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 list_head
*walker
;
473 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
475 walker
= auth_tok_list_head
->next
;
476 while (walker
!= auth_tok_list_head
) {
478 list_entry(walker
, struct ecryptfs_auth_tok_list_item
,
480 walker
= auth_tok_list_item
->list
.next
;
481 memset(auth_tok_list_item
, 0,
482 sizeof(struct ecryptfs_auth_tok_list_item
));
483 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
486 auth_tok_list_head
->next
= NULL
;
489 struct kmem_cache
*ecryptfs_auth_tok_list_item_cache
;
494 * @crypt_stat: The cryptographic context to modify based on packet
496 * @data: The raw bytes of the packet.
497 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
498 * a new authentication token will be placed at the end
499 * of this list for this packet.
500 * @new_auth_tok: Pointer to a pointer to memory that this function
501 * allocates; sets the memory address of the pointer to
502 * NULL on error. This object is added to the
504 * @packet_size: This function writes the size of the parsed packet
505 * into this memory location; zero on error.
507 * Returns zero on success; non-zero on error.
510 parse_tag_1_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
511 unsigned char *data
, struct list_head
*auth_tok_list
,
512 struct ecryptfs_auth_tok
**new_auth_tok
,
513 size_t *packet_size
, size_t max_packet_size
)
516 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
521 (*new_auth_tok
) = NULL
;
524 * one byte for the Tag 1 ID flag
525 * two bytes for the body size
526 * do not exceed the maximum_packet_size
528 if (unlikely((*packet_size
) + 3 > max_packet_size
)) {
529 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
533 /* check for Tag 1 identifier - one byte */
534 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_1_PACKET_TYPE
) {
535 ecryptfs_printk(KERN_ERR
, "Enter w/ first byte != 0x%.2x\n",
536 ECRYPTFS_TAG_1_PACKET_TYPE
);
540 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
541 * at end of function upon failure */
543 kmem_cache_alloc(ecryptfs_auth_tok_list_item_cache
,
545 if (!auth_tok_list_item
) {
546 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
550 memset(auth_tok_list_item
, 0,
551 sizeof(struct ecryptfs_auth_tok_list_item
));
552 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
553 /* check for body size - one to two bytes
555 * ***** TAG 1 Packet Format *****
556 * | version number | 1 byte |
557 * | key ID | 8 bytes |
558 * | public key algorithm | 1 byte |
559 * | encrypted session key | arbitrary |
561 rc
= parse_packet_length(&data
[(*packet_size
)], &body_size
,
564 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
568 if (unlikely(body_size
< (0x02 + ECRYPTFS_SIG_SIZE
))) {
569 ecryptfs_printk(KERN_WARNING
, "Invalid body size ([%d])\n",
574 (*packet_size
) += length_size
;
575 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
576 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
580 /* Version 3 (from RFC2440) - one byte */
581 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
582 ecryptfs_printk(KERN_DEBUG
, "Unknown version number "
583 "[%d]\n", data
[(*packet_size
) - 1]);
588 ecryptfs_to_hex((*new_auth_tok
)->token
.private_key
.signature
,
589 &data
[(*packet_size
)], ECRYPTFS_SIG_SIZE
);
590 *packet_size
+= ECRYPTFS_SIG_SIZE
;
591 /* This byte is skipped because the kernel does not need to
592 * know which public key encryption algorithm was used */
594 (*new_auth_tok
)->session_key
.encrypted_key_size
=
595 body_size
- (0x02 + ECRYPTFS_SIG_SIZE
);
596 if ((*new_auth_tok
)->session_key
.encrypted_key_size
597 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
598 ecryptfs_printk(KERN_ERR
, "Tag 1 packet contains key larger "
599 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
603 ecryptfs_printk(KERN_DEBUG
, "Encrypted key size = [%d]\n",
604 (*new_auth_tok
)->session_key
.encrypted_key_size
);
605 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
606 &data
[(*packet_size
)], (body_size
- 0x02 - ECRYPTFS_SIG_SIZE
));
607 (*packet_size
) += (*new_auth_tok
)->session_key
.encrypted_key_size
;
608 (*new_auth_tok
)->session_key
.flags
&=
609 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
610 (*new_auth_tok
)->session_key
.flags
|=
611 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
612 (*new_auth_tok
)->token_type
= ECRYPTFS_PRIVATE_KEY
;
613 (*new_auth_tok
)->flags
|= ECRYPTFS_PRIVATE_KEY
;
614 /* TODO: Why are we setting this flag here? Don't we want the
615 * userspace to decrypt the session key? */
616 (*new_auth_tok
)->session_key
.flags
&=
617 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
618 (*new_auth_tok
)->session_key
.flags
&=
619 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
620 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
623 (*new_auth_tok
) = NULL
;
624 memset(auth_tok_list_item
, 0,
625 sizeof(struct ecryptfs_auth_tok_list_item
));
626 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
636 * @crypt_stat: The cryptographic context to modify based on packet
638 * @data: The raw bytes of the packet.
639 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
640 * a new authentication token will be placed at the end
641 * of this list for this packet.
642 * @new_auth_tok: Pointer to a pointer to memory that this function
643 * allocates; sets the memory address of the pointer to
644 * NULL on error. This object is added to the
646 * @packet_size: This function writes the size of the parsed packet
647 * into this memory location; zero on error.
648 * @max_packet_size: maximum number of bytes to parse
650 * Returns zero on success; non-zero on error.
