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 <linux/slab.h>
36 #include "ecryptfs_kernel.h"
39 * request_key returned an error instead of a valid key address;
40 * determine the type of error, make appropriate log entries, and
41 * return an error code.
43 static int process_request_key_err(long err_code)
49 ecryptfs_printk(KERN_WARNING, "No key\n");
53 ecryptfs_printk(KERN_WARNING, "Key expired\n");
57 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
61 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
62 "[0x%.16lx]\n", err_code);
68 static int process_find_global_auth_tok_for_sig_err(int err_code)
74 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
77 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
80 rc = process_request_key_err(err_code);
87 * ecryptfs_parse_packet_length
88 * @data: Pointer to memory containing length at offset
89 * @size: This function writes the decoded size to this memory
90 * address; zero on error
91 * @length_size: The number of bytes occupied by the encoded length
93 * Returns zero on success; non-zero on error
95 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
103 /* One-byte length */
104 (*size) = (unsigned char)data[0];
106 } else if (data[0] < 224) {
107 /* Two-byte length */
108 (*size) = (((unsigned char)(data[0]) - 192) * 256);
109 (*size) += ((unsigned char)(data[1]) + 192);
111 } else if (data[0] == 255) {
112 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
113 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
118 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
127 * ecryptfs_write_packet_length
128 * @dest: The byte array target into which to write the length. Must
129 * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
130 * @size: The length to write.
131 * @packet_size_length: The number of bytes used to encode the packet
132 * length is written to this address.
134 * Returns zero on success; non-zero on error.
136 int ecryptfs_write_packet_length(char *dest, size_t size,
137 size_t *packet_size_length)
143 (*packet_size_length) = 1;
144 } else if (size < 65536) {
145 dest[0] = (((size - 192) / 256) + 192);
146 dest[1] = ((size - 192) % 256);
147 (*packet_size_length) = 2;
149 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
151 ecryptfs_printk(KERN_WARNING,
152 "Unsupported packet size: [%zd]\n", size);
158 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
159 char **packet, size_t *packet_len)
163 size_t packet_size_len;
168 * ***** TAG 64 Packet Format *****
169 * | Content Type | 1 byte |
170 * | Key Identifier Size | 1 or 2 bytes |
171 * | Key Identifier | arbitrary |
172 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
173 * | Encrypted File Encryption Key | arbitrary |
175 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
176 + session_key->encrypted_key_size);
177 *packet = kmalloc(data_len, GFP_KERNEL);
180 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
184 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
185 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
188 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
189 "header; cannot generate packet length\n");
192 i += packet_size_len;
193 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
194 i += ECRYPTFS_SIG_SIZE_HEX;
195 rc = ecryptfs_write_packet_length(&message[i],
196 session_key->encrypted_key_size,
199 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
200 "header; cannot generate packet length\n");
203 i += packet_size_len;
204 memcpy(&message[i], session_key->encrypted_key,
205 session_key->encrypted_key_size);
206 i += session_key->encrypted_key_size;
213 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
214 struct ecryptfs_message *msg)
222 u16 expected_checksum = 0;
226 * ***** TAG 65 Packet Format *****
227 * | Content Type | 1 byte |
228 * | Status Indicator | 1 byte |
229 * | File Encryption Key Size | 1 or 2 bytes |
230 * | File Encryption Key | arbitrary |
232 message_len = msg->data_len;
234 if (message_len < 4) {
238 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
239 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
244 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
245 "[%d]\n", data[i-1]);
249 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
251 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
256 if (message_len < (i + m_size)) {
257 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
258 "is shorter than expected\n");
263 ecryptfs_printk(KERN_ERR,
264 "The decrypted key is not long enough to "
265 "include a cipher code and checksum\n");
269 *cipher_code = data[i++];
270 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
271 session_key->decrypted_key_size = m_size - 3;
272 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
273 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
274 "the maximum key size [%d]\n",
275 session_key->decrypted_key_size,
276 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
280 memcpy(session_key->decrypted_key, &data[i],
281 session_key->decrypted_key_size);
282 i += session_key->decrypted_key_size;
283 expected_checksum += (unsigned char)(data[i++]) << 8;
284 expected_checksum += (unsigned char)(data[i++]);
285 for (i = 0; i < session_key->decrypted_key_size; i++)
286 checksum += session_key->decrypted_key[i];
287 if (expected_checksum != checksum) {
288 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
289 "encryption key; expected [%x]; calculated "
290 "[%x]\n", expected_checksum, checksum);
299 write_tag_66_packet(char *signature, u8 cipher_code,
300 struct ecryptfs_crypt_stat *crypt_stat, char **packet,
307 size_t packet_size_len;
312 * ***** TAG 66 Packet Format *****
313 * | Content Type | 1 byte |
314 * | Key Identifier Size | 1 or 2 bytes |
315 * | Key Identifier | arbitrary |
316 * | File Encryption Key Size | 1 or 2 bytes |
317 * | File Encryption Key | arbitrary |
319 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
320 *packet = kmalloc(data_len, GFP_KERNEL);
323 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
327 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
328 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
331 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
332 "header; cannot generate packet length\n");
335 i += packet_size_len;
336 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
337 i += ECRYPTFS_SIG_SIZE_HEX;
338 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
339 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
342 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
343 "header; cannot generate packet length\n");
346 i += packet_size_len;
347 message[i++] = cipher_code;
348 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
349 i += crypt_stat->key_size;
350 for (j = 0; j < crypt_stat->key_size; j++)
351 checksum += crypt_stat->key[j];
352 message[i++] = (checksum / 256) % 256;
353 message[i++] = (checksum % 256);
360 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
361 struct ecryptfs_message *msg)
370 * ***** TAG 65 Packet Format *****
371 * | Content Type | 1 byte |
372 * | Status Indicator | 1 byte |
373 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
374 * | Encrypted File Encryption Key | arbitrary |
376 message_len = msg->data_len;
378 /* verify that everything through the encrypted FEK size is present */
379 if (message_len < 4) {
381 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
382 "message length is [%d]\n", __func__, message_len, 4);
385 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
387 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
393 printk(KERN_ERR "%s: Status indicator has non zero "
394 "value [%d]\n", __func__, data[i-1]);
398 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
401 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
406 if (message_len < (i + key_rec->enc_key_size)) {
408 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
409 __func__, message_len, (i + key_rec->enc_key_size));
412 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
414 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
415 "the maximum key size [%d]\n", __func__,
416 key_rec->enc_key_size,
417 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
420 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
426 * ecryptfs_verify_version
427 * @version: The version number to confirm
429 * Returns zero on good version; non-zero otherwise
431 static int ecryptfs_verify_version(u16 version)
437 major = ((version >> 8) & 0xFF);
438 minor = (version & 0xFF);
439 if (major != ECRYPTFS_VERSION_MAJOR) {
440 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
441 "Expected [%d]; got [%d]\n",
442 ECRYPTFS_VERSION_MAJOR, major);
446 if (minor != ECRYPTFS_VERSION_MINOR) {
447 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
448 "Expected [%d]; got [%d]\n",
449 ECRYPTFS_VERSION_MINOR, minor);
458 * ecryptfs_verify_auth_tok_from_key
459 * @auth_tok_key: key containing the authentication token
460 * @auth_tok: authentication token
462 * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
463 * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
466 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
467 struct ecryptfs_auth_tok **auth_tok)
471 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
472 if (IS_ERR(*auth_tok)) {
473 rc = PTR_ERR(*auth_tok);
478 if (ecryptfs_verify_version((*auth_tok)->version)) {
479 printk(KERN_ERR "Data structure version mismatch. Userspace "
480 "tools must match eCryptfs kernel module with major "
481 "version [%d] and minor version [%d]\n",
482 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
486 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
487 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
488 printk(KERN_ERR "Invalid auth_tok structure "
489 "returned from key query\n");
498 ecryptfs_find_global_auth_tok_for_sig(
499 struct key **auth_tok_key,
500 struct ecryptfs_auth_tok **auth_tok,
501 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
503 struct ecryptfs_global_auth_tok *walker;
506 (*auth_tok_key) = NULL;
508 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
509 list_for_each_entry(walker,
510 &mount_crypt_stat->global_auth_tok_list,
511 mount_crypt_stat_list) {
512 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
515 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
520 rc = key_validate(walker->global_auth_tok_key);
522 if (rc == -EKEYEXPIRED)
524 goto out_invalid_auth_tok;
527 down_write(&(walker->global_auth_tok_key->sem));
528 rc = ecryptfs_verify_auth_tok_from_key(
529 walker->global_auth_tok_key, auth_tok);
531 goto out_invalid_auth_tok_unlock;
533 (*auth_tok_key) = walker->global_auth_tok_key;
534 key_get(*auth_tok_key);
539 out_invalid_auth_tok_unlock:
540 up_write(&(walker->global_auth_tok_key->sem));
541 out_invalid_auth_tok:
542 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
543 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
544 key_put(walker->global_auth_tok_key);
545 walker->global_auth_tok_key = NULL;
547 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
552 * ecryptfs_find_auth_tok_for_sig
553 * @auth_tok: Set to the matching auth_tok; NULL if not found
554 * @crypt_stat: inode crypt_stat crypto context
555 * @sig: Sig of auth_tok to find
557 * For now, this function simply looks at the registered auth_tok's
558 * linked off the mount_crypt_stat, so all the auth_toks that can be
559 * used must be registered at mount time. This function could
560 * potentially try a lot harder to find auth_tok's (e.g., by calling
561 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
562 * that static registration of auth_tok's will no longer be necessary.
