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
;
517 * one byte for the Tag 1 ID flag
518 * two bytes for the body size
519 * do not exceed the maximum_packet_size
521 if (unlikely((*packet_size
) + 3 > max_packet_size
)) {
522 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
526 /* check for Tag 1 identifier - one byte */
527 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_1_PACKET_TYPE
) {
528 ecryptfs_printk(KERN_ERR
, "Enter w/ first byte != 0x%.2x\n",
529 ECRYPTFS_TAG_1_PACKET_TYPE
);
533 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
534 * at end of function upon failure */
536 kmem_cache_alloc(ecryptfs_auth_tok_list_item_cache
,
538 if (!auth_tok_list_item
) {
539 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
543 memset(auth_tok_list_item
, 0,
544 sizeof(struct ecryptfs_auth_tok_list_item
));
545 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
546 /* check for body size - one to two bytes
548 * ***** TAG 1 Packet Format *****
549 * | version number | 1 byte |
550 * | key ID | 8 bytes |
551 * | public key algorithm | 1 byte |
552 * | encrypted session key | arbitrary |
554 rc
= parse_packet_length(&data
[(*packet_size
)], &body_size
,
557 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
561 if (unlikely(body_size
< (0x02 + ECRYPTFS_SIG_SIZE
))) {
562 ecryptfs_printk(KERN_WARNING
, "Invalid body size ([%d])\n",
567 (*packet_size
) += length_size
;
568 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
569 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
573 /* Version 3 (from RFC2440) - one byte */
574 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
575 ecryptfs_printk(KERN_DEBUG
, "Unknown version number "
576 "[%d]\n", data
[(*packet_size
) - 1]);
581 ecryptfs_to_hex((*new_auth_tok
)->token
.private_key
.signature
,
582 &data
[(*packet_size
)], ECRYPTFS_SIG_SIZE
);
583 *packet_size
+= ECRYPTFS_SIG_SIZE
;
584 /* This byte is skipped because the kernel does not need to
585 * know which public key encryption algorithm was used */
587 (*new_auth_tok
)->session_key
.encrypted_key_size
=
588 body_size
- (0x02 + ECRYPTFS_SIG_SIZE
);
589 if ((*new_auth_tok
)->session_key
.encrypted_key_size
590 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
591 ecryptfs_printk(KERN_ERR
, "Tag 1 packet contains key larger "
592 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
596 ecryptfs_printk(KERN_DEBUG
, "Encrypted key size = [%d]\n",
597 (*new_auth_tok
)->session_key
.encrypted_key_size
);
598 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
599 &data
[(*packet_size
)], (body_size
- 0x02 - ECRYPTFS_SIG_SIZE
));
600 (*packet_size
) += (*new_auth_tok
)->session_key
.encrypted_key_size
;
601 (*new_auth_tok
)->session_key
.flags
&=
602 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
603 (*new_auth_tok
)->session_key
.flags
|=
604 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
605 (*new_auth_tok
)->token_type
= ECRYPTFS_PRIVATE_KEY
;
606 (*new_auth_tok
)->flags
|= ECRYPTFS_PRIVATE_KEY
;
607 /* TODO: Why are we setting this flag here? Don't we want the
608 * userspace to decrypt the session key? */
609 (*new_auth_tok
)->session_key
.flags
&=
610 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
611 (*new_auth_tok
)->session_key
.flags
&=
612 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
613 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
616 (*new_auth_tok
) = NULL
;
617 memset(auth_tok_list_item
, 0,
618 sizeof(struct ecryptfs_auth_tok_list_item
));
619 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
629 * @crypt_stat: The cryptographic context to modify based on packet
631 * @data: The raw bytes of the packet.
632 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
633 * a new authentication token will be placed at the end
634 * of this list for this packet.
635 * @new_auth_tok: Pointer to a pointer to memory that this function
636 * allocates; sets the memory address of the pointer to
637 * NULL on error. This object is added to the
639 * @packet_size: This function writes the size of the parsed packet
640 * into this memory location; zero on error.
641 * @max_packet_size: maximum number of bytes to parse
643 * Returns zero on success; non-zero on error.
