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 otherwise
465 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
466 struct ecryptfs_auth_tok **auth_tok)
470 (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
471 if (ecryptfs_verify_version((*auth_tok)->version)) {
472 printk(KERN_ERR "Data structure version mismatch. Userspace "
473 "tools must match eCryptfs kernel module with major "
474 "version [%d] and minor version [%d]\n",
475 ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
479 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
480 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
481 printk(KERN_ERR "Invalid auth_tok structure "
482 "returned from key query\n");
491 ecryptfs_find_global_auth_tok_for_sig(
492 struct key **auth_tok_key,
493 struct ecryptfs_auth_tok **auth_tok,
494 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
496 struct ecryptfs_global_auth_tok *walker;
499 (*auth_tok_key) = NULL;
501 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
502 list_for_each_entry(walker,
503 &mount_crypt_stat->global_auth_tok_list,
504 mount_crypt_stat_list) {
505 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
508 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
513 rc = key_validate(walker->global_auth_tok_key);
515 if (rc == -EKEYEXPIRED)
517 goto out_invalid_auth_tok;
520 down_write(&(walker->global_auth_tok_key->sem));
521 rc = ecryptfs_verify_auth_tok_from_key(
522 walker->global_auth_tok_key, auth_tok);
524 goto out_invalid_auth_tok_unlock;
526 (*auth_tok_key) = walker->global_auth_tok_key;
527 key_get(*auth_tok_key);
532 out_invalid_auth_tok_unlock:
533 up_write(&(walker->global_auth_tok_key->sem));
534 out_invalid_auth_tok:
535 printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
536 walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
537 key_put(walker->global_auth_tok_key);
538 walker->global_auth_tok_key = NULL;
540 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
545 * ecryptfs_find_auth_tok_for_sig
546 * @auth_tok: Set to the matching auth_tok; NULL if not found
547 * @crypt_stat: inode crypt_stat crypto context
548 * @sig: Sig of auth_tok to find
550 * For now, this function simply looks at the registered auth_tok's
551 * linked off the mount_crypt_stat, so all the auth_toks that can be
552 * used must be registered at mount time. This function could
553 * potentially try a lot harder to find auth_tok's (e.g., by calling
554 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
555 * that static registration of auth_tok's will no longer be necessary.
557 * Returns zero on no error; non-zero on error
560 ecryptfs_find_auth_tok_for_sig(
561 struct key **auth_tok_key,
562 struct ecryptfs_auth_tok **auth_tok,
563 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
568 rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
569 mount_crypt_stat, sig);
571 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
572 * mount_crypt_stat structure, we prevent to use auth toks that
573 * are not inserted through the ecryptfs_add_global_auth_tok
576 if (mount_crypt_stat->flags
577 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
580 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
587 * write_tag_70_packet can gobble a lot of stack space. We stuff most
588 * of the function's parameters in a kmalloc'd struct to help reduce
589 * eCryptfs' overall stack usage.
591 struct ecryptfs_write_tag_70_packet_silly_stack {
593 size_t max_packet_size;
594 size_t packet_size_len;
595 size_t block_aligned_filename_size;
599 size_t num_rand_bytes;
600 struct mutex *tfm_mutex;
601 char *block_aligned_filename;
602 struct ecryptfs_auth_tok *auth_tok;
603 struct scatterlist src_sg[2];
604 struct scatterlist dst_sg[2];
605 struct blkcipher_desc desc;
606 char iv[ECRYPTFS_MAX_IV_BYTES];
607 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
608 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
609 struct hash_desc hash_desc;
610 struct scatterlist hash_sg;
614 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
615 * @filename: NULL-terminated filename string
617 * This is the simplest mechanism for achieving filename encryption in
618 * eCryptfs. It encrypts the given filename with the mount-wide
619 * filename encryption key (FNEK) and stores it in a packet to @dest,
620 * which the callee will encode and write directly into the dentry
624 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
626 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
627 char *filename, size_t filename_size)
629 struct ecryptfs_write_tag_70_packet_silly_stack *s;
630 struct key *auth_tok_key = NULL;
633 s = kmalloc(sizeof(*s), GFP_KERNEL);
635 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
636 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
640 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
642 rc = ecryptfs_find_auth_tok_for_sig(
644 &s->auth_tok, mount_crypt_stat,
645 mount_crypt_stat->global_default_fnek_sig);
647 printk(KERN_ERR "%s: Error attempting to find auth tok for "
648 "fnek sig [%s]; rc = [%d]\n", __func__,
649 mount_crypt_stat->global_default_fnek_sig, rc);
652 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
654 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
656 printk(KERN_ERR "Internal error whilst attempting to get "
657 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
658 mount_crypt_stat->global_default_fn_cipher_name, rc);
661 mutex_lock(s->tfm_mutex);
662 s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
663 /* Plus one for the \0 separator between the random prefix
664 * and the plaintext filename */
665 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
666 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
667 if ((s->block_aligned_filename_size % s->block_size) != 0) {
668 s->num_rand_bytes += (s->block_size
669 - (s->block_aligned_filename_size
671 s->block_aligned_filename_size = (s->num_rand_bytes
674 /* Octet 0: Tag 70 identifier
675 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
676 * and block-aligned encrypted filename size)
677 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
678 * Octet N2-N3: Cipher identifier (1 octet)
679 * Octets N3-N4: Block-aligned encrypted filename
680 * - Consists of a minimum number of random characters, a \0
681 * separator, and then the filename */
682 s->max_packet_size = (1 /* Tag 70 identifier */
683 + 3 /* Max Tag 70 packet size */
684 + ECRYPTFS_SIG_SIZE /* FNEK sig */
685 + 1 /* Cipher identifier */
686 + s->block_aligned_filename_size);
688 (*packet_size) = s->max_packet_size;
691 if (s->max_packet_size > (*remaining_bytes)) {
692 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
693 "[%zd] available\n", __func__, s->max_packet_size,
698 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
700 if (!s->block_aligned_filename) {
701 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
702 "kzalloc [%zd] bytes\n", __func__,
703 s->block_aligned_filename_size);
708 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
709 rc = ecryptfs_write_packet_length(&dest[s->i],
711 + 1 /* Cipher code */
712 + s->block_aligned_filename_size),
713 &s->packet_size_len);
715 printk(KERN_ERR "%s: Error generating tag 70 packet "
716 "header; cannot generate packet length; rc = [%d]\n",
718 goto out_free_unlock;
720 s->i += s->packet_size_len;
721 ecryptfs_from_hex(&dest[s->i],
722 mount_crypt_stat->global_default_fnek_sig,
724 s->i += ECRYPTFS_SIG_SIZE;
725 s->cipher_code = ecryptfs_code_for_cipher_string(
726 mount_crypt_stat->global_default_fn_cipher_name,
