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);
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 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 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 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 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
405 switch (auth_tok->token_type) {
406 case ECRYPTFS_PASSWORD:
407 (*sig) = auth_tok->token.password.signature;
409 case ECRYPTFS_PRIVATE_KEY:
410 (*sig) = auth_tok->token.private_key.signature;
413 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
414 auth_tok->token_type);
421 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
422 * @auth_tok: The key authentication token used to decrypt the session key
423 * @crypt_stat: The cryptographic context
425 * Returns zero on success; non-zero error otherwise.
428 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
429 struct ecryptfs_crypt_stat *crypt_stat)
432 struct ecryptfs_msg_ctx *msg_ctx;
433 struct ecryptfs_message *msg = NULL;
435 char *netlink_message;
436 size_t netlink_message_length;
439 if ((rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok))) {
440 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
441 auth_tok->token_type);
444 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
445 &netlink_message, &netlink_message_length);
447 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet");
450 rc = ecryptfs_send_message(ecryptfs_transport, netlink_message,
451 netlink_message_length, &msg_ctx);
453 ecryptfs_printk(KERN_ERR, "Error sending netlink message\n");
456 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
458 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
459 "from the user space daemon\n");
463 rc = parse_tag_65_packet(&(auth_tok->session_key),
466 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
470 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
471 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
472 auth_tok->session_key.decrypted_key_size);
473 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
474 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
476 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
480 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
481 if (ecryptfs_verbosity > 0) {
482 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
483 ecryptfs_dump_hex(crypt_stat->key,
484 crypt_stat->key_size);
492 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
494 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
495 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
497 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
498 auth_tok_list_head, list) {
499 list_del(&auth_tok_list_item->list);
500 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
505 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
509 * @crypt_stat: The cryptographic context to modify based on packet contents
510 * @data: The raw bytes of the packet.
511 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
512 * a new authentication token will be placed at the
513 * end of this list for this packet.
514 * @new_auth_tok: Pointer to a pointer to memory that this function
515 * allocates; sets the memory address of the pointer to
516 * NULL on error. This object is added to the
518 * @packet_size: This function writes the size of the parsed packet
519 * into this memory location; zero on error.
520 * @max_packet_size: The maximum allowable packet size
522 * Returns zero on success; non-zero on error.
525 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
526 unsigned char *data, struct list_head *auth_tok_list,
527 struct ecryptfs_auth_tok **new_auth_tok,
528 size_t *packet_size, size_t max_packet_size)
531 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
536 (*new_auth_tok) = NULL;
538 * This format is inspired by OpenPGP; see RFC 2440
541 * Tag 1 identifier (1 byte)
542 * Max Tag 1 packet size (max 3 bytes)
544 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
545 * Cipher identifier (1 byte)
546 * Encrypted key size (arbitrary)
548 * 12 bytes minimum packet size
550 if (unlikely(max_packet_size < 12)) {
551 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
555 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
556 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
557 ECRYPTFS_TAG_1_PACKET_TYPE);
561 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
562 * at end of function upon failure */
564 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
566 if (!auth_tok_list_item) {
567 printk(KERN_ERR "Unable to allocate memory\n");
571 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
572 if ((rc = parse_packet_length(&data[(*packet_size)], &body_size,
574 printk(KERN_WARNING "Error parsing packet length; "
578 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
579 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
583 (*packet_size) += length_size;
584 if (unlikely((*packet_size) + body_size > max_packet_size)) {
585 printk(KERN_WARNING "Packet size exceeds max\n");
589 if (unlikely(data[(*packet_size)++] != 0x03)) {
590 printk(KERN_WARNING "Unknown version number [%d]\n",
591 data[(*packet_size) - 1]);
595 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
596 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
597 *packet_size += ECRYPTFS_SIG_SIZE;
598 /* This byte is skipped because the kernel does not need to
599 * know which public key encryption algorithm was used */
601 (*new_auth_tok)->session_key.encrypted_key_size =
602 body_size - (ECRYPTFS_SIG_SIZE + 2);
603 if ((*new_auth_tok)->session_key.encrypted_key_size
604 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
605 printk(KERN_WARNING "Tag 1 packet contains key larger "
606 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
610 memcpy((*new_auth_tok)->session_key.encrypted_key,
611 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
612 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
613 (*new_auth_tok)->session_key.flags &=
614 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
615 (*new_auth_tok)->session_key.flags |=
616 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
617 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
618 (*new_auth_tok)->flags = 0;
619 (*new_auth_tok)->session_key.flags &=
620 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
621 (*new_auth_tok)->session_key.flags &=
622 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
623 list_add(&auth_tok_list_item->list, auth_tok_list);
626 (*new_auth_tok) = NULL;
627 memset(auth_tok_list_item, 0,
628 sizeof(struct ecryptfs_auth_tok_list_item));
629 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
639 * @crypt_stat: The cryptographic context to modify based on packet
641 * @data: The raw bytes of the packet.
