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 ([%d])\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 ([%d])\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;
808 * one byte for the Tag 11 ID flag
809 * two bytes for the Tag 11 length
810 * do not exceed the maximum_packet_size
812 if (unlikely((*packet_size
) + 3 > max_packet_size
)) {
813 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
818 /* check for Tag 11 identifyer - one byte */
819 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
820 ecryptfs_printk(KERN_WARNING
,
821 "Invalid tag 11 packet format\n");
826 /* get Tag 11 content length - one or two bytes */
827 rc
= parse_packet_length(&data
[(*packet_size
)], &body_size
,
830 ecryptfs_printk(KERN_WARNING
,
831 "Invalid tag 11 packet format\n");
834 (*packet_size
) += length_size
;
836 if (body_size
< 13) {
837 ecryptfs_printk(KERN_WARNING
, "Invalid body size ([%d])\n",
842 /* We have 13 bytes of surrounding packet values */
843 (*tag_11_contents_size
) = (body_size
- 13);
845 /* now we know the length of the remainting Tag 11 packet size:
846 * 14 fix bytes for: special flag one, special flag two,
848 * body_size bytes minus the stuff above is the Tag 11 content
850 /* FIXME why is the body size one byte smaller than the actual
852 * this seems to be an error here as well as in
853 * write_tag_11_packet() */
854 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
855 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
860 /* special flag one - one byte */
861 if (data
[(*packet_size
)++] != 0x62) {
862 ecryptfs_printk(KERN_WARNING
, "Unrecognizable packet\n");
867 /* special flag two - one byte */
868 if (data
[(*packet_size
)++] != 0x08) {
869 ecryptfs_printk(KERN_WARNING
, "Unrecognizable packet\n");
874 /* skip the next 12 bytes */
875 (*packet_size
) += 12; /* We don't care about the filename or
878 /* get the Tag 11 contents - tag_11_contents_size bytes */
879 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
880 (*packet_size
) += (*tag_11_contents_size
);
885 (*tag_11_contents_size
) = 0;
891 ecryptfs_find_global_auth_tok_for_sig(
892 struct ecryptfs_global_auth_tok
**global_auth_tok
,
893 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
, char *sig
)
895 struct ecryptfs_global_auth_tok
*walker
;
898 (*global_auth_tok
) = NULL
;
899 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
900 list_for_each_entry(walker
,
901 &mount_crypt_stat
->global_auth_tok_list
,
902 mount_crypt_stat_list
) {
903 if (memcmp(walker
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
) == 0) {
904 (*global_auth_tok
) = walker
;
910 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
915 * ecryptfs_verify_version
916 * @version: The version number to confirm
918 * Returns zero on good version; non-zero otherwise
920 static int ecryptfs_verify_version(u16 version
)
926 major
= ((version
>> 8) & 0xFF);
927 minor
= (version
& 0xFF);
928 if (major
!= ECRYPTFS_VERSION_MAJOR
) {
929 ecryptfs_printk(KERN_ERR
, "Major version number mismatch. "
930 "Expected [%d]; got [%d]\n",
931 ECRYPTFS_VERSION_MAJOR
, major
);
935 if (minor
!= ECRYPTFS_VERSION_MINOR
) {
936 ecryptfs_printk(KERN_ERR
, "Minor version number mismatch. "
937 "Expected [%d]; got [%d]\n",
938 ECRYPTFS_VERSION_MINOR
, minor
);
946 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
947 struct ecryptfs_auth_tok
**auth_tok
,
952 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
953 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
954 printk(KERN_ERR
"Could not find key with description: [%s]\n",
956 process_request_key_err(PTR_ERR(*auth_tok_key
));
960 (*auth_tok
) = ecryptfs_get_key_payload_data(*auth_tok_key
);
961 if (ecryptfs_verify_version((*auth_tok
)->version
)) {
963 "Data structure version mismatch. "
964 "Userspace tools must match eCryptfs "
965 "kernel module with major version [%d] "
966 "and minor version [%d]\n",
967 ECRYPTFS_VERSION_MAJOR
,
968 ECRYPTFS_VERSION_MINOR
);
972 if ((*auth_tok
)->token_type
!= ECRYPTFS_PASSWORD
973 && (*auth_tok
)->token_type
!= ECRYPTFS_PRIVATE_KEY
) {
974 printk(KERN_ERR
"Invalid auth_tok structure "
975 "returned from key query\n");
984 * ecryptfs_find_auth_tok_for_sig
985 * @auth_tok: Set to the matching auth_tok; NULL if not found
986 * @crypt_stat: inode crypt_stat crypto context
987 * @sig: Sig of auth_tok to find
989 * For now, this function simply looks at the registered auth_tok's
990 * linked off the mount_crypt_stat, so all the auth_toks that can be
991 * used must be registered at mount time. This function could
992 * potentially try a lot harder to find auth_tok's (e.g., by calling
993 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
994 * that static registration of auth_tok's will no longer be necessary.
