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