642 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
643 * a new authentication token will be placed at the end
644 * of this list for this packet.
645 * @new_auth_tok: Pointer to a pointer to memory that this function
646 * allocates; sets the memory address of the pointer to
647 * NULL on error. This object is added to the
649 * @packet_size: This function writes the size of the parsed packet
650 * into this memory location; zero on error.
651 * @max_packet_size: maximum number of bytes to parse
653 * Returns zero on success; non-zero on error.
656 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
657 unsigned char *data, struct list_head *auth_tok_list,
658 struct ecryptfs_auth_tok **new_auth_tok,
659 size_t *packet_size, size_t max_packet_size)
662 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
667 (*new_auth_tok) = NULL;
669 *This format is inspired by OpenPGP; see RFC 2440
672 * Tag 3 identifier (1 byte)
673 * Max Tag 3 packet size (max 3 bytes)
675 * Cipher code (1 byte)
676 * S2K specifier (1 byte)
677 * Hash identifier (1 byte)
678 * Salt (ECRYPTFS_SALT_SIZE)
679 * Hash iterations (1 byte)
680 * Encrypted key (arbitrary)
682 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
684 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
685 printk(KERN_ERR "Max packet size too large\n");
689 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
690 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
691 ECRYPTFS_TAG_3_PACKET_TYPE);
695 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
696 * at end of function upon failure */
698 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
699 if (!auth_tok_list_item) {
700 printk(KERN_ERR "Unable to allocate memory\n");
704 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
705 if ((rc = parse_packet_length(&data[(*packet_size)], &body_size,
707 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
711 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
712 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
716 (*packet_size) += length_size;
717 if (unlikely((*packet_size) + body_size > max_packet_size)) {
718 printk(KERN_ERR "Packet size exceeds max\n");
722 (*new_auth_tok)->session_key.encrypted_key_size =
723 (body_size - (ECRYPTFS_SALT_SIZE + 5));
724 if (unlikely(data[(*packet_size)++] != 0x04)) {
725 printk(KERN_WARNING "Unknown version number [%d]\n",
726 data[(*packet_size) - 1]);
730 ecryptfs_cipher_code_to_string(crypt_stat->cipher,
731 (u16)data[(*packet_size)]);
732 /* A little extra work to differentiate among the AES key
733 * sizes; see RFC2440 */
734 switch(data[(*packet_size)++]) {
735 case RFC2440_CIPHER_AES_192:
736 crypt_stat->key_size = 24;
739 crypt_stat->key_size =
740 (*new_auth_tok)->session_key.encrypted_key_size;
742 ecryptfs_init_crypt_ctx(crypt_stat);
743 if (unlikely(data[(*packet_size)++] != 0x03)) {
744 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
748 /* TODO: finish the hash mapping */
749 switch (data[(*packet_size)++]) {
750 case 0x01: /* See RFC2440 for these numbers and their mappings */
752 memcpy((*new_auth_tok)->token.password.salt,
753 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
754 (*packet_size) += ECRYPTFS_SALT_SIZE;
755 /* This conversion was taken straight from RFC2440 */
756 (*new_auth_tok)->token.password.hash_iterations =
757 ((u32) 16 + (data[(*packet_size)] & 15))
758 << ((data[(*packet_size)] >> 4) + 6);
760 /* Friendly reminder:
761 * (*new_auth_tok)->session_key.encrypted_key_size =
762 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
763 memcpy((*new_auth_tok)->session_key.encrypted_key,
764 &data[(*packet_size)],
765 (*new_auth_tok)->session_key.encrypted_key_size);
767 (*new_auth_tok)->session_key.encrypted_key_size;
768 (*new_auth_tok)->session_key.flags &=
769 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
770 (*new_auth_tok)->session_key.flags |=
771 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
772 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
775 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
776 "[%d]\n", data[(*packet_size) - 1]);
780 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
781 /* TODO: Parametarize; we might actually want userspace to
782 * decrypt the session key. */
783 (*new_auth_tok)->session_key.flags &=
784 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
785 (*new_auth_tok)->session_key.flags &=
786 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
787 list_add(&auth_tok_list_item->list, auth_tok_list);
790 (*new_auth_tok) = NULL;
791 memset(auth_tok_list_item, 0,
792 sizeof(struct ecryptfs_auth_tok_list_item));
793 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
802 * parse_tag_11_packet
803 * @data: The raw bytes of the packet
804 * @contents: This function writes the data contents of the literal
805 * packet into this memory location
806 * @max_contents_bytes: The maximum number of bytes that this function
807 * is allowed to write into contents
808 * @tag_11_contents_size: This function writes the size of the parsed
809 * contents into this memory location; zero on
811 * @packet_size: This function writes the size of the parsed packet
812 * into this memory location; zero on error
813 * @max_packet_size: maximum number of bytes to parse
815 * Returns zero on success; non-zero on error.