653 parse_tag_3_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
654 unsigned char *data
, struct list_head
*auth_tok_list
,
655 struct ecryptfs_auth_tok
**new_auth_tok
,
656 size_t *packet_size
, size_t max_packet_size
)
659 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
664 (*new_auth_tok
) = NULL
;
667 * one byte for the Tag 3 ID flag
668 * two bytes for the body size
669 * do not exceed the maximum_packet_size
671 if (unlikely((*packet_size
) + 3 > max_packet_size
)) {
672 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
677 /* check for Tag 3 identifyer - one byte */
678 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_3_PACKET_TYPE
) {
679 ecryptfs_printk(KERN_ERR
, "Enter w/ first byte != 0x%.2x\n",
680 ECRYPTFS_TAG_3_PACKET_TYPE
);
684 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
685 * at end of function upon failure */
687 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
, GFP_KERNEL
);
688 if (!auth_tok_list_item
) {
689 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
693 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
695 /* check for body size - one to two bytes */
696 rc
= parse_packet_length(&data
[(*packet_size
)], &body_size
,
699 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
703 if (unlikely(body_size
< (0x05 + ECRYPTFS_SALT_SIZE
))) {
704 ecryptfs_printk(KERN_WARNING
, "Invalid body size ([%d])\n",
709 (*packet_size
) += length_size
;
711 /* now we know the length of the remainting Tag 3 packet size:
712 * 5 fix bytes for: version string, cipher, S2K ID, hash algo,
713 * number of hash iterations
714 * ECRYPTFS_SALT_SIZE bytes for salt
715 * body_size bytes minus the stuff above is the encrypted key size
717 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
718 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
723 /* There are 5 characters of additional information in the
725 (*new_auth_tok
)->session_key
.encrypted_key_size
=
726 body_size
- (0x05 + ECRYPTFS_SALT_SIZE
);
727 ecryptfs_printk(KERN_DEBUG
, "Encrypted key size = [%d]\n",
728 (*new_auth_tok
)->session_key
.encrypted_key_size
);
730 /* Version 4 (from RFC2440) - one byte */
731 if (unlikely(data
[(*packet_size
)++] != 0x04)) {
732 ecryptfs_printk(KERN_DEBUG
, "Unknown version number "
733 "[%d]\n", data
[(*packet_size
) - 1]);
738 /* cipher - one byte */
739 ecryptfs_cipher_code_to_string(crypt_stat
->cipher
,
740 (u16
)data
[(*packet_size
)]);
741 /* A little extra work to differentiate among the AES key
742 * sizes; see RFC2440 */
743 switch(data
[(*packet_size
)++]) {
744 case RFC2440_CIPHER_AES_192
:
745 crypt_stat
->key_size
= 24;
748 crypt_stat
->key_size
=
749 (*new_auth_tok
)->session_key
.encrypted_key_size
;
751 ecryptfs_init_crypt_ctx(crypt_stat
);
752 /* S2K identifier 3 (from RFC2440) */
753 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
754 ecryptfs_printk(KERN_ERR
, "Only S2K ID 3 is currently "
760 /* TODO: finish the hash mapping */
761 /* hash algorithm - one byte */
762 switch (data
[(*packet_size
)++]) {
763 case 0x01: /* See RFC2440 for these numbers and their mappings */
765 /* salt - ECRYPTFS_SALT_SIZE bytes */
766 memcpy((*new_auth_tok
)->token
.password
.salt
,
767 &data
[(*packet_size
)], ECRYPTFS_SALT_SIZE
);
768 (*packet_size
) += ECRYPTFS_SALT_SIZE
;
770 /* This conversion was taken straight from RFC2440 */
771 /* number of hash iterations - one byte */
772 (*new_auth_tok
)->token
.password
.hash_iterations
=
773 ((u32
) 16 + (data
[(*packet_size
)] & 15))
774 << ((data
[(*packet_size
)] >> 4) + 6);
777 /* encrypted session key -
778 * (body_size-5-ECRYPTFS_SALT_SIZE) bytes */
779 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
780 &data
[(*packet_size
)],
781 (*new_auth_tok
)->session_key
.encrypted_key_size
);
783 (*new_auth_tok
)->session_key
.encrypted_key_size
;
784 (*new_auth_tok
)->session_key
.flags
&=
785 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
786 (*new_auth_tok
)->session_key
.flags
|=
787 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
788 (*new_auth_tok
)->token
.password
.hash_algo
= 0x01;
791 ecryptfs_printk(KERN_ERR
, "Unsupported hash algorithm: "
792 "[%d]\n", data
[(*packet_size
) - 1]);
796 (*new_auth_tok
)->token_type
= ECRYPTFS_PASSWORD
;
797 /* TODO: Parametarize; we might actually want userspace to
798 * decrypt the session key. */
799 (*new_auth_tok
)->session_key
.flags
&=
800 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
801 (*new_auth_tok
)->session_key
.flags
&=
802 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
803 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
806 (*new_auth_tok
) = NULL
;
807 memset(auth_tok_list_item
, 0,
808 sizeof(struct ecryptfs_auth_tok_list_item
));
809 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
818 * parse_tag_11_packet
819 * @data: The raw bytes of the packet
820 * @contents: This function writes the data contents of the literal
821 * packet into this memory location
822 * @max_contents_bytes: The maximum number of bytes that this function
823 * is allowed to write into contents
824 * @tag_11_contents_size: This function writes the size of the parsed
825 * contents into this memory location; zero on
827 * @packet_size: This function writes the size of the parsed packet
828 * into this memory location; zero on error
829 * @max_packet_size: maximum number of bytes to parse
831 * Returns zero on success; non-zero on error.
