2 * eCryptfs: Linux filesystem encryption layer
3 * In-kernel key management code. Includes functions to parse and
4 * write authentication token-related packets with the underlying
7 * Copyright (C) 2004-2006 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
9 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * Trevor S. Highland <trevor.highland@gmail.com>
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
28 #include <linux/string.h>
29 #include <linux/syscalls.h>
30 #include <linux/pagemap.h>
31 #include <linux/key.h>
32 #include <linux/random.h>
33 #include <linux/crypto.h>
34 #include <linux/scatterlist.h>
35 #include "ecryptfs_kernel.h"
38 * request_key returned an error instead of a valid key address;
39 * determine the type of error, make appropriate log entries, and
40 * return an error code.
42 static int process_request_key_err(long err_code)
48 ecryptfs_printk(KERN_WARNING, "No key\n");
52 ecryptfs_printk(KERN_WARNING, "Key expired\n");
56 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
60 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
61 "[0x%.16x]\n", err_code);
68 * ecryptfs_parse_packet_length
69 * @data: Pointer to memory containing length at offset
70 * @size: This function writes the decoded size to this memory
71 * address; zero on error
72 * @length_size: The number of bytes occupied by the encoded length
74 * Returns zero on success; non-zero on error
76 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
85 (*size) = (unsigned char)data[0];
87 } else if (data[0] < 224) {
89 (*size) = (((unsigned char)(data[0]) - 192) * 256);
90 (*size) += ((unsigned char)(data[1]) + 192);
92 } else if (data[0] == 255) {
93 /* Five-byte length; we're not supposed to see this */
94 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
99 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
108 * ecryptfs_write_packet_length
109 * @dest: The byte array target into which to write the length. Must
110 * have at least 5 bytes allocated.
111 * @size: The length to write.
112 * @packet_size_length: The number of bytes used to encode the packet
113 * length is written to this address.
115 * Returns zero on success; non-zero on error.
117 int ecryptfs_write_packet_length(char *dest, size_t size,
118 size_t *packet_size_length)
124 (*packet_size_length) = 1;
125 } else if (size < 65536) {
126 dest[0] = (((size - 192) / 256) + 192);
127 dest[1] = ((size - 192) % 256);
128 (*packet_size_length) = 2;
131 ecryptfs_printk(KERN_WARNING,
132 "Unsupported packet size: [%d]\n", size);
138 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
139 char **packet, size_t *packet_len)
143 size_t packet_size_len;
148 * ***** TAG 64 Packet Format *****
149 * | Content Type | 1 byte |
150 * | Key Identifier Size | 1 or 2 bytes |
151 * | Key Identifier | arbitrary |
152 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
153 * | Encrypted File Encryption Key | arbitrary |
155 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
156 + session_key->encrypted_key_size);
157 *packet = kmalloc(data_len, GFP_KERNEL);
160 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
164 message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
165 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
168 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
169 "header; cannot generate packet length\n");
172 i += packet_size_len;
173 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
174 i += ECRYPTFS_SIG_SIZE_HEX;
175 rc = ecryptfs_write_packet_length(&message[i],
176 session_key->encrypted_key_size,
179 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
180 "header; cannot generate packet length\n");
183 i += packet_size_len;
184 memcpy(&message[i], session_key->encrypted_key,
185 session_key->encrypted_key_size);
186 i += session_key->encrypted_key_size;
193 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
194 struct ecryptfs_message *msg)
202 u16 expected_checksum = 0;
206 * ***** TAG 65 Packet Format *****
207 * | Content Type | 1 byte |
208 * | Status Indicator | 1 byte |
209 * | File Encryption Key Size | 1 or 2 bytes |
210 * | File Encryption Key | arbitrary |
212 message_len = msg->data_len;
214 if (message_len < 4) {
218 if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
219 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
224 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
225 "[%d]\n", data[i-1]);
229 rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
231 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
236 if (message_len < (i + m_size)) {
237 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
238 "is shorter than expected\n");
243 ecryptfs_printk(KERN_ERR,
244 "The decrypted key is not long enough to "
245 "include a cipher code and checksum\n");
249 *cipher_code = data[i++];
250 /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
251 session_key->decrypted_key_size = m_size - 3;
252 if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
253 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
254 "the maximum key size [%d]\n",
255 session_key->decrypted_key_size,
256 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
260 memcpy(session_key->decrypted_key, &data[i],
261 session_key->decrypted_key_size);
262 i += session_key->decrypted_key_size;
263 expected_checksum += (unsigned char)(data[i++]) << 8;
