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1544 crypt_stat
->cipher
, rc
);
1547 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
1548 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(desc
.tfm
);
1550 printk(KERN_WARNING
"No key size specified at mount; "
1551 "defaulting to [%d]\n", alg
->max_keysize
);
1552 mount_crypt_stat
->global_default_cipher_key_size
=
1555 if (crypt_stat
->key_size
== 0)
1556 crypt_stat
->key_size
=
1557 mount_crypt_stat
->global_default_cipher_key_size
;
1558 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1559 auth_tok
->session_key
.encrypted_key_size
=
1560 crypt_stat
->key_size
;
1561 if (crypt_stat
->key_size
== 24
1562 && strcmp("aes", crypt_stat
->cipher
) == 0) {
1563 memset((crypt_stat
->key
+ 24), 0, 8);
1564 auth_tok
->session_key
.encrypted_key_size
= 32;
1566 auth_tok
->session_key
.encrypted_key_size
= crypt_stat
->key_size
;
1567 key_rec
->enc_key_size
=
1568 auth_tok
->session_key
.encrypted_key_size
;
1569 encrypted_session_key_valid
= 0;
1570 for (i
= 0; i
< auth_tok
->session_key
.encrypted_key_size
; i
++)
1571 encrypted_session_key_valid
|=
1572 auth_tok
->session_key
.encrypted_key
[i
];
1573 if (encrypted_session_key_valid
) {
1574 ecryptfs_printk(KERN_DEBUG
, "encrypted_session_key_valid != 0; "
1575 "using auth_tok->session_key.encrypted_key, "
1576 "where key_rec->enc_key_size = [%d]\n",
1577 key_rec
->enc_key_size
);
1578 memcpy(key_rec
->enc_key
,
1579 auth_tok
->session_key
.encrypted_key
,
1580 key_rec
->enc_key_size
);
1581 goto encrypted_session_key_set
;
1583 if (auth_tok
->token
.password
.flags
&
1584 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET
) {
1585 ecryptfs_printk(KERN_DEBUG
, "Using previously generated "
1586 "session key encryption key of size [%d]\n",
1587 auth_tok
->token
.password
.
1588 session_key_encryption_key_bytes
);
1589 memcpy(session_key_encryption_key
,
1590 auth_tok
->token
.password
.session_key_encryption_key
,
1591 crypt_stat
->key_size
);
1592 ecryptfs_printk(KERN_DEBUG
,
1593 "Cached session key " "encryption key: \n");
1594 if (ecryptfs_verbosity
> 0)
1595 ecryptfs_dump_hex(session_key_encryption_key
, 16);
1597 if (unlikely(ecryptfs_verbosity
> 0)) {
1598 ecryptfs_printk(KERN_DEBUG
, "Session key encryption key:\n");
1599 ecryptfs_dump_hex(session_key_encryption_key
, 16);
1601 if ((rc
= virt_to_scatterlist(crypt_stat
->key
,
1602 key_rec
->enc_key_size
, &src_sg
, 1))
1604 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
1605 "for crypt_stat session key; expected rc = 1; "
1606 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
1607 rc
, key_rec
->enc_key_size
);
1611 if ((rc
= virt_to_scatterlist(key_rec
->enc_key
,
1612 key_rec
->enc_key_size
, &dst_sg
, 1))
1614 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
1615 "for crypt_stat encrypted session key; "
1616 "expected rc = 1; got rc = [%d]. "
1617 "key_rec->enc_key_size = [%d]\n", rc
,
1618 key_rec
->enc_key_size
);
1622 mutex_lock(tfm_mutex
);
1623 rc
= crypto_blkcipher_setkey(desc
.tfm
, session_key_encryption_key
,
1624 crypt_stat
->key_size
);
1626 mutex_unlock(tfm_mutex
);
1627 ecryptfs_printk(KERN_ERR
, "Error setting key for crypto "
1628 "context; rc = [%d]\n", rc
);
1632 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%d] bytes of the key\n",
1633 crypt_stat
->key_size
);
1634 rc
= crypto_blkcipher_encrypt(&desc
, &dst_sg
, &src_sg
,
1635 (*key_rec
).enc_key_size
);
1636 mutex_unlock(tfm_mutex
);
1638 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
1641 ecryptfs_printk(KERN_DEBUG
, "This should be the encrypted key:\n");
1642 if (ecryptfs_verbosity
> 0) {
1643 ecryptfs_printk(KERN_DEBUG
, "EFEK of size [%d]:\n",
1644 key_rec
->enc_key_size
);
1645 ecryptfs_dump_hex(key_rec
->enc_key
,
1646 key_rec
->enc_key_size
);
1648 encrypted_session_key_set
:
1649 /* This format is inspired by OpenPGP; see RFC 2440
1651 max_packet_size
= (1 /* Tag 3 identifier */
1652 + 3 /* Max Tag 3 packet size */
1654 + 1 /* Cipher code */
1655 + 1 /* S2K specifier */
1656 + 1 /* Hash identifier */
1657 + ECRYPTFS_SALT_SIZE
/* Salt */
1658 + 1 /* Hash iterations */
1659 + key_rec
->enc_key_size
); /* Encrypted key size */
1660 if (max_packet_size
> (*remaining_bytes
)) {
1661 printk(KERN_ERR
"Packet too large; need up to [%td] bytes, but "
1662 "there are only [%td] available\n", max_packet_size
,
1663 (*remaining_bytes
));
1667 dest
[(*packet_size
)++] = ECRYPTFS_TAG_3_PACKET_TYPE
;
1668 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
1669 * to get the number of octets in the actual Tag 3 packet */
1670 rc
= write_packet_length(&dest
[(*packet_size
)], (max_packet_size
- 4),
1671 &packet_size_length
);
1673 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
1674 "generate packet length. rc = [%d]\n", rc
);
1677 (*packet_size
) += packet_size_length
;
1678 dest
[(*packet_size