834 parse_tag_11_packet(unsigned char *data
, unsigned char *contents
,
835 size_t max_contents_bytes
, size_t *tag_11_contents_size
,
836 size_t *packet_size
, size_t max_packet_size
)
843 (*tag_11_contents_size
) = 0;
846 * one byte for the Tag 11 ID flag
847 * two bytes for the Tag 11 length
848 * do not exceed the maximum_packet_size
850 if (unlikely((*packet_size
) + 3 > max_packet_size
)) {
851 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
856 /* check for Tag 11 identifyer - one byte */
857 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
858 ecryptfs_printk(KERN_WARNING
,
859 "Invalid tag 11 packet format\n");
864 /* get Tag 11 content length - one or two bytes */
865 rc
= parse_packet_length(&data
[(*packet_size
)], &body_size
,
868 ecryptfs_printk(KERN_WARNING
,
869 "Invalid tag 11 packet format\n");
872 (*packet_size
) += length_size
;
874 if (body_size
< 13) {
875 ecryptfs_printk(KERN_WARNING
, "Invalid body size ([%d])\n",
880 /* We have 13 bytes of surrounding packet values */
881 (*tag_11_contents_size
) = (body_size
- 13);
883 /* now we know the length of the remainting Tag 11 packet size:
884 * 14 fix bytes for: special flag one, special flag two,
886 * body_size bytes minus the stuff above is the Tag 11 content
888 /* FIXME why is the body size one byte smaller than the actual
890 * this seems to be an error here as well as in
891 * write_tag_11_packet() */
892 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
893 ecryptfs_printk(KERN_ERR
, "Packet size exceeds max\n");
898 /* special flag one - one byte */
899 if (data
[(*packet_size
)++] != 0x62) {
900 ecryptfs_printk(KERN_WARNING
, "Unrecognizable packet\n");
905 /* special flag two - one byte */
906 if (data
[(*packet_size
)++] != 0x08) {
907 ecryptfs_printk(KERN_WARNING
, "Unrecognizable packet\n");
912 /* skip the next 12 bytes */
913 (*packet_size
) += 12; /* We don't care about the filename or
916 /* get the Tag 11 contents - tag_11_contents_size bytes */
917 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
918 (*packet_size
) += (*tag_11_contents_size
);
923 (*tag_11_contents_size
) = 0;
929 ecryptfs_find_global_auth_tok_for_sig(
930 struct ecryptfs_global_auth_tok
**global_auth_tok
,
931 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
, char *sig
)
933 struct ecryptfs_global_auth_tok
*walker
;
936 (*global_auth_tok
) = NULL
;
937 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
938 list_for_each_entry(walker
,
939 &mount_crypt_stat
->global_auth_tok_list
,
940 mount_crypt_stat_list
) {
941 if (memcmp(walker
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
) == 0) {
942 (*global_auth_tok
) = walker
;
948 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
953 * ecryptfs_verify_version
954 * @version: The version number to confirm
956 * Returns zero on good version; non-zero otherwise
958 static int ecryptfs_verify_version(u16 version
)
964 major
= ((version
>> 8) & 0xFF);
965 minor
= (version
& 0xFF);
966 if (major
!= ECRYPTFS_VERSION_MAJOR
) {
967 ecryptfs_printk(KERN_ERR
, "Major version number mismatch. "
968 "Expected [%d]; got [%d]\n",
969 ECRYPTFS_VERSION_MAJOR
, major
);
973 if (minor
!= ECRYPTFS_VERSION_MINOR
) {
974 ecryptfs_printk(KERN_ERR
, "Minor version number mismatch. "
975 "Expected [%d]; got [%d]\n",
976 ECRYPTFS_VERSION_MINOR
, minor
);
984 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
985 struct ecryptfs_auth_tok
**auth_tok
,
990 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
991 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
992 printk(KERN_ERR
"Could not find key with description: [%s]\n",
994 process_request_key_err(PTR_ERR(*auth_tok_key
));
998 (*auth_tok
) = ecryptfs_get_key_payload_data(*auth_tok_key
);
999 if (ecryptfs_verify_version((*auth_tok
)->version
)) {
1001 "Data structure version mismatch. "
1002 "Userspace tools must match eCryptfs "
1003 "kernel module with major version [%d] "
1004 "and minor version [%d]\n",
1005 ECRYPTFS_VERSION_MAJOR
,
1006 ECRYPTFS_VERSION_MINOR
);
1010 if ((*auth_tok
)->token_type
!= ECRYPTFS_PASSWORD
1011 && (*auth_tok
)->token_type
!= ECRYPTFS_PRIVATE_KEY
) {
1012 printk(KERN_ERR
"Invalid auth_tok structure "
1013 "returned from key query\n");
1022 * ecryptfs_find_auth_tok_for_sig
1023 * @auth_tok: Set to the matching auth_tok; NULL if not found
1024 * @crypt_stat: inode crypt_stat crypto context
1025 * @sig: Sig of auth_tok to find
1027 * For now, this function simply looks at the registered auth_tok's
1028 * linked off the mount_crypt_stat, so all the auth_toks that can be
1029 * used must be registered at mount time. This function could
1030 * potentially try a lot harder to find auth_tok's (e.g., by calling
1031 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
1032 * that static registration of auth_tok's will no longer be necessary.
1034 * Returns zero on no error; non-zero on error
1037 ecryptfs_find_auth_tok_for_sig(
1038 struct ecryptfs_auth_tok
**auth_tok
,
1039 struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
1041 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1042 crypt_stat
->mount_crypt_stat
;
1043 struct ecryptfs_global_auth_tok
*global_auth_tok
;
1047 if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
1048 mount_crypt_stat
, sig
)) {
1049 struct key
*auth_tok_key
;
1051 rc
= ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key
, auth_tok
,
1054 (*auth_tok
) = global_auth_tok
->global_auth_tok
;
1059 * decrypt_passphrase_encrypted_session_key - Decrypt the session key
1060 * with the given auth_tok.