996 * Returns zero on no error; non-zero on error
999 ecryptfs_find_auth_tok_for_sig(
1000 struct ecryptfs_auth_tok
**auth_tok
,
1001 struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
1003 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1004 crypt_stat
->mount_crypt_stat
;
1005 struct ecryptfs_global_auth_tok
*global_auth_tok
;
1009 if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
1010 mount_crypt_stat
, sig
)) {
1011 struct key
*auth_tok_key
;
1013 rc
= ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key
, auth_tok
,
1016 (*auth_tok
) = global_auth_tok
->global_auth_tok
;
1021 * decrypt_passphrase_encrypted_session_key - Decrypt the session key
1022 * with the given auth_tok.
1024 * Returns Zero on success; non-zero error otherwise.
1027 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1028 struct ecryptfs_crypt_stat
*crypt_stat
)
1030 struct scatterlist dst_sg
;
1031 struct scatterlist src_sg
;
1032 struct mutex
*tfm_mutex
= NULL
;
1033 struct blkcipher_desc desc
= {
1034 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1038 if (unlikely(ecryptfs_verbosity
> 0)) {
1040 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1041 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1043 auth_tok
->token
.password
.session_key_encryption_key
,
1044 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1046 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1047 crypt_stat
->cipher
);
1049 printk(KERN_ERR
"Internal error whilst attempting to get "
1050 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1051 crypt_stat
->cipher
, rc
);
1054 if ((rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1055 auth_tok
->session_key
.encrypted_key_size
,
1056 &src_sg
, 1)) != 1) {
1057 printk(KERN_ERR
"Internal error whilst attempting to convert "
1058 "auth_tok->session_key.encrypted_key to scatterlist; "
1059 "expected rc = 1; got rc = [%d]. "
1060 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc
,
1061 auth_tok
->session_key
.encrypted_key_size
);
1064 auth_tok
->session_key
.decrypted_key_size
=
1065 auth_tok
->session_key
.encrypted_key_size
;
1066 if ((rc
= virt_to_scatterlist(auth_tok
->session_key
.decrypted_key
,
1067 auth_tok
->session_key
.decrypted_key_size
,
1068 &dst_sg
, 1)) != 1) {
1069 printk(KERN_ERR
"Internal error whilst attempting to convert "
1070 "auth_tok->session_key.decrypted_key to scatterlist; "
1071 "expected rc = 1; got rc = [%d]\n", rc
);
1074 mutex_lock(tfm_mutex
);
1075 rc
= crypto_blkcipher_setkey(
1076 desc
.tfm
, auth_tok
->token
.password
.session_key_encryption_key
,
1077 crypt_stat
->key_size
);
1078 if (unlikely(rc
< 0)) {
1079 mutex_unlock(tfm_mutex
);
1080 printk(KERN_ERR
"Error setting key for crypto context\n");
1084 rc
= crypto_blkcipher_decrypt(&desc
, &dst_sg
, &src_sg
,
1085 auth_tok
->session_key
.encrypted_key_size
);
1086 mutex_unlock(tfm_mutex
);
1088 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
1091 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1092 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1093 auth_tok
->session_key
.decrypted_key_size
);
1094 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1095 if (unlikely(ecryptfs_verbosity
> 0)) {
1096 ecryptfs_printk(KERN_DEBUG
, "FEK of size [%d]:\n",
1097 crypt_stat
->key_size
);
1098 ecryptfs_dump_hex(crypt_stat
->key
,
1099 crypt_stat
->key_size
);
1105 int ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
1110 switch (auth_tok
->token_type
) {
1111 case ECRYPTFS_PASSWORD
:
1112 (*sig
) = auth_tok
->token
.password
.signature
;
1114 case ECRYPTFS_PRIVATE_KEY
:
1115 (*sig
) = auth_tok
->token
.private_key
.signature
;
1118 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
1119 auth_tok
->token_type
);
1126 * ecryptfs_parse_packet_set
1127 * @dest: The header page in memory
1128 * @version: Version of file format, to guide parsing behavior
1130 * Get crypt_stat to have the file's session key if the requisite key
1131 * is available to decrypt the session key.
