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 static 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
);
68 * ecryptfs_parse_packet_length
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; non-zero on error
76 int ecryptfs_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 * ecryptfs_write_packet_length
109 * @dest: The byte array target into which to write the length. Must
110 * have at least 5 bytes allocated.
111 * @size: The length to write.
112 * @packet_size_length: The number of bytes used to encode the packet
113 * length is written to this address.
115 * Returns zero on success; non-zero on error.
117 int ecryptfs_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
= ecryptfs_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
= ecryptfs_write_packet_length(&message
[i
],
176 session_key
->encrypted_key_size
,
179 ecryptfs_printk(KERN_ERR
, "Error generating tag 64 packet "
180 "header; cannot generate packet length\n");
183 i
+= packet_size_len
;
184 memcpy(&message
[i
], session_key
->encrypted_key
,
185 session_key
->encrypted_key_size
);
186 i
+= session_key
->encrypted_key_size
;
193 parse_tag_65_packet(struct ecryptfs_session_key
*session_key
, u8
*cipher_code
,
194 struct ecryptfs_message
*msg
)
202 u16 expected_checksum
= 0;
206 * ***** TAG 65 Packet Format *****
207 * | Content Type | 1 byte |
208 * | Status Indicator | 1 byte |
209 * | File Encryption Key Size | 1 or 2 bytes |
210 * | File Encryption Key | arbitrary |
212 message_len
= msg
->data_len
;
214 if (message_len
< 4) {
218 if (data
[i
++] != ECRYPTFS_TAG_65_PACKET_TYPE
) {
219 ecryptfs_printk(KERN_ERR
, "Type should be ECRYPTFS_TAG_65\n");
224 ecryptfs_printk(KERN_ERR
, "Status indicator has non-zero value "
225 "[%d]\n", data
[i
-1]);
229 rc
= ecryptfs_parse_packet_length(&data
[i
], &m_size
, &data_len
);
231 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
236 if (message_len
< (i
+ m_size
)) {
237 ecryptfs_printk(KERN_ERR
, "The message received from ecryptfsd "
238 "is shorter than expected\n");
243 ecryptfs_printk(KERN_ERR
,
244 "The decrypted key is not long enough to "
245 "include a cipher code and checksum\n");
249 *cipher_code
= data
[i
++];
250 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
251 session_key
->decrypted_key_size
= m_size
- 3;
252 if (session_key
->decrypted_key_size
> ECRYPTFS_MAX_KEY_BYTES
) {
253 ecryptfs_printk(KERN_ERR
, "key_size [%d] larger than "
254 "the maximum key size [%d]\n",
255 session_key
->decrypted_key_size
,
256 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
);
260 memcpy(session_key
->decrypted_key
, &data
[i
],
261 session_key
->decrypted_key_size
);
262 i
+= session_key
->decrypted_key_size
;
263 expected_checksum
+= (unsigned char)(data
[i
++]) << 8;
264 expected_checksum
+= (unsigned char)(data
[i
++]);
265 for (i
= 0; i
< session_key
->decrypted_key_size
; i
++)
266 checksum
+= session_key
->decrypted_key
[i
];
267 if (expected_checksum
!= checksum
) {
268 ecryptfs_printk(KERN_ERR
, "Invalid checksum for file "
269 "encryption key; expected [%x]; calculated "
270 "[%x]\n", expected_checksum
, checksum
);
279 write_tag_66_packet(char *signature
, u8 cipher_code
,
280 struct ecryptfs_crypt_stat
*crypt_stat
, char **packet
,
287 size_t packet_size_len
;
292 * ***** TAG 66 Packet Format *****
293 * | Content Type | 1 byte |
294 * | Key Identifier Size | 1 or 2 bytes |
295 * | Key Identifier | arbitrary |
296 * | File Encryption Key Size | 1 or 2 bytes |
297 * | File Encryption Key | arbitrary |
299 data_len
= (5 + ECRYPTFS_SIG_SIZE_HEX
+ crypt_stat
->key_size
);
300 *packet
= kmalloc(data_len
, GFP_KERNEL
);
303 ecryptfs_printk(KERN_ERR
, "Unable to allocate memory\n");
307 message
[i
++] = ECRYPTFS_TAG_66_PACKET_TYPE
;
308 rc
= ecryptfs_write_packet_length(&message
[i
], ECRYPTFS_SIG_SIZE_HEX
,
311 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
312 "header; cannot generate packet length\n");
315 i
+= packet_size_len
;
316 memcpy(&message
[i
], signature
, ECRYPTFS_SIG_SIZE_HEX
);
317 i
+= ECRYPTFS_SIG_SIZE_HEX
;
318 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
319 rc
= ecryptfs_write_packet_length(&message
[i
], crypt_stat
->key_size
+ 3,
322 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet "
323 "header; cannot generate packet length\n");
326 i
+= packet_size_len
;
327 message
[i
++] = cipher_code
;
328 memcpy(&message
[i
], crypt_stat
->key
, crypt_stat
->key_size
);
329 i
+= crypt_stat
->key_size
;
330 for (j
= 0; j
< crypt_stat
->key_size
; j
++)
331 checksum
+= crypt_stat
->key
[j
];
332 message
[i
++] = (checksum
/ 256) % 256;
333 message
[i
++] = (checksum
% 256);
340 parse_tag_67_packet(struct ecryptfs_key_record
*key_rec
,
341 struct ecryptfs_message
*msg
)
350 * ***** TAG 65 Packet Format *****
351 * | Content Type | 1 byte |
352 * | Status Indicator | 1 byte |
353 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
354 * | Encrypted File Encryption Key | arbitrary |
356 message_len
= msg
->data_len
;
358 /* verify that everything through the encrypted FEK size is present */
359 if (message_len
< 4) {
361 printk(KERN_ERR
"%s: message_len is [%Zd]; minimum acceptable "
362 "message length is [%d]\n", __func__
, message_len
, 4);
365 if (data
[i
++] != ECRYPTFS_TAG_67_PACKET_TYPE
) {
367 printk(KERN_ERR
"%s: Type should be ECRYPTFS_TAG_67\n",
373 printk(KERN_ERR
"%s: Status indicator has non zero "
374 "value [%d]\n", __func__
, data
[i
-1]);
378 rc
= ecryptfs_parse_packet_length(&data
[i
], &key_rec
->enc_key_size
,
381 ecryptfs_printk(KERN_WARNING
, "Error parsing packet length; "
386 if (message_len
< (i
+ key_rec
->enc_key_size
)) {
388 printk(KERN_ERR
"%s: message_len [%Zd]; max len is [%Zd]\n",
389 __func__
, message_len
, (i
+ key_rec
->enc_key_size
));
392 if (key_rec
->enc_key_size
> ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
394 printk(KERN_ERR
"%s: Encrypted key_size [%Zd] larger than "
395 "the maximum key size [%d]\n", __func__
,
396 key_rec
->enc_key_size
,
397 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
);
400 memcpy(key_rec
->enc_key
, &data
[i
], key_rec
->enc_key_size
);
406 ecryptfs_get_auth_tok_sig(char **sig
, struct ecryptfs_auth_tok
*auth_tok
)
411 switch (auth_tok
->token_type
) {
412 case ECRYPTFS_PASSWORD
:
413 (*sig
) = auth_tok
->token
.password
.signature
;
415 case ECRYPTFS_PRIVATE_KEY
:
416 (*sig
) = auth_tok
->token
.private_key
.signature
;
419 printk(KERN_ERR
"Cannot get sig for auth_tok of type [%d]\n",
420 auth_tok
->token_type
);
427 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
428 * @auth_tok: The key authentication token used to decrypt the session key
429 * @crypt_stat: The cryptographic context
431 * Returns zero on success; non-zero error otherwise.