1062 * Returns Zero on success; non-zero error otherwise.
1065 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1066 struct ecryptfs_crypt_stat
*crypt_stat
)
1068 struct scatterlist dst_sg
;
1069 struct scatterlist src_sg
;
1070 struct mutex
*tfm_mutex
= NULL
;
1071 struct blkcipher_desc desc
= {
1072 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1076 if (unlikely(ecryptfs_verbosity
> 0)) {
1078 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1079 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1081 auth_tok
->token
.password
.session_key_encryption_key
,
1082 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1084 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1085 crypt_stat
->cipher
);
1087 printk(KERN_ERR
"Internal error whilst attempting to get "
1088 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1089 crypt_stat
->cipher
, rc
);
1092 if ((rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1093 auth_tok
->session_key
.encrypted_key_size
,
1094 &src_sg
, 1)) != 1) {
1095 printk(KERN_ERR
"Internal error whilst attempting to convert "
1096 "auth_tok->session_key.encrypted_key to scatterlist; "
1097 "expected rc = 1; got rc = [%d]. "
1098 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc
,
1099 auth_tok
->session_key
.encrypted_key_size
);
1102 auth_tok
->session_key
.decrypted_key_size
=
1103 auth_tok
->session_key
.encrypted_key_size
;
1104 if ((rc
= virt_to_scatterlist(auth_tok
->session_key
.decrypted_key
,
1105 auth_tok
->session_key
.decrypted_key_size
,
1106 &dst_sg
, 1)) != 1) {
1107 printk(KERN_ERR
"Internal error whilst attempting to convert "
1108 "auth_tok->session_key.decrypted_key to scatterlist; "
1109 "expected rc = 1; got rc = [%d]\n", rc
);
1112 mutex_lock(tfm_mutex
);
1113 rc
= crypto_blkcipher_setkey(
1114 desc
.tfm
, auth_tok
->token
.password
.session_key_encryption_key
,
1115 crypt_stat
->key_size
);
1116 if (unlikely(rc
< 0)) {
1117 mutex_unlock(tfm_mutex
);
1118 printk(KERN_ERR
"Error setting key for crypto context\n");
1122 rc
= crypto_blkcipher_decrypt(&desc
, &dst_sg
, &src_sg
,
1123 auth_tok
->session_key
.encrypted_key_size
);
1124 mutex_unlock(tfm_mutex
);
1126 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
1129 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1130 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1131 auth_tok
->session_key
.decrypted_key_size
);
1132 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1133 if (unlikely(ecryptfs_verbosity
> 0)) {
1134 ecryptfs_printk(KERN_DEBUG
, "FEK of size [%d]:\n",
1135 crypt_stat
->key_size
);
1136 ecryptfs_dump_hex(crypt_stat
->key
,
1137 crypt_stat
->key_size
);
1143 int ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
1148 switch (auth_tok
->token_type
) {
1149 case ECRYPTFS_PASSWORD
:
1150 (*sig
) = auth_tok
->token
.password
.signature
;
1152 case ECRYPTFS_PRIVATE_KEY
:
1153 (*sig
) = auth_tok
->token
.private_key
.signature
;
1156 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
1157 auth_tok
->token_type
);
1164 * ecryptfs_parse_packet_set
1165 * @dest: The header page in memory
1166 * @version: Version of file format, to guide parsing behavior
1168 * Get crypt_stat to have the file's session key if the requisite key
1169 * is available to decrypt the session key.
1171 * Returns Zero if a valid authentication token was retrieved and
1172 * processed; negative value for file not encrypted or for error
1175 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1177 struct dentry
*ecryptfs_dentry
)
1180 size_t found_auth_tok
;
1181 size_t next_packet_is_auth_tok_packet
;
1182 struct list_head auth_tok_list
;
1183 struct ecryptfs_auth_tok
*matching_auth_tok
= NULL
;
1184 struct ecryptfs_auth_tok
*candidate_auth_tok
= NULL
;
1185 char *candidate_auth_tok_sig
;
1187 struct ecryptfs_auth_tok
*new_auth_tok
;
1188 unsigned char sig_tmp_space
[ECRYPTFS_SIG_SIZE
];
1189 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1190 size_t tag_11_contents_size
;
1191 size_t tag_11_packet_size
;
1194 INIT_LIST_HEAD(&auth_tok_list
);
1195 /* Parse the header to find as many packets as we can; these will be
1196 * added the our &auth_tok_list */
1197 next_packet_is_auth_tok_packet
= 1;
1198 while (next_packet_is_auth_tok_packet
) {
1199 size_t max_packet_size
= ((PAGE_CACHE_SIZE
- 8) - i
);
1202 case ECRYPTFS_TAG_3_PACKET_TYPE
:
1203 rc
= parse_tag_3_packet(crypt_stat
,
1204 (unsigned char *)&src
[i
],
1205 &auth_tok_list
, &new_auth_tok
,
1206 &packet_size
, max_packet_size
);
1208 ecryptfs_printk(KERN_ERR
, "Error parsing "
1214 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1217 &tag_11_contents_size
,
1218 &tag_11_packet_size
,
1221 ecryptfs_printk(KERN_ERR
, "No valid "
1222 "(ecryptfs-specific) literal "
1223 "packet containing "
1224 "authentication token "
1225 "signature found after "
1230 i
+= tag_11_packet_size
;
1231 if (ECRYPTFS_SIG_SIZE
!= tag_11_contents_size
) {
1232 ecryptfs_printk(KERN_ERR
, "Expected "
1233 "signature of size [%d]; "
1236 tag_11_contents_size
);
1240 ecryptfs_to_hex(new_auth_tok
->token
.password
.signature
,
1241 sig_tmp_space
, tag_11_contents_size
);
1242 new_auth_tok
->token
.password
.signature
[
1243 ECRYPTFS_PASSWORD_SIG_SIZE
