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 <crypto/hash.h>
29 #include <crypto/skcipher.h>
30 #include <linux/string.h>
31 #include <linux/pagemap.h>
32 #include <linux/key.h>
33 #include <linux/random.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 */
106 } else if (data[0] < 224) {
107 /* Two-byte length */
108 (*size) = (data[0] - 192) * 256;
109 (*size) += 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 crypto_skcipher *skcipher_tfm;
613 struct skcipher_request *skcipher_req;
614 char iv[ECRYPTFS_MAX_IV_BYTES];
615 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
616 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
617 struct crypto_shash *hash_tfm;
618 struct shash_desc *hash_desc;
622 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
623 * @filename: NULL-terminated filename string
625 * This is the simplest mechanism for achieving filename encryption in
626 * eCryptfs. It encrypts the given filename with the mount-wide
627 * filename encryption key (FNEK) and stores it in a packet to @dest,
628 * which the callee will encode and write directly into the dentry
632 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
634 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
635 char *filename, size_t filename_size)
637 struct ecryptfs_write_tag_70_packet_silly_stack *s;
638 struct key *auth_tok_key = NULL;
641 s = kzalloc(sizeof(*s), GFP_KERNEL);
646 rc = ecryptfs_find_auth_tok_for_sig(
648 &s->auth_tok, mount_crypt_stat,
649 mount_crypt_stat->global_default_fnek_sig);
651 printk(KERN_ERR "%s: Error attempting to find auth tok for "
652 "fnek sig [%s]; rc = [%d]\n", __func__,
653 mount_crypt_stat->global_default_fnek_sig, rc);
656 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
658 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
660 printk(KERN_ERR "Internal error whilst attempting to get "
661 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
662 mount_crypt_stat->global_default_fn_cipher_name, rc);
665 mutex_lock(s->tfm_mutex);
666 s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
667 /* Plus one for the \0 separator between the random prefix
668 * and the plaintext filename */
669 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
670 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
671 if ((s->block_aligned_filename_size % s->block_size) != 0) {
672 s->num_rand_bytes += (s->block_size
673 - (s->block_aligned_filename_size
675 s->block_aligned_filename_size = (s->num_rand_bytes
678 /* Octet 0: Tag 70 identifier
679 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
680 * and block-aligned encrypted filename size)
681 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
682 * Octet N2-N3: Cipher identifier (1 octet)
683 * Octets N3-N4: Block-aligned encrypted filename
684 * - Consists of a minimum number of random characters, a \0
685 * separator, and then the filename */
686 s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
687 + s->block_aligned_filename_size);
689 (*packet_size) = s->max_packet_size;
692 if (s->max_packet_size > (*remaining_bytes)) {
693 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
694 "[%zd] available\n", __func__, s->max_packet_size,
700 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
701 if (!s->skcipher_req) {
702 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
703 "skcipher_request_alloc for %s\n", __func__,
704 crypto_skcipher_driver_name(s->skcipher_tfm));
709 skcipher_request_set_callback(s->skcipher_req,
710 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
712 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
714 if (!s->block_aligned_filename) {
718 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
719 rc = ecryptfs_write_packet_length(&dest[s->i],
721 + 1 /* Cipher code */
722 + s->block_aligned_filename_size),
723 &s->packet_size_len);
725 printk(KERN_ERR "%s: Error generating tag 70 packet "
726 "header; cannot generate packet length; rc = [%d]\n",
728 goto out_free_unlock;
730 s->i += s->packet_size_len;
731 ecryptfs_from_hex(&dest[s->i],
732 mount_crypt_stat->global_default_fnek_sig,
734 s->i += ECRYPTFS_SIG_SIZE;
735 s->cipher_code = ecryptfs_code_for_cipher_string(
736 mount_crypt_stat->global_default_fn_cipher_name,
737 mount_crypt_stat->global_default_fn_cipher_key_bytes);
738 if (s->cipher_code == 0) {
739 printk(KERN_WARNING "%s: Unable to generate code for "
740 "cipher [%s] with key bytes [%zd]\n", __func__,
741 mount_crypt_stat->global_default_fn_cipher_name,
742 mount_crypt_stat->global_default_fn_cipher_key_bytes);
744 goto out_free_unlock;
746 dest[s->i++] = s->cipher_code;
747 /* TODO: Support other key modules than passphrase for
748 * filename encryption */
749 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
751 printk(KERN_INFO "%s: Filename encryption only supports "
752 "password tokens\n", __func__);
753 goto out_free_unlock;
755 s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
756 if (IS_ERR(s->hash_tfm)) {
757 rc = PTR_ERR(s->hash_tfm);
758 printk(KERN_ERR "%s: Error attempting to "
759 "allocate hash crypto context; rc = [%d]\n",
761 goto out_free_unlock;
764 s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
765 crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
768 goto out_release_free_unlock;
771 s->hash_desc->tfm = s->hash_tfm;
773 rc = crypto_shash_digest(s->hash_desc,
774 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
775 s->auth_tok->token.password.session_key_encryption_key_bytes,
779 "%s: Error computing crypto hash; rc = [%d]\n",
781 goto out_release_free_unlock;
783 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
784 s->block_aligned_filename[s->j] =
785 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
786 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
787 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
788 rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
789 ECRYPTFS_TAG_70_DIGEST_SIZE,
793 "%s: Error computing crypto hash; "
794 "rc = [%d]\n", __func__, rc);
795 goto out_release_free_unlock;
797 memcpy(s->hash, s->tmp_hash,
798 ECRYPTFS_TAG_70_DIGEST_SIZE);
800 if (s->block_aligned_filename[s->j] == '\0')
801 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
803 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
805 rc = virt_to_scatterlist(s->block_aligned_filename,
806 s->block_aligned_filename_size, s->src_sg, 2);
808 printk(KERN_ERR "%s: Internal error whilst attempting to "
809 "convert filename memory to scatterlist; rc = [%d]. "
810 "block_aligned_filename_size = [%zd]\n", __func__, rc,
811 s->block_aligned_filename_size);
812 goto out_release_free_unlock;
814 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
817 printk(KERN_ERR "%s: Internal error whilst attempting to "
818 "convert encrypted filename memory to scatterlist; "
819 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
820 __func__, rc, s->block_aligned_filename_size);
821 goto out_release_free_unlock;
823 /* The characters in the first block effectively do the job
824 * of the IV here, so we just use 0's for the IV. Note the
825 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
826 * >= ECRYPTFS_MAX_IV_BYTES. */
827 rc = crypto_skcipher_setkey(
829 s->auth_tok->token.password.session_key_encryption_key,
830 mount_crypt_stat->global_default_fn_cipher_key_bytes);
832 printk(KERN_ERR "%s: Error setting key for crypto context; "