434 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
435 struct ecryptfs_crypt_stat
*crypt_stat
)
438 struct ecryptfs_msg_ctx
*msg_ctx
;
439 struct ecryptfs_message
*msg
= NULL
;
445 rc
= ecryptfs_get_auth_tok_sig(&auth_tok_sig
, auth_tok
);
447 printk(KERN_ERR
"Unrecognized auth tok type: [%d]\n",
448 auth_tok
->token_type
);
451 rc
= write_tag_64_packet(auth_tok_sig
, &(auth_tok
->session_key
),
452 &payload
, &payload_len
);
454 ecryptfs_printk(KERN_ERR
, "Failed to write tag 64 packet\n");
457 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
459 ecryptfs_printk(KERN_ERR
, "Error sending message to "
463 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
465 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 65 packet "
466 "from the user space daemon\n");
470 rc
= parse_tag_65_packet(&(auth_tok
->session_key
),
473 printk(KERN_ERR
"Failed to parse tag 65 packet; rc = [%d]\n",
477 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
478 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
479 auth_tok
->session_key
.decrypted_key_size
);
480 crypt_stat
->key_size
= auth_tok
->session_key
.decrypted_key_size
;
481 rc
= ecryptfs_cipher_code_to_string(crypt_stat
->cipher
, cipher_code
);
483 ecryptfs_printk(KERN_ERR
, "Cipher code [%d] is invalid\n",
487 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
488 if (ecryptfs_verbosity
> 0) {
489 ecryptfs_printk(KERN_DEBUG
, "Decrypted session key:\n");
490 ecryptfs_dump_hex(crypt_stat
->key
,
491 crypt_stat
->key_size
);
499 static void wipe_auth_tok_list(struct list_head
*auth_tok_list_head
)
501 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
502 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
504 list_for_each_entry_safe(auth_tok_list_item
, auth_tok_list_item_tmp
,
505 auth_tok_list_head
, list
) {
506 list_del(&auth_tok_list_item
->list
);
507 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
512 struct kmem_cache
*ecryptfs_auth_tok_list_item_cache
;
516 * @crypt_stat: The cryptographic context to modify based on packet contents
517 * @data: The raw bytes of the packet.
518 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
519 * a new authentication token will be placed at the
520 * end of this list for this packet.
521 * @new_auth_tok: Pointer to a pointer to memory that this function
522 * allocates; sets the memory address of the pointer to
523 * NULL on error. This object is added to the
525 * @packet_size: This function writes the size of the parsed packet
526 * into this memory location; zero on error.
527 * @max_packet_size: The maximum allowable packet size
529 * Returns zero on success; non-zero on error.
532 parse_tag_1_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
533 unsigned char *data
, struct list_head
*auth_tok_list
,
534 struct ecryptfs_auth_tok
**new_auth_tok
,
535 size_t *packet_size
, size_t max_packet_size
)
538 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
543 (*new_auth_tok
) = NULL
;
545 * This format is inspired by OpenPGP; see RFC 2440
548 * Tag 1 identifier (1 byte)
549 * Max Tag 1 packet size (max 3 bytes)
551 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
552 * Cipher identifier (1 byte)
553 * Encrypted key size (arbitrary)
555 * 12 bytes minimum packet size
557 if (unlikely(max_packet_size
< 12)) {
558 printk(KERN_ERR
"Invalid max packet size; must be >=12\n");
562 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_1_PACKET_TYPE
) {
563 printk(KERN_ERR
"Enter w/ first byte != 0x%.2x\n",
564 ECRYPTFS_TAG_1_PACKET_TYPE
);
568 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
569 * at end of function upon failure */
571 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
,
573 if (!auth_tok_list_item
) {
574 printk(KERN_ERR
"Unable to allocate memory\n");
578 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
579 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
582 printk(KERN_WARNING
"Error parsing packet length; "
586 if (unlikely(body_size
< (ECRYPTFS_SIG_SIZE
+ 2))) {
587 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
591 (*packet_size
) += length_size
;
592 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
593 printk(KERN_WARNING
"Packet size exceeds max\n");
597 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
598 printk(KERN_WARNING
"Unknown version number [%d]\n",
599 data
[(*packet_size
) - 1]);
603 ecryptfs_to_hex((*new_auth_tok
)->token
.private_key
.signature
,
604 &data
[(*packet_size
)], ECRYPTFS_SIG_SIZE
);
605 *packet_size
+= ECRYPTFS_SIG_SIZE
;
606 /* This byte is skipped because the kernel does not need to
607 * know which public key encryption algorithm was used */
609 (*new_auth_tok
)->session_key
.encrypted_key_size
=
610 body_size
- (ECRYPTFS_SIG_SIZE
+ 2);
611 if ((*new_auth_tok
)->session_key
.encrypted_key_size
612 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES
) {
613 printk(KERN_WARNING
"Tag 1 packet contains key larger "
614 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
618 memcpy((*new_auth_tok
)->session_key
.encrypted_key
,
619 &data
[(*packet_size
)], (body_size
- (ECRYPTFS_SIG_SIZE
+ 2)));
620 (*packet_size
) += (*new_auth_tok
)->session_key
.encrypted_key_size
;
621 (*new_auth_tok
)->session_key
.flags
&=
622 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
623 (*new_auth_tok
)->session_key
.flags
|=
624 ECRYPTFS_CONTAINS_ENCRYPTED_KEY
;
625 (*new_auth_tok
)->token_type
= ECRYPTFS_PRIVATE_KEY
;
626 (*new_auth_tok
)->flags
= 0;
627 (*new_auth_tok
)->session_key
.flags
&=
628 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT
);
629 (*new_auth_tok
)->session_key
.flags
&=
630 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT
);
631 list_add(&auth_tok_list_item
->list
, auth_tok_list
);
634 (*new_auth_tok
) = NULL
;
635 memset(auth_tok_list_item
, 0,
636 sizeof(struct ecryptfs_auth_tok_list_item
));
637 kmem_cache_free(ecryptfs_auth_tok_list_item_cache
,
647 * @crypt_stat: The cryptographic context to modify based on packet
649 * @data: The raw bytes of the packet.