727 mount_crypt_stat->global_default_fn_cipher_key_bytes);
728 if (s->cipher_code == 0) {
729 printk(KERN_WARNING "%s: Unable to generate code for "
730 "cipher [%s] with key bytes [%zd]\n", __func__,
731 mount_crypt_stat->global_default_fn_cipher_name,
732 mount_crypt_stat->global_default_fn_cipher_key_bytes);
734 goto out_free_unlock;
736 dest[s->i++] = s->cipher_code;
737 /* TODO: Support other key modules than passphrase for
738 * filename encryption */
739 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
741 printk(KERN_INFO "%s: Filename encryption only supports "
742 "password tokens\n", __func__);
743 goto out_free_unlock;
747 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
748 s->auth_tok->token.password.session_key_encryption_key_bytes);
749 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
750 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
752 if (IS_ERR(s->hash_desc.tfm)) {
753 rc = PTR_ERR(s->hash_desc.tfm);
754 printk(KERN_ERR "%s: Error attempting to "
755 "allocate hash crypto context; rc = [%d]\n",
757 goto out_free_unlock;
759 rc = crypto_hash_init(&s->hash_desc);
762 "%s: Error initializing crypto hash; rc = [%d]\n",
764 goto out_release_free_unlock;
766 rc = crypto_hash_update(
767 &s->hash_desc, &s->hash_sg,
768 s->auth_tok->token.password.session_key_encryption_key_bytes);
771 "%s: Error updating crypto hash; rc = [%d]\n",
773 goto out_release_free_unlock;
775 rc = crypto_hash_final(&s->hash_desc, s->hash);
778 "%s: Error finalizing crypto hash; rc = [%d]\n",
780 goto out_release_free_unlock;
782 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
783 s->block_aligned_filename[s->j] =
784 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
785 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
786 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
787 sg_init_one(&s->hash_sg, (u8 *)s->hash,
788 ECRYPTFS_TAG_70_DIGEST_SIZE);
789 rc = crypto_hash_init(&s->hash_desc);
792 "%s: Error initializing crypto hash; "
793 "rc = [%d]\n", __func__, rc);
794 goto out_release_free_unlock;
796 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
797 ECRYPTFS_TAG_70_DIGEST_SIZE);
800 "%s: Error updating crypto hash; "
801 "rc = [%d]\n", __func__, rc);
802 goto out_release_free_unlock;
804 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
807 "%s: Error finalizing crypto hash; "
808 "rc = [%d]\n", __func__, rc);
809 goto out_release_free_unlock;
811 memcpy(s->hash, s->tmp_hash,
812 ECRYPTFS_TAG_70_DIGEST_SIZE);
814 if (s->block_aligned_filename[s->j] == '\0')
815 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
817 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
819 rc = virt_to_scatterlist(s->block_aligned_filename,
820 s->block_aligned_filename_size, s->src_sg, 2);
822 printk(KERN_ERR "%s: Internal error whilst attempting to "
823 "convert filename memory to scatterlist; rc = [%d]. "
824 "block_aligned_filename_size = [%zd]\n", __func__, rc,
825 s->block_aligned_filename_size);
826 goto out_release_free_unlock;
828 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
831 printk(KERN_ERR "%s: Internal error whilst attempting to "
832 "convert encrypted filename memory to scatterlist; "
833 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
834 __func__, rc, s->block_aligned_filename_size);
835 goto out_release_free_unlock;
837 /* The characters in the first block effectively do the job
838 * of the IV here, so we just use 0's for the IV. Note the
839 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
840 * >= ECRYPTFS_MAX_IV_BYTES. */
841 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
842 s->desc.info = s->iv;
843 rc = crypto_blkcipher_setkey(
845 s->auth_tok->token.password.session_key_encryption_key,
846 mount_crypt_stat->global_default_fn_cipher_key_bytes);
848 printk(KERN_ERR "%s: Error setting key for crypto context; "
849 "rc = [%d]. s->auth_tok->token.password.session_key_"
850 "encryption_key = [0x%p]; mount_crypt_stat->"
851 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
853 s->auth_tok->token.password.session_key_encryption_key,
854 mount_crypt_stat->global_default_fn_cipher_key_bytes);
855 goto out_release_free_unlock;
857 rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
858 s->block_aligned_filename_size);
860 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
861 "rc = [%d]\n", __func__, rc);
862 goto out_release_free_unlock;
864 s->i += s->block_aligned_filename_size;
865 (*packet_size) = s->i;
866 (*remaining_bytes) -= (*packet_size);
867 out_release_free_unlock:
868 crypto_free_hash(s->hash_desc.tfm);
870 kzfree(s->block_aligned_filename);
872 mutex_unlock(s->tfm_mutex);
875 up_write(&(auth_tok_key->sem));
876 key_put(auth_tok_key);
882 struct ecryptfs_parse_tag_70_packet_silly_stack {
884 size_t max_packet_size;
885 size_t packet_size_len;
886 size_t parsed_tag_70_packet_size;
887 size_t block_aligned_filename_size;
890 struct mutex *tfm_mutex;
891 char *decrypted_filename;
892 struct ecryptfs_auth_tok *auth_tok;
893 struct scatterlist src_sg[2];
894 struct scatterlist dst_sg[2];
895 struct blkcipher_desc desc;
896 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
897 char iv[ECRYPTFS_MAX_IV_BYTES];
898 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
902 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
903 * @filename: This function kmalloc's the memory for the filename
904 * @filename_size: This function sets this to the amount of memory
905 * kmalloc'd for the filename
906 * @packet_size: This function sets this to the the number of octets
907 * in the packet parsed
908 * @mount_crypt_stat: The mount-wide cryptographic context
909 * @data: The memory location containing the start of the tag 70
911 * @max_packet_size: The maximum legal size of the packet to be parsed
914 * Returns zero on success; non-zero otherwise
917 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
919 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
920 char *data, size_t max_packet_size)
922 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
923 struct key *auth_tok_key = NULL;
927 (*filename_size) = 0;
929 s = kmalloc(sizeof(*s), GFP_KERNEL);
931 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
932 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
936 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
937 if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
938 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
939 "at least [%d]\n", __func__, max_packet_size,
940 (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
944 /* Octet 0: Tag 70 identifier
945 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
946 * and block-aligned encrypted filename size)
947 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
948 * Octet N2-N3: Cipher identifier (1 octet)
949 * Octets N3-N4: Block-aligned encrypted filename
950 * - Consists of a minimum number of random numbers, a \0
951 * separator, and then the filename */
952 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
953 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
954 "tag [0x%.2x]\n", __func__,
955 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
959 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
960 &s->parsed_tag_70_packet_size,
961 &s->packet_size_len);
963 printk(KERN_WARNING "%s: Error parsing packet length; "
964 "rc = [%d]\n", __func__, rc);
967 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
968 - ECRYPTFS_SIG_SIZE - 1);
969 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
971 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