833 "rc = [%d]. s->auth_tok->token.password.session_key_"
834 "encryption_key = [0x%p]; mount_crypt_stat->"
835 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
837 s->auth_tok->token.password.session_key_encryption_key,
838 mount_crypt_stat->global_default_fn_cipher_key_bytes);
839 goto out_release_free_unlock;
841 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
842 s->block_aligned_filename_size, s->iv);
843 rc = crypto_skcipher_encrypt(s->skcipher_req);
845 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
846 "rc = [%d]\n", __func__, rc);
847 goto out_release_free_unlock;
849 s->i += s->block_aligned_filename_size;
850 (*packet_size) = s->i;
851 (*remaining_bytes) -= (*packet_size);
852 out_release_free_unlock:
853 crypto_free_shash(s->hash_tfm);
855 kzfree(s->block_aligned_filename);
857 mutex_unlock(s->tfm_mutex);
860 up_write(&(auth_tok_key->sem));
861 key_put(auth_tok_key);
863 skcipher_request_free(s->skcipher_req);
864 kzfree(s->hash_desc);
869 struct ecryptfs_parse_tag_70_packet_silly_stack {
871 size_t max_packet_size;
872 size_t packet_size_len;
873 size_t parsed_tag_70_packet_size;
874 size_t block_aligned_filename_size;
877 struct mutex *tfm_mutex;
878 char *decrypted_filename;
879 struct ecryptfs_auth_tok *auth_tok;
880 struct scatterlist src_sg[2];
881 struct scatterlist dst_sg[2];
882 struct crypto_skcipher *skcipher_tfm;
883 struct skcipher_request *skcipher_req;
884 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
885 char iv[ECRYPTFS_MAX_IV_BYTES];
886 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
890 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
891 * @filename: This function kmalloc's the memory for the filename
892 * @filename_size: This function sets this to the amount of memory
893 * kmalloc'd for the filename
894 * @packet_size: This function sets this to the the number of octets
895 * in the packet parsed
896 * @mount_crypt_stat: The mount-wide cryptographic context
897 * @data: The memory location containing the start of the tag 70
899 * @max_packet_size: The maximum legal size of the packet to be parsed
902 * Returns zero on success; non-zero otherwise
905 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
907 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
908 char *data, size_t max_packet_size)
910 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
911 struct key *auth_tok_key = NULL;
915 (*filename_size) = 0;
917 s = kzalloc(sizeof(*s), GFP_KERNEL);
921 if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
922 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
923 "at least [%d]\n", __func__, max_packet_size,
924 ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
928 /* Octet 0: Tag 70 identifier
929 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
930 * and block-aligned encrypted filename size)
931 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
932 * Octet N2-N3: Cipher identifier (1 octet)
933 * Octets N3-N4: Block-aligned encrypted filename
934 * - Consists of a minimum number of random numbers, a \0
935 * separator, and then the filename */
936 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
937 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
938 "tag [0x%.2x]\n", __func__,
939 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
943 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
944 &s->parsed_tag_70_packet_size,
945 &s->packet_size_len);
947 printk(KERN_WARNING "%s: Error parsing packet length; "
948 "rc = [%d]\n", __func__, rc);
951 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
952 - ECRYPTFS_SIG_SIZE - 1);
953 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
955 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
956 "size is [%zd]\n", __func__, max_packet_size,
957 (1 + s->packet_size_len + 1
958 + s->block_aligned_filename_size));
962 (*packet_size) += s->packet_size_len;
963 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
965 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
966 (*packet_size) += ECRYPTFS_SIG_SIZE;
967 s->cipher_code = data[(*packet_size)++];
968 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
970 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
971 __func__, s->cipher_code);
974 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
975 &s->auth_tok, mount_crypt_stat,
978 printk(KERN_ERR "%s: Error attempting to find auth tok for "
979 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
983 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
987 printk(KERN_ERR "Internal error whilst attempting to get "
988 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
989 s->cipher_string, rc);
992 mutex_lock(s->tfm_mutex);
993 rc = virt_to_scatterlist(&data[(*packet_size)],
994 s->block_aligned_filename_size, s->src_sg, 2);
996 printk(KERN_ERR "%s: Internal error whilst attempting to "
997 "convert encrypted filename memory to scatterlist; "
998 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
999 __func__, rc, s->block_aligned_filename_size);
1002 (*packet_size) += s->block_aligned_filename_size;
1003 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1005 if (!s->decrypted_filename) {
1009 rc = virt_to_scatterlist(s->decrypted_filename,
1010 s->block_aligned_filename_size, s->dst_sg, 2);
1012 printk(KERN_ERR "%s: Internal error whilst attempting to "
1013 "convert decrypted filename memory to scatterlist; "
1014 "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1015 __func__, rc, s->block_aligned_filename_size);
1016 goto out_free_unlock;
1019 s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
1020 if (!s->skcipher_req) {
1021 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1022 "skcipher_request_alloc for %s\n", __func__,
1023 crypto_skcipher_driver_name(s->skcipher_tfm));
1025 goto out_free_unlock;
1028 skcipher_request_set_callback(s->skcipher_req,
1029 CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
1031 /* The characters in the first block effectively do the job of
1032 * the IV here, so we just use 0's for the IV. Note the
1033 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1034 * >= ECRYPTFS_MAX_IV_BYTES. */
1035 /* TODO: Support other key modules than passphrase for
1036 * filename encryption */
1037 if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1039 printk(KERN_INFO "%s: Filename encryption only supports "
1040 "password tokens\n", __func__);
1041 goto out_free_unlock;
1043 rc = crypto_skcipher_setkey(
1045 s->auth_tok->token.password.session_key_encryption_key,
1046 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1048 printk(KERN_ERR "%s: Error setting key for crypto context; "
1049 "rc = [%d]. s->auth_tok->token.password.session_key_"
1050 "encryption_key = [0x%p]; mount_crypt_stat->"
1051 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1053 s->auth_tok->token.password.session_key_encryption_key,
1054 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1055 goto out_free_unlock;
1057 skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
1058 s->block_aligned_filename_size, s->iv);
1059 rc = crypto_skcipher_decrypt(s->skcipher_req);
1061 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1062 "rc = [%d]\n", __func__, rc);
1063 goto out_free_unlock;
1065 while (s->decrypted_filename[s->i] != '\0'
1066 && s->i < s->block_aligned_filename_size)
1068 if (s->i == s->block_aligned_filename_size) {