818 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
819 size_t max_contents_bytes, size_t *tag_11_contents_size,
820 size_t *packet_size, size_t max_packet_size)
827 (*tag_11_contents_size) = 0;
828 /* This format is inspired by OpenPGP; see RFC 2440
831 * Tag 11 identifier (1 byte)
832 * Max Tag 11 packet size (max 3 bytes)
833 * Binary format specifier (1 byte)
834 * Filename length (1 byte)
835 * Filename ("_CONSOLE") (8 bytes)
836 * Modification date (4 bytes)
837 * Literal data (arbitrary)
839 * We need at least 16 bytes of data for the packet to even be
842 if (max_packet_size < 16) {
843 printk(KERN_ERR "Maximum packet size too small\n");
847 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
848 printk(KERN_WARNING "Invalid tag 11 packet format\n");
852 if ((rc = parse_packet_length(&data[(*packet_size)], &body_size,
854 printk(KERN_WARNING "Invalid tag 11 packet format\n");
857 if (body_size < 14) {
858 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
862 (*packet_size) += length_size;
863 (*tag_11_contents_size) = (body_size - 14);
864 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
865 printk(KERN_ERR "Packet size exceeds max\n");
869 if (data[(*packet_size)++] != 0x62) {
870 printk(KERN_WARNING "Unrecognizable packet\n");
874 if (data[(*packet_size)++] != 0x08) {
875 printk(KERN_WARNING "Unrecognizable packet\n");
879 (*packet_size) += 12; /* Ignore filename and modification date */
880 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
881 (*packet_size) += (*tag_11_contents_size);
885 (*tag_11_contents_size) = 0;
891 ecryptfs_find_global_auth_tok_for_sig(
892 struct ecryptfs_global_auth_tok **global_auth_tok,
893 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
895 struct ecryptfs_global_auth_tok *walker;
898 (*global_auth_tok) = NULL;
899 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
900 list_for_each_entry(walker,
901 &mount_crypt_stat->global_auth_tok_list,
902 mount_crypt_stat_list) {
903 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX) == 0) {
904 (*global_auth_tok) = walker;
910 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
915 * ecryptfs_verify_version
916 * @version: The version number to confirm
918 * Returns zero on good version; non-zero otherwise
920 static int ecryptfs_verify_version(u16 version)
926 major = ((version >> 8) & 0xFF);
927 minor = (version & 0xFF);
928 if (major != ECRYPTFS_VERSION_MAJOR) {
929 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
930 "Expected [%d]; got [%d]\n",
931 ECRYPTFS_VERSION_MAJOR, major);
935 if (minor != ECRYPTFS_VERSION_MINOR) {
936 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
937 "Expected [%d]; got [%d]\n",
938 ECRYPTFS_VERSION_MINOR, minor);
946 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
947 struct ecryptfs_auth_tok **auth_tok,
952 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
953 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
954 printk(KERN_ERR "Could not find key with description: [%s]\n",
956 process_request_key_err(PTR_ERR(*auth_tok_key));
960 (*auth_tok) = ecryptfs_get_key_payload_data(*auth_tok_key);
961 if (ecryptfs_verify_version((*auth_tok)->version)) {
963 "Data structure version mismatch. "
964 "Userspace tools must match eCryptfs "
965 "kernel module with major version [%d] "
966 "and minor version [%d]\n",
967 ECRYPTFS_VERSION_MAJOR,
968 ECRYPTFS_VERSION_MINOR);
972 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
973 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
974 printk(KERN_ERR "Invalid auth_tok structure "
975 "returned from key query\n");
984 * ecryptfs_find_auth_tok_for_sig
985 * @auth_tok: Set to the matching auth_tok; NULL if not found
986 * @crypt_stat: inode crypt_stat crypto context
987 * @sig: Sig of auth_tok to find
989 * For now, this function simply looks at the registered auth_tok's
990 * linked off the mount_crypt_stat, so all the auth_toks that can be
991 * used must be registered at mount time. This function could
992 * potentially try a lot harder to find auth_tok's (e.g., by calling
993 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
994 * that static registration of auth_tok's will no longer be necessary.