972 "size is [%zd]\n", __func__, max_packet_size,
973 (1 + s->packet_size_len + 1
974 + s->block_aligned_filename_size));
978 (*packet_size) += s->packet_size_len;
979 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
981 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
982 (*packet_size) += ECRYPTFS_SIG_SIZE;
983 s->cipher_code = data[(*packet_size)++];
984 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
986 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
987 __func__, s->cipher_code);
990 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
991 &s->auth_tok, mount_crypt_stat,
994 printk(KERN_ERR "%s: Error attempting to find auth tok for "
995 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
999 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
1003 printk(KERN_ERR "Internal error whilst attempting to get "
1004 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1005 s->cipher_string, rc);
1008 mutex_lock(s->tfm_mutex);
1009 rc = virt_to_scatterlist(&data[(*packet_size)],
1010 s->block_aligned_filename_size, s->src_sg, 2);
1012 printk(KERN_ERR "%s: Internal error whilst attempting to "
1013 "convert encrypted filename memory to scatterlist; "
1014 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1015 __func__, rc, s->block_aligned_filename_size);
1018 (*packet_size) += s->block_aligned_filename_size;
1019 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1021 if (!s->decrypted_filename) {
1022 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1023 "kmalloc [%zd] bytes\n", __func__,
1024 s->block_aligned_filename_size);
1028 rc = virt_to_scatterlist(s->decrypted_filename,
1029 s->block_aligned_filename_size, s->dst_sg, 2);
1031 printk(KERN_ERR "%s: Internal error whilst attempting to "
1032 "convert decrypted filename memory to scatterlist; "
1033 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1034 __func__, rc, s->block_aligned_filename_size);
1035 goto out_free_unlock;
1037 /* The characters in the first block effectively do the job of
1038 * the IV here, so we just use 0's for the IV. Note the
1039 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1040 * >= ECRYPTFS_MAX_IV_BYTES. */
1041 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1042 s->desc.info = s->iv;
1043 /* TODO: Support other key modules than passphrase for
1044 * filename encryption */
1045 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1047 printk(KERN_INFO "%s: Filename encryption only supports "
1048 "password tokens\n", __func__);
1049 goto out_free_unlock;
1051 rc = crypto_blkcipher_setkey(
1053 s->auth_tok->token.password.session_key_encryption_key,
1054 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1056 printk(KERN_ERR "%s: Error setting key for crypto context; "
1057 "rc = [%d]. s->auth_tok->token.password.session_key_"
1058 "encryption_key = [0x%p]; mount_crypt_stat->"
1059 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1061 s->auth_tok->token.password.session_key_encryption_key,
1062 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1063 goto out_free_unlock;
1065 rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
1066 s->block_aligned_filename_size);
1068 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1069 "rc = [%d]\n", __func__, rc);
1070 goto out_free_unlock;
1073 while (s->decrypted_filename[s->i] != '\0'
1074 && s->i < s->block_aligned_filename_size)
1076 if (s->i == s->block_aligned_filename_size) {
1077 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1078 "find valid separator between random characters and "
1079 "the filename\n", __func__);
1081 goto out_free_unlock;
1084 (*filename_size) = (s->block_aligned_filename_size - s->i);
1085 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1086 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1087 "invalid\n", __func__, (*filename_size));
1089 goto out_free_unlock;
1091 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1093 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1094 "kmalloc [%zd] bytes\n", __func__,
1095 ((*filename_size) + 1));
1097 goto out_free_unlock;
1099 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1100 (*filename)[(*filename_size)] = '\0';
1102 kfree(s->decrypted_filename);
1104 mutex_unlock(s->tfm_mutex);
1108 (*filename_size) = 0;
1112 up_write(&(auth_tok_key->sem));
1113 key_put(auth_tok_key);
1120 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1125 switch (auth_tok->token_type) {
1126 case ECRYPTFS_PASSWORD:
1127 (*sig) = auth_tok->token.password.signature;
1129 case ECRYPTFS_PRIVATE_KEY:
1130 (*sig) = auth_tok->token.private_key.signature;
1133 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1134 auth_tok->token_type);
1141 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1142 * @auth_tok: The key authentication token used to decrypt the session key
1143 * @crypt_stat: The cryptographic context
1145 * Returns zero on success; non-zero error otherwise.
1148 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1149 struct ecryptfs_crypt_stat *crypt_stat)
1152 struct ecryptfs_msg_ctx *msg_ctx;
1153 struct ecryptfs_message *msg = NULL;
1155 char *payload = NULL;
1159 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1161 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1162 auth_tok->token_type);
1165 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1166 &payload, &payload_len);
1168 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1171 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1173 ecryptfs_printk(KERN_ERR, "Error sending message to "
1177 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1179 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1180 "from the user space daemon\n");
1184 rc = parse_tag_65_packet(&(auth_tok->session_key),
1187 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1191 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1192 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1193 auth_tok->session_key.decrypted_key_size);
1194 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1195 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1197 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1201 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1202 if (ecryptfs_verbosity > 0) {
1203 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1204 ecryptfs_dump_hex(crypt_stat->key,
1205 crypt_stat->key_size);
1214 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1216 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1217 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1219 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1220 auth_tok_list_head, list) {
1221 list_del(&auth_tok_list_item->list);
1222 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1223 auth_tok_list_item);
1227 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1230 * parse_tag_1_packet
1231 * @crypt_stat: The cryptographic context to modify based on packet contents
1232 * @data: The raw bytes of the packet.
1233 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1234 * a new authentication token will be placed at the
1235 * end of this list for this packet.
1236 * @new_auth_tok: Pointer to a pointer to memory that this function
1237 * allocates; sets the memory address of the pointer to
1238 * NULL on error. This object is added to the
1240 * @packet_size: This function writes the size of the parsed packet
1241 * into this memory location; zero on error.
1242 * @max_packet_size: The maximum allowable packet size
1244 * Returns zero on success; non-zero on error.