564 * Returns zero on no error; non-zero on error
567 ecryptfs_find_auth_tok_for_sig(
568 struct key **auth_tok_key,
569 struct ecryptfs_auth_tok **auth_tok,
570 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
575 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
576 mount_crypt_stat, sig);
578 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
579 * mount_crypt_stat structure, we prevent to use auth toks that
580 * are not inserted through the ecryptfs_add_global_auth_tok
583 if (mount_crypt_stat->flags
584 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
587 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
594 * write_tag_70_packet can gobble a lot of stack space. We stuff most
595 * of the function's parameters in a kmalloc'd struct to help reduce
596 * eCryptfs' overall stack usage.
598 struct ecryptfs_write_tag_70_packet_silly_stack {
600 size_t max_packet_size;
601 size_t packet_size_len;
602 size_t block_aligned_filename_size;
606 size_t num_rand_bytes;
607 struct mutex *tfm_mutex;
608 char *block_aligned_filename;
609 struct ecryptfs_auth_tok *auth_tok;
610 struct scatterlist src_sg[2];
611 struct scatterlist dst_sg[2];
612 struct blkcipher_desc desc;
613 char iv[ECRYPTFS_MAX_IV_BYTES];
614 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
615 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
616 struct hash_desc hash_desc;
617 struct scatterlist hash_sg;
621 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
622 * @filename: NULL-terminated filename string
624 * This is the simplest mechanism for achieving filename encryption in
625 * eCryptfs. It encrypts the given filename with the mount-wide
626 * filename encryption key (FNEK) and stores it in a packet to @dest,
627 * which the callee will encode and write directly into the dentry
631 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
633 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
634 char *filename, size_t filename_size)
636 struct ecryptfs_write_tag_70_packet_silly_stack *s;
637 struct key *auth_tok_key = NULL;
640 s = kmalloc(sizeof(*s), GFP_KERNEL);
642 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
643 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
647 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
649 rc = ecryptfs_find_auth_tok_for_sig(
651 &s->auth_tok, mount_crypt_stat,
652 mount_crypt_stat->global_default_fnek_sig);
654 printk(KERN_ERR "%s: Error attempting to find auth tok for "
655 "fnek sig [%s]; rc = [%d]\n", __func__,
656 mount_crypt_stat->global_default_fnek_sig, rc);
659 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
661 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
663 printk(KERN_ERR "Internal error whilst attempting to get "
664 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
665 mount_crypt_stat->global_default_fn_cipher_name, rc);
668 mutex_lock(s->tfm_mutex);
669 s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
670 /* Plus one for the \0 separator between the random prefix
671 * and the plaintext filename */
672 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
673 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
674 if ((s->block_aligned_filename_size % s->block_size) != 0) {
675 s->num_rand_bytes += (s->block_size
676 - (s->block_aligned_filename_size
678 s->block_aligned_filename_size = (s->num_rand_bytes
681 /* Octet 0: Tag 70 identifier
682 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
683 * and block-aligned encrypted filename size)
684 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
685 * Octet N2-N3: Cipher identifier (1 octet)
686 * Octets N3-N4: Block-aligned encrypted filename
687 * - Consists of a minimum number of random characters, a \0
688 * separator, and then the filename */
689 s->max_packet_size = (1 /* Tag 70 identifier */
690 + 3 /* Max Tag 70 packet size */
691 + ECRYPTFS_SIG_SIZE /* FNEK sig */
692 + 1 /* Cipher identifier */
693 + s->block_aligned_filename_size);
695 (*packet_size) = s->max_packet_size;
698 if (s->max_packet_size > (*remaining_bytes)) {
699 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
700 "[%zd] available\n", __func__, s->max_packet_size,
705 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
707 if (!s->block_aligned_filename) {
708 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
709 "kzalloc [%zd] bytes\n", __func__,
710 s->block_aligned_filename_size);
715 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
716 rc = ecryptfs_write_packet_length(&dest[s->i],
718 + 1 /* Cipher code */
719 + s->block_aligned_filename_size),
720 &s->packet_size_len);
722 printk(KERN_ERR "%s: Error generating tag 70 packet "
723 "header; cannot generate packet length; rc = [%d]\n",
725 goto out_free_unlock;
727 s->i += s->packet_size_len;
728 ecryptfs_from_hex(&dest[s->i],
729 mount_crypt_stat->global_default_fnek_sig,
731 s->i += ECRYPTFS_SIG_SIZE;
732 s->cipher_code = ecryptfs_code_for_cipher_string(
733 mount_crypt_stat->global_default_fn_cipher_name,
734 mount_crypt_stat->global_default_fn_cipher_key_bytes);
735 if (s->cipher_code == 0) {
736 printk(KERN_WARNING "%s: Unable to generate code for "
737 "cipher [%s] with key bytes [%zd]\n", __func__,
738 mount_crypt_stat->global_default_fn_cipher_name,
739 mount_crypt_stat->global_default_fn_cipher_key_bytes);
741 goto out_free_unlock;
743 dest[s->i++] = s->cipher_code;
744 /* TODO: Support other key modules than passphrase for
745 * filename encryption */
746 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
748 printk(KERN_INFO "%s: Filename encryption only supports "
749 "password tokens\n", __func__);
750 goto out_free_unlock;
754 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
755 s->auth_tok->token.password.session_key_encryption_key_bytes);
756 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
757 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
759 if (IS_ERR(s->hash_desc.tfm)) {
760 rc = PTR_ERR(s->hash_desc.tfm);
761 printk(KERN_ERR "%s: Error attempting to "
762 "allocate hash crypto context; rc = [%d]\n",
764 goto out_free_unlock;
766 rc = crypto_hash_init(&s->hash_desc);
769 "%s: Error initializing crypto hash; rc = [%d]\n",
771 goto out_release_free_unlock;
773 rc = crypto_hash_update(
774 &s->hash_desc, &s->hash_sg,
775 s->auth_tok->token.password.session_key_encryption_key_bytes);
778 "%s: Error updating crypto hash; rc = [%d]\n",
780 goto out_release_free_unlock;
782 rc = crypto_hash_final(&s->hash_desc, s->hash);
785 "%s: Error finalizing crypto hash; rc = [%d]\n",
787 goto out_release_free_unlock;
789 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
790 s->block_aligned_filename[s->j] =
791 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
792 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
793 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
794 sg_init_one(&s->hash_sg, (u8 *)s->hash,
795 ECRYPTFS_TAG_70_DIGEST_SIZE);
796 rc = crypto_hash_init(&s->hash_desc);
799 "%s: Error initializing crypto hash; "
800 "rc = [%d]\n", __func__, rc);
801 goto out_release_free_unlock;
803 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
804 ECRYPTFS_TAG_70_DIGEST_SIZE);
807 "%s: Error updating crypto hash; "
808 "rc = [%d]\n", __func__, rc);
809 goto out_release_free_unlock;
811 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
814 "%s: Error finalizing crypto hash; "
815 "rc = [%d]\n", __func__, rc);
816 goto out_release_free_unlock;
818 memcpy(s->hash, s->tmp_hash,
819 ECRYPTFS_TAG_70_DIGEST_SIZE);
821 if (s->block_aligned_filename[s->j] == '\0')
822 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
824 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
826 rc = virt_to_scatterlist(s->block_aligned_filename,
827 s->block_aligned_filename_size, s->src_sg, 2);
829 printk(KERN_ERR "%s: Internal error whilst attempting to "
830 "convert filename memory to scatterlist; rc = [%d]. "
831 "block_aligned_filename_size = [%zd]\n", __func__, rc,
832 s->block_aligned_filename_size);