996 * Returns zero on no error; non-zero on error
999 ecryptfs_find_auth_tok_for_sig(
1000 struct ecryptfs_auth_tok **auth_tok,
1001 struct ecryptfs_crypt_stat *crypt_stat, char *sig)
1003 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1004 crypt_stat->mount_crypt_stat;
1005 struct ecryptfs_global_auth_tok *global_auth_tok;
1009 if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
1010 mount_crypt_stat, sig)) {
1011 struct key *auth_tok_key;
1013 rc = ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key, auth_tok,
1016 (*auth_tok) = global_auth_tok->global_auth_tok;
1021 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1022 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1023 * @crypt_stat: The cryptographic context
1025 * Returns zero on success; non-zero error otherwise
1028 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1029 struct ecryptfs_crypt_stat *crypt_stat)
1031 struct scatterlist dst_sg;
1032 struct scatterlist src_sg;
1033 struct mutex *tfm_mutex;
1034 struct blkcipher_desc desc = {
1035 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1039 if (unlikely(ecryptfs_verbosity > 0)) {
1041 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1042 auth_tok->token.password.session_key_encryption_key_bytes);
1044 auth_tok->token.password.session_key_encryption_key,
1045 auth_tok->token.password.session_key_encryption_key_bytes);
1047 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1048 crypt_stat->cipher);
1050 printk(KERN_ERR "Internal error whilst attempting to get "
1051 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1052 crypt_stat->cipher, rc);
1055 if ((rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1056 auth_tok->session_key.encrypted_key_size,
1057 &src_sg, 1)) != 1) {
1058 printk(KERN_ERR "Internal error whilst attempting to convert "
1059 "auth_tok->session_key.encrypted_key to scatterlist; "
1060 "expected rc = 1; got rc = [%d]. "
1061 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1062 auth_tok->session_key.encrypted_key_size);
1065 auth_tok->session_key.decrypted_key_size =
1066 auth_tok->session_key.encrypted_key_size;
1067 if ((rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1068 auth_tok->session_key.decrypted_key_size,
1069 &dst_sg, 1)) != 1) {
1070 printk(KERN_ERR "Internal error whilst attempting to convert "
1071 "auth_tok->session_key.decrypted_key to scatterlist; "
1072 "expected rc = 1; got rc = [%d]\n", rc);
1075 mutex_lock(tfm_mutex);
1076 rc = crypto_blkcipher_setkey(
1077 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1078 crypt_stat->key_size);
1079 if (unlikely(rc < 0)) {
1080 mutex_unlock(tfm_mutex);
1081 printk(KERN_ERR "Error setting key for crypto context\n");
1085 rc = crypto_blkcipher_decrypt(&desc, &dst_sg, &src_sg,
1086 auth_tok->session_key.encrypted_key_size);
1087 mutex_unlock(tfm_mutex);
1089 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1092 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1093 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1094 auth_tok->session_key.decrypted_key_size);
1095 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1096 if (unlikely(ecryptfs_verbosity > 0)) {
1097 ecryptfs_printk(KERN_DEBUG, "FEK of size [%d]:\n",
1098 crypt_stat->key_size);
1099 ecryptfs_dump_hex(crypt_stat->key,
1100 crypt_stat->key_size);
1107 * ecryptfs_parse_packet_set
1108 * @crypt_stat: The cryptographic context
1109 * @src: Virtual address of region of memory containing the packets
1110 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1112 * Get crypt_stat to have the file's session key if the requisite key
1113 * is available to decrypt the session key.
1115 * Returns Zero if a valid authentication token was retrieved and
1116 * processed; negative value for file not encrypted or for error
1119 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1121 struct dentry *ecryptfs_dentry)
1124 size_t found_auth_tok;
1125 size_t next_packet_is_auth_tok_packet;
1126 struct list_head auth_tok_list;
1127 struct ecryptfs_auth_tok *matching_auth_tok;
1128 struct ecryptfs_auth_tok *candidate_auth_tok;
1129 char *candidate_auth_tok_sig;
1131 struct ecryptfs_auth_tok *new_auth_tok;
1132 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1133 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1134 size_t tag_11_contents_size;
1135 size_t tag_11_packet_size;
1138 INIT_LIST_HEAD(&auth_tok_list);
1139 /* Parse the header to find as many packets as we can; these will be
1140 * added the our &auth_tok_list */
1141 next_packet_is_auth_tok_packet = 1;
1142 while (next_packet_is_auth_tok_packet) {
1143 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1146 case ECRYPTFS_TAG_3_PACKET_TYPE:
1147 rc = parse_tag_3_packet(crypt_stat,
1148 (unsigned char *)&src[i],
1149 &auth_tok_list, &new_auth_tok,
1150 &packet_size, max_packet_size);
1152 ecryptfs_printk(KERN_ERR, "Error parsing "
1158 rc = parse_tag_11_packet((unsigned char *)&src[i],
1161 &tag_11_contents_size,
1162 &tag_11_packet_size,
1165 ecryptfs_printk(KERN_ERR, "No valid "
1166 "(ecryptfs-specific) literal "
1167 "packet containing "
1168 "authentication token "
1169 "signature found after "
1174 i += tag_11_packet_size;
1175 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1176 ecryptfs_printk(KERN_ERR, "Expected "
1177 "signature of size [%d]; "
1180 tag_11_contents_size);