1247 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1248 unsigned char *data, struct list_head *auth_tok_list,
1249 struct ecryptfs_auth_tok **new_auth_tok,
1250 size_t *packet_size, size_t max_packet_size)
1253 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1258 (*new_auth_tok) = NULL;
1260 * This format is inspired by OpenPGP; see RFC 2440
1263 * Tag 1 identifier (1 byte)
1264 * Max Tag 1 packet size (max 3 bytes)
1266 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1267 * Cipher identifier (1 byte)
1268 * Encrypted key size (arbitrary)
1270 * 12 bytes minimum packet size
1272 if (unlikely(max_packet_size < 12)) {
1273 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1277 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1278 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1279 ECRYPTFS_TAG_1_PACKET_TYPE);
1283 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1284 * at end of function upon failure */
1285 auth_tok_list_item =
1286 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1288 if (!auth_tok_list_item) {
1289 printk(KERN_ERR "Unable to allocate memory\n");
1293 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1294 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1297 printk(KERN_WARNING "Error parsing packet length; "
1301 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1302 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1306 (*packet_size) += length_size;
1307 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1308 printk(KERN_WARNING "Packet size exceeds max\n");
1312 if (unlikely(data[(*packet_size)++] != 0x03)) {
1313 printk(KERN_WARNING "Unknown version number [%d]\n",
1314 data[(*packet_size) - 1]);
1318 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1319 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1320 *packet_size += ECRYPTFS_SIG_SIZE;
1321 /* This byte is skipped because the kernel does not need to
1322 * know which public key encryption algorithm was used */
1324 (*new_auth_tok)->session_key.encrypted_key_size =
1325 body_size - (ECRYPTFS_SIG_SIZE + 2);
1326 if ((*new_auth_tok)->session_key.encrypted_key_size
1327 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1328 printk(KERN_WARNING "Tag 1 packet contains key larger "
1329 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1333 memcpy((*new_auth_tok)->session_key.encrypted_key,
1334 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1335 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1336 (*new_auth_tok)->session_key.flags &=
1337 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1338 (*new_auth_tok)->session_key.flags |=
1339 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1340 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1341 (*new_auth_tok)->flags = 0;
1342 (*new_auth_tok)->session_key.flags &=
1343 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1344 (*new_auth_tok)->session_key.flags &=
1345 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1346 list_add(&auth_tok_list_item->list, auth_tok_list);
1349 (*new_auth_tok) = NULL;
1350 memset(auth_tok_list_item, 0,
1351 sizeof(struct ecryptfs_auth_tok_list_item));
1352 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1353 auth_tok_list_item);
1361 * parse_tag_3_packet
1362 * @crypt_stat: The cryptographic context to modify based on packet
1364 * @data: The raw bytes of the packet.
1365 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1366 * a new authentication token will be placed at the end
1367 * of this list for this packet.
1368 * @new_auth_tok: Pointer to a pointer to memory that this function
1369 * allocates; sets the memory address of the pointer to
1370 * NULL on error. This object is added to the
1372 * @packet_size: This function writes the size of the parsed packet
1373 * into this memory location; zero on error.
1374 * @max_packet_size: maximum number of bytes to parse
1376 * Returns zero on success; non-zero on error.
1379 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1380 unsigned char *data, struct list_head *auth_tok_list,
1381 struct ecryptfs_auth_tok **new_auth_tok,
1382 size_t *packet_size, size_t max_packet_size)
1385 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1390 (*new_auth_tok) = NULL;
1392 *This format is inspired by OpenPGP; see RFC 2440
1395 * Tag 3 identifier (1 byte)
1396 * Max Tag 3 packet size (max 3 bytes)
1398 * Cipher code (1 byte)
1399 * S2K specifier (1 byte)
1400 * Hash identifier (1 byte)
1401 * Salt (ECRYPTFS_SALT_SIZE)
1402 * Hash iterations (1 byte)
1403 * Encrypted key (arbitrary)
1405 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1407 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1408 printk(KERN_ERR "Max packet size too large\n");
1412 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1413 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1414 ECRYPTFS_TAG_3_PACKET_TYPE);
1418 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1419 * at end of function upon failure */
1420 auth_tok_list_item =
1421 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1422 if (!auth_tok_list_item) {
1423 printk(KERN_ERR "Unable to allocate memory\n");
1427 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1428 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1431 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1435 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1436 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1440 (*packet_size) += length_size;
1441 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1442 printk(KERN_ERR "Packet size exceeds max\n");
1446 (*new_auth_tok)->session_key.encrypted_key_size =
1447 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1448 if ((*new_auth_tok)->session_key.encrypted_key_size
1449 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1450 printk(KERN_WARNING "Tag 3 packet contains key larger "
1451 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1455 if (unlikely(data[(*packet_size)++] != 0x04)) {
1456 printk(KERN_WARNING "Unknown version number [%d]\n",
1457 data[(*packet_size) - 1]);
1461 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1462 (u16)data[(*packet_size)]);
1465 /* A little extra work to differentiate among the AES key
1466 * sizes; see RFC2440 */
1467 switch(data[(*packet_size)++]) {
1468 case RFC2440_CIPHER_AES_192:
1469 crypt_stat->key_size = 24;
1472 crypt_stat->key_size =
1473 (*new_auth_tok)->session_key.encrypted_key_size;
1475 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1478 if (unlikely(data[(*packet_size)++] != 0x03)) {
1479 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1483 /* TODO: finish the hash mapping */
1484 switch (data[(*packet_size)++]) {
1485 case 0x01: /* See RFC2440 for these numbers and their mappings */
1487 memcpy((*new_auth_tok)->token.password.salt,
1488 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1489 (*packet_size) += ECRYPTFS_SALT_SIZE;
1490 /* This conversion was taken straight from RFC2440 */
1491 (*new_auth_tok)->token.password.hash_iterations =
1492 ((u32) 16 + (data[(*packet_size)] & 15))
1493 << ((data[(*packet_size)] >> 4) + 6);
1495 /* Friendly reminder:
1496 * (*new_auth_tok)->session_key.encrypted_key_size =
1497 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1498 memcpy((*new_auth_tok)->session_key.encrypted_key,
1499 &data[(*packet_size)],
1500 (*new_auth_tok)->session_key.encrypted_key_size);
1502 (*new_auth_tok)->session_key.encrypted_key_size;
1503 (*new_auth_tok)->session_key.flags &=
1504 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1505 (*new_auth_tok)->session_key.flags |=
1506 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1507 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1510 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1511 "[%d]\n", data[(*packet_size) - 1]);
1515 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1516 /* TODO: Parametarize; we might actually want userspace to
1517 * decrypt the session key. */
1518 (*new_auth_tok)->session_key.flags &=
1519 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1520 (*new_auth_tok)->session_key.flags &=
1521 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1522 list_add(&auth_tok_list_item->list, auth_tok_list);
1525 (*new_auth_tok) = NULL;
1526 memset(auth_tok_list_item, 0,
1527 sizeof(struct ecryptfs_auth_tok_list_item));
1528 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1529 auth_tok_list_item);
1537 * parse_tag_11_packet
1538 * @data: The raw bytes of the packet
1539 * @contents: This function writes the data contents of the literal
1540 * packet into this memory location
1541 * @max_contents_bytes: The maximum number of bytes that this function
1542 * is allowed to write into contents
1543 * @tag_11_contents_size: This function writes the size of the parsed
1544 * contents into this memory location; zero on
1546 * @packet_size: This function writes the size of the parsed packet
1547 * into this memory location; zero on error
1548 * @max_packet_size: maximum number of bytes to parse
1550 * Returns zero on success; non-zero on error.