833 goto out_release_free_unlock;
835 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
838 printk(KERN_ERR "%s: Internal error whilst attempting to "
839 "convert encrypted filename memory to scatterlist; "
840 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
841 __func__, rc, s->block_aligned_filename_size);
842 goto out_release_free_unlock;
844 /* The characters in the first block effectively do the job
845 * of the IV here, so we just use 0's for the IV. Note the
846 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
847 * >= ECRYPTFS_MAX_IV_BYTES. */
848 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
849 s->desc.info = s->iv;
850 rc = crypto_blkcipher_setkey(
852 s->auth_tok->token.password.session_key_encryption_key,
853 mount_crypt_stat->global_default_fn_cipher_key_bytes);
855 printk(KERN_ERR "%s: Error setting key for crypto context; "
856 "rc = [%d]. s->auth_tok->token.password.session_key_"
857 "encryption_key = [0x%p]; mount_crypt_stat->"
858 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
860 s->auth_tok->token.password.session_key_encryption_key,
861 mount_crypt_stat->global_default_fn_cipher_key_bytes);
862 goto out_release_free_unlock;
864 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
865 s->block_aligned_filename_size);
867 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
868 "rc = [%d]\n", __func__, rc);
869 goto out_release_free_unlock;
871 s->i += s->block_aligned_filename_size;
872 (*packet_size) = s->i;
873 (*remaining_bytes) -= (*packet_size);
874 out_release_free_unlock:
875 crypto_free_hash(s->hash_desc.tfm);
877 kzfree(s->block_aligned_filename);
879 mutex_unlock(s->tfm_mutex);
882 up_write(&(auth_tok_key->sem));
883 key_put(auth_tok_key);
889 struct ecryptfs_parse_tag_70_packet_silly_stack {
891 size_t max_packet_size;
892 size_t packet_size_len;
893 size_t parsed_tag_70_packet_size;
894 size_t block_aligned_filename_size;
897 struct mutex *tfm_mutex;
898 char *decrypted_filename;
899 struct ecryptfs_auth_tok *auth_tok;
900 struct scatterlist src_sg[2];
901 struct scatterlist dst_sg[2];
902 struct blkcipher_desc desc;
903 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
904 char iv[ECRYPTFS_MAX_IV_BYTES];
905 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
909 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
910 * @filename: This function kmalloc's the memory for the filename
911 * @filename_size: This function sets this to the amount of memory
912 * kmalloc'd for the filename
913 * @packet_size: This function sets this to the the number of octets
914 * in the packet parsed
915 * @mount_crypt_stat: The mount-wide cryptographic context
916 * @data: The memory location containing the start of the tag 70
918 * @max_packet_size: The maximum legal size of the packet to be parsed
921 * Returns zero on success; non-zero otherwise
924 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
926 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
927 char *data, size_t max_packet_size)
929 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
930 struct key *auth_tok_key = NULL;
934 (*filename_size) = 0;
936 s = kmalloc(sizeof(*s), GFP_KERNEL);
938 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
939 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
943 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
944 if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
945 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
946 "at least [%d]\n", __func__, max_packet_size,
947 (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
951 /* Octet 0: Tag 70 identifier
952 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
953 * and block-aligned encrypted filename size)
954 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
955 * Octet N2-N3: Cipher identifier (1 octet)
956 * Octets N3-N4: Block-aligned encrypted filename
957 * - Consists of a minimum number of random numbers, a \0
958 * separator, and then the filename */
959 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
960 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
961 "tag [0x%.2x]\n", __func__,
962 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
966 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
967 &s->parsed_tag_70_packet_size,
968 &s->packet_size_len);
970 printk(KERN_WARNING "%s: Error parsing packet length; "
971 "rc = [%d]\n", __func__, rc);
974 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
975 - ECRYPTFS_SIG_SIZE - 1);
976 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
978 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
979 "size is [%zd]\n", __func__, max_packet_size,
980 (1 + s->packet_size_len + 1
981 + s->block_aligned_filename_size));
985 (*packet_size) += s->packet_size_len;
986 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
988 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
989 (*packet_size) += ECRYPTFS_SIG_SIZE;
990 s->cipher_code = data[(*packet_size)++];
991 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
993 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
994 __func__, s->cipher_code);
997 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
998 &s->auth_tok, mount_crypt_stat,
1001 printk(KERN_ERR "%s: Error attempting to find auth tok for "
1002 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
1006 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
1010 printk(KERN_ERR "Internal error whilst attempting to get "
1011 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1012 s->cipher_string, rc);
1015 mutex_lock(s->tfm_mutex);
1016 rc = virt_to_scatterlist(&data[(*packet_size)],
1017 s->block_aligned_filename_size, s->src_sg, 2);
1019 printk(KERN_ERR "%s: Internal error whilst attempting to "
1020 "convert encrypted filename memory to scatterlist; "
1021 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1022 __func__, rc, s->block_aligned_filename_size);
1025 (*packet_size) += s->block_aligned_filename_size;
1026 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1028 if (!s->decrypted_filename) {
1029 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1030 "kmalloc [%zd] bytes\n", __func__,
1031 s->block_aligned_filename_size);
1035 rc = virt_to_scatterlist(s->decrypted_filename,
1036 s->block_aligned_filename_size, s->dst_sg, 2);
1038 printk(KERN_ERR "%s: Internal error whilst attempting to "
1039 "convert decrypted filename memory to scatterlist; "
1040 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1041 __func__, rc, s->block_aligned_filename_size);
1042 goto out_free_unlock;
1044 /* The characters in the first block effectively do the job of
1045 * the IV here, so we just use 0's for the IV. Note the
1046 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1047 * >= ECRYPTFS_MAX_IV_BYTES. */
1048 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1049 s->desc.info = s->iv;
1050 /* TODO: Support other key modules than passphrase for
1051 * filename encryption */
1052 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1054 printk(KERN_INFO "%s: Filename encryption only supports "
1055 "password tokens\n", __func__);
1056 goto out_free_unlock;
1058 rc = crypto_blkcipher_setkey(
1060 s->auth_tok->token.password.session_key_encryption_key,
1061 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1063 printk(KERN_ERR "%s: Error setting key for crypto context; "
1064 "rc = [%d]. s->auth_tok->token.password.session_key_"
1065 "encryption_key = [0x%p]; mount_crypt_stat->"
1066 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1068 s->auth_tok->token.password.session_key_encryption_key,
1069 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1070 goto out_free_unlock;
1072 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
1073 s->block_aligned_filename_size);
1075 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1076 "rc = [%d]\n", __func__, rc);
1077 goto out_free_unlock;
1080 while (s->decrypted_filename[s->i] != '\0'
1081 && s->i < s->block_aligned_filename_size)