646 parse_tag_3_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
647 unsigned char *data
, struct list_head
*auth_tok_list
,
648 struct ecryptfs_auth_tok
**new_auth_tok
,
649 size_t *packet_size
, size_t max_packet_size
)
652 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
657 (*new_auth_tok
) = NULL
;
660 * one byte for the Tag 3 ID flag
661 * two bytes for the body size
662 * do not exceed the maximum_packet_size
664 if (unlikely((*packet_size
) + 3 > max_packet_size
)) {
665 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
670 /* check for Tag 3 identifyer - one byte */
671 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_3_PACKET_TYPE
) {
672 ecryptfs_printk(KERN_ERR
, "Enter w/ first byte != 0x%.2x\n",
673 ECRYPTFS_TAG_3_PACKET_TYPE
);
677 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
678 * at end of function upon failure */
680 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
, GFP_KERNEL
);
681 if (!auth_tok_list_item
) {
682 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
686 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
688 /* check for body size - one to two bytes */
689 rc
= parse_packet_length(&data
[(*packet_size
)], &body_size
,
692 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
696 if (unlikely(body_size
< (0x05 + ECRYPTFS_SALT_SIZE
))) {
697 ecryptfs_printk(KERN_WARNING
, "Invalid body size ([%d])\n",
702 (*packet_size
) += length_size
;
704 /* now we know the length of the remainting Tag 3 packet size:
705 * 5 fix bytes for: version string, cipher, S2K ID, hash algo,
706 * number of hash iterations
707 * ECRYPTFS_SALT_SIZE bytes for salt
708 * body_size bytes minus the stuff above is the encrypted key size
710 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
711 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
716 /* There are 5 characters of additional information in the
718 (*new_auth_tok
)->session_key
.encrypted_key_size
=
719 body_size
- (0x05 + ECRYPTFS_SALT_SIZE
);
720 ecryptfs_printk(KERN_DEBUG
, "Encrypted key size = [%d]\n",
721 (*new_auth_tok
)->session_key
.encrypted_key_size
);
723 /* Version 4 (from RFC2440) - one byte */
724 if (unlikely(data
[(*packet_size
)++] != 0x04)) {
725 ecryptfs_printk(KERN_DEBUG
, "Unknown version number "
726 "[%d]\n", data
[(*packet_size
) - 1]);
731 /* cipher - one byte */
732 ecryptfs_cipher_code_to_string(crypt_stat
->cipher
,
733 (u16
)data
[(*packet_size
)]);
734 /* A little extra work to differentiate among the AES key
735 * sizes; see RFC2440 */
736 switch(data
[(*packet_size
)++]) {
737 case RFC2440_CIPHER_AES_192
:
738 crypt_stat
->key_size
= 24;
741 crypt_stat
->key_size
=
742 (*new_auth_tok
)->session_key
.encrypted_key_size
;
744 ecryptfs_init_crypt_ctx(crypt_stat
);
745 /* S2K identifier 3 (from RFC2440) */
746 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
747 ecryptfs_printk(KERN_ERR
, "Only S2K ID 3 is currently "
753 /* TODO: finish the hash mapping */
754 /* hash algorithm - one byte */
755 switch (data
[(*packet_size
)++]) {
756 case 0x01: /* See RFC2440 for these numbers and their mappings */
758 /* salt - ECRYPTFS_SALT_SIZE bytes */
759 memcpy((*new_auth_tok
)->token
.password
.salt
,
760 &data
[(*packet_size
)], ECRYPTFS_SALT_SIZE
);
761 (*packet_size
) += ECRYPTFS_SALT_SIZE
;
763 /* This conversion was taken straight from RFC2440 */
764 /* number of hash iterations - one byte */
765 (*new_auth_tok
)->token
.password
.hash_iterations
=
766 ((u32
) 16 + (data
[(*packet_size
)] & 15))
767 << ((data
[(*packet_size
)] >> 4) + 6);
770 /* encrypted session key -
771 * (body_size-5-ECRYPTFS_SALT_SIZE) bytes */
772 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
773 &data
[(*packet_size
)],
774 (*new_auth_tok
)->session_key
.encrypted_key_size
);
776 (*new_auth_tok
)->session_key
.encrypted_key_size
;
777 (*new_auth_tok
)->session_key
.flags
&=
778 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
779 (*new_auth_tok
)->session_key
.flags
|=
780 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
781 (*new_auth_tok
)->token
.password
.hash_algo
= 0x01;
784 ecryptfs_printk(KERN_ERR
, "Unsupported hash algorithm: "
785 "[%d]\n", data
[(*packet_size
) - 1]);
789 (*new_auth_tok
)->token_type
= ECRYPTFS_PASSWORD
;
790 /* TODO: Parametarize; we might actually want userspace to
791 * decrypt the session key. */
792 (*new_auth_tok
)->session_key
.flags
&=
793 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
794 (*new_auth_tok
)->session_key
.flags
&=
795 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
796 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
799 (*new_auth_tok
) = NULL
;
800 memset(auth_tok_list_item
, 0,
801 sizeof(struct ecryptfs_auth_tok_list_item
));
802 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
811 * parse_tag_11_packet
812 * @data: The raw bytes of the packet
813 * @contents: This function writes the data contents of the literal
814 * packet into this memory location
815 * @max_contents_bytes: The maximum number of bytes that this function
816 * is allowed to write into contents
817 * @tag_11_contents_size: This function writes the size of the parsed
818 * contents into this memory location; zero on
820 * @packet_size: This function writes the size of the parsed packet
821 * into this memory location; zero on error
822 * @max_packet_size: maximum number of bytes to parse
824 * Returns zero on success; non-zero on error.