] = '\0';
1244 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1246 case ECRYPTFS_TAG_1_PACKET_TYPE
:
1247 rc
= parse_tag_1_packet(crypt_stat
,
1248 (unsigned char *)&src
[i
],
1249 &auth_tok_list
, &new_auth_tok
,
1250 &packet_size
, max_packet_size
);
1252 ecryptfs_printk(KERN_ERR
, "Error parsing "
1258 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1260 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1261 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1262 "(Tag 11 not allowed by itself)\n");
1267 ecryptfs_printk(KERN_DEBUG
, "No packet at offset "
1268 "[%d] of the file header; hex value of "
1269 "character is [0x%.2x]\n", i
, src
[i
]);
1270 next_packet_is_auth_tok_packet
= 0;
1273 if (list_empty(&auth_tok_list
)) {
1274 printk(KERN_ERR
"The lower file appears to be a non-encrypted "
1275 "eCryptfs file; this is not supported in this version "
1276 "of the eCryptfs kernel module\n");
1280 /* auth_tok_list contains the set of authentication tokens
1281 * parsed from the metadata. We need to find a matching
1282 * authentication token that has the secret component(s)
1283 * necessary to decrypt the EFEK in the auth_tok parsed from
1284 * the metadata. There may be several potential matches, but
1285 * just one will be sufficient to decrypt to get the FEK. */
1286 find_next_matching_auth_tok
:
1288 list_for_each_entry(auth_tok_list_item
, &auth_tok_list
, list
) {
1289 candidate_auth_tok
= &auth_tok_list_item
->auth_tok
;
1290 if (unlikely(ecryptfs_verbosity
> 0)) {
1291 ecryptfs_printk(KERN_DEBUG
,
1292 "Considering cadidate auth tok:\n");
1293 ecryptfs_dump_auth_tok(candidate_auth_tok
);
1295 if ((rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1296 candidate_auth_tok
))) {
1298 "Unrecognized candidate auth tok type: [%d]\n",
1299 candidate_auth_tok
->token_type
);
1303 if ((rc
= ecryptfs_find_auth_tok_for_sig(
1304 &matching_auth_tok
, crypt_stat
,
1305 candidate_auth_tok_sig
)))
1307 if (matching_auth_tok
) {
1309 goto found_matching_auth_tok
;
1312 if (!found_auth_tok
) {
1313 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1314 "authentication token\n");
1318 found_matching_auth_tok
:
1319 if (candidate_auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1320 memcpy(&(candidate_auth_tok
->token
.private_key
),
1321 &(matching_auth_tok
->token
.private_key
),
1322 sizeof(struct ecryptfs_private_key
));
1323 rc
= decrypt_pki_encrypted_session_key(candidate_auth_tok
,
1325 } else if (candidate_auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1326 memcpy(&(candidate_auth_tok
->token
.password
),
1327 &(matching_auth_tok
->token
.password
),
1328 sizeof(struct ecryptfs_password
));
1329 rc
= decrypt_passphrase_encrypted_session_key(
1330 candidate_auth_tok
, crypt_stat
);
1333 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1335 ecryptfs_printk(KERN_WARNING
, "Error decrypting the "
1336 "session key for authentication token with sig "
1337 "[%.*s]; rc = [%d]. Removing auth tok "
1338 "candidate from the list and searching for "
1339 "the next match.\n", candidate_auth_tok_sig
,
1340 ECRYPTFS_SIG_SIZE_HEX
, rc
);
1341 list_for_each_entry_safe(auth_tok_list_item
,
1342 auth_tok_list_item_tmp
,
1343 &auth_tok_list
, list
) {
1344 if (candidate_auth_tok
1345 == &auth_tok_list_item
->auth_tok
) {
1346 list_del(&auth_tok_list_item
->list
);
1348 ecryptfs_auth_tok_list_item_cache
,
1349 auth_tok_list_item
);
1350 goto find_next_matching_auth_tok
;
1355 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1357 ecryptfs_printk(KERN_ERR
, "Error computing "
1361 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1363 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1364 "context for cipher [%s]; rc = [%d]\n",
1365 crypt_stat
->cipher
, rc
);
1368 wipe_auth_tok_list(&auth_tok_list
);
1374 pki_encrypt_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1375 struct ecryptfs_crypt_stat
*crypt_stat
,
1376 struct ecryptfs_key_record
*key_rec
)
1378 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1379 char *netlink_payload
;
1380 size_t netlink_payload_length
;
1381 struct ecryptfs_message
*msg
;
1384 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1385 ecryptfs_code_for_cipher_string(crypt_stat
),
1386 crypt_stat
, &netlink_payload
,
1387 &netlink_payload_length
);
1389 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
1392 rc
= ecryptfs_send_message(ecryptfs_transport
, netlink_payload
,
1393 netlink_payload_length
, &msg_ctx
);
1395 ecryptfs_printk(KERN_ERR
, "Error sending netlink message\n");
1398 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1400 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
1401 "from the user space daemon\n");
1405 rc
= parse_tag_67_packet(key_rec
, msg
);
1407 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
1410 if (netlink_payload
)
1411 kfree(netlink_payload
);
1415 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1416 * @dest: Buffer into which to write the packet
1417 * @max: Maximum number of bytes that can be writtn
1418 * @packet_size: This function will write the number of bytes that end
1419 * up constituting the packet; set to zero on error
1421 * Returns zero on success; non-zero on error.