1553 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1554 size_t max_contents_bytes, size_t *tag_11_contents_size,
1555 size_t *packet_size, size_t max_packet_size)
1562 (*tag_11_contents_size) = 0;
1563 /* This format is inspired by OpenPGP; see RFC 2440
1566 * Tag 11 identifier (1 byte)
1567 * Max Tag 11 packet size (max 3 bytes)
1568 * Binary format specifier (1 byte)
1569 * Filename length (1 byte)
1570 * Filename ("_CONSOLE") (8 bytes)
1571 * Modification date (4 bytes)
1572 * Literal data (arbitrary)
1574 * We need at least 16 bytes of data for the packet to even be
1577 if (max_packet_size < 16) {
1578 printk(KERN_ERR "Maximum packet size too small\n");
1582 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1583 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1587 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1590 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1593 if (body_size < 14) {
1594 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1598 (*packet_size) += length_size;
1599 (*tag_11_contents_size) = (body_size - 14);
1600 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1601 printk(KERN_ERR "Packet size exceeds max\n");
1605 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1606 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1611 if (data[(*packet_size)++] != 0x62) {
1612 printk(KERN_WARNING "Unrecognizable packet\n");
1616 if (data[(*packet_size)++] != 0x08) {
1617 printk(KERN_WARNING "Unrecognizable packet\n");
1621 (*packet_size) += 12; /* Ignore filename and modification date */
1622 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1623 (*packet_size) += (*tag_11_contents_size);
1627 (*tag_11_contents_size) = 0;
1632 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1633 struct ecryptfs_auth_tok **auth_tok,
1638 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1639 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1640 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1641 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1642 printk(KERN_ERR "Could not find key with description: [%s]\n",
1644 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1645 (*auth_tok_key) = NULL;
1649 down_write(&(*auth_tok_key)->sem);
1650 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1652 up_write(&(*auth_tok_key)->sem);
1653 key_put(*auth_tok_key);
1654 (*auth_tok_key) = NULL;
1662 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1663 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1664 * @crypt_stat: The cryptographic context
1666 * Returns zero on success; non-zero error otherwise
1669 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1670 struct ecryptfs_crypt_stat *crypt_stat)
1672 struct scatterlist dst_sg[2];
1673 struct scatterlist src_sg[2];
1674 struct mutex *tfm_mutex;
1675 struct blkcipher_desc desc = {
1676 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1680 if (unlikely(ecryptfs_verbosity > 0)) {
1682 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1683 auth_tok->token.password.session_key_encryption_key_bytes);
1685 auth_tok->token.password.session_key_encryption_key,
1686 auth_tok->token.password.session_key_encryption_key_bytes);
1688 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1689 crypt_stat->cipher);
1691 printk(KERN_ERR "Internal error whilst attempting to get "
1692 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1693 crypt_stat->cipher, rc);
1696 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1697 auth_tok->session_key.encrypted_key_size,
1699 if (rc < 1 || rc > 2) {
1700 printk(KERN_ERR "Internal error whilst attempting to convert "
1701 "auth_tok->session_key.encrypted_key to scatterlist; "
1702 "expected rc = 1; got rc = [%d]. "
1703 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1704 auth_tok->session_key.encrypted_key_size);
1707 auth_tok->session_key.decrypted_key_size =
1708 auth_tok->session_key.encrypted_key_size;
1709 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1710 auth_tok->session_key.decrypted_key_size,
1712 if (rc < 1 || rc > 2) {
1713 printk(KERN_ERR "Internal error whilst attempting to convert "
1714 "auth_tok->session_key.decrypted_key to scatterlist; "
1715 "expected rc = 1; got rc = [%d]\n", rc);
1718 mutex_lock(tfm_mutex);
1719 rc = crypto_blkcipher_setkey(
1720 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1721 crypt_stat->key_size);
1722 if (unlikely(rc < 0)) {
1723 mutex_unlock(tfm_mutex);
1724 printk(KERN_ERR "Error setting key for crypto context\n");
1728 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1729 auth_tok->session_key.encrypted_key_size);
1730 mutex_unlock(tfm_mutex);
1732 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1735 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1736 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1737 auth_tok->session_key.decrypted_key_size);
1738 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1739 if (unlikely(ecryptfs_verbosity > 0)) {
1740 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1741 crypt_stat->key_size);
1742 ecryptfs_dump_hex(crypt_stat->key,
1743 crypt_stat->key_size);
1750 * ecryptfs_parse_packet_set
1751 * @crypt_stat: The cryptographic context
1752 * @src: Virtual address of region of memory containing the packets
1753 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1755 * Get crypt_stat to have the file's session key if the requisite key
1756 * is available to decrypt the session key.