827 parse_tag_11_packet(unsigned char *data
, unsigned char *contents
,
828 size_t max_contents_bytes
, size_t *tag_11_contents_size
,
829 size_t *packet_size
, size_t max_packet_size
)
836 (*tag_11_contents_size
) = 0;
839 * one byte for the Tag 11 ID flag
840 * two bytes for the Tag 11 length
841 * do not exceed the maximum_packet_size
843 if (unlikely((*packet_size
) + 3 > max_packet_size
)) {
844 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
849 /* check for Tag 11 identifyer - one byte */
850 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
851 ecryptfs_printk(KERN_WARNING
,
852 "Invalid tag 11 packet format\n");
857 /* get Tag 11 content length - one or two bytes */
858 rc
= parse_packet_length(&data
[(*packet_size
)], &body_size
,
861 ecryptfs_printk(KERN_WARNING
,
862 "Invalid tag 11 packet format\n");
865 (*packet_size
) += length_size
;
867 if (body_size
< 13) {
868 ecryptfs_printk(KERN_WARNING
, "Invalid body size ([%d])\n",
873 /* We have 13 bytes of surrounding packet values */
874 (*tag_11_contents_size
) = (body_size
- 13);
876 /* now we know the length of the remainting Tag 11 packet size:
877 * 14 fix bytes for: special flag one, special flag two,
879 * body_size bytes minus the stuff above is the Tag 11 content
881 /* FIXME why is the body size one byte smaller than the actual
883 * this seems to be an error here as well as in
884 * write_tag_11_packet() */
885 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
886 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
891 /* special flag one - one byte */
892 if (data
[(*packet_size
)++] != 0x62) {
893 ecryptfs_printk(KERN_WARNING
, "Unrecognizable packet\n");
898 /* special flag two - one byte */
899 if (data
[(*packet_size
)++] != 0x08) {
900 ecryptfs_printk(KERN_WARNING
, "Unrecognizable packet\n");
905 /* skip the next 12 bytes */
906 (*packet_size
) += 12; /* We don't care about the filename or
909 /* get the Tag 11 contents - tag_11_contents_size bytes */
910 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
911 (*packet_size
) += (*tag_11_contents_size
);
916 (*tag_11_contents_size
) = 0;
922 ecryptfs_find_global_auth_tok_for_sig(
923 struct ecryptfs_global_auth_tok
**global_auth_tok
,
924 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
, char *sig
)
926 struct ecryptfs_global_auth_tok
*walker
;
929 (*global_auth_tok
) = NULL
;
930 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
931 list_for_each_entry(walker
,
932 &mount_crypt_stat
->global_auth_tok_list
,
933 mount_crypt_stat_list
) {
934 if (memcmp(walker
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
) == 0) {
935 (*global_auth_tok
) = walker
;
941 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
946 * ecryptfs_verify_version
947 * @version: The version number to confirm
949 * Returns zero on good version; non-zero otherwise
951 static int ecryptfs_verify_version(u16 version
)
957 major
= ((version
>> 8) & 0xFF);
958 minor
= (version
& 0xFF);
959 if (major
!= ECRYPTFS_VERSION_MAJOR
) {
960 ecryptfs_printk(KERN_ERR
, "Major version number mismatch. "
961 "Expected [%d]; got [%d]\n",
962 ECRYPTFS_VERSION_MAJOR
, major
);
966 if (minor
!= ECRYPTFS_VERSION_MINOR
) {
967 ecryptfs_printk(KERN_ERR
, "Minor version number mismatch. "
968 "Expected [%d]; got [%d]\n",
969 ECRYPTFS_VERSION_MINOR
, minor
);
977 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
978 struct ecryptfs_auth_tok
**auth_tok
,
983 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
984 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
985 printk(KERN_ERR
"Could not find key with description: [%s]\n",
987 process_request_key_err(PTR_ERR(*auth_tok_key
));
991 (*auth_tok
) = ecryptfs_get_key_payload_data(*auth_tok_key
);
992 if (ecryptfs_verify_version((*auth_tok
)->version
)) {
994 "Data structure version mismatch. "
995 "Userspace tools must match eCryptfs "
996 "kernel module with major version [%d] "
997 "and minor version [%d]\n",
998 ECRYPTFS_VERSION_MAJOR
,
999 ECRYPTFS_VERSION_MINOR
);
1003 if ((*auth_tok
)->token_type
!= ECRYPTFS_PASSWORD
1004 && (*auth_tok
)->token_type
!= ECRYPTFS_PRIVATE_KEY
) {
1005 printk(KERN_ERR
"Invalid auth_tok structure "
1006 "returned from key query\n");
1015 * ecryptfs_find_auth_tok_for_sig
1016 * @auth_tok: Set to the matching auth_tok; NULL if not found
1017 * @crypt_stat: inode crypt_stat crypto context
1018 * @sig: Sig of auth_tok to find
1020 * For now, this function simply looks at the registered auth_tok's
1021 * linked off the mount_crypt_stat, so all the auth_toks that can be
1022 * used must be registered at mount time. This function could
1023 * potentially try a lot harder to find auth_tok's (e.g., by calling
1024 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
1025 * that static registration of auth_tok's will no longer be necessary.
1027 * Returns zero on no error; non-zero on error
1030 ecryptfs_find_auth_tok_for_sig(
1031 struct ecryptfs_auth_tok
**auth_tok
,
1032 struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
1034 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1035 crypt_stat
->mount_crypt_stat
;
1036 struct ecryptfs_global_auth_tok
*global_auth_tok
;
1040 if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
1041 mount_crypt_stat
, sig
)) {
1042 struct key
*auth_tok_key
;
1044 rc
= ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key
, auth_tok
,
1047 (*auth_tok
) = global_auth_tok
->global_auth_tok
;
1052 * decrypt_passphrase_encrypted_session_key - Decrypt the session key
1053 * with the given auth_tok.
1055 * Returns Zero on success; non-zero error otherwise.