1069 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1070 "find valid separator between random characters and "
1071 "the filename\n", __func__);
1073 goto out_free_unlock;
1076 (*filename_size) = (s->block_aligned_filename_size - s->i);
1077 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1078 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1079 "invalid\n", __func__, (*filename_size));
1081 goto out_free_unlock;
1083 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1086 goto out_free_unlock;
1088 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1089 (*filename)[(*filename_size)] = '\0';
1091 kfree(s->decrypted_filename);
1093 mutex_unlock(s->tfm_mutex);
1097 (*filename_size) = 0;
1101 up_write(&(auth_tok_key->sem));
1102 key_put(auth_tok_key);
1104 skcipher_request_free(s->skcipher_req);
1110 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1115 switch (auth_tok->token_type) {
1116 case ECRYPTFS_PASSWORD:
1117 (*sig) = auth_tok->token.password.signature;
1119 case ECRYPTFS_PRIVATE_KEY:
1120 (*sig) = auth_tok->token.private_key.signature;
1123 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1124 auth_tok->token_type);
1131 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1132 * @auth_tok: The key authentication token used to decrypt the session key
1133 * @crypt_stat: The cryptographic context
1135 * Returns zero on success; non-zero error otherwise.
1138 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1139 struct ecryptfs_crypt_stat *crypt_stat)
1142 struct ecryptfs_msg_ctx *msg_ctx;
1143 struct ecryptfs_message *msg = NULL;
1145 char *payload = NULL;
1146 size_t payload_len = 0;
1149 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1151 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1152 auth_tok->token_type);
1155 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1156 &payload, &payload_len);
1158 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1161 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1163 ecryptfs_printk(KERN_ERR, "Error sending message to "
1164 "ecryptfsd: %d\n", rc);
1167 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1169 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1170 "from the user space daemon\n");
1174 rc = parse_tag_65_packet(&(auth_tok->session_key),
1177 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1181 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1182 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1183 auth_tok->session_key.decrypted_key_size);
1184 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1185 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1187 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1191 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1192 if (ecryptfs_verbosity > 0) {
1193 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1194 ecryptfs_dump_hex(crypt_stat->key,
1195 crypt_stat->key_size);
1203 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1205 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1206 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1208 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1209 auth_tok_list_head, list) {
1210 list_del(&auth_tok_list_item->list);
1211 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1212 auth_tok_list_item);
1216 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1219 * parse_tag_1_packet
1220 * @crypt_stat: The cryptographic context to modify based on packet contents
1221 * @data: The raw bytes of the packet.
1222 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1223 * a new authentication token will be placed at the
1224 * end of this list for this packet.
1225 * @new_auth_tok: Pointer to a pointer to memory that this function
1226 * allocates; sets the memory address of the pointer to
1227 * NULL on error. This object is added to the
1229 * @packet_size: This function writes the size of the parsed packet
1230 * into this memory location; zero on error.
1231 * @max_packet_size: The maximum allowable packet size
1233 * Returns zero on success; non-zero on error.
1236 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1237 unsigned char *data, struct list_head *auth_tok_list,
1238 struct ecryptfs_auth_tok **new_auth_tok,
1239 size_t *packet_size, size_t max_packet_size)
1242 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1247 (*new_auth_tok) = NULL;
1249 * This format is inspired by OpenPGP; see RFC 2440
1252 * Tag 1 identifier (1 byte)
1253 * Max Tag 1 packet size (max 3 bytes)
1255 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1256 * Cipher identifier (1 byte)
1257 * Encrypted key size (arbitrary)
1259 * 12 bytes minimum packet size
1261 if (unlikely(max_packet_size < 12)) {
1262 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1266 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1267 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1268 ECRYPTFS_TAG_1_PACKET_TYPE);
1272 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1273 * at end of function upon failure */
1274 auth_tok_list_item =
1275 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1277 if (!auth_tok_list_item) {
1278 printk(KERN_ERR "Unable to allocate memory\n");
1282 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1283 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1286 printk(KERN_WARNING "Error parsing packet length; "
1290 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1291 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1295 (*packet_size) += length_size;
1296 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1297 printk(KERN_WARNING "Packet size exceeds max\n");
1301 if (unlikely(data[(*packet_size)++] != 0x03)) {
1302 printk(KERN_WARNING "Unknown version number [%d]\n",
1303 data[(*packet_size) - 1]);
1307 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1308 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1309 *packet_size += ECRYPTFS_SIG_SIZE;
1310 /* This byte is skipped because the kernel does not need to
1311 * know which public key encryption algorithm was used */
1313 (*new_auth_tok)->session_key.encrypted_key_size =
1314 body_size - (ECRYPTFS_SIG_SIZE + 2);
1315 if ((*new_auth_tok)->session_key.encrypted_key_size
1316 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1317 printk(KERN_WARNING "Tag 1 packet contains key larger "
1318 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1322 memcpy((*new_auth_tok)->session_key.encrypted_key,
1323 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1324 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1325 (*new_auth_tok)->session_key.flags &=
1326 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1327 (*new_auth_tok)->session_key.flags |=
1328 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1329 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1330 (*new_auth_tok)->flags = 0;
1331 (*new_auth_tok)->session_key.flags &=
1332 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1333 (*new_auth_tok)->session_key.flags &=
1334 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1335 list_add(&auth_tok_list_item->list, auth_tok_list);
1338 (*new_auth_tok) = NULL;
1339 memset(auth_tok_list_item, 0,
1340 sizeof(struct ecryptfs_auth_tok_list_item));
1341 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1342 auth_tok_list_item);
1350 * parse_tag_3_packet
1351 * @crypt_stat: The cryptographic context to modify based on packet
1353 * @data: The raw bytes of the packet.