1424 write_tag_1_packet(char *dest
, size_t *remaining_bytes
,
1425 struct ecryptfs_auth_tok
*auth_tok
,
1426 struct ecryptfs_crypt_stat
*crypt_stat
,
1427 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1430 size_t encrypted_session_key_valid
= 0;
1431 size_t packet_size_length
;
1432 size_t max_packet_size
;
1436 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
1438 encrypted_session_key_valid
= 0;
1439 for (i
= 0; i
< crypt_stat
->key_size
; i
++)
1440 encrypted_session_key_valid
|=
1441 auth_tok
->session_key
.encrypted_key
[i
];
1442 if (encrypted_session_key_valid
) {
1443 memcpy(key_rec
->enc_key
,
1444 auth_tok
->session_key
.encrypted_key
,
1445 auth_tok
->session_key
.encrypted_key_size
);
1446 goto encrypted_session_key_set
;
1448 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1449 auth_tok
->session_key
.encrypted_key_size
=
1450 auth_tok
->token
.private_key
.key_size
;
1451 rc
= pki_encrypt_session_key(auth_tok
, crypt_stat
, key_rec
);
1453 ecryptfs_printk(KERN_ERR
, "Failed to encrypt session key "
1457 if (ecryptfs_verbosity
> 0) {
1458 ecryptfs_printk(KERN_DEBUG
, "Encrypted key:\n");
1459 ecryptfs_dump_hex(key_rec
->enc_key
, key_rec
->enc_key_size
);
1461 encrypted_session_key_set
:
1462 /* This format is inspired by OpenPGP; see RFC 2440
1464 max_packet_size
= (1 /* Tag 1 identifier */
1465 + 3 /* Max Tag 1 packet size */
1467 + ECRYPTFS_SIG_SIZE
/* Key identifier */
1468 + 1 /* Cipher identifier */
1469 + key_rec
->enc_key_size
); /* Encrypted key size */
1470 if (max_packet_size
> (*remaining_bytes
)) {
1471 printk(KERN_ERR
"Packet length larger than maximum allowable; "
1472 "need up to [%d] bytes, but there are only [%d] "
1473 "available\n", max_packet_size
, (*remaining_bytes
));
1477 dest
[(*packet_size
)++] = ECRYPTFS_TAG_1_PACKET_TYPE
;
1478 rc
= write_packet_length(&dest
[(*packet_size
)], (max_packet_size
- 4),
1479 &packet_size_length
);
1481 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
1482 "header; cannot generate packet length\n");
1485 (*packet_size
) += packet_size_length
;
1486 dest
[(*packet_size
)++] = 0x03; /* version 3 */
1487 memcpy(&dest
[(*packet_size
)], key_rec
->sig
, ECRYPTFS_SIG_SIZE
);
1488 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
1489 dest
[(*packet_size
)++] = RFC2440_CIPHER_RSA
;
1490 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1491 key_rec
->enc_key_size
);
1492 (*packet_size
) += key_rec
->enc_key_size
;
1497 (*remaining_bytes
) -= (*packet_size
);
1502 * write_tag_11_packet
1503 * @dest: Target into which Tag 11 packet is to be written
1504 * @max: Maximum packet length
1505 * @contents: Byte array of contents to copy in
1506 * @contents_length: Number of bytes in contents
1507 * @packet_length: Length of the Tag 11 packet written; zero on error
1509 * Returns zero on success; non-zero on error.
1512 write_tag_11_packet(char *dest
, int max
, char *contents
, size_t contents_length
,
1513 size_t *packet_length
)
1515 size_t packet_size_length
;
1518 (*packet_length
) = 0;
1519 if ((13 + contents_length
) > max
) {
1521 ecryptfs_printk(KERN_ERR
, "Packet length larger than "
1522 "maximum allowable\n");
1525 /* General packet header */
1527 dest
[(*packet_length
)++] = ECRYPTFS_TAG_11_PACKET_TYPE
;
1529 rc
= write_packet_length(&dest
[(*packet_length
)],
1530 (13 + contents_length
), &packet_size_length
);
1532 ecryptfs_printk(KERN_ERR
, "Error generating tag 11 packet "
1533 "header; cannot generate packet length\n");
1536 (*packet_length
) += packet_size_length
;
1537 /* Tag 11 specific */
1538 /* One-octet field that describes how the data is formatted */
1539 dest
[(*packet_length
)++] = 0x62; /* binary data */
1540 /* One-octet filename length followed by filename */
1541 dest
[(*packet_length
)++] = 8;
1542 memcpy(&dest
[(*packet_length
)], "_CONSOLE", 8);
1543 (*packet_length
) += 8;
1544 /* Four-octet number indicating modification date */
1545 memset(&dest
[(*packet_length
)], 0x00, 4);
1546 (*packet_length
) += 4;
1547 /* Remainder is literal data */
1548 memcpy(&dest
[(*packet_length
)], contents
, contents_length
);
1549 (*packet_length
) += contents_length
;
1552 (*packet_length
) = 0;
1557 * write_tag_3_packet
1558 * @dest: Buffer into which to write the packet
1559 * @max: Maximum number of bytes that can be written
1560 * @auth_tok: Authentication token
1561 * @crypt_stat: The cryptographic context
1562 * @key_rec: encrypted key
1563 * @packet_size: This function will write the number of bytes that end
1564 * up constituting the packet; set to zero on error
1566 * Returns zero on success; non-zero on error.