1083 if (s->i == s->block_aligned_filename_size) {
1084 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1085 "find valid separator between random characters and "
1086 "the filename\n", __func__);
1088 goto out_free_unlock;
1091 (*filename_size) = (s->block_aligned_filename_size - s->i);
1092 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1093 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1094 "invalid\n", __func__, (*filename_size));
1096 goto out_free_unlock;
1098 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1100 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1101 "kmalloc [%zd] bytes\n", __func__,
1102 ((*filename_size) + 1));
1104 goto out_free_unlock;
1106 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1107 (*filename)[(*filename_size)] = '\0';
1109 kfree(s->decrypted_filename);
1111 mutex_unlock(s->tfm_mutex);
1115 (*filename_size) = 0;
1119 up_write(&(auth_tok_key->sem));
1120 key_put(auth_tok_key);
1127 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1132 switch (auth_tok->token_type) {
1133 case ECRYPTFS_PASSWORD:
1134 (*sig) = auth_tok->token.password.signature;
1136 case ECRYPTFS_PRIVATE_KEY:
1137 (*sig) = auth_tok->token.private_key.signature;
1140 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1141 auth_tok->token_type);
1148 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1149 * @auth_tok: The key authentication token used to decrypt the session key
1150 * @crypt_stat: The cryptographic context
1152 * Returns zero on success; non-zero error otherwise.
1155 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1156 struct ecryptfs_crypt_stat *crypt_stat)
1159 struct ecryptfs_msg_ctx *msg_ctx;
1160 struct ecryptfs_message *msg = NULL;
1162 char *payload = NULL;
1163 size_t payload_len = 0;
1166 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1168 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1169 auth_tok->token_type);
1172 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1173 &payload, &payload_len);
1175 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1178 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1180 ecryptfs_printk(KERN_ERR, "Error sending message to "
1184 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1186 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1187 "from the user space daemon\n");
1191 rc = parse_tag_65_packet(&(auth_tok->session_key),
1194 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1198 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1199 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1200 auth_tok->session_key.decrypted_key_size);
1201 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1202 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1204 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1208 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1209 if (ecryptfs_verbosity > 0) {
1210 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1211 ecryptfs_dump_hex(crypt_stat->key,
1212 crypt_stat->key_size);
1221 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1223 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1224 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1226 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1227 auth_tok_list_head, list) {
1228 list_del(&auth_tok_list_item->list);
1229 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1230 auth_tok_list_item);
1234 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1237 * parse_tag_1_packet
1238 * @crypt_stat: The cryptographic context to modify based on packet contents
1239 * @data: The raw bytes of the packet.
1240 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1241 * a new authentication token will be placed at the
1242 * end of this list for this packet.
1243 * @new_auth_tok: Pointer to a pointer to memory that this function
1244 * allocates; sets the memory address of the pointer to
1245 * NULL on error. This object is added to the
1247 * @packet_size: This function writes the size of the parsed packet
1248 * into this memory location; zero on error.
1249 * @max_packet_size: The maximum allowable packet size
1251 * Returns zero on success; non-zero on error.
1254 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1255 unsigned char *data, struct list_head *auth_tok_list,
1256 struct ecryptfs_auth_tok **new_auth_tok,
1257 size_t *packet_size, size_t max_packet_size)
1260 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1265 (*new_auth_tok) = NULL;
1267 * This format is inspired by OpenPGP; see RFC 2440
1270 * Tag 1 identifier (1 byte)
1271 * Max Tag 1 packet size (max 3 bytes)
1273 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1274 * Cipher identifier (1 byte)
1275 * Encrypted key size (arbitrary)
1277 * 12 bytes minimum packet size
1279 if (unlikely(max_packet_size < 12)) {
1280 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1284 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1285 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1286 ECRYPTFS_TAG_1_PACKET_TYPE);
1290 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1291 * at end of function upon failure */
1292 auth_tok_list_item =
1293 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1295 if (!auth_tok_list_item) {
1296 printk(KERN_ERR "Unable to allocate memory\n");
1300 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1301 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1304 printk(KERN_WARNING "Error parsing packet length; "
1308 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1309 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1313 (*packet_size) += length_size;
1314 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1315 printk(KERN_WARNING "Packet size exceeds max\n");
1319 if (unlikely(data[(*packet_size)++] != 0x03)) {
1320 printk(KERN_WARNING "Unknown version number [%d]\n",
1321 data[(*packet_size) - 1]);
1325 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1326 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1327 *packet_size += ECRYPTFS_SIG_SIZE;
1328 /* This byte is skipped because the kernel does not need to
1329 * know which public key encryption algorithm was used */
1331 (*new_auth_tok)->session_key.encrypted_key_size =
1332 body_size - (ECRYPTFS_SIG_SIZE + 2);
1333 if ((*new_auth_tok)->session_key.encrypted_key_size
1334 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1335 printk(KERN_WARNING "Tag 1 packet contains key larger "
1336 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1340 memcpy((*new_auth_tok)->session_key.encrypted_key,
1341 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1342 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1343 (*new_auth_tok)->session_key.flags &=
1344 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1345 (*new_auth_tok)->session_key.flags |=
1346 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1347 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1348 (*new_auth_tok)->flags = 0;
1349 (*new_auth_tok)->session_key.flags &=
1350 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1351 (*new_auth_tok)->session_key.flags &=
1352 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1353 list_add(&auth_tok_list_item->list, auth_tok_list);
1356 (*new_auth_tok) = NULL;
1357 memset(auth_tok_list_item, 0,
1358 sizeof(struct ecryptfs_auth_tok_list_item));
1359 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1360 auth_tok_list_item);
1368 * parse_tag_3_packet
1369 * @crypt_stat: The cryptographic context to modify based on packet
1371 * @data: The raw bytes of the packet.
1372 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1373 * a new authentication token will be placed at the end
1374 * of this list for this packet.
1375 * @new_auth_tok: Pointer to a pointer to memory that this function
1376 * allocates; sets the memory address of the pointer to
1377 * NULL on error. This object is added to the
1379 * @packet_size: This function writes the size of the parsed packet
1380 * into this memory location; zero on error.