650 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
651 * a new authentication token will be placed at the end
652 * of this list for this packet.
653 * @new_auth_tok: Pointer to a pointer to memory that this function
654 * allocates; sets the memory address of the pointer to
655 * NULL on error. This object is added to the
657 * @packet_size: This function writes the size of the parsed packet
658 * into this memory location; zero on error.
659 * @max_packet_size: maximum number of bytes to parse
661 * Returns zero on success; non-zero on error.
664 parse_tag_3_packet(struct ecryptfs_crypt_stat
*crypt_stat
,
665 unsigned char *data
, struct list_head
*auth_tok_list
,
666 struct ecryptfs_auth_tok
**new_auth_tok
,
667 size_t *packet_size
, size_t max_packet_size
)
670 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
675 (*new_auth_tok
) = NULL
;
677 *This format is inspired by OpenPGP; see RFC 2440
680 * Tag 3 identifier (1 byte)
681 * Max Tag 3 packet size (max 3 bytes)
683 * Cipher code (1 byte)
684 * S2K specifier (1 byte)
685 * Hash identifier (1 byte)
686 * Salt (ECRYPTFS_SALT_SIZE)
687 * Hash iterations (1 byte)
688 * Encrypted key (arbitrary)
690 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
692 if (max_packet_size
< (ECRYPTFS_SALT_SIZE
+ 7)) {
693 printk(KERN_ERR
"Max packet size too large\n");
697 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_3_PACKET_TYPE
) {
698 printk(KERN_ERR
"First byte != 0x%.2x; invalid packet\n",
699 ECRYPTFS_TAG_3_PACKET_TYPE
);
703 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
704 * at end of function upon failure */
706 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache
, GFP_KERNEL
);
707 if (!auth_tok_list_item
) {
708 printk(KERN_ERR
"Unable to allocate memory\n");
712 (*new_auth_tok
) = &auth_tok_list_item
->auth_tok
;
713 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
716 printk(KERN_WARNING
"Error parsing packet length; rc = [%d]\n",
720 if (unlikely(body_size
< (ECRYPTFS_SALT_SIZE
+ 5))) {
721 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
725 (*packet_size
) += length_size
;
726 if (unlikely((*packet_size
) + body_size
> max_packet_size
)) {
727 printk(KERN_ERR
"Packet size exceeds max\n");
731 (*new_auth_tok
)->session_key
.encrypted_key_size
=
732 (body_size
- (ECRYPTFS_SALT_SIZE
+ 5));
733 if (unlikely(data
[(*packet_size
)++] != 0x04)) {
734 printk(KERN_WARNING
"Unknown version number [%d]\n",
735 data
[(*packet_size
) - 1]);
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 if (unlikely(data
[(*packet_size
)++] != 0x03)) {
753 printk(KERN_WARNING
"Only S2K ID 3 is currently supported\n");
757 /* TODO: finish the hash mapping */
758 switch (data
[(*packet_size
)++]) {
759 case 0x01: /* See RFC2440 for these numbers and their mappings */
761 memcpy((*new_auth_tok
)->token
.password
.salt
,
762 &data
[(*packet_size
)], ECRYPTFS_SALT_SIZE
);
763 (*packet_size
) += ECRYPTFS_SALT_SIZE
;
764 /* This conversion was taken straight from RFC2440 */
765 (*new_auth_tok
)->token
.password
.hash_iterations
=
766 ((u32
) 16 + (data
[(*packet_size
)] & 15))
767 << ((data
[(*packet_size
)] >> 4) + 6);
769 /* Friendly reminder:
770 * (*new_auth_tok)->session_key.encrypted_key_size =
771 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
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; /* MD5 */
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;
837 /* This format is inspired by OpenPGP; see RFC 2440
840 * Tag 11 identifier (1 byte)
841 * Max Tag 11 packet size (max 3 bytes)
842 * Binary format specifier (1 byte)
843 * Filename length (1 byte)
844 * Filename ("_CONSOLE") (8 bytes)
845 * Modification date (4 bytes)
846 * Literal data (arbitrary)
848 * We need at least 16 bytes of data for the packet to even be
851 if (max_packet_size
< 16) {
852 printk(KERN_ERR
"Maximum packet size too small\n");
856 if (data
[(*packet_size
)++] != ECRYPTFS_TAG_11_PACKET_TYPE
) {
857 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
861 rc
= ecryptfs_parse_packet_length(&data
[(*packet_size
)], &body_size
,
864 printk(KERN_WARNING
"Invalid tag 11 packet format\n");
867 if (body_size
< 14) {
868 printk(KERN_WARNING
"Invalid body size ([%td])\n", body_size
);
872 (*packet_size
) += length_size
;
873 (*tag_11_contents_size
) = (body_size
- 14);
874 if (unlikely((*packet_size
) + body_size
+ 1 > max_packet_size
)) {
875 printk(KERN_ERR
"Packet size exceeds max\n");
879 if (data
[(*packet_size
)++] != 0x62) {
880 printk(KERN_WARNING
"Unrecognizable packet\n");
884 if (data
[(*packet_size
)++] != 0x08) {
885 printk(KERN_WARNING
"Unrecognizable packet\n");
889 (*packet_size
) += 12; /* Ignore filename and modification date */
890 memcpy(contents
, &data
[(*packet_size
)], (*tag_11_contents_size
));
891 (*packet_size
) += (*tag_11_contents_size
);
895 (*tag_11_contents_size
) = 0;
901 ecryptfs_find_global_auth_tok_for_sig(
902 struct ecryptfs_global_auth_tok
**global_auth_tok
,
903 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
, char *sig
)
905 struct ecryptfs_global_auth_tok
*walker
;
908 (*global_auth_tok
) = NULL
;
909 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
910 list_for_each_entry(walker
,
911 &mount_crypt_stat
->global_auth_tok_list
,
912 mount_crypt_stat_list
) {
913 if (memcmp(walker
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
) == 0) {
914 (*global_auth_tok
) = walker
;
920 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
925 * ecryptfs_verify_version
926 * @version: The version number to confirm
928 * Returns zero on good version; non-zero otherwise
930 static int ecryptfs_verify_version(u16 version
)
936 major
= ((version
>> 8) & 0xFF);
937 minor
= (version
& 0xFF);
938 if (major
!= ECRYPTFS_VERSION_MAJOR
) {
939 ecryptfs_printk(KERN_ERR
, "Major version number mismatch. "
940 "Expected [%d]; got [%d]\n",
941 ECRYPTFS_VERSION_MAJOR
, major
);
945 if (minor
!= ECRYPTFS_VERSION_MINOR
) {
946 ecryptfs_printk(KERN_ERR
, "Minor version number mismatch. "
947 "Expected [%d]; got [%d]\n",
948 ECRYPTFS_VERSION_MINOR
, minor
);
956 int ecryptfs_keyring_auth_tok_for_sig(struct key
**auth_tok_key
,
957 struct ecryptfs_auth_tok
**auth_tok
,
962 (*auth_tok_key
) = request_key(&key_type_user
, sig
, NULL
);
963 if (!(*auth_tok_key
) || IS_ERR(*auth_tok_key
)) {
964 printk(KERN_ERR
"Could not find key with description: [%s]\n",
966 rc
= process_request_key_err(PTR_ERR(*auth_tok_key
));
969 (*auth_tok
) = ecryptfs_get_key_payload_data(*auth_tok_key
);
970 if (ecryptfs_verify_version((*auth_tok
)->version
)) {
972 "Data structure version mismatch. "
973 "Userspace tools must match eCryptfs "
974 "kernel module with major version [%d] "
975 "and minor version [%d]\n",
976 ECRYPTFS_VERSION_MAJOR
,
977 ECRYPTFS_VERSION_MINOR
);
981 if ((*auth_tok
)->token_type
!= ECRYPTFS_PASSWORD
982 && (*auth_tok
)->token_type
!= ECRYPTFS_PRIVATE_KEY
) {
983 printk(KERN_ERR
"Invalid auth_tok structure "
984 "returned from key query\n");
993 * ecryptfs_find_auth_tok_for_sig
994 * @auth_tok: Set to the matching auth_tok; NULL if not found
995 * @crypt_stat: inode crypt_stat crypto context
996 * @sig: Sig of auth_tok to find
998 * For now, this function simply looks at the registered auth_tok's
999 * linked off the mount_crypt_stat, so all the auth_toks that can be
1000 * used must be registered at mount time. This function could
1001 * potentially try a lot harder to find auth_tok's (e.g., by calling
1002 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
1003 * that static registration of auth_tok's will no longer be necessary.