1569 write_tag_3_packet(char *dest
, size_t *remaining_bytes
,
1570 struct ecryptfs_auth_tok
*auth_tok
,
1571 struct ecryptfs_crypt_stat
*crypt_stat
,
1572 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1575 size_t encrypted_session_key_valid
= 0;
1576 char session_key_encryption_key
[ECRYPTFS_MAX_KEY_BYTES
];
1577 struct scatterlist dst_sg
;
1578 struct scatterlist src_sg
;
1579 struct mutex
*tfm_mutex
= NULL
;
1581 size_t packet_size_length
;
1582 size_t max_packet_size
;
1583 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1584 crypt_stat
->mount_crypt_stat
;
1585 struct blkcipher_desc desc
= {
1587 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1592 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
1594 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1595 crypt_stat
->cipher
);
1597 printk(KERN_ERR
"Internal error whilst attempting to get "
1598 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1599 crypt_stat
->cipher
, rc
);
1602 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
1603 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(desc
.tfm
);
1605 printk(KERN_WARNING
"No key size specified at mount; "
1606 "defaulting to [%d]\n", alg
->max_keysize
);
1607 mount_crypt_stat
->global_default_cipher_key_size
=
1610 if (crypt_stat
->key_size
== 0)
1611 crypt_stat
->key_size
=
1612 mount_crypt_stat
->global_default_cipher_key_size
;
1613 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1614 auth_tok
->session_key
.encrypted_key_size
=
1615 crypt_stat
->key_size
;
1616 if (crypt_stat
->key_size
== 24
1617 && strcmp("aes", crypt_stat
->cipher
) == 0) {
1618 memset((crypt_stat
->key
+ 24), 0, 8);
1619 auth_tok
->session_key
.encrypted_key_size
= 32;
1621 auth_tok
->session_key
.encrypted_key_size
= crypt_stat
->key_size
;
1622 key_rec
->enc_key_size
=
1623 auth_tok
->session_key
.encrypted_key_size
;
1624 encrypted_session_key_valid
= 0;
1625 for (i
= 0; i
< auth_tok
->session_key
.encrypted_key_size
; i
++)
1626 encrypted_session_key_valid
|=
1627 auth_tok
->session_key
.encrypted_key
[i
];
1628 if (encrypted_session_key_valid
) {
1629 ecryptfs_printk(KERN_DEBUG
, "encrypted_session_key_valid != 0; "
1630 "using auth_tok->session_key.encrypted_key, "
1631 "where key_rec->enc_key_size = [%d]\n",
1632 key_rec
->enc_key_size
);
1633 memcpy(key_rec
->enc_key
,
1634 auth_tok
->session_key
.encrypted_key
,
1635 key_rec
->enc_key_size
);
1636 goto encrypted_session_key_set
;
1638 if (auth_tok
->token
.password
.flags
&
1639 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET
) {
1640 ecryptfs_printk(KERN_DEBUG
, "Using previously generated "
1641 "session key encryption key of size [%d]\n",
1642 auth_tok
->token
.password
.
1643 session_key_encryption_key_bytes
);
1644 memcpy(session_key_encryption_key
,
1645 auth_tok
->token
.password
.session_key_encryption_key
,
1646 crypt_stat
->key_size
);
1647 ecryptfs_printk(KERN_DEBUG
,
1648 "Cached session key " "encryption key: \n");
1649 if (ecryptfs_verbosity
> 0)
1650 ecryptfs_dump_hex(session_key_encryption_key
, 16);
1652 if (unlikely(ecryptfs_verbosity
> 0)) {
1653 ecryptfs_printk(KERN_DEBUG
, "Session key encryption key:\n");
1654 ecryptfs_dump_hex(session_key_encryption_key
, 16);
1656 if ((rc
= virt_to_scatterlist(crypt_stat
->key
,
1657 key_rec
->enc_key_size
, &src_sg
, 1))
1659 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
1660 "for crypt_stat session key; expected rc = 1; "
1661 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
1662 rc
, key_rec
->enc_key_size
);
1666 if ((rc
= virt_to_scatterlist(key_rec
->enc_key
,
1667 key_rec
->enc_key_size
, &dst_sg
, 1))
1669 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
1670 "for crypt_stat encrypted session key; "
1671 "expected rc = 1; got rc = [%d]. "
1672 "key_rec->enc_key_size = [%d]\n", rc
,
1673 key_rec
->enc_key_size
);
1677 mutex_lock(tfm_mutex
);
1678 rc
= crypto_blkcipher_setkey(desc
.tfm
, session_key_encryption_key
,
1679 crypt_stat
->key_size
);
1681 mutex_unlock(tfm_mutex
);
1682 ecryptfs_printk(KERN_ERR
, "Error setting key for crypto "
1683 "context; rc = [%d]\n", rc
);
1687 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%d] bytes of the key\n",
1688 crypt_stat
->key_size
);
1689 rc
= crypto_blkcipher_encrypt(&desc
, &dst_sg
, &src_sg
,
1690 (*key_rec
).enc_key_size
);
1691 mutex_unlock(tfm_mutex
);
1693 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
1696 ecryptfs_printk(KERN_DEBUG
, "This should be the encrypted key:\n");
1697 if (ecryptfs_verbosity
> 0) {
1698 ecryptfs_printk(KERN_DEBUG
, "EFEK of size [%d]:\n",
1699 key_rec
->enc_key_size
);
1700 ecryptfs_dump_hex(key_rec
->enc_key
,
1701 key_rec
->enc_key_size
);
1703 encrypted_session_key_set
:
1704 /* This format is inspired by OpenPGP; see RFC 2440
1706 max_packet_size
= (1 /* Tag 3 identifier */
1707 + 3 /* Max Tag 3 packet size */
1709 + 1 /* Cipher code */
1710 + 1 /* S2K specifier */
1711 + 1 /* Hash identifier */
1712 + ECRYPTFS_SALT_SIZE
/* Salt */
1713 + 1 /* Hash iterations */
1714 + key_rec
->enc_key_size
); /* Encrypted key size */
1715 if (max_packet_size
> (*remaining_bytes
)) {
1716 printk(KERN_ERR
"Packet too large; need up to [%d] bytes, but "
1717 "there are only [%d] available\n", max_packet_size
,
1718 (*remaining_bytes
));
1722 dest
[(*packet_size