1133 * Returns Zero if a valid authentication token was retrieved and
1134 * processed; negative value for file not encrypted or for error
1137 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1139 struct dentry
*ecryptfs_dentry
)
1142 size_t found_auth_tok
;
1143 size_t next_packet_is_auth_tok_packet
;
1144 struct list_head auth_tok_list
;
1145 struct ecryptfs_auth_tok
*matching_auth_tok
= NULL
;
1146 struct ecryptfs_auth_tok
*candidate_auth_tok
= NULL
;
1147 char *candidate_auth_tok_sig
;
1149 struct ecryptfs_auth_tok
*new_auth_tok
;
1150 unsigned char sig_tmp_space
[ECRYPTFS_SIG_SIZE
];
1151 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1152 size_t tag_11_contents_size
;
1153 size_t tag_11_packet_size
;
1156 INIT_LIST_HEAD(&auth_tok_list
);
1157 /* Parse the header to find as many packets as we can; these will be
1158 * added the our &auth_tok_list */
1159 next_packet_is_auth_tok_packet
= 1;
1160 while (next_packet_is_auth_tok_packet
) {
1161 size_t max_packet_size
= ((PAGE_CACHE_SIZE
- 8) - i
);
1164 case ECRYPTFS_TAG_3_PACKET_TYPE
:
1165 rc
= parse_tag_3_packet(crypt_stat
,
1166 (unsigned char *)&src
[i
],
1167 &auth_tok_list
, &new_auth_tok
,
1168 &packet_size
, max_packet_size
);
1170 ecryptfs_printk(KERN_ERR
, "Error parsing "
1176 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1179 &tag_11_contents_size
,
1180 &tag_11_packet_size
,
1183 ecryptfs_printk(KERN_ERR
, "No valid "
1184 "(ecryptfs-specific) literal "
1185 "packet containing "
1186 "authentication token "
1187 "signature found after "
1192 i
+= tag_11_packet_size
;
1193 if (ECRYPTFS_SIG_SIZE
!= tag_11_contents_size
) {
1194 ecryptfs_printk(KERN_ERR
, "Expected "
1195 "signature of size [%d]; "
1198 tag_11_contents_size
);
1202 ecryptfs_to_hex(new_auth_tok
->token
.password
.signature
,
1203 sig_tmp_space
, tag_11_contents_size
);
1204 new_auth_tok
->token
.password
.signature
[
1205 ECRYPTFS_PASSWORD_SIG_SIZE
] = '\0';
1206 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1208 case ECRYPTFS_TAG_1_PACKET_TYPE
:
1209 rc
= parse_tag_1_packet(crypt_stat
,
1210 (unsigned char *)&src
[i
],
1211 &auth_tok_list
, &new_auth_tok
,
1212 &packet_size
, max_packet_size
);
1214 ecryptfs_printk(KERN_ERR
, "Error parsing "
1220 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1222 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1223 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1224 "(Tag 11 not allowed by itself)\n");
1229 ecryptfs_printk(KERN_DEBUG
, "No packet at offset "
1230 "[%d] of the file header; hex value of "
1231 "character is [0x%.2x]\n", i
, src
[i
]);
1232 next_packet_is_auth_tok_packet
= 0;
1235 if (list_empty(&auth_tok_list
)) {
1236 printk(KERN_ERR
"The lower file appears to be a non-encrypted "
1237 "eCryptfs file; this is not supported in this version "
1238 "of the eCryptfs kernel module\n");
1242 /* auth_tok_list contains the set of authentication tokens
1243 * parsed from the metadata. We need to find a matching
1244 * authentication token that has the secret component(s)
1245 * necessary to decrypt the EFEK in the auth_tok parsed from
1246 * the metadata. There may be several potential matches, but
1247 * just one will be sufficient to decrypt to get the FEK. */
1248 find_next_matching_auth_tok
:
1250 list_for_each_entry(auth_tok_list_item
, &auth_tok_list
, list
) {
1251 candidate_auth_tok
= &auth_tok_list_item
->auth_tok
;
1252 if (unlikely(ecryptfs_verbosity
> 0)) {
1253 ecryptfs_printk(KERN_DEBUG
,
1254 "Considering cadidate auth tok:\n");
1255 ecryptfs_dump_auth_tok(candidate_auth_tok