1005 * Returns zero on no error; non-zero on error
1008 ecryptfs_find_auth_tok_for_sig(
1009 struct ecryptfs_auth_tok
**auth_tok
,
1010 struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
1012 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1013 crypt_stat
->mount_crypt_stat
;
1014 struct ecryptfs_global_auth_tok
*global_auth_tok
;
1018 if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
1019 mount_crypt_stat
, sig
)) {
1020 struct key
*auth_tok_key
;
1022 rc
= ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key
, auth_tok
,
1025 (*auth_tok
) = global_auth_tok
->global_auth_tok
;
1030 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1031 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1032 * @crypt_stat: The cryptographic context
1034 * Returns zero on success; non-zero error otherwise
1037 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1038 struct ecryptfs_crypt_stat
*crypt_stat
)
1040 struct scatterlist dst_sg
[2];
1041 struct scatterlist src_sg
[2];
1042 struct mutex
*tfm_mutex
;
1043 struct blkcipher_desc desc
= {
1044 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1048 if (unlikely(ecryptfs_verbosity
> 0)) {
1050 KERN_DEBUG
, "Session key encryption key (size [%d]):\n",
1051 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1053 auth_tok
->token
.password
.session_key_encryption_key
,
1054 auth_tok
->token
.password
.session_key_encryption_key_bytes
);
1056 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1057 crypt_stat
->cipher
);
1059 printk(KERN_ERR
"Internal error whilst attempting to get "
1060 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1061 crypt_stat
->cipher
, rc
);
1064 rc
= virt_to_scatterlist(auth_tok
->session_key
.encrypted_key
,
1065 auth_tok
->session_key
.encrypted_key_size
,
1067 if (rc
< 1 || rc
> 2) {
1068 printk(KERN_ERR
"Internal error whilst attempting to convert "
1069 "auth_tok->session_key.encrypted_key to scatterlist; "
1070 "expected rc = 1; got rc = [%d]. "
1071 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc
,
1072 auth_tok
->session_key
.encrypted_key_size
);
1075 auth_tok
->session_key
.decrypted_key_size
=
1076 auth_tok
->session_key
.encrypted_key_size
;
1077 rc
= virt_to_scatterlist(auth_tok
->session_key
.decrypted_key
,
1078 auth_tok
->session_key
.decrypted_key_size
,
1080 if (rc
< 1 || rc
> 2) {
1081 printk(KERN_ERR
"Internal error whilst attempting to convert "
1082 "auth_tok->session_key.decrypted_key to scatterlist; "
1083 "expected rc = 1; got rc = [%d]\n", rc
);
1086 mutex_lock(tfm_mutex
);
1087 rc
= crypto_blkcipher_setkey(
1088 desc
.tfm
, auth_tok
->token
.password
.session_key_encryption_key
,
1089 crypt_stat
->key_size
);
1090 if (unlikely(rc
< 0)) {
1091 mutex_unlock(tfm_mutex
);
1092 printk(KERN_ERR
"Error setting key for crypto context\n");
1096 rc
= crypto_blkcipher_decrypt(&desc
, dst_sg
, src_sg
,
1097 auth_tok
->session_key
.encrypted_key_size
);
1098 mutex_unlock(tfm_mutex
);
1100 printk(KERN_ERR
"Error decrypting; rc = [%d]\n", rc
);
1103 auth_tok
->session_key
.flags
|= ECRYPTFS_CONTAINS_DECRYPTED_KEY
;
1104 memcpy(crypt_stat
->key
, auth_tok
->session_key
.decrypted_key
,
1105 auth_tok
->session_key
.decrypted_key_size
);
1106 crypt_stat
->flags
|= ECRYPTFS_KEY_VALID
;
1107 if (unlikely(ecryptfs_verbosity
> 0)) {
1108 ecryptfs_printk(KERN_DEBUG
, "FEK of size [%d]:\n",
1109 crypt_stat
->key_size
);
1110 ecryptfs_dump_hex(crypt_stat
->key
,
1111 crypt_stat
->key_size
);
1118 * ecryptfs_parse_packet_set
1119 * @crypt_stat: The cryptographic context
1120 * @src: Virtual address of region of memory containing the packets
1121 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1123 * Get crypt_stat to have the file's session key if the requisite key
1124 * is available to decrypt the session key.