1058 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1059 struct ecryptfs_crypt_stat
*crypt_stat
)
1061 struct scatterlist dst_sg
;
1062 struct scatterlist src_sg
;
1063 struct mutex
*tfm_mutex
= NULL
;
1064 struct blkcipher_desc desc
= {
1065 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1069 if (unlikely(ecryptfs_verbosity
> 0)) {
1071 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1072 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1074 auth_tok
->token
.password
.session_key_encryption_key
,
1075 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1077 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1078 crypt_stat
->cipher
);
1080 printk(KERN_ERR
"Internal error whilst attempting to get "
1081 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1082 crypt_stat
->cipher
, rc
);
1085 if ((rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1086 auth_tok
->session_key
.encrypted_key_size
,
1087 &src_sg
, 1)) != 1) {
1088 printk(KERN_ERR
"Internal error whilst attempting to convert "
1089 "auth_tok->session_key.encrypted_key to scatterlist; "
1090 "expected rc = 1; got rc = [%d]. "
1091 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc
,
1092 auth_tok
->session_key
.encrypted_key_size
);
1095 auth_tok
->session_key
.decrypted_key_size
=
1096 auth_tok
->session_key
.encrypted_key_size
;
1097 if ((rc
= virt_to_scatterlist(auth_tok
->session_key
.decrypted_key
,
1098 auth_tok
->session_key
.decrypted_key_size
,
1099 &dst_sg
, 1)) != 1) {
1100 printk(KERN_ERR
"Internal error whilst attempting to convert "
1101 "auth_tok->session_key.decrypted_key to scatterlist; "
1102 "expected rc = 1; got rc = [%d]\n", rc
);
1105 mutex_lock(tfm_mutex
);
1106 rc
= crypto_blkcipher_setkey(
1107 desc
.tfm
, auth_tok
->token
.password
.session_key_encryption_key
,
1108 crypt_stat
->key_size
);
1109 if (unlikely(rc
< 0)) {
1110 mutex_unlock(tfm_mutex
);
1111 printk(KERN_ERR
"Error setting key for crypto context\n");
1115 rc
= crypto_blkcipher_decrypt(&desc
, &dst_sg
, &src_sg
,
1116 auth_tok
->session_key
.encrypted_key_size
);
1117 mutex_unlock(tfm_mutex
);
1119 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
1122 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1123 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1124 auth_tok
->session_key
.decrypted_key_size
);
1125 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1126 if (unlikely(ecryptfs_verbosity
> 0)) {
1127 ecryptfs_printk(KERN_DEBUG
, "FEK of size [%d]:\n",
1128 crypt_stat
->key_size
);
1129 ecryptfs_dump_hex(crypt_stat
->key
,
1130 crypt_stat
->key_size
);
1136 int ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
1141 switch (auth_tok
->token_type
) {
1142 case ECRYPTFS_PASSWORD
:
1143 (*sig
) = auth_tok
->token
.password
.signature
;
1145 case ECRYPTFS_PRIVATE_KEY
:
1146 (*sig
) = auth_tok
->token
.private_key
.signature
;
1149 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
1150 auth_tok
->token_type
);
1157 * ecryptfs_parse_packet_set
1158 * @dest: The header page in memory
1159 * @version: Version of file format, to guide parsing behavior
1161 * Get crypt_stat to have the file's session key if the requisite key
1162 * is available to decrypt the session key.
1164 * Returns Zero if a valid authentication token was retrieved and
1165 * processed; negative value for file not encrypted or for error
1168 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1170 struct dentry
*ecryptfs_dentry
)
1173 size_t found_auth_tok
;
1174 size_t next_packet_is_auth_tok_packet
;
1175 struct list_head auth_tok_list
;
1176 struct ecryptfs_auth_tok
*matching_auth_tok
= NULL
;
1177 struct ecryptfs_auth_tok
*candidate_auth_tok
= NULL
;
1178 char *candidate_auth_tok_sig
;
1180 struct ecryptfs_auth_tok
*new_auth_tok
;
1181 unsigned char sig_tmp_space
[ECRYPTFS_SIG_SIZE
];
1182 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1183 size_t tag_11_contents_size
;
1184 size_t tag_11_packet_size
;
1187 INIT_LIST_HEAD(&auth_tok_list
);
1188 /* Parse the header to find as many packets as we can; these will be
1189 * added the our &auth_tok_list */
1190 next_packet_is_auth_tok_packet
= 1;
1191 while (next_packet_is_auth_tok_packet
) {
1192 size_t max_packet_size
= ((PAGE_CACHE_SIZE
- 8) - i
);
1195 case ECRYPTFS_TAG_3_PACKET_TYPE
:
1196 rc
= parse_tag_3_packet(crypt_stat
,
1197 (unsigned char *)&src
[i
],
1198 &auth_tok_list
, &new_auth_tok
,
1199 &packet_size
, max_packet_size
);
1201 ecryptfs_printk(KERN_ERR
, "Error parsing "
1207 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1210 &tag_11_contents_size
,
1211 &tag_11_packet_size
,
1214 ecryptfs_printk(KERN_ERR
, "No valid "
1215 "(ecryptfs-specific) literal "
1216 "packet containing "
1217 "authentication token "
1218 "signature found after "
1223 i
+= tag_11_packet_size
;
1224 if (ECRYPTFS_SIG_SIZE
!= tag_11_contents_size
) {
1225 ecryptfs_printk(KERN_ERR
, "Expected "
1226 "signature of size [%d]; "
1229 tag_11_contents_size
);
1233 ecryptfs_to_hex(new_auth_tok
->token
.password
.signature
,
1234 sig_tmp_space
, tag_11_contents_size
);
1235 new_auth_tok
->token
.password
.signature
[
1236 ECRYPTFS_PASSWORD_SIG_SIZE
] = '\0';