);
1257 if ((rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1258 candidate_auth_tok
))) {
1260 "Unrecognized candidate auth tok type: [%d]\n",
1261 candidate_auth_tok
->token_type
);
1265 if ((rc
= ecryptfs_find_auth_tok_for_sig(
1266 &matching_auth_tok
, crypt_stat
,
1267 candidate_auth_tok_sig
)))
1269 if (matching_auth_tok
) {
1271 goto found_matching_auth_tok
;
1274 if (!found_auth_tok
) {
1275 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1276 "authentication token\n");
1280 found_matching_auth_tok
:
1281 if (candidate_auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1282 memcpy(&(candidate_auth_tok
->token
.private_key
),
1283 &(matching_auth_tok
->token
.private_key
),
1284 sizeof(struct ecryptfs_private_key
));
1285 rc
= decrypt_pki_encrypted_session_key(candidate_auth_tok
,
1287 } else if (candidate_auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1288 memcpy(&(candidate_auth_tok
->token
.password
),
1289 &(matching_auth_tok
->token
.password
),
1290 sizeof(struct ecryptfs_password
));
1291 rc
= decrypt_passphrase_encrypted_session_key(
1292 candidate_auth_tok
, crypt_stat
);
1295 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1297 ecryptfs_printk(KERN_WARNING
, "Error decrypting the "
1298 "session key for authentication token with sig "
1299 "[%.*s]; rc = [%d]. Removing auth tok "
1300 "candidate from the list and searching for "
1301 "the next match.\n", candidate_auth_tok_sig
,
1302 ECRYPTFS_SIG_SIZE_HEX
, rc
);
1303 list_for_each_entry_safe(auth_tok_list_item
,
1304 auth_tok_list_item_tmp
,
1305 &auth_tok_list
, list
) {
1306 if (candidate_auth_tok
1307 == &auth_tok_list_item
->auth_tok
) {
1308 list_del(&auth_tok_list_item
->list
);
1310 ecryptfs_auth_tok_list_item_cache
,
1311 auth_tok_list_item
);
1312 goto find_next_matching_auth_tok
;
1317 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1319 ecryptfs_printk(KERN_ERR
, "Error computing "
1323 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1325 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1326 "context for cipher [%s]; rc = [%d]\n",
1327 crypt_stat
->cipher
, rc
);
1330 wipe_auth_tok_list(&auth_tok_list
);
1336 pki_encrypt_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1337 struct ecryptfs_crypt_stat
*crypt_stat
,
1338 struct ecryptfs_key_record
*key_rec
)
1340 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1341 char *netlink_payload
;
1342 size_t netlink_payload_length
;
1343 struct ecryptfs_message
*msg
;
1346 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1347 ecryptfs_code_for_cipher_string(crypt_stat
),
1348 crypt_stat
, &netlink_payload
,
1349 &netlink_payload_length
);
1351 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
1354 rc
= ecryptfs_send_message(ecryptfs_transport
, netlink_payload
,
1355 netlink_payload_length
, &msg_ctx
);
1357 ecryptfs_printk(KERN_ERR
, "Error sending netlink message\n");
1360 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1362 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
1363 "from the user space daemon\n");
1367 rc
= parse_tag_67_packet(key_rec
, msg
);
1369 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
1372 if (netlink_payload
)
1373 kfree(netlink_payload
);
1377 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1378 * @dest: Buffer into which to write the packet
1379 * @max: Maximum number of bytes that can be writtn
1380 * @packet_size: This function will write the number of bytes that end
1381 * up constituting the packet; set to zero on error
1383 * Returns zero on success; non-zero on error.