1184 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1185 sig_tmp_space, tag_11_contents_size);
1186 new_auth_tok->token.password.signature[
1187 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1188 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1190 case ECRYPTFS_TAG_1_PACKET_TYPE:
1191 rc = parse_tag_1_packet(crypt_stat,
1192 (unsigned char *)&src[i],
1193 &auth_tok_list, &new_auth_tok,
1194 &packet_size, max_packet_size);
1196 ecryptfs_printk(KERN_ERR, "Error parsing "
1202 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1204 case ECRYPTFS_TAG_11_PACKET_TYPE:
1205 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1206 "(Tag 11 not allowed by itself)\n");
1211 ecryptfs_printk(KERN_DEBUG, "No packet at offset "
1212 "[%d] of the file header; hex value of "
1213 "character is [0x%.2x]\n", i, src[i]);
1214 next_packet_is_auth_tok_packet = 0;
1217 if (list_empty(&auth_tok_list)) {
1218 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1219 "eCryptfs file; this is not supported in this version "
1220 "of the eCryptfs kernel module\n");
1224 /* auth_tok_list contains the set of authentication tokens
1225 * parsed from the metadata. We need to find a matching
1226 * authentication token that has the secret component(s)
1227 * necessary to decrypt the EFEK in the auth_tok parsed from
1228 * the metadata. There may be several potential matches, but
1229 * just one will be sufficient to decrypt to get the FEK. */
1230 find_next_matching_auth_tok:
1232 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1233 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1234 if (unlikely(ecryptfs_verbosity > 0)) {
1235 ecryptfs_printk(KERN_DEBUG,
1236 "Considering cadidate auth tok:\n");
1237 ecryptfs_dump_auth_tok(candidate_auth_tok);
1239 if ((rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1240 candidate_auth_tok))) {
1242 "Unrecognized candidate auth tok type: [%d]\n",
1243 candidate_auth_tok->token_type);
1247 if ((rc = ecryptfs_find_auth_tok_for_sig(
1248 &matching_auth_tok, crypt_stat,
1249 candidate_auth_tok_sig)))
1251 if (matching_auth_tok) {
1253 goto found_matching_auth_tok;
1256 if (!found_auth_tok) {
1257 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1258 "authentication token\n");
1262 found_matching_auth_tok:
1263 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1264 memcpy(&(candidate_auth_tok->token.private_key),
1265 &(matching_auth_tok->token.private_key),
1266 sizeof(struct ecryptfs_private_key));
1267 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1269 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1270 memcpy(&(candidate_auth_tok->token.password),
1271 &(matching_auth_tok->token.password),
1272 sizeof(struct ecryptfs_password));
1273 rc = decrypt_passphrase_encrypted_session_key(
1274 candidate_auth_tok, crypt_stat);
1277 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1279 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1280 "session key for authentication token with sig "
1281 "[%.*s]; rc = [%d]. Removing auth tok "
1282 "candidate from the list and searching for "
1283 "the next match.\n", candidate_auth_tok_sig,
1284 ECRYPTFS_SIG_SIZE_HEX, rc);
1285 list_for_each_entry_safe(auth_tok_list_item,
1286 auth_tok_list_item_tmp,
1287 &auth_tok_list, list) {
1288 if (candidate_auth_tok
1289 == &auth_tok_list_item->auth_tok) {
1290 list_del(&auth_tok_list_item->list);
1292 ecryptfs_auth_tok_list_item_cache,
1293 auth_tok_list_item);
1294 goto find_next_matching_auth_tok;
1299 rc = ecryptfs_compute_root_iv(crypt_stat);
1301 ecryptfs_printk(KERN_ERR, "Error computing "
1305 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1307 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1308 "context for cipher [%s]; rc = [%d]\n",
1309 crypt_stat->cipher, rc);
1312 wipe_auth_tok_list(&auth_tok_list);
1318 pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
1319 struct ecryptfs_crypt_stat *crypt_stat,
1320 struct ecryptfs_key_record *key_rec)
1322 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1323 char *netlink_payload;
1324 size_t netlink_payload_length;
1325 struct ecryptfs_message *msg;
1328 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1329 ecryptfs_code_for_cipher_string(crypt_stat),
1330 crypt_stat, &netlink_payload,
1331 &netlink_payload_length);
1333 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1336 rc = ecryptfs_send_message(ecryptfs_transport, netlink_payload,
1337 netlink_payload_length, &msg_ctx);
1339 ecryptfs_printk(KERN_ERR, "Error sending netlink message\n");
1342 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1344 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1345 "from the user space daemon\n");
1349 rc = parse_tag_67_packet(key_rec, msg);
1351 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
1354 if (netlink_payload)
1355 kfree(netlink_payload);
1359 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1360 * @dest: Buffer into which to write the packet
1361 * @remaining_bytes: Maximum number of bytes that can be writtn
1362 * @auth_tok: The authentication token used for generating the tag 1 packet
1363 * @crypt_stat: The cryptographic context
1364 * @key_rec: The key record struct for the tag 1 packet
1365 * @packet_size: This function will write the number of bytes that end
1366 * up constituting the packet; set to zero on error
1368 * Returns zero on success; non-zero on error.