1237 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1239 case ECRYPTFS_TAG_1_PACKET_TYPE
:
1240 rc
= parse_tag_1_packet(crypt_stat
,
1241 (unsigned char *)&src
[i
],
1242 &auth_tok_list
, &new_auth_tok
,
1243 &packet_size
, max_packet_size
);
1245 ecryptfs_printk(KERN_ERR
, "Error parsing "
1251 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1253 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1254 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1255 "(Tag 11 not allowed by itself)\n");
1260 ecryptfs_printk(KERN_DEBUG
, "No packet at offset "
1261 "[%d] of the file header; hex value of "
1262 "character is [0x%.2x]\n", i
, src
[i
]);
1263 next_packet_is_auth_tok_packet
= 0;
1266 if (list_empty(&auth_tok_list
)) {
1267 printk(KERN_ERR
"The lower file appears to be a non-encrypted "
1268 "eCryptfs file; this is not supported in this version "
1269 "of the eCryptfs kernel module\n");
1273 /* auth_tok_list contains the set of authentication tokens
1274 * parsed from the metadata. We need to find a matching
1275 * authentication token that has the secret component(s)
1276 * necessary to decrypt the EFEK in the auth_tok parsed from
1277 * the metadata. There may be several potential matches, but
1278 * just one will be sufficient to decrypt to get the FEK. */
1279 find_next_matching_auth_tok
:
1281 list_for_each_entry(auth_tok_list_item
, &auth_tok_list
, list
) {
1282 candidate_auth_tok
= &auth_tok_list_item
->auth_tok
;
1283 if (unlikely(ecryptfs_verbosity
> 0)) {
1284 ecryptfs_printk(KERN_DEBUG
,
1285 "Considering cadidate auth tok:\n");
1286 ecryptfs_dump_auth_tok(candidate_auth_tok
);
1288 if ((rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1289 candidate_auth_tok
))) {
1291 "Unrecognized candidate auth tok type: [%d]\n",
1292 candidate_auth_tok
->token_type
);
1296 if ((rc
= ecryptfs_find_auth_tok_for_sig(
1297 &matching_auth_tok
, crypt_stat
,
1298 candidate_auth_tok_sig
)))
1300 if (matching_auth_tok
) {
1302 goto found_matching_auth_tok
;
1305 if (!found_auth_tok
) {
1306 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1307 "authentication token\n");
1311 found_matching_auth_tok
:
1312 if (candidate_auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1313 memcpy(&(candidate_auth_tok
->token
.private_key
),
1314 &(matching_auth_tok
->token
.private_key
),
1315 sizeof(struct ecryptfs_private_key
));
1316 rc
= decrypt_pki_encrypted_session_key(candidate_auth_tok
,
1318 } else if (candidate_auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1319 memcpy(&(candidate_auth_tok
->token
.password
),
1320 &(matching_auth_tok
->token
.password
),
1321 sizeof(struct ecryptfs_password
));
1322 rc
= decrypt_passphrase_encrypted_session_key(
1323 candidate_auth_tok
, crypt_stat
);
1326 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1328 ecryptfs_printk(KERN_WARNING
, "Error decrypting the "
1329 "session key for authentication token with sig "
1330 "[%.*s]; rc = [%d]. Removing auth tok "
1331 "candidate from the list and searching for "
1332 "the next match.\n", candidate_auth_tok_sig
,
1333 ECRYPTFS_SIG_SIZE_HEX
, rc
);
1334 list_for_each_entry_safe(auth_tok_list_item
,
1335 auth_tok_list_item_tmp
,
1336 &auth_tok_list
, list
) {
1337 if (candidate_auth_tok
1338 == &auth_tok_list_item
->auth_tok
) {
1339 list_del(&auth_tok_list_item
->list
);
1341 ecryptfs_auth_tok_list_item_cache
,
1342 auth_tok_list_item
);
1343 goto find_next_matching_auth_tok
;
1348 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1350 ecryptfs_printk(KERN_ERR
, "Error computing "
1354 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1356 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1357 "context for cipher [%s]; rc = [%d]\n",
1358 crypt_stat
->cipher
, rc
);
1361 wipe_auth_tok_list(&auth_tok_list
);
1367 pki_encrypt_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1368 struct ecryptfs_crypt_stat
*crypt_stat
,
1369 struct ecryptfs_key_record
*key_rec
)
1371 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1372 char *netlink_payload
;
1373 size_t netlink_payload_length
;
1374 struct ecryptfs_message
*msg
;
1377 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1378 ecryptfs_code_for_cipher_string(crypt_stat
),
1379 crypt_stat
, &netlink_payload
,
1380 &netlink_payload_length
);
1382 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
1385 rc
= ecryptfs_send_message(ecryptfs_transport
, netlink_payload
,
1386 netlink_payload_length
, &msg_ctx
);
1388 ecryptfs_printk(KERN_ERR
, "Error sending netlink message\n");
1391 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1393 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
1394 "from the user space daemon\n");
1398 rc
= parse_tag_67_packet(key_rec
, msg
);
1400 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
1403 if (netlink_payload
)
1404 kfree(netlink_payload
);
1408 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1409 * @dest: Buffer into which to write the packet
1410 * @max: Maximum number of bytes that can be writtn
1411 * @packet_size: This function will write the number of bytes that end
1412 * up constituting the packet; set to zero on error
1414 * Returns zero on success; non-zero on error.