1126 * Returns Zero if a valid authentication token was retrieved and
1127 * processed; negative value for file not encrypted or for error
1130 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat
*crypt_stat
,
1132 struct dentry
*ecryptfs_dentry
)
1135 size_t found_auth_tok
;
1136 size_t next_packet_is_auth_tok_packet
;
1137 struct list_head auth_tok_list
;
1138 struct ecryptfs_auth_tok
*matching_auth_tok
;
1139 struct ecryptfs_auth_tok
*candidate_auth_tok
;
1140 char *candidate_auth_tok_sig
;
1142 struct ecryptfs_auth_tok
*new_auth_tok
;
1143 unsigned char sig_tmp_space
[ECRYPTFS_SIG_SIZE
];
1144 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item
;
1145 size_t tag_11_contents_size
;
1146 size_t tag_11_packet_size
;
1149 INIT_LIST_HEAD(&auth_tok_list
);
1150 /* Parse the header to find as many packets as we can; these will be
1151 * added the our &auth_tok_list */
1152 next_packet_is_auth_tok_packet
= 1;
1153 while (next_packet_is_auth_tok_packet
) {
1154 size_t max_packet_size
= ((PAGE_CACHE_SIZE
- 8) - i
);
1157 case ECRYPTFS_TAG_3_PACKET_TYPE
:
1158 rc
= parse_tag_3_packet(crypt_stat
,
1159 (unsigned char *)&src
[i
],
1160 &auth_tok_list
, &new_auth_tok
,
1161 &packet_size
, max_packet_size
);
1163 ecryptfs_printk(KERN_ERR
, "Error parsing "
1169 rc
= parse_tag_11_packet((unsigned char *)&src
[i
],
1172 &tag_11_contents_size
,
1173 &tag_11_packet_size
,
1176 ecryptfs_printk(KERN_ERR
, "No valid "
1177 "(ecryptfs-specific) literal "
1178 "packet containing "
1179 "authentication token "
1180 "signature found after "
1185 i
+= tag_11_packet_size
;
1186 if (ECRYPTFS_SIG_SIZE
!= tag_11_contents_size
) {
1187 ecryptfs_printk(KERN_ERR
, "Expected "
1188 "signature of size [%d]; "
1191 tag_11_contents_size
);
1195 ecryptfs_to_hex(new_auth_tok
->token
.password
.signature
,
1196 sig_tmp_space
, tag_11_contents_size
);
1197 new_auth_tok
->token
.password
.signature
[
1198 ECRYPTFS_PASSWORD_SIG_SIZE
] = '\0';
1199 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1201 case ECRYPTFS_TAG_1_PACKET_TYPE
:
1202 rc
= parse_tag_1_packet(crypt_stat
,
1203 (unsigned char *)&src
[i
],
1204 &auth_tok_list
, &new_auth_tok
,
1205 &packet_size
, max_packet_size
);
1207 ecryptfs_printk(KERN_ERR
, "Error parsing "
1213 crypt_stat
->flags
|= ECRYPTFS_ENCRYPTED
;
1215 case ECRYPTFS_TAG_11_PACKET_TYPE
:
1216 ecryptfs_printk(KERN_WARNING
, "Invalid packet set "
1217 "(Tag 11 not allowed by itself)\n");
1222 ecryptfs_printk(KERN_DEBUG
, "No packet at offset "
1223 "[%d] of the file header; hex value of "
1224 "character is [0x%.2x]\n", i
, src
[i
]);
1225 next_packet_is_auth_tok_packet
= 0;
1228 if (list_empty(&auth_tok_list
)) {
1229 printk(KERN_ERR
"The lower file appears to be a non-encrypted "
1230 "eCryptfs file; this is not supported in this version "
1231 "of the eCryptfs kernel module\n");
1235 /* auth_tok_list contains the set of authentication tokens
1236 * parsed from the metadata. We need to find a matching
1237 * authentication token that has the secret component(s)
1238 * necessary to decrypt the EFEK in the auth_tok parsed from
1239 * the metadata. There may be several potential matches, but
1240 * just one will be sufficient to decrypt to get the FEK. */
1241 find_next_matching_auth_tok
:
1243 list_for_each_entry(auth_tok_list_item
, &auth_tok_list
, list
) {
1244 candidate_auth_tok
= &auth_tok_list_item
->auth_tok
;
1245 if (unlikely(ecryptfs_verbosity
> 0)) {
1246 ecryptfs_printk(KERN_DEBUG
,
1247 "Considering cadidate auth tok:\n");
1248 ecryptfs_dump_auth_tok(candidate_auth_tok
);
1250 rc
= ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig
,
1251 candidate_auth_tok
);
1254 "Unrecognized candidate auth tok type: [%d]\n",
1255 candidate_auth_tok
->token_type
);
1259 ecryptfs_find_auth_tok_for_sig(&matching_auth_tok
, crypt_stat
,
1260 candidate_auth_tok_sig
);
1261 if (matching_auth_tok
) {
1263 goto found_matching_auth_tok
;
1266 if (!found_auth_tok
) {
1267 ecryptfs_printk(KERN_ERR
, "Could not find a usable "
1268 "authentication token\n");
1272 found_matching_auth_tok
:
1273 if (candidate_auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1274 memcpy(&(candidate_auth_tok
->token
.private_key
),
1275 &(matching_auth_tok
->token
.private_key
),
1276 sizeof(struct ecryptfs_private_key
));
1277 rc
= decrypt_pki_encrypted_session_key(candidate_auth_tok
,
1279 } else if (candidate_auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1280 memcpy(&(candidate_auth_tok
->token
.password
),
1281 &(matching_auth_tok
->token
.password
),
1282 sizeof(struct ecryptfs_password
));
1283 rc
= decrypt_passphrase_encrypted_session_key(
1284 candidate_auth_tok
, crypt_stat
);
1287 struct ecryptfs_auth_tok_list_item
*auth_tok_list_item_tmp
;
1289 ecryptfs_printk(KERN_WARNING
, "Error decrypting the "
1290 "session key for authentication token with sig "
1291 "[%.*s]; rc = [%d]. Removing auth tok "
1292 "candidate from the list and searching for "
1293 "the next match.\n", candidate_auth_tok_sig
,
1294 ECRYPTFS_SIG_SIZE_HEX
, rc
);
1295 list_for_each_entry_safe(auth_tok_list_item
,
1296 auth_tok_list_item_tmp
,
1297 &auth_tok_list
, list
) {
1298 if (candidate_auth_tok
1299 == &auth_tok_list_item
->auth_tok
) {
1300 list_del(&auth_tok_list_item
->list
);
1302 ecryptfs_auth_tok_list_item_cache
,
1303 auth_tok_list_item
);
1304 goto find_next_matching_auth_tok
;
1309 rc
= ecryptfs_compute_root_iv(crypt_stat
);
1311 ecryptfs_printk(KERN_ERR
, "Error computing "
1315 rc
= ecryptfs_init_crypt_ctx(crypt_stat
);
1317 ecryptfs_printk(KERN_ERR
, "Error initializing crypto "
1318 "context for cipher [%s]; rc = [%d]\n",
1319 crypt_stat
->cipher
, rc
);
1322 wipe_auth_tok_list(&auth_tok_list
);
1328 pki_encrypt_session_key(struct ecryptfs_auth_tok
*auth_tok
,
1329 struct ecryptfs_crypt_stat
*crypt_stat
,
1330 struct ecryptfs_key_record
*key_rec
)
1332 struct ecryptfs_msg_ctx
*msg_ctx
= NULL
;
1333 char *payload
= NULL
;
1335 struct ecryptfs_message
*msg
;
1338 rc
= write_tag_66_packet(auth_tok
->token
.private_key
.signature
,
1339 ecryptfs_code_for_cipher_string(crypt_stat
),
1340 crypt_stat
, &payload
, &payload_len
);
1342 ecryptfs_printk(KERN_ERR
, "Error generating tag 66 packet\n");
1345 rc
= ecryptfs_send_message(payload
, payload_len
, &msg_ctx
);
1347 ecryptfs_printk(KERN_ERR
, "Error sending message to "
1351 rc
= ecryptfs_wait_for_response(msg_ctx
, &msg
);
1353 ecryptfs_printk(KERN_ERR
, "Failed to receive tag 67 packet "
1354 "from the user space daemon\n");
1358 rc
= parse_tag_67_packet(key_rec
, msg
);
1360 ecryptfs_printk(KERN_ERR
, "Error parsing tag 67 packet\n");
1367 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1368 * @dest: Buffer into which to write the packet
1369 * @remaining_bytes: Maximum number of bytes that can be writtn
1370 * @auth_tok: The authentication token used for generating the tag 1 packet
1371 * @crypt_stat: The cryptographic context
1372 * @key_rec: The key record struct for the tag 1 packet
1373 * @packet_size: This function will write the number of bytes that end
1374 * up constituting the packet; set to zero on error
1376 * Returns zero on success; non-zero on error.