1371 write_tag_1_packet(char *dest, size_t *remaining_bytes,
1372 struct ecryptfs_auth_tok *auth_tok,
1373 struct ecryptfs_crypt_stat *crypt_stat,
1374 struct ecryptfs_key_record *key_rec, size_t *packet_size)
1377 size_t encrypted_session_key_valid = 0;
1378 size_t packet_size_length;
1379 size_t max_packet_size;
1383 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
1385 encrypted_session_key_valid = 0;
1386 for (i = 0; i < crypt_stat->key_size; i++)
1387 encrypted_session_key_valid |=
1388 auth_tok->session_key.encrypted_key[i];
1389 if (encrypted_session_key_valid) {
1390 memcpy(key_rec->enc_key,
1391 auth_tok->session_key.encrypted_key,
1392 auth_tok->session_key.encrypted_key_size);
1393 goto encrypted_session_key_set;
1395 if (auth_tok->session_key.encrypted_key_size == 0)
1396 auth_tok->session_key.encrypted_key_size =
1397 auth_tok->token.private_key.key_size;
1398 rc = pki_encrypt_session_key(auth_tok, crypt_stat, key_rec);
1400 ecryptfs_printk(KERN_ERR, "Failed to encrypt session key "
1404 if (ecryptfs_verbosity > 0) {
1405 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
1406 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
1408 encrypted_session_key_set:
1409 /* This format is inspired by OpenPGP; see RFC 2440
1411 max_packet_size = (1 /* Tag 1 identifier */
1412 + 3 /* Max Tag 1 packet size */
1414 + ECRYPTFS_SIG_SIZE /* Key identifier */
1415 + 1 /* Cipher identifier */
1416 + key_rec->enc_key_size); /* Encrypted key size */
1417 if (max_packet_size > (*remaining_bytes)) {
1418 printk(KERN_ERR "Packet length larger than maximum allowable; "
1419 "need up to [%td] bytes, but there are only [%td] "
1420 "available\n", max_packet_size, (*remaining_bytes));
1424 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
1425 rc = write_packet_length(&dest[(*packet_size)], (max_packet_size - 4),
1426 &packet_size_length);
1428 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
1429 "header; cannot generate packet length\n");
1432 (*packet_size) += packet_size_length;
1433 dest[(*packet_size)++] = 0x03; /* version 3 */
1434 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
1435 (*packet_size) += ECRYPTFS_SIG_SIZE;
1436 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
1437 memcpy(&dest[(*packet_size)], key_rec->enc_key,
1438 key_rec->enc_key_size);
1439 (*packet_size) += key_rec->enc_key_size;
1444 (*remaining_bytes) -= (*packet_size);
1449 * write_tag_11_packet
1450 * @dest: Target into which Tag 11 packet is to be written
1451 * @remaining_bytes: Maximum packet length
1452 * @contents: Byte array of contents to copy in
1453 * @contents_length: Number of bytes in contents
1454 * @packet_length: Length of the Tag 11 packet written; zero on error
1456 * Returns zero on success; non-zero on error.
1459 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
1460 size_t contents_length, size_t *packet_length)
1462 size_t packet_size_length;
1463 size_t max_packet_size;
1466 (*packet_length) = 0;
1467 /* This format is inspired by OpenPGP; see RFC 2440
1469 max_packet_size = (1 /* Tag 11 identifier */
1470 + 3 /* Max Tag 11 packet size */
1471 + 1 /* Binary format specifier */
1472 + 1 /* Filename length */
1473 + 8 /* Filename ("_CONSOLE") */
1474 + 4 /* Modification date */
1475 + contents_length); /* Literal data */
1476 if (max_packet_size > (*remaining_bytes)) {
1477 printk(KERN_ERR "Packet length larger than maximum allowable; "
1478 "need up to [%td] bytes, but there are only [%td] "
1479 "available\n", max_packet_size, (*remaining_bytes));
1483 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
1484 rc = write_packet_length(&dest[(*packet_length)],
1485 (max_packet_size - 4), &packet_size_length);
1487 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
1488 "generate packet length. rc = [%d]\n", rc);
1491 (*packet_length) += packet_size_length;
1492 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
1493 dest[(*packet_length)++] = 8;
1494 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
1495 (*packet_length) += 8;
1496 memset(&dest[(*packet_length)], 0x00, 4);
1497 (*packet_length) += 4;
1498 memcpy(&dest[(*packet_length)], contents, contents_length);
1499 (*packet_length) += contents_length;
1502 (*packet_length) = 0;
1504 (*remaining_bytes) -= (*packet_length);
1509 * write_tag_3_packet
1510 * @dest: Buffer into which to write the packet
1511 * @remaining_bytes: Maximum number of bytes that can be written
1512 * @auth_tok: Authentication token
1513 * @crypt_stat: The cryptographic context
1514 * @key_rec: encrypted key
1515 * @packet_size: This function will write the number of bytes that end
1516 * up constituting the packet; set to zero on error
1518 * Returns zero on success; non-zero on error.