1354 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1355 * a new authentication token will be placed at the end
1356 * of this list for this packet.
1357 * @new_auth_tok: Pointer to a pointer to memory that this function
1358 * allocates; sets the memory address of the pointer to
1359 * NULL on error. This object is added to the
1361 * @packet_size: This function writes the size of the parsed packet
1362 * into this memory location; zero on error.
1363 * @max_packet_size: maximum number of bytes to parse
1365 * Returns zero on success; non-zero on error.
1368 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1369 unsigned char *data, struct list_head *auth_tok_list,
1370 struct ecryptfs_auth_tok **new_auth_tok,
1371 size_t *packet_size, size_t max_packet_size)
1374 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1379 (*new_auth_tok) = NULL;
1381 *This format is inspired by OpenPGP; see RFC 2440
1384 * Tag 3 identifier (1 byte)
1385 * Max Tag 3 packet size (max 3 bytes)
1387 * Cipher code (1 byte)
1388 * S2K specifier (1 byte)
1389 * Hash identifier (1 byte)
1390 * Salt (ECRYPTFS_SALT_SIZE)
1391 * Hash iterations (1 byte)
1392 * Encrypted key (arbitrary)
1394 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1396 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1397 printk(KERN_ERR "Max packet size too large\n");
1401 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1402 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1403 ECRYPTFS_TAG_3_PACKET_TYPE);
1407 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1408 * at end of function upon failure */
1409 auth_tok_list_item =
1410 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1411 if (!auth_tok_list_item) {
1412 printk(KERN_ERR "Unable to allocate memory\n");
1416 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1417 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1420 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1424 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1425 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1429 (*packet_size) += length_size;
1430 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1431 printk(KERN_ERR "Packet size exceeds max\n");
1435 (*new_auth_tok)->session_key.encrypted_key_size =
1436 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1437 if ((*new_auth_tok)->session_key.encrypted_key_size
1438 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1439 printk(KERN_WARNING "Tag 3 packet contains key larger "
1440 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1444 if (unlikely(data[(*packet_size)++] != 0x04)) {
1445 printk(KERN_WARNING "Unknown version number [%d]\n",
1446 data[(*packet_size) - 1]);
1450 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1451 (u16)data[(*packet_size)]);
1454 /* A little extra work to differentiate among the AES key
1455 * sizes; see RFC2440 */
1456 switch(data[(*packet_size)++]) {
1457 case RFC2440_CIPHER_AES_192:
1458 crypt_stat->key_size = 24;
1461 crypt_stat->key_size =
1462 (*new_auth_tok)->session_key.encrypted_key_size;
1464 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1467 if (unlikely(data[(*packet_size)++] != 0x03)) {
1468 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1472 /* TODO: finish the hash mapping */
1473 switch (data[(*packet_size)++]) {
1474 case 0x01: /* See RFC2440 for these numbers and their mappings */
1476 memcpy((*new_auth_tok)->token.password.salt,
1477 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1478 (*packet_size) += ECRYPTFS_SALT_SIZE;
1479 /* This conversion was taken straight from RFC2440 */
1480 (*new_auth_tok)->token.password.hash_iterations =
1481 ((u32) 16 + (data[(*packet_size)] & 15))
1482 << ((data[(*packet_size)] >> 4) + 6);
1484 /* Friendly reminder:
1485 * (*new_auth_tok)->session_key.encrypted_key_size =
1486 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1487 memcpy((*new_auth_tok)->session_key.encrypted_key,
1488 &data[(*packet_size)],
1489 (*new_auth_tok)->session_key.encrypted_key_size);
1491 (*new_auth_tok)->session_key.encrypted_key_size;
1492 (*new_auth_tok)->session_key.flags &=
1493 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1494 (*new_auth_tok)->session_key.flags |=
1495 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1496 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1499 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1500 "[%d]\n", data[(*packet_size) - 1]);
1504 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1505 /* TODO: Parametarize; we might actually want userspace to
1506 * decrypt the session key. */
1507 (*new_auth_tok)->session_key.flags &=
1508 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1509 (*new_auth_tok)->session_key.flags &=
1510 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1511 list_add(&auth_tok_list_item->list, auth_tok_list);
1514 (*new_auth_tok) = NULL;
1515 memset(auth_tok_list_item, 0,
1516 sizeof(struct ecryptfs_auth_tok_list_item));
1517 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1518 auth_tok_list_item);
1526 * parse_tag_11_packet
1527 * @data: The raw bytes of the packet
1528 * @contents: This function writes the data contents of the literal
1529 * packet into this memory location
1530 * @max_contents_bytes: The maximum number of bytes that this function
1531 * is allowed to write into contents
1532 * @tag_11_contents_size: This function writes the size of the parsed
1533 * contents into this memory location; zero on
1535 * @packet_size: This function writes the size of the parsed packet
1536 * into this memory location; zero on error
1537 * @max_packet_size: maximum number of bytes to parse
1539 * Returns zero on success; non-zero on error.