1381 * @max_packet_size: maximum number of bytes to parse
1383 * Returns zero on success; non-zero on error.
1386 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1387 unsigned char *data, struct list_head *auth_tok_list,
1388 struct ecryptfs_auth_tok **new_auth_tok,
1389 size_t *packet_size, size_t max_packet_size)
1392 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1397 (*new_auth_tok) = NULL;
1399 *This format is inspired by OpenPGP; see RFC 2440
1402 * Tag 3 identifier (1 byte)
1403 * Max Tag 3 packet size (max 3 bytes)
1405 * Cipher code (1 byte)
1406 * S2K specifier (1 byte)
1407 * Hash identifier (1 byte)
1408 * Salt (ECRYPTFS_SALT_SIZE)
1409 * Hash iterations (1 byte)
1410 * Encrypted key (arbitrary)
1412 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1414 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1415 printk(KERN_ERR "Max packet size too large\n");
1419 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1420 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1421 ECRYPTFS_TAG_3_PACKET_TYPE);
1425 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1426 * at end of function upon failure */
1427 auth_tok_list_item =
1428 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1429 if (!auth_tok_list_item) {
1430 printk(KERN_ERR "Unable to allocate memory\n");
1434 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1435 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1438 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1442 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1443 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1447 (*packet_size) += length_size;
1448 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1449 printk(KERN_ERR "Packet size exceeds max\n");
1453 (*new_auth_tok)->session_key.encrypted_key_size =
1454 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1455 if ((*new_auth_tok)->session_key.encrypted_key_size
1456 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1457 printk(KERN_WARNING "Tag 3 packet contains key larger "
1458 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1462 if (unlikely(data[(*packet_size)++] != 0x04)) {
1463 printk(KERN_WARNING "Unknown version number [%d]\n",
1464 data[(*packet_size) - 1]);
1468 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1469 (u16)data[(*packet_size)]);
1472 /* A little extra work to differentiate among the AES key
1473 * sizes; see RFC2440 */
1474 switch(data[(*packet_size)++]) {
1475 case RFC2440_CIPHER_AES_192:
1476 crypt_stat->key_size = 24;
1479 crypt_stat->key_size =
1480 (*new_auth_tok)->session_key.encrypted_key_size;
1482 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1485 if (unlikely(data[(*packet_size)++] != 0x03)) {
1486 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1490 /* TODO: finish the hash mapping */
1491 switch (data[(*packet_size)++]) {
1492 case 0x01: /* See RFC2440 for these numbers and their mappings */
1494 memcpy((*new_auth_tok)->token.password.salt,
1495 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1496 (*packet_size) += ECRYPTFS_SALT_SIZE;
1497 /* This conversion was taken straight from RFC2440 */
1498 (*new_auth_tok)->token.password.hash_iterations =
1499 ((u32) 16 + (data[(*packet_size)] & 15))
1500 << ((data[(*packet_size)] >> 4) + 6);
1502 /* Friendly reminder:
1503 * (*new_auth_tok)->session_key.encrypted_key_size =
1504 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1505 memcpy((*new_auth_tok)->session_key.encrypted_key,
1506 &data[(*packet_size)],
1507 (*new_auth_tok)->session_key.encrypted_key_size);
1509 (*new_auth_tok)->session_key.encrypted_key_size;
1510 (*new_auth_tok)->session_key.flags &=
1511 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1512 (*new_auth_tok)->session_key.flags |=
1513 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1514 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1517 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1518 "[%d]\n", data[(*packet_size) - 1]);
1522 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1523 /* TODO: Parametarize; we might actually want userspace to
1524 * decrypt the session key. */
1525 (*new_auth_tok)->session_key.flags &=
1526 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1527 (*new_auth_tok)->session_key.flags &=
1528 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1529 list_add(&auth_tok_list_item->list, auth_tok_list);
1532 (*new_auth_tok) = NULL;
1533 memset(auth_tok_list_item, 0,
1534 sizeof(struct ecryptfs_auth_tok_list_item));
1535 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1536 auth_tok_list_item);
1544 * parse_tag_11_packet
1545 * @data: The raw bytes of the packet
1546 * @contents: This function writes the data contents of the literal
1547 * packet into this memory location
1548 * @max_contents_bytes: The maximum number of bytes that this function
1549 * is allowed to write into contents
1550 * @tag_11_contents_size: This function writes the size of the parsed
1551 * contents into this memory location; zero on
1553 * @packet_size: This function writes the size of the parsed packet
1554 * into this memory location; zero on error
1555 * @max_packet_size: maximum number of bytes to parse
1557 * Returns zero on success; non-zero on error.
1560 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1561 size_t max_contents_bytes, size_t *tag_11_contents_size,
1562 size_t *packet_size, size_t max_packet_size)
1569 (*tag_11_contents_size) = 0;
1570 /* This format is inspired by OpenPGP; see RFC 2440
1573 * Tag 11 identifier (1 byte)
1574 * Max Tag 11 packet size (max 3 bytes)
1575 * Binary format specifier (1 byte)
1576 * Filename length (1 byte)
1577 * Filename ("_CONSOLE") (8 bytes)
1578 * Modification date (4 bytes)
1579 * Literal data (arbitrary)
1581 * We need at least 16 bytes of data for the packet to even be
1584 if (max_packet_size < 16) {
1585 printk(KERN_ERR "Maximum packet size too small\n");
1589 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1590 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1594 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1597 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1600 if (body_size < 14) {
1601 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1605 (*packet_size) += length_size;
1606 (*tag_11_contents_size) = (body_size - 14);
1607 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1608 printk(KERN_ERR "Packet size exceeds max\n");
1612 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1613 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1618 if (data[(*packet_size)++] != 0x62) {
1619 printk(KERN_WARNING "Unrecognizable packet\n");
1623 if (data[(*packet_size)++] != 0x08) {
1624 printk(KERN_WARNING "Unrecognizable packet\n");
1628 (*packet_size) += 12; /* Ignore filename and modification date */
1629 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1630 (*packet_size) += (*tag_11_contents_size);
1634 (*tag_11_contents_size) = 0;
1639 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1640 struct ecryptfs_auth_tok **auth_tok,
1645 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1646 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1647 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1648 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1649 printk(KERN_ERR "Could not find key with description: [%s]\n",
1651 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1652 (*auth_tok_key) = NULL;
1656 down_write(&(*auth_tok_key)->sem);
1657 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1659 up_write(&(*auth_tok_key)->sem);
1660 key_put(*auth_tok_key);
1661 (*auth_tok_key) = NULL;
1669 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1670 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1671 * @crypt_stat: The cryptographic context
1673 * Returns zero on success; non-zero error otherwise
1676 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1677 struct ecryptfs_crypt_stat *crypt_stat)
1679 struct scatterlist dst_sg[2];
1680 struct scatterlist src_sg[2];
1681 struct mutex *tfm_mutex;
1682 struct blkcipher_desc desc = {
1683 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1687 if (unlikely(ecryptfs_verbosity > 0)) {
1689 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1690 auth_tok->token.password.session_key_encryption_key_bytes);
1692 auth_tok->token.password.session_key_encryption_key,
1693 auth_tok->token.password.session_key_encryption_key_bytes);
1695 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1696 crypt_stat->cipher);
1698 printk(KERN_ERR "Internal error whilst attempting to get "
1699 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1700 crypt_stat->cipher, rc);
1703 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1704 auth_tok->session_key.encrypted_key_size,
1706 if (rc < 1 || rc > 2) {
1707 printk(KERN_ERR "Internal error whilst attempting to convert "
1708 "auth_tok->session_key.encrypted_key to scatterlist; "
1709 "expected rc = 1; got rc = [%d]. "
1710 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1711 auth_tok->session_key.encrypted_key_size);
1714 auth_tok->session_key.decrypted_key_size =
1715 auth_tok->session_key.encrypted_key_size;
1716 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1717 auth_tok->session_key.decrypted_key_size,
1719 if (rc < 1 || rc > 2) {
1720 printk(KERN_ERR "Internal error whilst attempting to convert "
1721 "auth_tok->session_key.decrypted_key to scatterlist; "
1722 "expected rc = 1; got rc = [%d]\n", rc);
1725 mutex_lock(tfm_mutex);
1726 rc = crypto_blkcipher_setkey(
1727 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1728 crypt_stat->key_size);
1729 if (unlikely(rc < 0)) {
1730 mutex_unlock(tfm_mutex);
1731 printk(KERN_ERR "Error setting key for crypto context\n");
1735 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1736 auth_tok->session_key.encrypted_key_size);
1737 mutex_unlock(tfm_mutex);
1739 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1742 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1743 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1744 auth_tok->session_key.decrypted_key_size);
1745 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1746 if (unlikely(ecryptfs_verbosity > 0)) {
1747 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1748 crypt_stat->key_size);
1749 ecryptfs_dump_hex(crypt_stat->key,
1750 crypt_stat->key_size);
1757 * ecryptfs_parse_packet_set
1758 * @crypt_stat: The cryptographic context
1759 * @src: Virtual address of region of memory containing the packets
1760 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1762 * Get crypt_stat to have the file's session key if the requisite key
1763 * is available to decrypt the session key.