1417 write_tag_1_packet(char *dest
, size_t *remaining_bytes
,
1418 struct ecryptfs_auth_tok
*auth_tok
,
1419 struct ecryptfs_crypt_stat
*crypt_stat
,
1420 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1423 size_t encrypted_session_key_valid
= 0;
1424 size_t packet_size_length
;
1425 size_t max_packet_size
;
1429 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
1431 encrypted_session_key_valid
= 0;
1432 for (i
= 0; i
< crypt_stat
->key_size
; i
++)
1433 encrypted_session_key_valid
|=
1434 auth_tok
->session_key
.encrypted_key
[i
];
1435 if (encrypted_session_key_valid
) {
1436 memcpy(key_rec
->enc_key
,
1437 auth_tok
->session_key
.encrypted_key
,
1438 auth_tok
->session_key
.encrypted_key_size
);
1439 goto encrypted_session_key_set
;
1441 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1442 auth_tok
->session_key
.encrypted_key_size
=
1443 auth_tok
->token
.private_key
.key_size
;
1444 rc
= pki_encrypt_session_key(auth_tok
, crypt_stat
, key_rec
);
1446 ecryptfs_printk(KERN_ERR
, "Failed to encrypt session key "
1450 if (ecryptfs_verbosity
> 0) {
1451 ecryptfs_printk(KERN_DEBUG
, "Encrypted key:\n");
1452 ecryptfs_dump_hex(key_rec
->enc_key
, key_rec
->enc_key_size
);
1454 encrypted_session_key_set
:
1455 /* This format is inspired by OpenPGP; see RFC 2440
1457 max_packet_size
= (1 /* Tag 1 identifier */
1458 + 3 /* Max Tag 1 packet size */
1460 + ECRYPTFS_SIG_SIZE
/* Key identifier */
1461 + 1 /* Cipher identifier */
1462 + key_rec
->enc_key_size
); /* Encrypted key size */
1463 if (max_packet_size
> (*remaining_bytes
)) {
1464 printk(KERN_ERR
"Packet length larger than maximum allowable; "
1465 "need up to [%d] bytes, but there are only [%d] "
1466 "available\n", max_packet_size
, (*remaining_bytes
));
1470 dest
[(*packet_size
)++] = ECRYPTFS_TAG_1_PACKET_TYPE
;
1471 rc
= write_packet_length(&dest
[(*packet_size
)], (max_packet_size
- 4),
1472 &packet_size_length
);
1474 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
1475 "header; cannot generate packet length\n");
1478 (*packet_size
) += packet_size_length
;
1479 dest
[(*packet_size
)++] = 0x03; /* version 3 */
1480 memcpy(&dest
[(*packet_size
)], key_rec
->sig
, ECRYPTFS_SIG_SIZE
);
1481 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
1482 dest
[(*packet_size
)++] = RFC2440_CIPHER_RSA
;
1483 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1484 key_rec
->enc_key_size
);
1485 (*packet_size
) += key_rec
->enc_key_size
;
1490 (*remaining_bytes
) -= (*packet_size
);
1495 * write_tag_11_packet
1496 * @dest: Target into which Tag 11 packet is to be written
1497 * @max: Maximum packet length
1498 * @contents: Byte array of contents to copy in
1499 * @contents_length: Number of bytes in contents
1500 * @packet_length: Length of the Tag 11 packet written; zero on error
1502 * Returns zero on success; non-zero on error.
1505 write_tag_11_packet(char *dest
, int max
, char *contents
, size_t contents_length
,
1506 size_t *packet_length
)
1508 size_t packet_size_length
;
1511 (*packet_length
) = 0;
1512 if ((13 + contents_length
) > max
) {
1514 ecryptfs_printk(KERN_ERR
, "Packet length larger than "
1515 "maximum allowable\n");
1518 /* General packet header */
1520 dest
[(*packet_length
)++] = ECRYPTFS_TAG_11_PACKET_TYPE
;
1522 rc
= write_packet_length(&dest
[(*packet_length
)],
1523 (13 + contents_length
), &packet_size_length
);
1525 ecryptfs_printk(KERN_ERR
, "Error generating tag 11 packet "
1526 "header; cannot generate packet length\n");
1529 (*packet_length
) += packet_size_length
;
1530 /* Tag 11 specific */
1531 /* One-octet field that describes how the data is formatted */
1532 dest
[(*packet_length
)++] = 0x62; /* binary data */
1533 /* One-octet filename length followed by filename */
1534 dest
[(*packet_length
)++] = 8;
1535 memcpy(&dest
[(*packet_length
)], "_CONSOLE", 8);
1536 (*packet_length
) += 8;
1537 /* Four-octet number indicating modification date */
1538 memset(&dest
[(*packet_length
)], 0x00, 4);
1539 (*packet_length
) += 4;
1540 /* Remainder is literal data */
1541 memcpy(&dest
[(*packet_length
)], contents
, contents_length
);
1542 (*packet_length
) += contents_length
;
1545 (*packet_length
) = 0;
1550 * write_tag_3_packet
1551 * @dest: Buffer into which to write the packet
1552 * @max: Maximum number of bytes that can be written
1553 * @auth_tok: Authentication token
1554 * @crypt_stat: The cryptographic context
1555 * @key_rec: encrypted key
1556 * @packet_size: This function will write the number of bytes that end
1557 * up constituting the packet; set to zero on error
1559 * Returns zero on success; non-zero on error.