1758 * Returns Zero if a valid authentication token was retrieved and
1759 * processed; negative value for file not encrypted or for error
1762 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1764 struct dentry *ecryptfs_dentry)
1767 size_t found_auth_tok;
1768 size_t next_packet_is_auth_tok_packet;
1769 struct list_head auth_tok_list;
1770 struct ecryptfs_auth_tok *matching_auth_tok;
1771 struct ecryptfs_auth_tok *candidate_auth_tok;
1772 char *candidate_auth_tok_sig;
1774 struct ecryptfs_auth_tok *new_auth_tok;
1775 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1776 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1777 size_t tag_11_contents_size;
1778 size_t tag_11_packet_size;
1779 struct key *auth_tok_key = NULL;
1782 INIT_LIST_HEAD(&auth_tok_list);
1783 /* Parse the header to find as many packets as we can; these will be
1784 * added the our &auth_tok_list */
1785 next_packet_is_auth_tok_packet = 1;
1786 while (next_packet_is_auth_tok_packet) {
1787 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1790 case ECRYPTFS_TAG_3_PACKET_TYPE:
1791 rc = parse_tag_3_packet(crypt_stat,
1792 (unsigned char *)&src[i],
1793 &auth_tok_list, &new_auth_tok,
1794 &packet_size, max_packet_size);
1796 ecryptfs_printk(KERN_ERR, "Error parsing "
1802 rc = parse_tag_11_packet((unsigned char *)&src[i],
1805 &tag_11_contents_size,
1806 &tag_11_packet_size,
1809 ecryptfs_printk(KERN_ERR, "No valid "
1810 "(ecryptfs-specific) literal "
1811 "packet containing "
1812 "authentication token "
1813 "signature found after "
1818 i += tag_11_packet_size;
1819 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1820 ecryptfs_printk(KERN_ERR, "Expected "
1821 "signature of size [%d]; "
1822 "read size [%zd]\n",
1824 tag_11_contents_size);
1828 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1829 sig_tmp_space, tag_11_contents_size);
1830 new_auth_tok->token.password.signature[
1831 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1832 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1834 case ECRYPTFS_TAG_1_PACKET_TYPE:
1835 rc = parse_tag_1_packet(crypt_stat,
1836 (unsigned char *)&src[i],
1837 &auth_tok_list, &new_auth_tok,
1838 &packet_size, max_packet_size);
1840 ecryptfs_printk(KERN_ERR, "Error parsing "
1846 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1848 case ECRYPTFS_TAG_11_PACKET_TYPE:
1849 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1850 "(Tag 11 not allowed by itself)\n");
1855 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1856 "of the file header; hex value of "
1857 "character is [0x%.2x]\n", i, src[i]);
1858 next_packet_is_auth_tok_packet = 0;
1861 if (list_empty(&auth_tok_list)) {
1862 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1863 "eCryptfs file; this is not supported in this version "
1864 "of the eCryptfs kernel module\n");
1868 /* auth_tok_list contains the set of authentication tokens
1869 * parsed from the metadata. We need to find a matching
1870 * authentication token that has the secret component(s)
1871 * necessary to decrypt the EFEK in the auth_tok parsed from
1872 * the metadata. There may be several potential matches, but
1873 * just one will be sufficient to decrypt to get the FEK. */
1874 find_next_matching_auth_tok:
1876 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1877 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1878 if (unlikely(ecryptfs_verbosity > 0)) {
1879 ecryptfs_printk(KERN_DEBUG,
1880 "Considering cadidate auth tok:\n");
1881 ecryptfs_dump_auth_tok(candidate_auth_tok);
1883 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1884 candidate_auth_tok);
1887 "Unrecognized candidate auth tok type: [%d]\n",
1888 candidate_auth_tok->token_type);
1892 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1894 crypt_stat->mount_crypt_stat,
1895 candidate_auth_tok_sig);
1898 goto found_matching_auth_tok;
1901 if (!found_auth_tok) {
1902 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1903 "authentication token\n");
1907 found_matching_auth_tok:
1908 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1909 memcpy(&(candidate_auth_tok->token.private_key),
1910 &(matching_auth_tok->token.private_key),
1911 sizeof(struct ecryptfs_private_key));
1912 up_write(&(auth_tok_key->sem));
1913 key_put(auth_tok_key);
1914 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1916 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1917 memcpy(&(candidate_auth_tok->token.password),
1918 &(matching_auth_tok->token.password),
1919 sizeof(struct ecryptfs_password));
1920 up_write(&(auth_tok_key->sem));
1921 key_put(auth_tok_key);
1922 rc = decrypt_passphrase_encrypted_session_key(
1923 candidate_auth_tok, crypt_stat);
1925 up_write(&(auth_tok_key->sem));
1926 key_put(auth_tok_key);
1930 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1932 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1933 "session key for authentication token with sig "
1934 "[%.*s]; rc = [%d]. Removing auth tok "
1935 "candidate from the list and searching for "
1936 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1937 candidate_auth_tok_sig, rc);
1938 list_for_each_entry_safe(auth_tok_list_item,
1939 auth_tok_list_item_tmp,
1940 &auth_tok_list, list) {
1941 if (candidate_auth_tok
1942 == &auth_tok_list_item->auth_tok) {
1943 list_del(&auth_tok_list_item->list);
1945 ecryptfs_auth_tok_list_item_cache,
1946 auth_tok_list_item);
1947 goto find_next_matching_auth_tok;
1952 rc = ecryptfs_compute_root_iv(crypt_stat);
1954 ecryptfs_printk(KERN_ERR, "Error computing "
1958 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1960 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1961 "context for cipher [%s]; rc = [%d]\n",
1962 crypt_stat->cipher, rc);
1965 wipe_auth_tok_list(&auth_tok_list);
1971 pki_encrypt_session_key(struct key *auth_tok_key,
1972 struct ecryptfs_auth_tok *auth_tok,
1973 struct ecryptfs_crypt_stat *crypt_stat,
1974 struct ecryptfs_key_record *key_rec)
1976 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1977 char *payload = NULL;
1978 size_t payload_len = 0;
1979 struct ecryptfs_message *msg;
1982 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1983 ecryptfs_code_for_cipher_string(
1985 crypt_stat->key_size),
1986 crypt_stat, &payload, &payload_len);
1987 up_write(&(auth_tok_key->sem));
1988 key_put(auth_tok_key);
1990 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1993 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1995 ecryptfs_printk(KERN_ERR, "Error sending message to "
1999 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
2001 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2002 "from the user space daemon\n");
2006 rc = parse_tag_67_packet(key_rec, msg);
2008 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2015 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2016 * @dest: Buffer into which to write the packet
2017 * @remaining_bytes: Maximum number of bytes that can be writtn
2018 * @auth_tok_key: The authentication token key to unlock and put when done with
2020 * @auth_tok: The authentication token used for generating the tag 1 packet
2021 * @crypt_stat: The cryptographic context
2022 * @key_rec: The key record struct for the tag 1 packet
2023 * @packet_size: This function will write the number of bytes that end
2024 * up constituting the packet; set to zero on error
2026 * Returns zero on success; non-zero on error.