1765 * Returns Zero if a valid authentication token was retrieved and
1766 * processed; negative value for file not encrypted or for error
1769 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1771 struct dentry *ecryptfs_dentry)
1774 size_t found_auth_tok;
1775 size_t next_packet_is_auth_tok_packet;
1776 struct list_head auth_tok_list;
1777 struct ecryptfs_auth_tok *matching_auth_tok;
1778 struct ecryptfs_auth_tok *candidate_auth_tok;
1779 char *candidate_auth_tok_sig;
1781 struct ecryptfs_auth_tok *new_auth_tok;
1782 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1783 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1784 size_t tag_11_contents_size;
1785 size_t tag_11_packet_size;
1786 struct key *auth_tok_key = NULL;
1789 INIT_LIST_HEAD(&auth_tok_list);
1790 /* Parse the header to find as many packets as we can; these will be
1791 * added the our &auth_tok_list */
1792 next_packet_is_auth_tok_packet = 1;
1793 while (next_packet_is_auth_tok_packet) {
1794 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1797 case ECRYPTFS_TAG_3_PACKET_TYPE:
1798 rc = parse_tag_3_packet(crypt_stat,
1799 (unsigned char *)&src[i],
1800 &auth_tok_list, &new_auth_tok,
1801 &packet_size, max_packet_size);
1803 ecryptfs_printk(KERN_ERR, "Error parsing "
1809 rc = parse_tag_11_packet((unsigned char *)&src[i],
1812 &tag_11_contents_size,
1813 &tag_11_packet_size,
1816 ecryptfs_printk(KERN_ERR, "No valid "
1817 "(ecryptfs-specific) literal "
1818 "packet containing "
1819 "authentication token "
1820 "signature found after "
1825 i += tag_11_packet_size;
1826 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1827 ecryptfs_printk(KERN_ERR, "Expected "
1828 "signature of size [%d]; "
1829 "read size [%zd]\n",
1831 tag_11_contents_size);
1835 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1836 sig_tmp_space, tag_11_contents_size);
1837 new_auth_tok->token.password.signature[
1838 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1839 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1841 case ECRYPTFS_TAG_1_PACKET_TYPE:
1842 rc = parse_tag_1_packet(crypt_stat,
1843 (unsigned char *)&src[i],
1844 &auth_tok_list, &new_auth_tok,
1845 &packet_size, max_packet_size);
1847 ecryptfs_printk(KERN_ERR, "Error parsing "
1853 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1855 case ECRYPTFS_TAG_11_PACKET_TYPE:
1856 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1857 "(Tag 11 not allowed by itself)\n");
1862 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1863 "of the file header; hex value of "
1864 "character is [0x%.2x]\n", i, src[i]);
1865 next_packet_is_auth_tok_packet = 0;
1868 if (list_empty(&auth_tok_list)) {
1869 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1870 "eCryptfs file; this is not supported in this version "
1871 "of the eCryptfs kernel module\n");
1875 /* auth_tok_list contains the set of authentication tokens
1876 * parsed from the metadata. We need to find a matching
1877 * authentication token that has the secret component(s)
1878 * necessary to decrypt the EFEK in the auth_tok parsed from
1879 * the metadata. There may be several potential matches, but
1880 * just one will be sufficient to decrypt to get the FEK. */
1881 find_next_matching_auth_tok:
1883 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1884 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1885 if (unlikely(ecryptfs_verbosity > 0)) {
1886 ecryptfs_printk(KERN_DEBUG,
1887 "Considering cadidate auth tok:\n");
1888 ecryptfs_dump_auth_tok(candidate_auth_tok);
1890 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1891 candidate_auth_tok);
1894 "Unrecognized candidate auth tok type: [%d]\n",
1895 candidate_auth_tok->token_type);
1899 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1901 crypt_stat->mount_crypt_stat,
1902 candidate_auth_tok_sig);
1905 goto found_matching_auth_tok;
1908 if (!found_auth_tok) {
1909 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1910 "authentication token\n");
1914 found_matching_auth_tok:
1915 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1916 memcpy(&(candidate_auth_tok->token.private_key),
1917 &(matching_auth_tok->token.private_key),
1918 sizeof(struct ecryptfs_private_key));
1919 up_write(&(auth_tok_key->sem));
1920 key_put(auth_tok_key);
1921 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1923 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1924 memcpy(&(candidate_auth_tok->token.password),
1925 &(matching_auth_tok->token.password),
1926 sizeof(struct ecryptfs_password));
1927 up_write(&(auth_tok_key->sem));
1928 key_put(auth_tok_key);
1929 rc = decrypt_passphrase_encrypted_session_key(
1930 candidate_auth_tok, crypt_stat);
1932 up_write(&(auth_tok_key->sem));
1933 key_put(auth_tok_key);
1937 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1939 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1940 "session key for authentication token with sig "
1941 "[%.*s]; rc = [%d]. Removing auth tok "
1942 "candidate from the list and searching for "
1943 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1944 candidate_auth_tok_sig, rc);
1945 list_for_each_entry_safe(auth_tok_list_item,
1946 auth_tok_list_item_tmp,
1947 &auth_tok_list, list) {
1948 if (candidate_auth_tok
1949 == &auth_tok_list_item->auth_tok) {
1950 list_del(&auth_tok_list_item->list);
1952 ecryptfs_auth_tok_list_item_cache,
1953 auth_tok_list_item);
1954 goto find_next_matching_auth_tok;
1959 rc = ecryptfs_compute_root_iv(crypt_stat);
1961 ecryptfs_printk(KERN_ERR, "Error computing "
1965 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1967 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1968 "context for cipher [%s]; rc = [%d]\n",
1969 crypt_stat->cipher, rc);
1972 wipe_auth_tok_list(&auth_tok_list);
1978 pki_encrypt_session_key(struct key *auth_tok_key,
1979 struct ecryptfs_auth_tok *auth_tok,
1980 struct ecryptfs_crypt_stat *crypt_stat,
1981 struct ecryptfs_key_record *key_rec)
1983 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1984 char *payload = NULL;
1985 size_t payload_len = 0;
1986 struct ecryptfs_message *msg;
1989 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1990 ecryptfs_code_for_cipher_string(
1992 crypt_stat->key_size),
1993 crypt_stat, &payload, &payload_len);
1994 up_write(&(auth_tok_key->sem));
1995 key_put(auth_tok_key);
1997 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
2000 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
2002 ecryptfs_printk(KERN_ERR, "Error sending message to "
2006 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
2008 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2009 "from the user space daemon\n");
2013 rc = parse_tag_67_packet(key_rec, msg);
2015 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2022 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2023 * @dest: Buffer into which to write the packet
2024 * @remaining_bytes: Maximum number of bytes that can be writtn
2025 * @auth_tok_key: The authentication token key to unlock and put when done with
2027 * @auth_tok: The authentication token used for generating the tag 1 packet
2028 * @crypt_stat: The cryptographic context
2029 * @key_rec: The key record struct for the tag 1 packet
2030 * @packet_size: This function will write the number of bytes that end
2031 * up constituting the packet; set to zero on error
2033 * Returns zero on success; non-zero on error.