1542 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1543 size_t max_contents_bytes, size_t *tag_11_contents_size,
1544 size_t *packet_size, size_t max_packet_size)
1551 (*tag_11_contents_size) = 0;
1552 /* This format is inspired by OpenPGP; see RFC 2440
1555 * Tag 11 identifier (1 byte)
1556 * Max Tag 11 packet size (max 3 bytes)
1557 * Binary format specifier (1 byte)
1558 * Filename length (1 byte)
1559 * Filename ("_CONSOLE") (8 bytes)
1560 * Modification date (4 bytes)
1561 * Literal data (arbitrary)
1563 * We need at least 16 bytes of data for the packet to even be
1566 if (max_packet_size < 16) {
1567 printk(KERN_ERR "Maximum packet size too small\n");
1571 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1572 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1576 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1579 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1582 if (body_size < 14) {
1583 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1587 (*packet_size) += length_size;
1588 (*tag_11_contents_size) = (body_size - 14);
1589 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1590 printk(KERN_ERR "Packet size exceeds max\n");
1594 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1595 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1600 if (data[(*packet_size)++] != 0x62) {
1601 printk(KERN_WARNING "Unrecognizable packet\n");
1605 if (data[(*packet_size)++] != 0x08) {
1606 printk(KERN_WARNING "Unrecognizable packet\n");
1610 (*packet_size) += 12; /* Ignore filename and modification date */
1611 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1612 (*packet_size) += (*tag_11_contents_size);
1616 (*tag_11_contents_size) = 0;
1621 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1622 struct ecryptfs_auth_tok **auth_tok,
1627 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1628 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1629 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1630 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1631 printk(KERN_ERR "Could not find key with description: [%s]\n",
1633 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1634 (*auth_tok_key) = NULL;
1638 down_write(&(*auth_tok_key)->sem);
1639 rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1641 up_write(&(*auth_tok_key)->sem);
1642 key_put(*auth_tok_key);
1643 (*auth_tok_key) = NULL;
1651 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1652 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1653 * @crypt_stat: The cryptographic context
1655 * Returns zero on success; non-zero error otherwise
1658 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1659 struct ecryptfs_crypt_stat *crypt_stat)
1661 struct scatterlist dst_sg[2];
1662 struct scatterlist src_sg[2];
1663 struct mutex *tfm_mutex;
1664 struct crypto_skcipher *tfm;
1665 struct skcipher_request *req = NULL;
1668 if (unlikely(ecryptfs_verbosity > 0)) {
1670 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1671 auth_tok->token.password.session_key_encryption_key_bytes);
1673 auth_tok->token.password.session_key_encryption_key,
1674 auth_tok->token.password.session_key_encryption_key_bytes);
1676 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
1677 crypt_stat->cipher);
1679 printk(KERN_ERR "Internal error whilst attempting to get "
1680 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1681 crypt_stat->cipher, rc);
1684 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1685 auth_tok->session_key.encrypted_key_size,
1687 if (rc < 1 || rc > 2) {
1688 printk(KERN_ERR "Internal error whilst attempting to convert "
1689 "auth_tok->session_key.encrypted_key to scatterlist; "
1690 "expected rc = 1; got rc = [%d]. "
1691 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1692 auth_tok->session_key.encrypted_key_size);
1695 auth_tok->session_key.decrypted_key_size =
1696 auth_tok->session_key.encrypted_key_size;
1697 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1698 auth_tok->session_key.decrypted_key_size,
1700 if (rc < 1 || rc > 2) {
1701 printk(KERN_ERR "Internal error whilst attempting to convert "
1702 "auth_tok->session_key.decrypted_key to scatterlist; "
1703 "expected rc = 1; got rc = [%d]\n", rc);
1706 mutex_lock(tfm_mutex);
1707 req = skcipher_request_alloc(tfm, GFP_KERNEL);
1709 mutex_unlock(tfm_mutex);
1710 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1711 "skcipher_request_alloc for %s\n", __func__,
1712 crypto_skcipher_driver_name(tfm));
1717 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
1719 rc = crypto_skcipher_setkey(
1720 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 skcipher_request_set_crypt(req, src_sg, dst_sg,
1729 auth_tok->session_key.encrypted_key_size,
1731 rc = crypto_skcipher_decrypt(req);
1732 mutex_unlock(tfm_mutex);
1734 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1737 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1738 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1739 auth_tok->session_key.decrypted_key_size);
1740 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1741 if (unlikely(ecryptfs_verbosity > 0)) {
1742 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1743 crypt_stat->key_size);
1744 ecryptfs_dump_hex(crypt_stat->key,
1745 crypt_stat->key_size);
1748 skcipher_request_free(req);
1753 * ecryptfs_parse_packet_set
1754 * @crypt_stat: The cryptographic context
1755 * @src: Virtual address of region of memory containing the packets
1756 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1758 * Get crypt_stat to have the file's session key if the requisite key
1759 * is available to decrypt the session key.
1761 * Returns Zero if a valid authentication token was retrieved and
1762 * processed; negative value for file not encrypted or for error
1765 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1767 struct dentry *ecryptfs_dentry)
1770 size_t found_auth_tok;
1771 size_t next_packet_is_auth_tok_packet;
1772 struct list_head auth_tok_list;
1773 struct ecryptfs_auth_tok *matching_auth_tok;
1774 struct ecryptfs_auth_tok *candidate_auth_tok;
1775 char *candidate_auth_tok_sig;
1777 struct ecryptfs_auth_tok *new_auth_tok;
1778 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1779 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1780 size_t tag_11_contents_size;
1781 size_t tag_11_packet_size;
1782 struct key *auth_tok_key = NULL;
1785 INIT_LIST_HEAD(&auth_tok_list);
1786 /* Parse the header to find as many packets as we can; these will be
1787 * added the our &auth_tok_list */
1788 next_packet_is_auth_tok_packet = 1;
1789 while (next_packet_is_auth_tok_packet) {
1790 size_t max_packet_size = ((PAGE_SIZE - 8) - i);
1793 case ECRYPTFS_TAG_3_PACKET_TYPE:
1794 rc = parse_tag_3_packet(crypt_stat,
1795 (unsigned char *)&src[i],
1796 &auth_tok_list, &new_auth_tok,
1797 &packet_size, max_packet_size);
1799 ecryptfs_printk(KERN_ERR, "Error parsing "
1805 rc = parse_tag_11_packet((unsigned char *)&src[i],
1808 &tag_11_contents_size,
1809 &tag_11_packet_size,
1812 ecryptfs_printk(KERN_ERR, "No valid "
1813 "(ecryptfs-specific) literal "
1814 "packet containing "
1815 "authentication token "
1816 "signature found after "
1821 i += tag_11_packet_size;
1822 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1823 ecryptfs_printk(KERN_ERR, "Expected "
1824 "signature of size [%d]; "
1825 "read size [%zd]\n",
1827 tag_11_contents_size);
1831 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1832 sig_tmp_space, tag_11_contents_size);
1833 new_auth_tok->token.password.signature[
1834 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1835 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1837 case ECRYPTFS_TAG_1_PACKET_TYPE:
1838 rc = parse_tag_1_packet(crypt_stat,
1839 (unsigned char *)&src[i],
1840 &auth_tok_list, &new_auth_tok,
1841 &packet_size, max_packet_size);
1843 ecryptfs_printk(KERN_ERR, "Error parsing "
1849 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1851 case ECRYPTFS_TAG_11_PACKET_TYPE:
1852 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1853 "(Tag 11 not allowed by itself)\n");
1857 ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1858 "of the file header; hex value of "
1859 "character is [0x%.2x]\n", i, src[i]);
1860 next_packet_is_auth_tok_packet = 0;
1863 if (list_empty(&auth_tok_list)) {
1864 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1865 "eCryptfs file; this is not supported in this version "
1866 "of the eCryptfs kernel module\n");
1870 /* auth_tok_list contains the set of authentication tokens
1871 * parsed from the metadata. We need to find a matching
1872 * authentication token that has the secret component(s)
1873 * necessary to decrypt the EFEK in the auth_tok parsed from
1874 * the metadata. There may be several potential matches, but
1875 * just one will be sufficient to decrypt to get the FEK. */
1876 find_next_matching_auth_tok:
1878 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1879 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1880 if (unlikely(ecryptfs_verbosity > 0)) {
1881 ecryptfs_printk(KERN_DEBUG,
1882 "Considering candidate auth tok:\n");
1883 ecryptfs_dump_auth_tok(candidate_auth_tok);
1885 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1886 candidate_auth_tok);
1889 "Unrecognized candidate auth tok type: [%d]\n",
1890 candidate_auth_tok->token_type);
1894 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1896 crypt_stat->mount_crypt_stat,
1897 candidate_auth_tok_sig);
1900 goto found_matching_auth_tok;
1903 if (!found_auth_tok) {
1904 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1905 "authentication token\n");
1909 found_matching_auth_tok:
1910 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1911 memcpy(&(candidate_auth_tok->token.private_key),
1912 &(matching_auth_tok->token.private_key),
1913 sizeof(struct ecryptfs_private_key));
1914 up_write(&(auth_tok_key->sem));
1915 key_put(auth_tok_key);
1916 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1918 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1919 memcpy(&(candidate_auth_tok->token.password),
1920 &(matching_auth_tok->token.password),
1921 sizeof(struct ecryptfs_password));
1922 up_write(&(auth_tok_key->sem));
1923 key_put(auth_tok_key);
1924 rc = decrypt_passphrase_encrypted_session_key(
1925 candidate_auth_tok, crypt_stat);
1927 up_write(&(auth_tok_key->sem));
1928 key_put(auth_tok_key);
1932 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1934 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1935 "session key for authentication token with sig "
1936 "[%.*s]; rc = [%d]. Removing auth tok "
1937 "candidate from the list and searching for "
1938 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1939 candidate_auth_tok_sig, rc);
1940 list_for_each_entry_safe(auth_tok_list_item,
1941 auth_tok_list_item_tmp,
1942 &auth_tok_list, list) {
1943 if (candidate_auth_tok
1944 == &auth_tok_list_item->auth_tok) {
1945 list_del(&auth_tok_list_item->list);
1947 ecryptfs_auth_tok_list_item_cache,
1948 auth_tok_list_item);
1949 goto find_next_matching_auth_tok;
1954 rc = ecryptfs_compute_root_iv(crypt_stat);
1956 ecryptfs_printk(KERN_ERR, "Error computing "
1960 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1962 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1963 "context for cipher [%s]; rc = [%d]\n",
1964 crypt_stat->cipher, rc);
1967 wipe_auth_tok_list(&auth_tok_list);
1973 pki_encrypt_session_key(struct key *auth_tok_key,
1974 struct ecryptfs_auth_tok *auth_tok,
1975 struct ecryptfs_crypt_stat *crypt_stat,
1976 struct ecryptfs_key_record *key_rec)
1978 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1979 char *payload = NULL;
1980 size_t payload_len = 0;
1981 struct ecryptfs_message *msg;
1984 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1985 ecryptfs_code_for_cipher_string(
1987 crypt_stat->key_size),
1988 crypt_stat, &payload, &payload_len);
1989 up_write(&(auth_tok_key->sem));
1990 key_put(auth_tok_key);
1992 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1995 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1997 ecryptfs_printk(KERN_ERR, "Error sending message to "
1998 "ecryptfsd: %d\n", rc);
2001 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
2003 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2004 "from the user space daemon\n");
2008 rc = parse_tag_67_packet(key_rec, msg);
2010 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2017 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2018 * @dest: Buffer into which to write the packet
2019 * @remaining_bytes: Maximum number of bytes that can be writtn
2020 * @auth_tok_key: The authentication token key to unlock and put when done with
2022 * @auth_tok: The authentication token used for generating the tag 1 packet
2023 * @crypt_stat: The cryptographic context
2024 * @key_rec: The key record struct for the tag 1 packet
2025 * @packet_size: This function will write the number of bytes that end
2026 * up constituting the packet; set to zero on error
2028 * Returns zero on success; non-zero on error.
2031 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2032 struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2033 struct ecryptfs_crypt_stat *crypt_stat,
2034 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2037 size_t encrypted_session_key_valid = 0;
2038 size_t packet_size_length;
2039 size_t max_packet_size;
2043 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2045 encrypted_session_key_valid = 0;
2046 for (i = 0; i < crypt_stat->key_size; i++)
2047 encrypted_session_key_valid |=
2048 auth_tok->session_key.encrypted_key[i];
2049 if (encrypted_session_key_valid) {
2050 memcpy(key_rec->enc_key,
2051 auth_tok->session_key.encrypted_key,
2052 auth_tok->session_key.encrypted_key_size);
2053 up_write(&(auth_tok_key->sem));
2054 key_put(auth_tok_key);
2055 goto encrypted_session_key_set;
2057 if (auth_tok->session_key.encrypted_key_size == 0)
2058 auth_tok->session_key.encrypted_key_size =
2059 auth_tok->token.private_key.key_size;
2060 rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2063 printk(KERN_ERR "Failed to encrypt session key via a key "
2064 "module; rc = [%d]\n", rc);
2067 if (ecryptfs_verbosity > 0) {
2068 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2069 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2071 encrypted_session_key_set:
2072 /* This format is inspired by OpenPGP; see RFC 2440
2074 max_packet_size = (1 /* Tag 1 identifier */
2075 + 3 /* Max Tag 1 packet size */
2077 + ECRYPTFS_SIG_SIZE /* Key identifier */
2078 + 1 /* Cipher identifier */
2079 + key_rec->enc_key_size); /* Encrypted key size */
2080 if (max_packet_size > (*remaining_bytes)) {
2081 printk(KERN_ERR "Packet length larger than maximum allowable; "
2082 "need up to [%td] bytes, but there are only [%td] "
2083 "available\n", max_packet_size, (*remaining_bytes));
2087 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2088 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2089 (max_packet_size - 4),
2090 &packet_size_length);
2092 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2093 "header; cannot generate packet length\n");
2096 (*packet_size) += packet_size_length;
2097 dest[(*packet_size)++] = 0x03; /* version 3 */
2098 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2099 (*packet_size) += ECRYPTFS_SIG_SIZE;
2100 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2101 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2102 key_rec->enc_key_size);
2103 (*packet_size) += key_rec->enc_key_size;
2108 (*remaining_bytes) -= (*packet_size);
2113 * write_tag_11_packet
2114 * @dest: Target into which Tag 11 packet is to be written
2115 * @remaining_bytes: Maximum packet length
2116 * @contents: Byte array of contents to copy in
2117 * @contents_length: Number of bytes in contents
2118 * @packet_length: Length of the Tag 11 packet written; zero on error
2120 * Returns zero on success; non-zero on error.