)++] = 0x04; /* version 4 */
1679 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
1680 * specified with strings */
1681 cipher_code
= ecryptfs_code_for_cipher_string(crypt_stat
);
1682 if (cipher_code
== 0) {
1683 ecryptfs_printk(KERN_WARNING
, "Unable to generate code for "
1684 "cipher [%s]\n", crypt_stat
->cipher
);
1688 dest
[(*packet_size
)++] = cipher_code
;
1689 dest
[(*packet_size
)++] = 0x03; /* S2K */
1690 dest
[(*packet_size
)++] = 0x01; /* MD5 (TODO: parameterize) */
1691 memcpy(&dest
[(*packet_size
)], auth_tok
->token
.password
.salt
,
1692 ECRYPTFS_SALT_SIZE
);
1693 (*packet_size
) += ECRYPTFS_SALT_SIZE
; /* salt */
1694 dest
[(*packet_size
)++] = 0x60; /* hash iterations (65536) */
1695 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1696 key_rec
->enc_key_size
);
1697 (*packet_size
) += key_rec
->enc_key_size
;
1702 (*remaining_bytes
) -= (*packet_size
);
1706 struct kmem_cache
*ecryptfs_key_record_cache
;
1709 * ecryptfs_generate_key_packet_set
1710 * @dest: Virtual address from which to write the key record set
1711 * @crypt_stat: The cryptographic context from which the
1712 * authentication tokens will be retrieved
1713 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
1714 * for the global parameters
1715 * @len: The amount written
1716 * @max: The maximum amount of data allowed to be written
1718 * Generates a key packet set and writes it to the virtual address
1721 * Returns zero on success; non-zero on error.
1724 ecryptfs_generate_key_packet_set(char *dest_base
,
1725 struct ecryptfs_crypt_stat
*crypt_stat
,
1726 struct dentry
*ecryptfs_dentry
, size_t *len
,
1729 struct ecryptfs_auth_tok
*auth_tok
;
1730 struct ecryptfs_global_auth_tok
*global_auth_tok
;
1731 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1732 &ecryptfs_superblock_to_private(
1733 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1735 struct ecryptfs_key_record
*key_rec
;
1736 struct ecryptfs_key_sig
*key_sig
;
1740 mutex_lock(&crypt_stat
->keysig_list_mutex
);
1741 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
1746 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
1748 memset(key_rec
, 0, sizeof(*key_rec
));
1749 rc
= ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
1753 printk(KERN_ERR
"Error attempting to get the global "
1754 "auth_tok; rc = [%d]\n", rc
);
1757 if (global_auth_tok
->flags
& ECRYPTFS_AUTH_TOK_INVALID
) {
1759 "Skipping invalid auth tok with sig = [%s]\n",
1760 global_auth_tok
->sig
);
1763 auth_tok
= global_auth_tok
->global_auth_tok
;
1764 if (auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1765 rc
= write_tag_3_packet((dest_base
+ (*len
)),
1767 crypt_stat
, key_rec
,
1770 ecryptfs_printk(KERN_WARNING
, "Error "
1771 "writing tag 3 packet\n");
1775 /* Write auth tok signature packet */
1776 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
1778 ECRYPTFS_SIG_SIZE
, &written
);
1780 ecryptfs_printk(KERN_ERR
, "Error writing "
1781 "auth tok signature packet\n");
1785 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1786 rc
= write_tag_1_packet(dest_base
+ (*len
),
1788 crypt_stat
, key_rec
, &written
);
1790 ecryptfs_printk(KERN_WARNING
, "Error "
1791 "writing tag 1 packet\n");
1796 ecryptfs_printk(KERN_WARNING
, "Unsupported "
1797 "authentication token type\n");
1802 if (likely(max
> 0)) {
1803 dest_base
[(*len
)] = 0x00;
1805 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
1809 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
1813 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
1817 struct kmem_cache
*ecryptfs_key_sig_cache
;
1819 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
1821 struct ecryptfs_key_sig
*new_key_sig
;
1824 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
1828 "Error allocating from ecryptfs_key_sig_cache\n");
1831 memcpy(new_key_sig
->keysig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
1832 mutex_lock(&crypt_stat
->keysig_list_mutex
);
1833 list_add(&new_key_sig
->crypt_stat_list
, &crypt_stat
->keysig_list
);
1834 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
1839 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
1842 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
1845 struct ecryptfs_global_auth_tok
*new_auth_tok
;
1848 new_auth_tok
= kmem_cache_alloc(ecryptfs_global_auth_tok_cache
,
1850 if (!new_auth_tok
) {
1852 printk(KERN_ERR
"Error allocating from "
1853 "ecryptfs_global_auth_tok_cache\n");
1856 memcpy(new_auth_tok
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
1857 new_auth_tok
->sig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
1858 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
1859 list_add(&new_auth_tok
->mount_crypt_stat_list
,
1860 &mount_crypt_stat
->global_auth_tok_list
);
1861 mount_crypt_stat
->num_global_auth_toks
++;
1862 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);