2036 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2037 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2038 struct ecryptfs_crypt_stat *crypt_stat,
2039 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2042 size_t encrypted_session_key_valid = 0;
2043 size_t packet_size_length;
2044 size_t max_packet_size;
2048 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2050 encrypted_session_key_valid = 0;
2051 for (i = 0; i < crypt_stat->key_size; i++)
2052 encrypted_session_key_valid |=
2053 auth_tok->session_key.encrypted_key[i];
2054 if (encrypted_session_key_valid) {
2055 memcpy(key_rec->enc_key,
2056 auth_tok->session_key.encrypted_key,
2057 auth_tok->session_key.encrypted_key_size);
2058 up_write(&(auth_tok_key->sem));
2059 key_put(auth_tok_key);
2060 goto encrypted_session_key_set;
2062 if (auth_tok->session_key.encrypted_key_size == 0)
2063 auth_tok->session_key.encrypted_key_size =
2064 auth_tok->token.private_key.key_size;
2065 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2068 printk(KERN_ERR "Failed to encrypt session key via a key "
2069 "module; rc = [%d]\n", rc);
2072 if (ecryptfs_verbosity > 0) {
2073 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2074 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2076 encrypted_session_key_set:
2077 /* This format is inspired by OpenPGP; see RFC 2440
2079 max_packet_size = (1 /* Tag 1 identifier */
2080 + 3 /* Max Tag 1 packet size */
2082 + ECRYPTFS_SIG_SIZE /* Key identifier */
2083 + 1 /* Cipher identifier */
2084 + key_rec->enc_key_size); /* Encrypted key size */
2085 if (max_packet_size > (*remaining_bytes)) {
2086 printk(KERN_ERR "Packet length larger than maximum allowable; "
2087 "need up to [%td] bytes, but there are only [%td] "
2088 "available\n", max_packet_size, (*remaining_bytes));
2092 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2093 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2094 (max_packet_size - 4),
2095 &packet_size_length);
2097 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2098 "header; cannot generate packet length\n");
2101 (*packet_size) += packet_size_length;
2102 dest[(*packet_size)++] = 0x03; /* version 3 */
2103 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2104 (*packet_size) += ECRYPTFS_SIG_SIZE;
2105 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2106 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2107 key_rec->enc_key_size);
2108 (*packet_size) += key_rec->enc_key_size;
2113 (*remaining_bytes) -= (*packet_size);
2118 * write_tag_11_packet
2119 * @dest: Target into which Tag 11 packet is to be written
2120 * @remaining_bytes: Maximum packet length
2121 * @contents: Byte array of contents to copy in
2122 * @contents_length: Number of bytes in contents
2123 * @packet_length: Length of the Tag 11 packet written; zero on error
2125 * Returns zero on success; non-zero on error.
2128 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2129 size_t contents_length, size_t *packet_length)
2131 size_t packet_size_length;
2132 size_t max_packet_size;
2135 (*packet_length) = 0;
2136 /* This format is inspired by OpenPGP; see RFC 2440
2138 max_packet_size = (1 /* Tag 11 identifier */
2139 + 3 /* Max Tag 11 packet size */
2140 + 1 /* Binary format specifier */
2141 + 1 /* Filename length */
2142 + 8 /* Filename ("_CONSOLE") */
2143 + 4 /* Modification date */
2144 + contents_length); /* Literal data */
2145 if (max_packet_size > (*remaining_bytes)) {
2146 printk(KERN_ERR "Packet length larger than maximum allowable; "
2147 "need up to [%td] bytes, but there are only [%td] "
2148 "available\n", max_packet_size, (*remaining_bytes));
2152 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2153 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2154 (max_packet_size - 4),
2155 &packet_size_length);
2157 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2158 "generate packet length. rc = [%d]\n", rc);
2161 (*packet_length) += packet_size_length;
2162 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2163 dest[(*packet_length)++] = 8;
2164 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2165 (*packet_length) += 8;
2166 memset(&dest[(*packet_length)], 0x00, 4);
2167 (*packet_length) += 4;
2168 memcpy(&dest[(*packet_length)], contents, contents_length);
2169 (*packet_length) += contents_length;
2172 (*packet_length) = 0;
2174 (*remaining_bytes) -= (*packet_length);
2179 * write_tag_3_packet
2180 * @dest: Buffer into which to write the packet
2181 * @remaining_bytes: Maximum number of bytes that can be written
2182 * @auth_tok: Authentication token
2183 * @crypt_stat: The cryptographic context
2184 * @key_rec: encrypted key
2185 * @packet_size: This function will write the number of bytes that end
2186 * up constituting the packet; set to zero on error
2188 * Returns zero on success; non-zero on error.
2191 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2192 struct ecryptfs_auth_tok *auth_tok,
2193 struct ecryptfs_crypt_stat *crypt_stat,
2194 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2197 size_t encrypted_session_key_valid = 0;
2198 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2199 struct scatterlist dst_sg[2];
2200 struct scatterlist src_sg[2];
2201 struct mutex *tfm_mutex = NULL;
2203 size_t packet_size_length;
2204 size_t max_packet_size;
2205 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2206 crypt_stat->mount_crypt_stat;
2207 struct blkcipher_desc desc = {
2209 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2214 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2216 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2217 crypt_stat->cipher);
2219 printk(KERN_ERR "Internal error whilst attempting to get "
2220 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2221 crypt_stat->cipher, rc);
2224 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2225 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2227 printk(KERN_WARNING "No key size specified at mount; "
2228 "defaulting to [%d]\n", alg->max_keysize);
2229 mount_crypt_stat->global_default_cipher_key_size =
2232 if (crypt_stat->key_size == 0)
2233 crypt_stat->key_size =
2234 mount_crypt_stat->global_default_cipher_key_size;
2235 if (auth_tok->session_key.encrypted_key_size == 0)
2236 auth_tok->session_key.encrypted_key_size =
2237 crypt_stat->key_size;
2238 if (crypt_stat->key_size == 24
2239 && strcmp("aes", crypt_stat->cipher) == 0) {
2240 memset((crypt_stat->key + 24), 0, 8);
2241 auth_tok->session_key.encrypted_key_size = 32;
2243 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2244 key_rec->enc_key_size =
2245 auth_tok->session_key.encrypted_key_size;
2246 encrypted_session_key_valid = 0;
2247 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2248 encrypted_session_key_valid |=
2249 auth_tok->session_key.encrypted_key[i];
2250 if (encrypted_session_key_valid) {
2251 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2252 "using auth_tok->session_key.encrypted_key, "
2253 "where key_rec->enc_key_size = [%zd]\n",
2254 key_rec->enc_key_size);
2255 memcpy(key_rec->enc_key,
2256 auth_tok->session_key.encrypted_key,
2257 key_rec->enc_key_size);
2258 goto encrypted_session_key_set;
2260 if (auth_tok->token.password.flags &
2261 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2262 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2263 "session key encryption key of size [%d]\n",
2264 auth_tok->token.password.