2123 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2124 size_t contents_length, size_t *packet_length)
2126 size_t packet_size_length;
2127 size_t max_packet_size;
2130 (*packet_length) = 0;
2131 /* This format is inspired by OpenPGP; see RFC 2440
2133 max_packet_size = (1 /* Tag 11 identifier */
2134 + 3 /* Max Tag 11 packet size */
2135 + 1 /* Binary format specifier */
2136 + 1 /* Filename length */
2137 + 8 /* Filename ("_CONSOLE") */
2138 + 4 /* Modification date */
2139 + contents_length); /* Literal data */
2140 if (max_packet_size > (*remaining_bytes)) {
2141 printk(KERN_ERR "Packet length larger than maximum allowable; "
2142 "need up to [%td] bytes, but there are only [%td] "
2143 "available\n", max_packet_size, (*remaining_bytes));
2147 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2148 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2149 (max_packet_size - 4),
2150 &packet_size_length);
2152 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2153 "generate packet length. rc = [%d]\n", rc);
2156 (*packet_length) += packet_size_length;
2157 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2158 dest[(*packet_length)++] = 8;
2159 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2160 (*packet_length) += 8;
2161 memset(&dest[(*packet_length)], 0x00, 4);
2162 (*packet_length) += 4;
2163 memcpy(&dest[(*packet_length)], contents, contents_length);
2164 (*packet_length) += contents_length;
2167 (*packet_length) = 0;
2169 (*remaining_bytes) -= (*packet_length);
2174 * write_tag_3_packet
2175 * @dest: Buffer into which to write the packet
2176 * @remaining_bytes: Maximum number of bytes that can be written
2177 * @auth_tok: Authentication token
2178 * @crypt_stat: The cryptographic context
2179 * @key_rec: encrypted key
2180 * @packet_size: This function will write the number of bytes that end
2181 * up constituting the packet; set to zero on error
2183 * Returns zero on success; non-zero on error.
2186 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2187 struct ecryptfs_auth_tok *auth_tok,
2188 struct ecryptfs_crypt_stat *crypt_stat,
2189 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2192 size_t encrypted_session_key_valid = 0;
2193 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2194 struct scatterlist dst_sg[2];
2195 struct scatterlist src_sg[2];
2196 struct mutex *tfm_mutex = NULL;
2198 size_t packet_size_length;
2199 size_t max_packet_size;
2200 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2201 crypt_stat->mount_crypt_stat;
2202 struct crypto_skcipher *tfm;
2203 struct skcipher_request *req;
2207 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2209 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&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 printk(KERN_WARNING "No key size specified at mount; "
2219 "defaulting to [%d]\n",
2220 crypto_skcipher_default_keysize(tfm));
2221 mount_crypt_stat->global_default_cipher_key_size =
2222 crypto_skcipher_default_keysize(tfm);
2224 if (crypt_stat->key_size == 0)
2225 crypt_stat->key_size =
2226 mount_crypt_stat->global_default_cipher_key_size;
2227 if (auth_tok->session_key.encrypted_key_size == 0)
2228 auth_tok->session_key.encrypted_key_size =
2229 crypt_stat->key_size;
2230 if (crypt_stat->key_size == 24
2231 && strcmp("aes", crypt_stat->cipher) == 0) {
2232 memset((crypt_stat->key + 24), 0, 8);
2233 auth_tok->session_key.encrypted_key_size = 32;
2235 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2236 key_rec->enc_key_size =
2237 auth_tok->session_key.encrypted_key_size;
2238 encrypted_session_key_valid = 0;
2239 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2240 encrypted_session_key_valid |=
2241 auth_tok->session_key.encrypted_key[i];
2242 if (encrypted_session_key_valid) {
2243 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2244 "using auth_tok->session_key.encrypted_key, "
2245 "where key_rec->enc_key_size = [%zd]\n",
2246 key_rec->enc_key_size);
2247 memcpy(key_rec->enc_key,
2248 auth_tok->session_key.encrypted_key,
2249 key_rec->enc_key_size);
2250 goto encrypted_session_key_set;
2252 if (auth_tok->token.password.flags &
2253 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2254 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2255 "session key encryption key of size [%d]\n",
2256 auth_tok->token.password.