)++] = ECRYPTFS_TAG_3_PACKET_TYPE
;
1723 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
1724 * to get the number of octets in the actual Tag 3 packet */
1725 rc
= write_packet_length(&dest
[(*packet_size
)], (max_packet_size
- 4),
1726 &packet_size_length
);
1728 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
1729 "generate packet length. rc = [%d]\n", rc
);
1732 (*packet_size
) += packet_size_length
;
1733 dest
[(*packet_size
)++] = 0x04; /* version 4 */
1734 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
1735 * specified with strings */
1736 cipher_code
= ecryptfs_code_for_cipher_string(crypt_stat
);
1737 if (cipher_code
== 0) {
1738 ecryptfs_printk(KERN_WARNING
, "Unable to generate code for "
1739 "cipher [%s]\n", crypt_stat
->cipher
);
1743 dest
[(*packet_size
)++] = cipher_code
;
1744 dest
[(*packet_size
)++] = 0x03; /* S2K */
1745 dest
[(*packet_size
)++] = 0x01; /* MD5 (TODO: parameterize) */
1746 memcpy(&dest
[(*packet_size
)], auth_tok
->token
.password
.salt
,
1747 ECRYPTFS_SALT_SIZE
);
1748 (*packet_size
) += ECRYPTFS_SALT_SIZE
; /* salt */
1749 dest
[(*packet_size
)++] = 0x60; /* hash iterations (65536) */
1750 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1751 key_rec
->enc_key_size
);
1752 (*packet_size
) += key_rec
->enc_key_size
;
1757 (*remaining_bytes
) -= (*packet_size
);
1761 struct kmem_cache
*ecryptfs_key_record_cache
;
1764 * ecryptfs_generate_key_packet_set
1765 * @dest: Virtual address from which to write the key record set
1766 * @crypt_stat: The cryptographic context from which the
1767 * authentication tokens will be retrieved
1768 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
1769 * for the global parameters
1770 * @len: The amount written
1771 * @max: The maximum amount of data allowed to be written
1773 * Generates a key packet set and writes it to the virtual address
1776 * Returns zero on success; non-zero on error.
1779 ecryptfs_generate_key_packet_set(char *dest_base
,
1780 struct ecryptfs_crypt_stat
*crypt_stat
,
1781 struct dentry
*ecryptfs_dentry
, size_t *len
,
1784 struct ecryptfs_auth_tok
*auth_tok
;
1785 struct ecryptfs_global_auth_tok
*global_auth_tok
;
1786 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1787 &ecryptfs_superblock_to_private(
1788 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1790 struct ecryptfs_key_record
*key_rec
;
1791 struct ecryptfs_key_sig
*key_sig
;
1795 mutex_lock(&crypt_stat
->keysig_list_mutex
);
1796 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
1801 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
1803 memset(key_rec
, 0, sizeof(*key_rec
));
1804 rc
= ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
1808 printk(KERN_ERR
"Error attempting to get the global "
1809 "auth_tok; rc = [%d]\n", rc
);
1812 if (global_auth_tok
->flags
& ECRYPTFS_AUTH_TOK_INVALID
) {
1814 "Skipping invalid auth tok with sig = [%s]\n",
1815 global_auth_tok
->sig
);
1818 auth_tok
= global_auth_tok
->global_auth_tok
;
1819 if (auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1820 rc
= write_tag_3_packet((dest_base
+ (*len
)),
1822 crypt_stat
, key_rec
,
1825 ecryptfs_printk(KERN_WARNING
, "Error "
1826 "writing tag 3 packet\n");
1830 /* Write auth tok signature packet */
1831 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
1833 ECRYPTFS_SIG_SIZE
, &written
);
1835 ecryptfs_printk(KERN_ERR
, "Error writing "
1836 "auth tok signature packet\n");
1840 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1841 rc
= write_tag_1_packet(dest_base
+ (*len
),
1843 crypt_stat
, key_rec
, &written
);
1845 ecryptfs_printk(KERN_WARNING
, "Error "
1846 "writing tag 1 packet\n");
1851 ecryptfs_printk(KERN_WARNING
, "Unsupported "
1852 "authentication token type\n");
1857 if (likely(max
> 0)) {
1858 dest_base
[(*len
)] = 0x00;
1860 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
1864 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
1868 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
1872 struct kmem_cache
*ecryptfs_key_sig_cache
;
1874 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
1876 struct ecryptfs_key_sig
*new_key_sig
;
1879 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
1883 "Error allocating from ecryptfs_key_sig_cache\n");
1886 memcpy(new_key_sig
->keysig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
1887 mutex_lock(&crypt_stat
->keysig_list_mutex
);
1888 list_add(&new_key_sig
->crypt_stat_list
, &crypt_stat
->keysig_list
);
1889 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
1894 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
1897 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
1900 struct ecryptfs_global_auth_tok
*new_auth_tok
;
1903 new_auth_tok
= kmem_cache_alloc(ecryptfs_global_auth_tok_cache
,
1905 if (!new_auth_tok
) {
1907 printk(KERN_ERR
"Error allocating from "
1908 "ecryptfs_global_auth_tok_cache\n");
1911 memcpy(new_auth_tok
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
1912 new_auth_tok
->sig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
1913 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
1914 list_add(&new_auth_tok
->mount_crypt_stat_list
,
1915 &mount_crypt_stat
->global_auth_tok_list
);
1916 mount_crypt_stat
->num_global_auth_toks
++;
1917 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);