2029 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2030 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2031 struct ecryptfs_crypt_stat *crypt_stat,
2032 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2035 size_t encrypted_session_key_valid = 0;
2036 size_t packet_size_length;
2037 size_t max_packet_size;
2041 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2043 encrypted_session_key_valid = 0;
2044 for (i = 0; i < crypt_stat->key_size; i++)
2045 encrypted_session_key_valid |=
2046 auth_tok->session_key.encrypted_key[i];
2047 if (encrypted_session_key_valid) {
2048 memcpy(key_rec->enc_key,
2049 auth_tok->session_key.encrypted_key,
2050 auth_tok->session_key.encrypted_key_size);
2051 up_write(&(auth_tok_key->sem));
2052 key_put(auth_tok_key);
2053 goto encrypted_session_key_set;
2055 if (auth_tok->session_key.encrypted_key_size == 0)
2056 auth_tok->session_key.encrypted_key_size =
2057 auth_tok->token.private_key.key_size;
2058 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2061 printk(KERN_ERR "Failed to encrypt session key via a key "
2062 "module; rc = [%d]\n", rc);
2065 if (ecryptfs_verbosity > 0) {
2066 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2067 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2069 encrypted_session_key_set:
2070 /* This format is inspired by OpenPGP; see RFC 2440
2072 max_packet_size = (1 /* Tag 1 identifier */
2073 + 3 /* Max Tag 1 packet size */
2075 + ECRYPTFS_SIG_SIZE /* Key identifier */
2076 + 1 /* Cipher identifier */
2077 + key_rec->enc_key_size); /* Encrypted key size */
2078 if (max_packet_size > (*remaining_bytes)) {
2079 printk(KERN_ERR "Packet length larger than maximum allowable; "
2080 "need up to [%td] bytes, but there are only [%td] "
2081 "available\n", max_packet_size, (*remaining_bytes));
2085 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2086 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2087 (max_packet_size - 4),
2088 &packet_size_length);
2090 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2091 "header; cannot generate packet length\n");
2094 (*packet_size) += packet_size_length;
2095 dest[(*packet_size)++] = 0x03; /* version 3 */
2096 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2097 (*packet_size) += ECRYPTFS_SIG_SIZE;
2098 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2099 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2100 key_rec->enc_key_size);
2101 (*packet_size) += key_rec->enc_key_size;
2106 (*remaining_bytes) -= (*packet_size);
2111 * write_tag_11_packet
2112 * @dest: Target into which Tag 11 packet is to be written
2113 * @remaining_bytes: Maximum packet length
2114 * @contents: Byte array of contents to copy in
2115 * @contents_length: Number of bytes in contents
2116 * @packet_length: Length of the Tag 11 packet written; zero on error
2118 * Returns zero on success; non-zero on error.
2121 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2122 size_t contents_length, size_t *packet_length)
2124 size_t packet_size_length;
2125 size_t max_packet_size;
2128 (*packet_length) = 0;
2129 /* This format is inspired by OpenPGP; see RFC 2440
2131 max_packet_size = (1 /* Tag 11 identifier */
2132 + 3 /* Max Tag 11 packet size */
2133 + 1 /* Binary format specifier */
2134 + 1 /* Filename length */
2135 + 8 /* Filename ("_CONSOLE") */
2136 + 4 /* Modification date */
2137 + contents_length); /* Literal data */
2138 if (max_packet_size > (*remaining_bytes)) {
2139 printk(KERN_ERR "Packet length larger than maximum allowable; "
2140 "need up to [%td] bytes, but there are only [%td] "
2141 "available\n", max_packet_size, (*remaining_bytes));
2145 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2146 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2147 (max_packet_size - 4),
2148 &packet_size_length);
2150 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2151 "generate packet length. rc = [%d]\n", rc);
2154 (*packet_length) += packet_size_length;
2155 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2156 dest[(*packet_length)++] = 8;
2157 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2158 (*packet_length) += 8;
2159 memset(&dest[(*packet_length)], 0x00, 4);
2160 (*packet_length) += 4;
2161 memcpy(&dest[(*packet_length)], contents, contents_length);
2162 (*packet_length) += contents_length;
2165 (*packet_length) = 0;
2167 (*remaining_bytes) -= (*packet_length);
2172 * write_tag_3_packet
2173 * @dest: Buffer into which to write the packet
2174 * @remaining_bytes: Maximum number of bytes that can be written
2175 * @auth_tok: Authentication token
2176 * @crypt_stat: The cryptographic context
2177 * @key_rec: encrypted key
2178 * @packet_size: This function will write the number of bytes that end
2179 * up constituting the packet; set to zero on error
2181 * Returns zero on success; non-zero on error.
2184 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2185 struct ecryptfs_auth_tok *auth_tok,
2186 struct ecryptfs_crypt_stat *crypt_stat,
2187 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2190 size_t encrypted_session_key_valid = 0;
2191 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2192 struct scatterlist dst_sg[2];
2193 struct scatterlist src_sg[2];
2194 struct mutex *tfm_mutex = NULL;
2196 size_t packet_size_length;
2197 size_t max_packet_size;
2198 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2199 crypt_stat->mount_crypt_stat;
2200 struct blkcipher_desc desc = {
2202 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2207 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2209 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2210 crypt_stat->cipher);
2212 printk(KERN_ERR "Internal error whilst attempting to get "
2213 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2214 crypt_stat->cipher, rc);
2217 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2218 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2220 printk(KERN_WARNING "No key size specified at mount; "
2221 "defaulting to [%d]\n", alg->max_keysize);
2222 mount_crypt_stat->global_default_cipher_key_size =
2225 if (crypt_stat->key_size == 0)
2226 crypt_stat->key_size =
2227 mount_crypt_stat->global_default_cipher_key_size;
2228 if (auth_tok->session_key.encrypted_key_size == 0)
2229 auth_tok->session_key.encrypted_key_size =
2230 crypt_stat->key_size;
2231 if (crypt_stat->key_size == 24
2232 && strcmp("aes", crypt_stat->cipher) == 0) {
2233 memset((crypt_stat->key + 24), 0, 8);
2234 auth_tok->session_key.encrypted_key_size = 32;
2236 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2237 key_rec->enc_key_size =
2238 auth_tok->session_key.encrypted_key_size;
2239 encrypted_session_key_valid = 0;
2240 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2241 encrypted_session_key_valid |=
2242 auth_tok->session_key.encrypted_key[i];
2243 if (encrypted_session_key_valid) {
2244 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2245 "using auth_tok->session_key.encrypted_key, "
2246 "where key_rec->enc_key_size = [%zd]\n",
2247 key_rec->enc_key_size);
2248 memcpy(key_rec->enc_key,
2249 auth_tok->session_key.encrypted_key,
2250 key_rec->enc_key_size);
2251 goto encrypted_session_key_set;
2253 if (auth_tok->token.password.flags &
2254 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2255 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2256 "session key encryption key of size [%d]\n",
2257 auth_tok->token.password.