1386 write_tag_1_packet(char *dest
, size_t *remaining_bytes
,
1387 struct ecryptfs_auth_tok
*auth_tok
,
1388 struct ecryptfs_crypt_stat
*crypt_stat
,
1389 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1392 size_t encrypted_session_key_valid
= 0;
1393 size_t packet_size_length
;
1394 size_t max_packet_size
;
1398 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
1400 encrypted_session_key_valid
= 0;
1401 for (i
= 0; i
< crypt_stat
->key_size
; i
++)
1402 encrypted_session_key_valid
|=
1403 auth_tok
->session_key
.encrypted_key
[i
];
1404 if (encrypted_session_key_valid
) {
1405 memcpy(key_rec
->enc_key
,
1406 auth_tok
->session_key
.encrypted_key
,
1407 auth_tok
->session_key
.encrypted_key_size
);
1408 goto encrypted_session_key_set
;
1410 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1411 auth_tok
->session_key
.encrypted_key_size
=
1412 auth_tok
->token
.private_key
.key_size
;
1413 rc
= pki_encrypt_session_key(auth_tok
, crypt_stat
, key_rec
);
1415 ecryptfs_printk(KERN_ERR
, "Failed to encrypt session key "
1419 if (ecryptfs_verbosity
> 0) {
1420 ecryptfs_printk(KERN_DEBUG
, "Encrypted key:\n");
1421 ecryptfs_dump_hex(key_rec
->enc_key
, key_rec
->enc_key_size
);
1423 encrypted_session_key_set
:
1424 /* This format is inspired by OpenPGP; see RFC 2440
1426 max_packet_size
= (1 /* Tag 1 identifier */
1427 + 3 /* Max Tag 1 packet size */
1429 + ECRYPTFS_SIG_SIZE
/* Key identifier */
1430 + 1 /* Cipher identifier */
1431 + key_rec
->enc_key_size
); /* Encrypted key size */
1432 if (max_packet_size
> (*remaining_bytes
)) {
1433 printk(KERN_ERR
"Packet length larger than maximum allowable; "
1434 "need up to [%d] bytes, but there are only [%d] "
1435 "available\n", max_packet_size
, (*remaining_bytes
));
1439 dest
[(*packet_size
)++] = ECRYPTFS_TAG_1_PACKET_TYPE
;
1440 rc
= write_packet_length(&dest
[(*packet_size
)], (max_packet_size
- 4),
1441 &packet_size_length
);
1443 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
1444 "header; cannot generate packet length\n");
1447 (*packet_size
) += packet_size_length
;
1448 dest
[(*packet_size
)++] = 0x03; /* version 3 */
1449 memcpy(&dest
[(*packet_size
)], key_rec
->sig
, ECRYPTFS_SIG_SIZE
);
1450 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
1451 dest
[(*packet_size
)++] = RFC2440_CIPHER_RSA
;
1452 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1453 key_rec
->enc_key_size
);
1454 (*packet_size
) += key_rec
->enc_key_size
;
1459 (*remaining_bytes
) -= (*packet_size
);
1464 * write_tag_11_packet
1465 * @dest: Target into which Tag 11 packet is to be written
1466 * @max: Maximum packet length
1467 * @contents: Byte array of contents to copy in
1468 * @contents_length: Number of bytes in contents
1469 * @packet_length: Length of the Tag 11 packet written; zero on error
1471 * Returns zero on success; non-zero on error.
1474 write_tag_11_packet(char *dest
, int max
, char *contents
, size_t contents_length
,
1475 size_t *packet_length
)
1477 size_t packet_size_length
;
1480 (*packet_length
) = 0;
1481 if ((13 + contents_length
) > max
) {
1483 ecryptfs_printk(KERN_ERR
, "Packet length larger than "
1484 "maximum allowable\n");
1487 /* General packet header */
1489 dest
[(*packet_length
)++] = ECRYPTFS_TAG_11_PACKET_TYPE
;
1491 rc
= write_packet_length(&dest
[(*packet_length
)],
1492 (13 + contents_length
), &packet_size_length
);
1494 ecryptfs_printk(KERN_ERR
, "Error generating tag 11 packet "
1495 "header; cannot generate packet length\n");
1498 (*packet_length
) += packet_size_length
;
1499 /* Tag 11 specific */
1500 /* One-octet field that describes how the data is formatted */
1501 dest
[(*packet_length
)++] = 0x62; /* binary data */
1502 /* One-octet filename length followed by filename */
1503 dest
[(*packet_length
)++] = 8;
1504 memcpy(&dest
[(*packet_length
)], "_CONSOLE", 8);
1505 (*packet_length
) += 8;
1506 /* Four-octet number indicating modification date */
1507 memset(&dest
[(*packet_length
)], 0x00, 4);
1508 (*packet_length
) += 4;
1509 /* Remainder is literal data */
1510 memcpy(&dest
[(*packet_length
)], contents
, contents_length
);
1511 (*packet_length
) += contents_length
;
1514 (*packet_length
) = 0;
1519 * write_tag_3_packet
1520 * @dest: Buffer into which to write the packet
1521 * @max: Maximum number of bytes that can be written
1522 * @auth_tok: Authentication token
1523 * @crypt_stat: The cryptographic context
1524 * @key_rec: encrypted key
1525 * @packet_size: This function will write the number of bytes that end
1526 * up constituting the packet; set to zero on error
1528 * Returns zero on success; non-zero on error.