1379 write_tag_1_packet(char *dest
, size_t *remaining_bytes
,
1380 struct ecryptfs_auth_tok
*auth_tok
,
1381 struct ecryptfs_crypt_stat
*crypt_stat
,
1382 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1385 size_t encrypted_session_key_valid
= 0;
1386 size_t packet_size_length
;
1387 size_t max_packet_size
;
1391 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.private_key
.signature
,
1393 encrypted_session_key_valid
= 0;
1394 for (i
= 0; i
< crypt_stat
->key_size
; i
++)
1395 encrypted_session_key_valid
|=
1396 auth_tok
->session_key
.encrypted_key
[i
];
1397 if (encrypted_session_key_valid
) {
1398 memcpy(key_rec
->enc_key
,
1399 auth_tok
->session_key
.encrypted_key
,
1400 auth_tok
->session_key
.encrypted_key_size
);
1401 goto encrypted_session_key_set
;
1403 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1404 auth_tok
->session_key
.encrypted_key_size
=
1405 auth_tok
->token
.private_key
.key_size
;
1406 rc
= pki_encrypt_session_key(auth_tok
, crypt_stat
, key_rec
);
1408 printk(KERN_ERR
"Failed to encrypt session key via a key "
1409 "module; rc = [%d]\n", rc
);
1412 if (ecryptfs_verbosity
> 0) {
1413 ecryptfs_printk(KERN_DEBUG
, "Encrypted key:\n");
1414 ecryptfs_dump_hex(key_rec
->enc_key
, key_rec
->enc_key_size
);
1416 encrypted_session_key_set
:
1417 /* This format is inspired by OpenPGP; see RFC 2440
1419 max_packet_size
= (1 /* Tag 1 identifier */
1420 + 3 /* Max Tag 1 packet size */
1422 + ECRYPTFS_SIG_SIZE
/* Key identifier */
1423 + 1 /* Cipher identifier */
1424 + key_rec
->enc_key_size
); /* Encrypted key size */
1425 if (max_packet_size
> (*remaining_bytes
)) {
1426 printk(KERN_ERR
"Packet length larger than maximum allowable; "
1427 "need up to [%td] bytes, but there are only [%td] "
1428 "available\n", max_packet_size
, (*remaining_bytes
));
1432 dest
[(*packet_size
)++] = ECRYPTFS_TAG_1_PACKET_TYPE
;
1433 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
1434 (max_packet_size
- 4),
1435 &packet_size_length
);
1437 ecryptfs_printk(KERN_ERR
, "Error generating tag 1 packet "
1438 "header; cannot generate packet length\n");
1441 (*packet_size
) += packet_size_length
;
1442 dest
[(*packet_size
)++] = 0x03; /* version 3 */
1443 memcpy(&dest
[(*packet_size
)], key_rec
->sig
, ECRYPTFS_SIG_SIZE
);
1444 (*packet_size
) += ECRYPTFS_SIG_SIZE
;
1445 dest
[(*packet_size
)++] = RFC2440_CIPHER_RSA
;
1446 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1447 key_rec
->enc_key_size
);
1448 (*packet_size
) += key_rec
->enc_key_size
;
1453 (*remaining_bytes
) -= (*packet_size
);
1458 * write_tag_11_packet
1459 * @dest: Target into which Tag 11 packet is to be written
1460 * @remaining_bytes: Maximum packet length
1461 * @contents: Byte array of contents to copy in
1462 * @contents_length: Number of bytes in contents
1463 * @packet_length: Length of the Tag 11 packet written; zero on error
1465 * Returns zero on success; non-zero on error.
1468 write_tag_11_packet(char *dest
, size_t *remaining_bytes
, char *contents
,
1469 size_t contents_length
, size_t *packet_length
)
1471 size_t packet_size_length
;
1472 size_t max_packet_size
;
1475 (*packet_length
) = 0;
1476 /* This format is inspired by OpenPGP; see RFC 2440
1478 max_packet_size
= (1 /* Tag 11 identifier */
1479 + 3 /* Max Tag 11 packet size */
1480 + 1 /* Binary format specifier */
1481 + 1 /* Filename length */
1482 + 8 /* Filename ("_CONSOLE") */
1483 + 4 /* Modification date */
1484 + contents_length
); /* Literal data */
1485 if (max_packet_size
> (*remaining_bytes
)) {
1486 printk(KERN_ERR
"Packet length larger than maximum allowable; "
1487 "need up to [%td] bytes, but there are only [%td] "
1488 "available\n", max_packet_size
, (*remaining_bytes
));
1492 dest
[(*packet_length
)++] = ECRYPTFS_TAG_11_PACKET_TYPE
;
1493 rc
= ecryptfs_write_packet_length(&dest
[(*packet_length
)],
1494 (max_packet_size
- 4),
1495 &packet_size_length
);
1497 printk(KERN_ERR
"Error generating tag 11 packet header; cannot "
1498 "generate packet length. rc = [%d]\n", rc
);
1501 (*packet_length
) += packet_size_length
;
1502 dest
[(*packet_length
)++] = 0x62; /* binary data format specifier */
1503 dest
[(*packet_length
)++] = 8;
1504 memcpy(&dest
[(*packet_length
)], "_CONSOLE", 8);
1505 (*packet_length
) += 8;
1506 memset(&dest
[(*packet_length
)], 0x00, 4);
1507 (*packet_length
) += 4;
1508 memcpy(&dest
[(*packet_length
)], contents
, contents_length
);
1509 (*packet_length
) += contents_length
;
1512 (*packet_length
) = 0;
1514 (*remaining_bytes
) -= (*packet_length
);
1519 * write_tag_3_packet
1520 * @dest: Buffer into which to write the packet
1521 * @remaining_bytes: Maximum number of bytes that can be written
1522 * @auth_tok: Authentication token
1523 * @crypt_stat: The cryptographic context
1524 * @key_rec: encrypted key
1525 * @packet_size: This function will write the number of bytes that end
1526 * up constituting the packet; set to zero on error
1528 * Returns zero on success; non-zero on error.