1521 write_tag_3_packet(char *dest, size_t *remaining_bytes,
1522 struct ecryptfs_auth_tok *auth_tok,
1523 struct ecryptfs_crypt_stat *crypt_stat,
1524 struct ecryptfs_key_record *key_rec, size_t *packet_size)
1527 size_t encrypted_session_key_valid = 0;
1528 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
1529 struct scatterlist dst_sg;
1530 struct scatterlist src_sg;
1531 struct mutex *tfm_mutex = NULL;
1533 size_t packet_size_length;
1534 size_t max_packet_size;
1535 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1536 crypt_stat->mount_crypt_stat;
1537 struct blkcipher_desc desc = {
1539 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1544 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
1546 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1547 crypt_stat->cipher);
1549 printk(KERN_ERR "Internal error whilst attempting to get "
1550 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1551 crypt_stat->cipher, rc);
1554 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
1555 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
1557 printk(KERN_WARNING "No key size specified at mount; "
1558 "defaulting to [%d]\n", alg->max_keysize);
1559 mount_crypt_stat->global_default_cipher_key_size =
1562 if (crypt_stat->key_size == 0)
1563 crypt_stat->key_size =
1564 mount_crypt_stat->global_default_cipher_key_size;
1565 if (auth_tok->session_key.encrypted_key_size == 0)
1566 auth_tok->session_key.encrypted_key_size =
1567 crypt_stat->key_size;
1568 if (crypt_stat->key_size == 24
1569 && strcmp("aes", crypt_stat->cipher) == 0) {
1570 memset((crypt_stat->key + 24), 0, 8);
1571 auth_tok->session_key.encrypted_key_size = 32;
1573 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
1574 key_rec->enc_key_size =
1575 auth_tok->session_key.encrypted_key_size;
1576 encrypted_session_key_valid = 0;
1577 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
1578 encrypted_session_key_valid |=
1579 auth_tok->session_key.encrypted_key[i];
1580 if (encrypted_session_key_valid) {
1581 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
1582 "using auth_tok->session_key.encrypted_key, "
1583 "where key_rec->enc_key_size = [%d]\n",
1584 key_rec->enc_key_size);
1585 memcpy(key_rec->enc_key,
1586 auth_tok->session_key.encrypted_key,
1587 key_rec->enc_key_size);
1588 goto encrypted_session_key_set;
1590 if (auth_tok->token.password.flags &
1591 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
1592 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
1593 "session key encryption key of size [%d]\n",
1594 auth_tok->token.password.
1595 session_key_encryption_key_bytes);
1596 memcpy(session_key_encryption_key,
1597 auth_tok->token.password.session_key_encryption_key,
1598 crypt_stat->key_size);
1599 ecryptfs_printk(KERN_DEBUG,
1600 "Cached session key " "encryption key: \n");
1601 if (ecryptfs_verbosity > 0)
1602 ecryptfs_dump_hex(session_key_encryption_key, 16);
1604 if (unlikely(ecryptfs_verbosity > 0)) {
1605 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
1606 ecryptfs_dump_hex(session_key_encryption_key, 16);
1608 if ((rc = virt_to_scatterlist(crypt_stat->key,
1609 key_rec->enc_key_size, &src_sg, 1))
1611 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
1612 "for crypt_stat session key; expected rc = 1; "
1613 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
1614 rc, key_rec->enc_key_size);
1618 if ((rc = virt_to_scatterlist(key_rec->enc_key,
1619 key_rec->enc_key_size, &dst_sg, 1))
1621 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
1622 "for crypt_stat encrypted session key; "
1623 "expected rc = 1; got rc = [%d]. "
1624 "key_rec->enc_key_size = [%d]\n", rc,
1625 key_rec->enc_key_size);
1629 mutex_lock(tfm_mutex);
1630 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
1631 crypt_stat->key_size);
1633 mutex_unlock(tfm_mutex);
1634 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
1635 "context; rc = [%d]\n", rc);
1639 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n",
1640 crypt_stat->key_size);
1641 rc = crypto_blkcipher_encrypt(&desc, &dst_sg, &src_sg,
1642 (*key_rec).enc_key_size);
1643 mutex_unlock(tfm_mutex);
1645 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
1648 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
1649 if (ecryptfs_verbosity > 0) {
1650 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%d]:\n",
1651 key_rec->enc_key_size);
1652 ecryptfs_dump_hex(key_rec->enc_key,
1653 key_rec->enc_key_size);
1655 encrypted_session_key_set:
1656 /* This format is inspired by OpenPGP; see RFC 2440
1658 max_packet_size = (1 /* Tag 3 identifier */
1659 + 3 /* Max Tag 3 packet size */
1661 + 1 /* Cipher code */
1662 + 1 /* S2K specifier */
1663 + 1 /* Hash identifier */
1664 + ECRYPTFS_SALT_SIZE /* Salt */
1665 + 1 /* Hash iterations */
1666 + key_rec->enc_key_size); /* Encrypted key size */
1667 if (max_packet_size > (*remaining_bytes)) {
1668 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
1669 "there are only [%td] available\n", max_packet_size,
1670 (*remaining_bytes));
1674 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