1531 write_tag_3_packet(char *dest
, size_t *remaining_bytes
,
1532 struct ecryptfs_auth_tok
*auth_tok
,
1533 struct ecryptfs_crypt_stat
*crypt_stat
,
1534 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1537 size_t encrypted_session_key_valid
= 0;
1538 char session_key_encryption_key
[ECRYPTFS_MAX_KEY_BYTES
];
1539 struct scatterlist dst_sg
;
1540 struct scatterlist src_sg
;
1541 struct mutex
*tfm_mutex
= NULL
;
1543 size_t packet_size_length
;
1544 size_t max_packet_size
;
1545 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1546 crypt_stat
->mount_crypt_stat
;
1547 struct blkcipher_desc desc
= {
1549 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1554 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
1556 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1557 crypt_stat
->cipher
);
1559 printk(KERN_ERR
"Internal error whilst attempting to get "
1560 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1561 crypt_stat
->cipher
, rc
);
1564 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
1565 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(desc
.tfm
);
1567 printk(KERN_WARNING
"No key size specified at mount; "
1568 "defaulting to [%d]\n", alg
->max_keysize
);
1569 mount_crypt_stat
->global_default_cipher_key_size
=
1572 if (crypt_stat
->key_size
== 0)
1573 crypt_stat
->key_size
=
1574 mount_crypt_stat
->global_default_cipher_key_size
;
1575 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1576 auth_tok
->session_key
.encrypted_key_size
=
1577 crypt_stat
->key_size
;
1578 if (crypt_stat
->key_size
== 24
1579 && strcmp("aes", crypt_stat
->cipher
) == 0) {
1580 memset((crypt_stat
->key
+ 24), 0, 8);
1581 auth_tok
->session_key
.encrypted_key_size
= 32;
1583 auth_tok
->session_key
.encrypted_key_size
= crypt_stat
->key_size
;
1584 key_rec
->enc_key_size
=
1585 auth_tok
->session_key
.encrypted_key_size
;
1586 encrypted_session_key_valid
= 0;
1587 for (i
= 0; i
< auth_tok
->session_key
.encrypted_key_size
; i
++)
1588 encrypted_session_key_valid
|=
1589 auth_tok
->session_key
.encrypted_key
[i
];
1590 if (encrypted_session_key_valid
) {
1591 ecryptfs_printk(KERN_DEBUG
, "encrypted_session_key_valid != 0; "
1592 "using auth_tok->session_key.encrypted_key, "
1593 "where key_rec->enc_key_size = [%d]\n",
1594 key_rec
->enc_key_size
);
1595 memcpy(key_rec
->enc_key
,
1596 auth_tok
->session_key
.encrypted_key
,
1597 key_rec
->enc_key_size
);
1598 goto encrypted_session_key_set
;
1600 if (auth_tok
->token
.password
.flags
&
1601 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET
) {
1602 ecryptfs_printk(KERN_DEBUG
, "Using previously generated "
1603 "session key encryption key of size [%d]\n",
1604 auth_tok
->token
.password
.