1562 write_tag_3_packet(char *dest
, size_t *remaining_bytes
,
1563 struct ecryptfs_auth_tok
*auth_tok
,
1564 struct ecryptfs_crypt_stat
*crypt_stat
,
1565 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1568 size_t encrypted_session_key_valid
= 0;
1569 char session_key_encryption_key
[ECRYPTFS_MAX_KEY_BYTES
];
1570 struct scatterlist dst_sg
;
1571 struct scatterlist src_sg
;
1572 struct mutex
*tfm_mutex
= NULL
;
1574 size_t packet_size_length
;
1575 size_t max_packet_size
;
1576 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1577 crypt_stat
->mount_crypt_stat
;
1578 struct blkcipher_desc desc
= {
1580 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1585 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
1587 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1588 crypt_stat
->cipher
);
1590 printk(KERN_ERR
"Internal error whilst attempting to get "
1591 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1592 crypt_stat
->cipher
, rc
);
1595 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
1596 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(desc
.tfm
);
1598 printk(KERN_WARNING
"No key size specified at mount; "
1599 "defaulting to [%d]\n", alg
->max_keysize
);
1600 mount_crypt_stat
->global_default_cipher_key_size
=
1603 if (crypt_stat
->key_size
== 0)
1604 crypt_stat
->key_size
=
1605 mount_crypt_stat
->global_default_cipher_key_size
;
1606 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1607 auth_tok
->session_key
.encrypted_key_size
=
1608 crypt_stat
->key_size
;
1609 if (crypt_stat
->key_size
== 24
1610 && strcmp("aes", crypt_stat
->cipher
) == 0) {
1611 memset((crypt_stat
->key
+ 24), 0, 8);
1612 auth_tok
->session_key
.encrypted_key_size
= 32;
1614 auth_tok
->session_key
.encrypted_key_size
= crypt_stat
->key_size
;
1615 key_rec
->enc_key_size
=
1616 auth_tok
->session_key
.encrypted_key_size
;
1617 encrypted_session_key_valid
= 0;
1618 for (i
= 0; i
< auth_tok
->session_key
.encrypted_key_size
; i
++)
1619 encrypted_session_key_valid
|=
1620 auth_tok
->session_key
.encrypted_key
[i
];
1621 if (encrypted_session_key_valid
) {
1622 ecryptfs_printk(KERN_DEBUG
, "encrypted_session_key_valid != 0; "
1623 "using auth_tok->session_key.encrypted_key, "
1624 "where key_rec->enc_key_size = [%d]\n",
1625 key_rec
->enc_key_size
);
1626 memcpy(key_rec
->enc_key
,
1627 auth_tok
->session_key
.encrypted_key
,
1628 key_rec
->enc_key_size
);
1629 goto encrypted_session_key_set
;
1631 if (auth_tok
->token
.password
.flags
&
1632 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET
) {
1633 ecryptfs_printk(KERN_DEBUG
, "Using previously generated "
1634 "session key encryption key of size [%d]\n",
1635 auth_tok
->token
.password
.
1636 session_key_encryption_key_bytes
);
1637 memcpy(session_key_encryption_key
,
1638 auth_tok
->token
.password
.session_key_encryption_key
,
1639 crypt_stat
->key_size
);
1640 ecryptfs_printk(KERN_DEBUG
,
1641 "Cached session key " "encryption key: \n");
1642 if (ecryptfs_verbosity
> 0)
1643 ecryptfs_dump_hex(session_key_encryption_key
, 16);
1645 if (unlikely(ecryptfs_verbosity
> 0)) {
1646 ecryptfs_printk(KERN_DEBUG
, "Session key encryption key:\n");
1647 ecryptfs_dump_hex(session_key_encryption_key
, 16);
1649 if ((rc
= virt_to_scatterlist(crypt_stat
->key
,
1650 key_rec
->enc_key_size
, &src_sg
, 1))
1652 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
1653 "for crypt_stat session key; expected rc = 1; "
1654 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
1655 rc
, key_rec
->enc_key_size
);
1659 if ((rc
= virt_to_scatterlist(key_rec
->enc_key
,
1660 key_rec
->enc_key_size
, &dst_sg
, 1))
1662 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
1663 "for crypt_stat encrypted session key; "
1664 "expected rc = 1; got rc = [%d]. "
1665 "key_rec->enc_key_size = [%d]\n", rc
,
1666 key_rec
->enc_key_size
);
1670 mutex_lock(tfm_mutex
);
1671 rc
= crypto_blkcipher_setkey(desc
.tfm
, session_key_encryption_key
,
1672 crypt_stat
->key_size
);
1674 mutex_unlock(tfm_mutex
);
1675 ecryptfs_printk(KERN_ERR
, "Error setting key for crypto "
1676 "context; rc = [%d]\n", rc
);
1680 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%d] bytes of the key\n",
1681 crypt_stat
->key_size
);
1682 rc
= crypto_blkcipher_encrypt(&desc
, &dst_sg
, &src_sg
,
1683 (*key_rec
).enc_key_size
);
1684 mutex_unlock(tfm_mutex
);
1686 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
1689 ecryptfs_printk(KERN_DEBUG
, "This should be the encrypted key:\n");
1690 if (ecryptfs_verbosity
> 0) {
1691 ecryptfs_printk(KERN_DEBUG
, "EFEK of size [%d]:\n",
1692 key_rec
->enc_key_size
);
1693 ecryptfs_dump_hex(key_rec
->enc_key
,
1694 key_rec
->enc_key_size
);
1696 encrypted_session_key_set
:
1697 /* This format is inspired by OpenPGP; see RFC 2440
1699 max_packet_size
= (1 /* Tag 3 identifier */
1700 + 3 /* Max Tag 3 packet size */
1702 + 1 /* Cipher code */
1703 + 1 /* S2K specifier */
1704 + 1 /* Hash identifier */
1705 + ECRYPTFS_SALT_SIZE
/* Salt */
1706 + 1 /* Hash iterations */
1707 + key_rec
->enc_key_size
); /* Encrypted key size */
1708 if (max_packet_size
> (*remaining_bytes
)) {
1709 printk(KERN_ERR
"Packet too large; need up to [%d] bytes, but "
1710 "there are only [%d] available\n", max_packet_size
,
1711 (*remaining_bytes
));
1715 dest
[(*packet_size