1531 write_tag_3_packet(char *dest
, size_t *remaining_bytes
,
1532 struct ecryptfs_auth_tok
*auth_tok
,
1533 struct ecryptfs_crypt_stat
*crypt_stat
,
1534 struct ecryptfs_key_record
*key_rec
, size_t *packet_size
)
1537 size_t encrypted_session_key_valid
= 0;
1538 char session_key_encryption_key
[ECRYPTFS_MAX_KEY_BYTES
];
1539 struct scatterlist dst_sg
[2];
1540 struct scatterlist src_sg
[2];
1541 struct mutex
*tfm_mutex
= NULL
;
1543 size_t packet_size_length
;
1544 size_t max_packet_size
;
1545 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1546 crypt_stat
->mount_crypt_stat
;
1547 struct blkcipher_desc desc
= {
1549 .flags
= CRYPTO_TFM_REQ_MAY_SLEEP
1554 ecryptfs_from_hex(key_rec
->sig
, auth_tok
->token
.password
.signature
,
1556 rc
= ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc
.tfm
, &tfm_mutex
,
1557 crypt_stat
->cipher
);
1559 printk(KERN_ERR
"Internal error whilst attempting to get "
1560 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1561 crypt_stat
->cipher
, rc
);
1564 if (mount_crypt_stat
->global_default_cipher_key_size
== 0) {
1565 struct blkcipher_alg
*alg
= crypto_blkcipher_alg(desc
.tfm
);
1567 printk(KERN_WARNING
"No key size specified at mount; "
1568 "defaulting to [%d]\n", alg
->max_keysize
);
1569 mount_crypt_stat
->global_default_cipher_key_size
=
1572 if (crypt_stat
->key_size
== 0)
1573 crypt_stat
->key_size
=
1574 mount_crypt_stat
->global_default_cipher_key_size
;
1575 if (auth_tok
->session_key
.encrypted_key_size
== 0)
1576 auth_tok
->session_key
.encrypted_key_size
=
1577 crypt_stat
->key_size
;
1578 if (crypt_stat
->key_size
== 24
1579 && strcmp("aes", crypt_stat
->cipher
) == 0) {
1580 memset((crypt_stat
->key
+ 24), 0, 8);
1581 auth_tok
->session_key
.encrypted_key_size
= 32;
1583 auth_tok
->session_key
.encrypted_key_size
= crypt_stat
->key_size
;
1584 key_rec
->enc_key_size
=
1585 auth_tok
->session_key
.encrypted_key_size
;
1586 encrypted_session_key_valid
= 0;
1587 for (i
= 0; i
< auth_tok
->session_key
.encrypted_key_size
; i
++)
1588 encrypted_session_key_valid
|=
1589 auth_tok
->session_key
.encrypted_key
[i
];
1590 if (encrypted_session_key_valid
) {
1591 ecryptfs_printk(KERN_DEBUG
, "encrypted_session_key_valid != 0; "
1592 "using auth_tok->session_key.encrypted_key, "
1593 "where key_rec->enc_key_size = [%d]\n",
1594 key_rec
->enc_key_size
);
1595 memcpy(key_rec
->enc_key
,
1596 auth_tok
->session_key
.encrypted_key
,
1597 key_rec
->enc_key_size
);
1598 goto encrypted_session_key_set
;
1600 if (auth_tok
->token
.password
.flags
&
1601 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET
) {
1602 ecryptfs_printk(KERN_DEBUG
, "Using previously generated "
1603 "session key encryption key of size [%d]\n",
1604 auth_tok
->token
.password
.
1605 session_key_encryption_key_bytes
);
1606 memcpy(session_key_encryption_key
,
1607 auth_tok
->token
.password
.session_key_encryption_key
,
1608 crypt_stat
->key_size
);
1609 ecryptfs_printk(KERN_DEBUG
,
1610 "Cached session key " "encryption key: \n");
1611 if (ecryptfs_verbosity
> 0)
1612 ecryptfs_dump_hex(session_key_encryption_key
, 16);
1614 if (unlikely(ecryptfs_verbosity
> 0)) {
1615 ecryptfs_printk(KERN_DEBUG
, "Session key encryption key:\n");
1616 ecryptfs_dump_hex(session_key_encryption_key
, 16);
1618 rc
= virt_to_scatterlist(crypt_stat
->key
, key_rec
->enc_key_size
,
1620 if (rc
< 1 || rc
> 2) {
1621 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
1622 "for crypt_stat session key; expected rc = 1; "
1623 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
1624 rc
, key_rec
->enc_key_size
);
1628 rc
= virt_to_scatterlist(key_rec
->enc_key
, key_rec
->enc_key_size
,
1630 if (rc
< 1 || rc
> 2) {
1631 ecryptfs_printk(KERN_ERR
, "Error generating scatterlist "
1632 "for crypt_stat encrypted session key; "
1633 "expected rc = 1; got rc = [%d]. "
1634 "key_rec->enc_key_size = [%d]\n", rc
,
1635 key_rec
->enc_key_size
);
1639 mutex_lock(tfm_mutex
);
1640 rc
= crypto_blkcipher_setkey(desc
.tfm
, session_key_encryption_key
,
1641 crypt_stat
->key_size
);
1643 mutex_unlock(tfm_mutex
);
1644 ecryptfs_printk(KERN_ERR
, "Error setting key for crypto "
1645 "context; rc = [%d]\n", rc
);
1649 ecryptfs_printk(KERN_DEBUG
, "Encrypting [%d] bytes of the key\n",
1650 crypt_stat
->key_size
);
1651 rc
= crypto_blkcipher_encrypt(&desc
, dst_sg
, src_sg
,
1652 (*key_rec
).enc_key_size
);
1653 mutex_unlock(tfm_mutex
);
1655 printk(KERN_ERR
"Error encrypting; rc = [%d]\n", rc
);
1658 ecryptfs_printk(KERN_DEBUG
, "This should be the encrypted key:\n");
1659 if (ecryptfs_verbosity
> 0) {
1660 ecryptfs_printk(KERN_DEBUG
, "EFEK of size [%d]:\n",
1661 key_rec
->enc_key_size
);
1662 ecryptfs_dump_hex(key_rec
->enc_key
,
1663 key_rec
->enc_key_size
);
1665 encrypted_session_key_set
:
1666 /* This format is inspired by OpenPGP; see RFC 2440
1668 max_packet_size
= (1 /* Tag 3 identifier */
1669 + 3 /* Max Tag 3 packet size */
1671 + 1 /* Cipher code */
1672 + 1 /* S2K specifier */
1673 + 1 /* Hash identifier */
1674 + ECRYPTFS_SALT_SIZE
/* Salt */
1675 + 1 /* Hash iterations */
1676 + key_rec
->enc_key_size
); /* Encrypted key size */
1677 if (max_packet_size
> (*remaining_bytes
)) {
1678 printk(KERN_ERR
"Packet too large; need up to [%td] bytes, but "
1679 "there are only [%td] available\n", max_packet_size
,
1680 (*remaining_bytes
));
1684 dest
[(*packet_size