1605 session_key_encryption_key_bytes
);
1606 memcpy(session_key_encryption_key
,
1607 auth_tok
->token
.password
.session_key_encryption_key
,
1608 crypt_stat
->key_size
);
1609 ecryptfs_printk(KERN_DEBUG
,
1610 "Cached session key " "encryption key: \n");
1611 if (ecryptfs_verbosity
> 0)
1612 ecryptfs_dump_hex(session_key_encryption_key
, 16);
1614 if (unlikely(ecryptfs_verbosity
> 0)) {
1615 ecryptfs_printk(KERN_DEBUG
, "Session key encryption key:\n");
1616 ecryptfs_dump_hex(session_key_encryption_key
, 16);
1618 if ((rc
= virt_to_scatterlist(crypt_stat
->key
,
1619 key_rec
->enc_key_size
, &src_sg
, 1))
1621 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
1622 "for crypt_stat session key; expected rc = 1; "
1623 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
1624 rc
, key_rec
->enc_key_size
);
1628 if ((rc
= virt_to_scatterlist(key_rec
->enc_key
,
1629 key_rec
->enc_key_size
, &dst_sg
, 1))
1631 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
1632 "for crypt_stat encrypted session key; "
1633 "expected rc = 1; got rc = [%d]. "
1634 "key_rec->enc_key_size = [%d]\n", rc
,
1635 key_rec
->enc_key_size
);
1639 mutex_lock(tfm_mutex
);
1640 rc
= crypto_blkcipher_setkey(desc
.tfm
, session_key_encryption_key
,
1641 crypt_stat
->key_size
);
1643 mutex_unlock(tfm_mutex
);
1644 ecryptfs_printk(KERN_ERR
, "Error setting key for crypto "
1645 "context; rc = [%d]\n", rc
);
1649 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%d] bytes of the key\n",
1650 crypt_stat
->key_size
);
1651 rc
= crypto_blkcipher_encrypt(&desc
, &dst_sg
, &src_sg
,
1652 (*key_rec
).enc_key_size
);
1653 mutex_unlock(tfm_mutex
);
1655 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
1658 ecryptfs_printk(KERN_DEBUG
, "This should be the encrypted key:\n");
1659 if (ecryptfs_verbosity
> 0) {
1660 ecryptfs_printk(KERN_DEBUG
, "EFEK of size [%d]:\n",
1661 key_rec
->enc_key_size
);
1662 ecryptfs_dump_hex(key_rec
->enc_key
,
1663 key_rec
->enc_key_size
);
1665 encrypted_session_key_set
:
1666 /* This format is inspired by OpenPGP; see RFC 2440
1668 max_packet_size
= (1 /* Tag 3 identifier */
1669 + 3 /* Max Tag 3 packet size */
1671 + 1 /* Cipher code */
1672 + 1 /* S2K specifier */
1673 + 1 /* Hash identifier */
1674 + ECRYPTFS_SALT_SIZE
/* Salt */
1675 + 1 /* Hash iterations */
1676 + key_rec
->enc_key_size
); /* Encrypted key size */
1677 if (max_packet_size
> (*remaining_bytes
)) {
1678 printk(KERN_ERR
"Packet too large; need up to [%d] bytes, but "
1679 "there are only [%d] available\n", max_packet_size
,
1680 (*remaining_bytes
));
1684 dest
[(*packet_size
)++] = ECRYPTFS_TAG_3_PACKET_TYPE
;
1685 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
1686 * to get the number of octets in the actual Tag 3 packet */
1687 rc
= write_packet_length(&dest
[(*packet_size
)], (max_packet_size
- 4),
1688 &packet_size_length
);
1690 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
1691 "generate packet length. rc = [%d]\n", rc
);
1694 (*packet_size
) += packet_size_length
;
1695 dest
[(*packet_size
)++] = 0x04; /* version 4 */
1696 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
1697 * specified with strings */
1698 cipher_code
= ecryptfs_code_for_cipher_string(crypt_stat
);
1699 if (cipher_code
== 0) {
1700 ecryptfs_printk(KERN_WARNING
, "Unable to generate code for "
1701 "cipher [%s]\n", crypt_stat
->cipher
);
1705 dest
[(*packet_size
)++] = cipher_code
;
1706 dest
[(*packet_size
)++] = 0x03; /* S2K */
1707 dest
[(*packet_size
)++] = 0x01; /* MD5 (TODO: parameterize) */
1708 memcpy(&dest
[(*packet_size
)], auth_tok
->token
.password
.salt
,
1709 ECRYPTFS_SALT_SIZE
);
1710 (*packet_size
) += ECRYPTFS_SALT_SIZE
; /* salt */
1711 dest
[(*packet_size
)++] = 0x60; /* hash iterations (65536) */
1712 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1713 key_rec
->enc_key_size
);
1714 (*packet_size
) += key_rec
->enc_key_size
;
1719 (*remaining_bytes
) -= (*packet_size
);
1723 struct kmem_cache
*ecryptfs_key_record_cache
;
1726 * ecryptfs_generate_key_packet_set
1727 * @dest: Virtual address from which to write the key record set
1728 * @crypt_stat: The cryptographic context from which the
1729 * authentication tokens will be retrieved
1730 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
1731 * for the global parameters
1732 * @len: The amount written
1733 * @max: The maximum amount of data allowed to be written
1735 * Generates a key packet set and writes it to the virtual address
1738 * Returns zero on success; non-zero on error.