)++] = ECRYPTFS_TAG_3_PACKET_TYPE
;
1716 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
1717 * to get the number of octets in the actual Tag 3 packet */
1718 rc
= write_packet_length(&dest
[(*packet_size
)], (max_packet_size
- 4),
1719 &packet_size_length
);
1721 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
1722 "generate packet length. rc = [%d]\n", rc
);
1725 (*packet_size
) += packet_size_length
;
1726 dest
[(*packet_size
)++] = 0x04; /* version 4 */
1727 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
1728 * specified with strings */
1729 cipher_code
= ecryptfs_code_for_cipher_string(crypt_stat
);
1730 if (cipher_code
== 0) {
1731 ecryptfs_printk(KERN_WARNING
, "Unable to generate code for "
1732 "cipher [%s]\n", crypt_stat
->cipher
);
1736 dest
[(*packet_size
)++] = cipher_code
;
1737 dest
[(*packet_size
)++] = 0x03; /* S2K */
1738 dest
[(*packet_size
)++] = 0x01; /* MD5 (TODO: parameterize) */
1739 memcpy(&dest
[(*packet_size
)], auth_tok
->token
.password
.salt
,
1740 ECRYPTFS_SALT_SIZE
);
1741 (*packet_size
) += ECRYPTFS_SALT_SIZE
; /* salt */
1742 dest
[(*packet_size
)++] = 0x60; /* hash iterations (65536) */
1743 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1744 key_rec
->enc_key_size
);
1745 (*packet_size
) += key_rec
->enc_key_size
;
1750 (*remaining_bytes
) -= (*packet_size
);
1754 struct kmem_cache
*ecryptfs_key_record_cache
;
1757 * ecryptfs_generate_key_packet_set
1758 * @dest: Virtual address from which to write the key record set
1759 * @crypt_stat: The cryptographic context from which the
1760 * authentication tokens will be retrieved
1761 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
1762 * for the global parameters
1763 * @len: The amount written
1764 * @max: The maximum amount of data allowed to be written
1766 * Generates a key packet set and writes it to the virtual address
1769 * Returns zero on success; non-zero on error.
1772 ecryptfs_generate_key_packet_set(char *dest_base
,
1773 struct ecryptfs_crypt_stat
*crypt_stat
,
1774 struct dentry
*ecryptfs_dentry
, size_t *len
,
1777 struct ecryptfs_auth_tok
*auth_tok
;
1778 struct ecryptfs_global_auth_tok
*global_auth_tok
;
1779 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1780 &ecryptfs_superblock_to_private(
1781 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1783 struct ecryptfs_key_record
*key_rec
;
1784 struct ecryptfs_key_sig
*key_sig
;
1788 mutex_lock(&crypt_stat
->keysig_list_mutex
);
1789 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
1794 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
1796 memset(key_rec
, 0, sizeof(*key_rec
));
1797 rc
= ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
1801 printk(KERN_ERR
"Error attempting to get the global "
1802 "auth_tok; rc = [%d]\n", rc
);
1805 if (global_auth_tok
->flags
& ECRYPTFS_AUTH_TOK_INVALID
) {
1807 "Skipping invalid auth tok with sig = [%s]\n",
1808 global_auth_tok
->sig
);
1811 auth_tok
= global_auth_tok
->global_auth_tok
;
1812 if (auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1813 rc
= write_tag_3_packet((dest_base
+ (*len
)),
1815 crypt_stat
, key_rec
,
1818 ecryptfs_printk(KERN_WARNING
, "Error "
1819 "writing tag 3 packet\n");
1823 /* Write auth tok signature packet */
1824 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
1826 ECRYPTFS_SIG_SIZE
, &written
);
1828 ecryptfs_printk(KERN_ERR
, "Error writing "
1829 "auth tok signature packet\n");
1833 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1834 rc
= write_tag_1_packet(dest_base
+ (*len
),
1836 crypt_stat
, key_rec
, &written
);
1838 ecryptfs_printk(KERN_WARNING
, "Error "
1839 "writing tag 1 packet\n");
1844 ecryptfs_printk(KERN_WARNING
, "Unsupported "
1845 "authentication token type\n");
1850 if (likely(max
> 0)) {
1851 dest_base
[(*len
)] = 0x00;
1853 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
1857 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
1861 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
1865 struct kmem_cache
*ecryptfs_key_sig_cache
;
1867 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
1869 struct ecryptfs_key_sig
*new_key_sig
;
1872 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
1876 "Error allocating from ecryptfs_key_sig_cache\n");
1879 memcpy(new_key_sig
->keysig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
1880 mutex_lock(&crypt_stat
->keysig_list_mutex
);
1881 list_add(&new_key_sig
->crypt_stat_list
, &crypt_stat
->keysig_list
);
1882 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
1887 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
1890 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
1893 struct ecryptfs_global_auth_tok
*new_auth_tok
;
1896 new_auth_tok
= kmem_cache_alloc(ecryptfs_global_auth_tok_cache
,
1898 if (!new_auth_tok
) {
1900 printk(KERN_ERR
"Error allocating from "
1901 "ecryptfs_global_auth_tok_cache\n");
1904 memcpy(new_auth_tok
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
1905 new_auth_tok
->sig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
1906 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
1907 list_add(&new_auth_tok
->mount_crypt_stat_list
,
1908 &mount_crypt_stat
->global_auth_tok_list
);
1909 mount_crypt_stat
->num_global_auth_toks
++;
1910 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);