2258 session_key_encryption_key_bytes);
2259 memcpy(session_key_encryption_key,
2260 auth_tok->token.password.session_key_encryption_key,
2261 crypt_stat->key_size);
2262 ecryptfs_printk(KERN_DEBUG,
2263 "Cached session key encryption key:\n");
2264 if (ecryptfs_verbosity > 0)
2265 ecryptfs_dump_hex(session_key_encryption_key, 16);
2267 if (unlikely(ecryptfs_verbosity > 0)) {
2268 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2269 ecryptfs_dump_hex(session_key_encryption_key, 16);
2271 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2273 if (rc < 1 || rc > 2) {
2274 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2275 "for crypt_stat session key; expected rc = 1; "
2276 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2277 rc, key_rec->enc_key_size);
2281 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2283 if (rc < 1 || rc > 2) {
2284 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2285 "for crypt_stat encrypted session key; "
2286 "expected rc = 1; got rc = [%d]. "
2287 "key_rec->enc_key_size = [%zd]\n", rc,
2288 key_rec->enc_key_size);
2292 mutex_lock(tfm_mutex);
2293 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2294 crypt_stat->key_size);
2296 mutex_unlock(tfm_mutex);
2297 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2298 "context; rc = [%d]\n", rc);
2302 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2303 crypt_stat->key_size);
2304 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2305 (*key_rec).enc_key_size);
2306 mutex_unlock(tfm_mutex);
2308 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2311 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2312 if (ecryptfs_verbosity > 0) {
2313 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2314 key_rec->enc_key_size);
2315 ecryptfs_dump_hex(key_rec->enc_key,
2316 key_rec->enc_key_size);
2318 encrypted_session_key_set:
2319 /* This format is inspired by OpenPGP; see RFC 2440
2321 max_packet_size = (1 /* Tag 3 identifier */
2322 + 3 /* Max Tag 3 packet size */
2324 + 1 /* Cipher code */
2325 + 1 /* S2K specifier */
2326 + 1 /* Hash identifier */
2327 + ECRYPTFS_SALT_SIZE /* Salt */
2328 + 1 /* Hash iterations */
2329 + key_rec->enc_key_size); /* Encrypted key size */
2330 if (max_packet_size > (*remaining_bytes)) {
2331 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2332 "there are only [%td] available\n", max_packet_size,
2333 (*remaining_bytes));
2337 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2338 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2339 * to get the number of octets in the actual Tag 3 packet */
2340 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2341 (max_packet_size - 4),
2342 &packet_size_length);
2344 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2345 "generate packet length. rc = [%d]\n", rc);
2348 (*packet_size) += packet_size_length;
2349 dest[(*packet_size)++] = 0x04; /* version 4 */
2350 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2351 * specified with strings */
2352 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2353 crypt_stat->key_size);
2354 if (cipher_code == 0) {
2355 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2356 "cipher [%s]\n", crypt_stat->cipher);
2360 dest[(*packet_size)++] = cipher_code;
2361 dest[(*packet_size)++] = 0x03; /* S2K */
2362 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2363 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2364 ECRYPTFS_SALT_SIZE);
2365 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2366 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2367 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2368 key_rec->enc_key_size);
2369 (*packet_size) += key_rec->enc_key_size;
2374 (*remaining_bytes) -= (*packet_size);
2378 struct kmem_cache *ecryptfs_key_record_cache;
2381 * ecryptfs_generate_key_packet_set
2382 * @dest_base: Virtual address from which to write the key record set
2383 * @crypt_stat: The cryptographic context from which the
2384 * authentication tokens will be retrieved
2385 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2386 * for the global parameters
2387 * @len: The amount written
2388 * @max: The maximum amount of data allowed to be written
2390 * Generates a key packet set and writes it to the virtual address
2393 * Returns zero on success; non-zero on error.
2396 ecryptfs_generate_key_packet_set(char *dest_base,
2397 struct ecryptfs_crypt_stat *crypt_stat,
2398 struct dentry *ecryptfs_dentry, size_t *len,
2401 struct ecryptfs_auth_tok *auth_tok;
2402 struct key *auth_tok_key = NULL;
2403 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2404 &ecryptfs_superblock_to_private(
2405 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2407 struct ecryptfs_key_record *key_rec;
2408 struct ecryptfs_key_sig *key_sig;
2412 mutex_lock(&crypt_stat->keysig_list_mutex);
2413 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2418 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2420 memset(key_rec, 0, sizeof(*key_rec));
2421 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2426 printk(KERN_WARNING "Unable to retrieve auth tok with "
2427 "sig = [%s]\n", key_sig->keysig);
2428 rc = process_find_global_auth_tok_for_sig_err(rc);
2431 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2432 rc = write_tag_3_packet((dest_base + (*len)),
2434 crypt_stat, key_rec,
2436 up_write(&(auth_tok_key->sem));
2437 key_put(auth_tok_key);
2439 ecryptfs_printk(KERN_WARNING, "Error "
2440 "writing tag 3 packet\n");
2444 /* Write auth tok signature packet */
2445 rc = write_tag_11_packet((dest_base + (*len)), &max,
2447 ECRYPTFS_SIG_SIZE, &written);
2449 ecryptfs_printk(KERN_ERR, "Error writing "
2450 "auth tok signature packet\n");
2454 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2455 rc = write_tag_1_packet(dest_base + (*len), &max,
2456 auth_tok_key, auth_tok,
2457 crypt_stat, key_rec, &written);
2459 ecryptfs_printk(KERN_WARNING, "Error "
2460 "writing tag 1 packet\n");
2465 up_write(&(auth_tok_key->sem));
2466 key_put(auth_tok_key);
2467 ecryptfs_printk(KERN_WARNING, "Unsupported "
2468 "authentication token type\n");
2473 if (likely(max > 0)) {
2474 dest_base[(*len)] = 0x00;
2476 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2480 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2484 mutex_unlock(&crypt_stat->keysig_list_mutex);
2488 struct kmem_cache *ecryptfs_key_sig_cache;
2490 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2492 struct ecryptfs_key_sig *new_key_sig;
2494 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2497 "Error allocating from ecryptfs_key_sig_cache\n");
2500 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2501 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2502 /* Caller must hold keysig_list_mutex */
2503 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2508 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2511 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2512 char *sig, u32 global_auth_tok_flags)
2514 struct ecryptfs_global_auth_tok *new_auth_tok;
2517 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2519 if (!new_auth_tok) {
2521 printk(KERN_ERR "Error allocating from "
2522 "ecryptfs_global_auth_tok_cache\n");
2525 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2526 new_auth_tok->flags = global_auth_tok_flags;
2527 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2528 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2529 list_add(&new_auth_tok->mount_crypt_stat_list,
2530 &mount_crypt_stat->global_auth_tok_list);
2531 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);