1741 ecryptfs_generate_key_packet_set(char *dest_base
,
1742 struct ecryptfs_crypt_stat
*crypt_stat
,
1743 struct dentry
*ecryptfs_dentry
, size_t *len
,
1746 struct ecryptfs_auth_tok
*auth_tok
;
1747 struct ecryptfs_global_auth_tok
*global_auth_tok
;
1748 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1749 &ecryptfs_superblock_to_private(
1750 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1752 struct ecryptfs_key_record
*key_rec
;
1753 struct ecryptfs_key_sig
*key_sig
;
1757 mutex_lock(&crypt_stat
->keysig_list_mutex
);
1758 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
1763 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
1765 memset(key_rec
, 0, sizeof(*key_rec
));
1766 rc
= ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
1770 printk(KERN_ERR
"Error attempting to get the global "
1771 "auth_tok; rc = [%d]\n", rc
);
1774 if (global_auth_tok
->flags
& ECRYPTFS_AUTH_TOK_INVALID
) {
1776 "Skipping invalid auth tok with sig = [%s]\n",
1777 global_auth_tok
->sig
);
1780 auth_tok
= global_auth_tok
->global_auth_tok
;
1781 if (auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1782 rc
= write_tag_3_packet((dest_base
+ (*len
)),
1784 crypt_stat
, key_rec
,
1787 ecryptfs_printk(KERN_WARNING
, "Error "
1788 "writing tag 3 packet\n");
1792 /* Write auth tok signature packet */
1793 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
1795 ECRYPTFS_SIG_SIZE
, &written
);
1797 ecryptfs_printk(KERN_ERR
, "Error writing "
1798 "auth tok signature packet\n");
1802 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1803 rc
= write_tag_1_packet(dest_base
+ (*len
),
1805 crypt_stat
, key_rec
, &written
);
1807 ecryptfs_printk(KERN_WARNING
, "Error "
1808 "writing tag 1 packet\n");
1813 ecryptfs_printk(KERN_WARNING
, "Unsupported "
1814 "authentication token type\n");
1819 if (likely(max
> 0)) {
1820 dest_base
[(*len
)] = 0x00;
1822 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
1826 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
1830 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
1834 struct kmem_cache
*ecryptfs_key_sig_cache
;
1836 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
1838 struct ecryptfs_key_sig
*new_key_sig
;
1841 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
1845 "Error allocating from ecryptfs_key_sig_cache\n");
1848 memcpy(new_key_sig
->keysig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
1849 mutex_lock(&crypt_stat
->keysig_list_mutex
);
1850 list_add(&new_key_sig
->crypt_stat_list
, &crypt_stat
->keysig_list
);
1851 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
1856 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
1859 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
1862 struct ecryptfs_global_auth_tok
*new_auth_tok
;
1865 new_auth_tok
= kmem_cache_alloc(ecryptfs_global_auth_tok_cache
,
1867 if (!new_auth_tok
) {
1869 printk(KERN_ERR
"Error allocating from "
1870 "ecryptfs_global_auth_tok_cache\n");
1873 memcpy(new_auth_tok
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
1874 new_auth_tok
->sig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
1875 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
1876 list_add(&new_auth_tok
->mount_crypt_stat_list
,
1877 &mount_crypt_stat
->global_auth_tok_list
);
1878 mount_crypt_stat
->num_global_auth_toks
++;
1879 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);