2265 session_key_encryption_key_bytes);
2266 memcpy(session_key_encryption_key,
2267 auth_tok->token.password.session_key_encryption_key,
2268 crypt_stat->key_size);
2269 ecryptfs_printk(KERN_DEBUG,
2270 "Cached session key encryption key:\n");
2271 if (ecryptfs_verbosity > 0)
2272 ecryptfs_dump_hex(session_key_encryption_key, 16);
2274 if (unlikely(ecryptfs_verbosity > 0)) {
2275 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2276 ecryptfs_dump_hex(session_key_encryption_key, 16);
2278 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2280 if (rc < 1 || rc > 2) {
2281 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2282 "for crypt_stat session key; expected rc = 1; "
2283 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2284 rc, key_rec->enc_key_size);
2288 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2290 if (rc < 1 || rc > 2) {
2291 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2292 "for crypt_stat encrypted session key; "
2293 "expected rc = 1; got rc = [%d]. "
2294 "key_rec->enc_key_size = [%zd]\n", rc,
2295 key_rec->enc_key_size);
2299 mutex_lock(tfm_mutex);
2300 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2301 crypt_stat->key_size);
2303 mutex_unlock(tfm_mutex);
2304 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2305 "context; rc = [%d]\n", rc);
2309 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2310 crypt_stat->key_size);
2311 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2312 (*key_rec).enc_key_size);
2313 mutex_unlock(tfm_mutex);
2315 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2318 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2319 if (ecryptfs_verbosity > 0) {
2320 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2321 key_rec->enc_key_size);
2322 ecryptfs_dump_hex(key_rec->enc_key,
2323 key_rec->enc_key_size);
2325 encrypted_session_key_set:
2326 /* This format is inspired by OpenPGP; see RFC 2440
2328 max_packet_size = (1 /* Tag 3 identifier */
2329 + 3 /* Max Tag 3 packet size */
2331 + 1 /* Cipher code */
2332 + 1 /* S2K specifier */
2333 + 1 /* Hash identifier */
2334 + ECRYPTFS_SALT_SIZE /* Salt */
2335 + 1 /* Hash iterations */
2336 + key_rec->enc_key_size); /* Encrypted key size */
2337 if (max_packet_size > (*remaining_bytes)) {
2338 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2339 "there are only [%td] available\n", max_packet_size,
2340 (*remaining_bytes));
2344 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2345 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2346 * to get the number of octets in the actual Tag 3 packet */
2347 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2348 (max_packet_size - 4),
2349 &packet_size_length);
2351 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2352 "generate packet length. rc = [%d]\n", rc);
2355 (*packet_size) += packet_size_length;
2356 dest[(*packet_size)++] = 0x04; /* version 4 */
2357 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2358 * specified with strings */
2359 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2360 crypt_stat->key_size);
2361 if (cipher_code == 0) {
2362 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2363 "cipher [%s]\n", crypt_stat->cipher);
2367 dest[(*packet_size)++] = cipher_code;
2368 dest[(*packet_size)++] = 0x03; /* S2K */
2369 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2370 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2371 ECRYPTFS_SALT_SIZE);
2372 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2373 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2374 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2375 key_rec->enc_key_size);
2376 (*packet_size) += key_rec->enc_key_size;
2381 (*remaining_bytes) -= (*packet_size);
2385 struct kmem_cache *ecryptfs_key_record_cache;
2388 * ecryptfs_generate_key_packet_set
2389 * @dest_base: Virtual address from which to write the key record set
2390 * @crypt_stat: The cryptographic context from which the
2391 * authentication tokens will be retrieved
2392 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2393 * for the global parameters
2394 * @len: The amount written
2395 * @max: The maximum amount of data allowed to be written
2397 * Generates a key packet set and writes it to the virtual address
2400 * Returns zero on success; non-zero on error.
2403 ecryptfs_generate_key_packet_set(char *dest_base,
2404 struct ecryptfs_crypt_stat *crypt_stat,
2405 struct dentry *ecryptfs_dentry, size_t *len,
2408 struct ecryptfs_auth_tok *auth_tok;
2409 struct key *auth_tok_key = NULL;
2410 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2411 &ecryptfs_superblock_to_private(
2412 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2414 struct ecryptfs_key_record *key_rec;
2415 struct ecryptfs_key_sig *key_sig;
2419 mutex_lock(&crypt_stat->keysig_list_mutex);
2420 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2425 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2427 memset(key_rec, 0, sizeof(*key_rec));
2428 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2433 printk(KERN_WARNING "Unable to retrieve auth tok with "
2434 "sig = [%s]\n", key_sig->keysig);
2435 rc = process_find_global_auth_tok_for_sig_err(rc);
2438 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2439 rc = write_tag_3_packet((dest_base + (*len)),
2441 crypt_stat, key_rec,
2443 up_write(&(auth_tok_key->sem));
2444 key_put(auth_tok_key);
2446 ecryptfs_printk(KERN_WARNING, "Error "
2447 "writing tag 3 packet\n");
2451 /* Write auth tok signature packet */
2452 rc = write_tag_11_packet((dest_base + (*len)), &max,
2454 ECRYPTFS_SIG_SIZE, &written);
2456 ecryptfs_printk(KERN_ERR, "Error writing "
2457 "auth tok signature packet\n");
2461 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2462 rc = write_tag_1_packet(dest_base + (*len), &max,
2463 auth_tok_key, auth_tok,
2464 crypt_stat, key_rec, &written);
2466 ecryptfs_printk(KERN_WARNING, "Error "
2467 "writing tag 1 packet\n");
2472 up_write(&(auth_tok_key->sem));
2473 key_put(auth_tok_key);
2474 ecryptfs_printk(KERN_WARNING, "Unsupported "
2475 "authentication token type\n");
2480 if (likely(max > 0)) {
2481 dest_base[(*len)] = 0x00;
2483 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2487 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2491 mutex_unlock(&crypt_stat->keysig_list_mutex);
2495 struct kmem_cache *ecryptfs_key_sig_cache;
2497 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2499 struct ecryptfs_key_sig *new_key_sig;
2501 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2504 "Error allocating from ecryptfs_key_sig_cache\n");
2507 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2508 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2509 /* Caller must hold keysig_list_mutex */
2510 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2515 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2518 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2519 char *sig, u32 global_auth_tok_flags)
2521 struct ecryptfs_global_auth_tok *new_auth_tok;
2524 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2526 if (!new_auth_tok) {
2528 printk(KERN_ERR "Error allocating from "
2529 "ecryptfs_global_auth_tok_cache\n");
2532 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2533 new_auth_tok->flags = global_auth_tok_flags;
2534 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2535 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2536 list_add(&new_auth_tok->mount_crypt_stat_list,
2537 &mount_crypt_stat->global_auth_tok_list);
2538 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);