1675 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
1676 * to get the number of octets in the actual Tag 3 packet */
1677 rc = write_packet_length(&dest[(*packet_size)], (max_packet_size - 4),
1678 &packet_size_length);
1680 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
1681 "generate packet length. rc = [%d]\n", rc);
1684 (*packet_size) += packet_size_length;
1685 dest[(*packet_size)++] = 0x04; /* version 4 */
1686 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
1687 * specified with strings */
1688 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat);
1689 if (cipher_code == 0) {
1690 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
1691 "cipher [%s]\n", crypt_stat->cipher);
1695 dest[(*packet_size)++] = cipher_code;
1696 dest[(*packet_size)++] = 0x03; /* S2K */
1697 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
1698 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
1699 ECRYPTFS_SALT_SIZE);
1700 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
1701 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
1702 memcpy(&dest[(*packet_size)], key_rec->enc_key,
1703 key_rec->enc_key_size);
1704 (*packet_size) += key_rec->enc_key_size;
1709 (*remaining_bytes) -= (*packet_size);
1713 struct kmem_cache *ecryptfs_key_record_cache;
1716 * ecryptfs_generate_key_packet_set
1717 * @dest_base: Virtual address from which to write the key record set
1718 * @crypt_stat: The cryptographic context from which the
1719 * authentication tokens will be retrieved
1720 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
1721 * for the global parameters
1722 * @len: The amount written
1723 * @max: The maximum amount of data allowed to be written
1725 * Generates a key packet set and writes it to the virtual address
1728 * Returns zero on success; non-zero on error.
1731 ecryptfs_generate_key_packet_set(char *dest_base,
1732 struct ecryptfs_crypt_stat *crypt_stat,
1733 struct dentry *ecryptfs_dentry, size_t *len,
1736 struct ecryptfs_auth_tok *auth_tok;
1737 struct ecryptfs_global_auth_tok *global_auth_tok;
1738 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1739 &ecryptfs_superblock_to_private(
1740 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1742 struct ecryptfs_key_record *key_rec;
1743 struct ecryptfs_key_sig *key_sig;
1747 mutex_lock(&crypt_stat->keysig_list_mutex);
1748 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
1753 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
1755 memset(key_rec, 0, sizeof(*key_rec));
1756 rc = ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
1760 printk(KERN_ERR "Error attempting to get the global "
1761 "auth_tok; rc = [%d]\n", rc);
1764 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID) {
1766 "Skipping invalid auth tok with sig = [%s]\n",
1767 global_auth_tok->sig);
1770 auth_tok = global_auth_tok->global_auth_tok;
1771 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
1772 rc = write_tag_3_packet((dest_base + (*len)),
1774 crypt_stat, key_rec,
1777 ecryptfs_printk(KERN_WARNING, "Error "
1778 "writing tag 3 packet\n");
1782 /* Write auth tok signature packet */
1783 rc = write_tag_11_packet((dest_base + (*len)), &max,
1785 ECRYPTFS_SIG_SIZE, &written);
1787 ecryptfs_printk(KERN_ERR, "Error writing "
1788 "auth tok signature packet\n");
1792 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1793 rc = write_tag_1_packet(dest_base + (*len),
1795 crypt_stat, key_rec, &written);
1797 ecryptfs_printk(KERN_WARNING, "Error "
1798 "writing tag 1 packet\n");
1803 ecryptfs_printk(KERN_WARNING, "Unsupported "
1804 "authentication token type\n");
1809 if (likely(max > 0)) {
1810 dest_base[(*len)] = 0x00;
1812 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
1816 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
1820 mutex_unlock(&crypt_stat->keysig_list_mutex);
1824 struct kmem_cache *ecryptfs_key_sig_cache;
1826 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
1828 struct ecryptfs_key_sig *new_key_sig;
1831 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
1835 "Error allocating from ecryptfs_key_sig_cache\n");
1838 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
1839 mutex_lock(&crypt_stat->keysig_list_mutex);
1840 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
1841 mutex_unlock(&crypt_stat->keysig_list_mutex);
1846 struct kmem_cache *ecryptfs_global_auth_tok_cache;
1849 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1852 struct ecryptfs_global_auth_tok *new_auth_tok;
1855 new_auth_tok = kmem_cache_alloc(ecryptfs_global_auth_tok_cache,
1857 if (!new_auth_tok) {
1859 printk(KERN_ERR "Error allocating from "
1860 "ecryptfs_global_auth_tok_cache\n");
1863 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
1864 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
1865 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
1866 list_add(&new_auth_tok->mount_crypt_stat_list,
1867 &mount_crypt_stat->global_auth_tok_list);
1868 mount_crypt_stat->num_global_auth_toks++;
1869 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);