)++] = ECRYPTFS_TAG_3_PACKET_TYPE
;
1685 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
1686 * to get the number of octets in the actual Tag 3 packet */
1687 rc
= ecryptfs_write_packet_length(&dest
[(*packet_size
)],
1688 (max_packet_size
- 4),
1689 &packet_size_length
);
1691 printk(KERN_ERR
"Error generating tag 3 packet header; cannot "
1692 "generate packet length. rc = [%d]\n", rc
);
1695 (*packet_size
) += packet_size_length
;
1696 dest
[(*packet_size
)++] = 0x04; /* version 4 */
1697 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
1698 * specified with strings */
1699 cipher_code
= ecryptfs_code_for_cipher_string(crypt_stat
);
1700 if (cipher_code
== 0) {
1701 ecryptfs_printk(KERN_WARNING
, "Unable to generate code for "
1702 "cipher [%s]\n", crypt_stat
->cipher
);
1706 dest
[(*packet_size
)++] = cipher_code
;
1707 dest
[(*packet_size
)++] = 0x03; /* S2K */
1708 dest
[(*packet_size
)++] = 0x01; /* MD5 (TODO: parameterize) */
1709 memcpy(&dest
[(*packet_size
)], auth_tok
->token
.password
.salt
,
1710 ECRYPTFS_SALT_SIZE
);
1711 (*packet_size
) += ECRYPTFS_SALT_SIZE
; /* salt */
1712 dest
[(*packet_size
)++] = 0x60; /* hash iterations (65536) */
1713 memcpy(&dest
[(*packet_size
)], key_rec
->enc_key
,
1714 key_rec
->enc_key_size
);
1715 (*packet_size
) += key_rec
->enc_key_size
;
1720 (*remaining_bytes
) -= (*packet_size
);
1724 struct kmem_cache
*ecryptfs_key_record_cache
;
1727 * ecryptfs_generate_key_packet_set
1728 * @dest_base: Virtual address from which to write the key record set
1729 * @crypt_stat: The cryptographic context from which the
1730 * authentication tokens will be retrieved
1731 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
1732 * for the global parameters
1733 * @len: The amount written
1734 * @max: The maximum amount of data allowed to be written
1736 * Generates a key packet set and writes it to the virtual address
1739 * Returns zero on success; non-zero on error.
1742 ecryptfs_generate_key_packet_set(char *dest_base
,
1743 struct ecryptfs_crypt_stat
*crypt_stat
,
1744 struct dentry
*ecryptfs_dentry
, size_t *len
,
1747 struct ecryptfs_auth_tok
*auth_tok
;
1748 struct ecryptfs_global_auth_tok
*global_auth_tok
;
1749 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
1750 &ecryptfs_superblock_to_private(
1751 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
1753 struct ecryptfs_key_record
*key_rec
;
1754 struct ecryptfs_key_sig
*key_sig
;
1758 mutex_lock(&crypt_stat
->keysig_list_mutex
);
1759 key_rec
= kmem_cache_alloc(ecryptfs_key_record_cache
, GFP_KERNEL
);
1764 list_for_each_entry(key_sig
, &crypt_stat
->keysig_list
,
1766 memset(key_rec
, 0, sizeof(*key_rec
));
1767 rc
= ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok
,
1771 printk(KERN_ERR
"Error attempting to get the global "
1772 "auth_tok; rc = [%d]\n", rc
);
1775 if (global_auth_tok
->flags
& ECRYPTFS_AUTH_TOK_INVALID
) {
1777 "Skipping invalid auth tok with sig = [%s]\n",
1778 global_auth_tok
->sig
);
1781 auth_tok
= global_auth_tok
->global_auth_tok
;
1782 if (auth_tok
->token_type
== ECRYPTFS_PASSWORD
) {
1783 rc
= write_tag_3_packet((dest_base
+ (*len
)),
1785 crypt_stat
, key_rec
,
1788 ecryptfs_printk(KERN_WARNING
, "Error "
1789 "writing tag 3 packet\n");
1793 /* Write auth tok signature packet */
1794 rc
= write_tag_11_packet((dest_base
+ (*len
)), &max
,
1796 ECRYPTFS_SIG_SIZE
, &written
);
1798 ecryptfs_printk(KERN_ERR
, "Error writing "
1799 "auth tok signature packet\n");
1803 } else if (auth_tok
->token_type
== ECRYPTFS_PRIVATE_KEY
) {
1804 rc
= write_tag_1_packet(dest_base
+ (*len
),
1806 crypt_stat
, key_rec
, &written
);
1808 ecryptfs_printk(KERN_WARNING
, "Error "
1809 "writing tag 1 packet\n");
1814 ecryptfs_printk(KERN_WARNING
, "Unsupported "
1815 "authentication token type\n");
1820 if (likely(max
> 0)) {
1821 dest_base
[(*len
)] = 0x00;
1823 ecryptfs_printk(KERN_ERR
, "Error writing boundary byte\n");
1827 kmem_cache_free(ecryptfs_key_record_cache
, key_rec
);
1831 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
1835 struct kmem_cache
*ecryptfs_key_sig_cache
;
1837 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat
*crypt_stat
, char *sig
)
1839 struct ecryptfs_key_sig
*new_key_sig
;
1842 new_key_sig
= kmem_cache_alloc(ecryptfs_key_sig_cache
, GFP_KERNEL
);
1846 "Error allocating from ecryptfs_key_sig_cache\n");
1849 memcpy(new_key_sig
->keysig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
1850 mutex_lock(&crypt_stat
->keysig_list_mutex
);
1851 list_add(&new_key_sig
->crypt_stat_list
, &crypt_stat
->keysig_list
);
1852 mutex_unlock(&crypt_stat
->keysig_list_mutex
);
1857 struct kmem_cache
*ecryptfs_global_auth_tok_cache
;
1860 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
,
1863 struct ecryptfs_global_auth_tok
*new_auth_tok
;
1866 new_auth_tok
= kmem_cache_zalloc(ecryptfs_global_auth_tok_cache
,
1868 if (!new_auth_tok
) {
1870 printk(KERN_ERR
"Error allocating from "
1871 "ecryptfs_global_auth_tok_cache\n");
1874 memcpy(new_auth_tok
->sig
, sig
, ECRYPTFS_SIG_SIZE_HEX
);
1875 new_auth_tok
->sig
[ECRYPTFS_SIG_SIZE_HEX
] = '\0';
1876 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
1877 list_add(&new_auth_tok
->mount_crypt_stat_list
,
1878 &mount_crypt_stat
->global_auth_tok_list
);
1879 mount_crypt_stat
->num_global_auth_toks
++;
1880 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);