2257 session_key_encryption_key_bytes);
2258 memcpy(session_key_encryption_key,
2259 auth_tok->token.password.session_key_encryption_key,
2260 crypt_stat->key_size);
2261 ecryptfs_printk(KERN_DEBUG,
2262 "Cached session key encryption key:\n");
2263 if (ecryptfs_verbosity > 0)
2264 ecryptfs_dump_hex(session_key_encryption_key, 16);
2266 if (unlikely(ecryptfs_verbosity > 0)) {
2267 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2268 ecryptfs_dump_hex(session_key_encryption_key, 16);
2270 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2272 if (rc < 1 || rc > 2) {
2273 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2274 "for crypt_stat session key; expected rc = 1; "
2275 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2276 rc, key_rec->enc_key_size);
2280 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2282 if (rc < 1 || rc > 2) {
2283 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2284 "for crypt_stat encrypted session key; "
2285 "expected rc = 1; got rc = [%d]. "
2286 "key_rec->enc_key_size = [%zd]\n", rc,
2287 key_rec->enc_key_size);
2291 mutex_lock(tfm_mutex);
2292 rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
2293 crypt_stat->key_size);
2295 mutex_unlock(tfm_mutex);
2296 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2297 "context; rc = [%d]\n", rc);
2301 req = skcipher_request_alloc(tfm, GFP_KERNEL);
2303 mutex_unlock(tfm_mutex);
2304 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
2305 "attempting to skcipher_request_alloc for "
2306 "%s\n", crypto_skcipher_driver_name(tfm));
2311 skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
2315 ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2316 crypt_stat->key_size);
2317 skcipher_request_set_crypt(req, src_sg, dst_sg,
2318 (*key_rec).enc_key_size, NULL);
2319 rc = crypto_skcipher_encrypt(req);
2320 mutex_unlock(tfm_mutex);
2321 skcipher_request_free(req);
2323 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2326 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2327 if (ecryptfs_verbosity > 0) {
2328 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2329 key_rec->enc_key_size);
2330 ecryptfs_dump_hex(key_rec->enc_key,
2331 key_rec->enc_key_size);
2333 encrypted_session_key_set:
2334 /* This format is inspired by OpenPGP; see RFC 2440
2336 max_packet_size = (1 /* Tag 3 identifier */
2337 + 3 /* Max Tag 3 packet size */
2339 + 1 /* Cipher code */
2340 + 1 /* S2K specifier */
2341 + 1 /* Hash identifier */
2342 + ECRYPTFS_SALT_SIZE /* Salt */
2343 + 1 /* Hash iterations */
2344 + key_rec->enc_key_size); /* Encrypted key size */
2345 if (max_packet_size > (*remaining_bytes)) {
2346 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2347 "there are only [%td] available\n", max_packet_size,
2348 (*remaining_bytes));
2352 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2353 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2354 * to get the number of octets in the actual Tag 3 packet */
2355 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2356 (max_packet_size - 4),
2357 &packet_size_length);
2359 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2360 "generate packet length. rc = [%d]\n", rc);
2363 (*packet_size) += packet_size_length;
2364 dest[(*packet_size)++] = 0x04; /* version 4 */
2365 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2366 * specified with strings */
2367 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2368 crypt_stat->key_size);
2369 if (cipher_code == 0) {
2370 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2371 "cipher [%s]\n", crypt_stat->cipher);
2375 dest[(*packet_size)++] = cipher_code;
2376 dest[(*packet_size)++] = 0x03; /* S2K */
2377 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2378 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2379 ECRYPTFS_SALT_SIZE);
2380 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2381 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2382 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2383 key_rec->enc_key_size);
2384 (*packet_size) += key_rec->enc_key_size;
2389 (*remaining_bytes) -= (*packet_size);
2393 struct kmem_cache *ecryptfs_key_record_cache;
2396 * ecryptfs_generate_key_packet_set
2397 * @dest_base: Virtual address from which to write the key record set
2398 * @crypt_stat: The cryptographic context from which the
2399 * authentication tokens will be retrieved
2400 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2401 * for the global parameters
2402 * @len: The amount written
2403 * @max: The maximum amount of data allowed to be written
2405 * Generates a key packet set and writes it to the virtual address
2408 * Returns zero on success; non-zero on error.
2411 ecryptfs_generate_key_packet_set(char *dest_base,
2412 struct ecryptfs_crypt_stat *crypt_stat,
2413 struct dentry *ecryptfs_dentry, size_t *len,
2416 struct ecryptfs_auth_tok *auth_tok;
2417 struct key *auth_tok_key = NULL;
2418 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2419 &ecryptfs_superblock_to_private(
2420 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2422 struct ecryptfs_key_record *key_rec;
2423 struct ecryptfs_key_sig *key_sig;
2427 mutex_lock(&crypt_stat->keysig_list_mutex);
2428 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2433 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2435 memset(key_rec, 0, sizeof(*key_rec));
2436 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2441 printk(KERN_WARNING "Unable to retrieve auth tok with "
2442 "sig = [%s]\n", key_sig->keysig);
2443 rc = process_find_global_auth_tok_for_sig_err(rc);
2446 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2447 rc = write_tag_3_packet((dest_base + (*len)),
2449 crypt_stat, key_rec,
2451 up_write(&(auth_tok_key->sem));
2452 key_put(auth_tok_key);
2454 ecryptfs_printk(KERN_WARNING, "Error "
2455 "writing tag 3 packet\n");
2459 /* Write auth tok signature packet */
2460 rc = write_tag_11_packet((dest_base + (*len)), &max,
2462 ECRYPTFS_SIG_SIZE, &written);
2464 ecryptfs_printk(KERN_ERR, "Error writing "
2465 "auth tok signature packet\n");
2469 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2470 rc = write_tag_1_packet(dest_base + (*len), &max,
2471 auth_tok_key, auth_tok,
2472 crypt_stat, key_rec, &written);
2474 ecryptfs_printk(KERN_WARNING, "Error "
2475 "writing tag 1 packet\n");
2480 up_write(&(auth_tok_key->sem));
2481 key_put(auth_tok_key);
2482 ecryptfs_printk(KERN_WARNING, "Unsupported "
2483 "authentication token type\n");
2488 if (likely(max > 0)) {
2489 dest_base[(*len)] = 0x00;
2491 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2495 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2499 mutex_unlock(&crypt_stat->keysig_list_mutex);
2503 struct kmem_cache *ecryptfs_key_sig_cache;
2505 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2507 struct ecryptfs_key_sig *new_key_sig;
2509 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2513 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2514 new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2515 /* Caller must hold keysig_list_mutex */
2516 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2521 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2524 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2525 char *sig, u32 global_auth_tok_flags)
2527 struct ecryptfs_global_auth_tok *new_auth_tok;
2529 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2534 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2535 new_auth_tok->flags = global_auth_tok_flags;
2536 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2537 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2538 list_add(&new_auth_tok->mount_crypt_stat_list,
2539 &mount_crypt_stat->global_auth_tok_list);
2540 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);