264 expected_checksum += (unsigned char)(data[i++]);
265 for (i = 0; i < session_key->decrypted_key_size; i++)
266 checksum += session_key->decrypted_key[i];
267 if (expected_checksum != checksum) {
268 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
269 "encryption key; expected [%x]; calculated "
270 "[%x]\n", expected_checksum, checksum);
279 write_tag_66_packet(char *signature, u8 cipher_code,
280 struct ecryptfs_crypt_stat *crypt_stat, char **packet,
287 size_t packet_size_len;
292 * ***** TAG 66 Packet Format *****
293 * | Content Type | 1 byte |
294 * | Key Identifier Size | 1 or 2 bytes |
295 * | Key Identifier | arbitrary |
296 * | File Encryption Key Size | 1 or 2 bytes |
297 * | File Encryption Key | arbitrary |
299 data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
300 *packet = kmalloc(data_len, GFP_KERNEL);
303 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
307 message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
308 rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
311 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
312 "header; cannot generate packet length\n");
315 i += packet_size_len;
316 memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
317 i += ECRYPTFS_SIG_SIZE_HEX;
318 /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
319 rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
322 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
323 "header; cannot generate packet length\n");
326 i += packet_size_len;
327 message[i++] = cipher_code;
328 memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
329 i += crypt_stat->key_size;
330 for (j = 0; j < crypt_stat->key_size; j++)
331 checksum += crypt_stat->key[j];
332 message[i++] = (checksum / 256) % 256;
333 message[i++] = (checksum % 256);
340 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
341 struct ecryptfs_message *msg)
350 * ***** TAG 65 Packet Format *****
351 * | Content Type | 1 byte |
352 * | Status Indicator | 1 byte |
353 * | Encrypted File Encryption Key Size | 1 or 2 bytes |
354 * | Encrypted File Encryption Key | arbitrary |
356 message_len = msg->data_len;
358 /* verify that everything through the encrypted FEK size is present */
359 if (message_len < 4) {
361 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
362 "message length is [%d]\n", __func__, message_len, 4);
365 if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
367 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
373 printk(KERN_ERR "%s: Status indicator has non zero "
374 "value [%d]\n", __func__, data[i-1]);
378 rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
381 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
386 if (message_len < (i + key_rec->enc_key_size)) {
388 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
389 __func__, message_len, (i + key_rec->enc_key_size));
392 if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
394 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
395 "the maximum key size [%d]\n", __func__,
396 key_rec->enc_key_size,
397 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
400 memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
406 ecryptfs_find_global_auth_tok_for_sig(
407 struct ecryptfs_global_auth_tok **global_auth_tok,
408 struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
410 struct ecryptfs_global_auth_tok *walker;
413 (*global_auth_tok) = NULL;
414 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
415 list_for_each_entry(walker,
416 &mount_crypt_stat->global_auth_tok_list,
417 mount_crypt_stat_list) {
418 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX) == 0) {
419 (*global_auth_tok) = walker;
425 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
430 * ecryptfs_find_auth_tok_for_sig
431 * @auth_tok: Set to the matching auth_tok; NULL if not found
432 * @crypt_stat: inode crypt_stat crypto context
433 * @sig: Sig of auth_tok to find
435 * For now, this function simply looks at the registered auth_tok's
436 * linked off the mount_crypt_stat, so all the auth_toks that can be
437 * used must be registered at mount time. This function could
438 * potentially try a lot harder to find auth_tok's (e.g., by calling
439 * out to ecryptfsd to dynamically retrieve an auth_tok object) so
440 * that static registration of auth_tok's will no longer be necessary.
442 * Returns zero on no error; non-zero on error
445 ecryptfs_find_auth_tok_for_sig(
446 struct ecryptfs_auth_tok **auth_tok,
447 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
450 struct ecryptfs_global_auth_tok *global_auth_tok;
454 if (ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
455 mount_crypt_stat, sig)) {
456 struct key *auth_tok_key;
458 rc = ecryptfs_keyring_auth_tok_for_sig(&auth_tok_key, auth_tok,
461 (*auth_tok) = global_auth_tok->global_auth_tok;
466 * write_tag_70_packet can gobble a lot of stack space. We stuff most
467 * of the function's parameters in a kmalloc'd struct to help reduce
468 * eCryptfs' overall stack usage.
470 struct ecryptfs_write_tag_70_packet_silly_stack {
472 size_t max_packet_size;
473 size_t packet_size_len;
474 size_t block_aligned_filename_size;
478 size_t num_rand_bytes;
479 struct mutex *tfm_mutex;
480 char *block_aligned_filename;
481 struct ecryptfs_auth_tok *auth_tok;
482 struct scatterlist src_sg;
483 struct scatterlist dst_sg;
484 struct blkcipher_desc desc;
485 char iv[ECRYPTFS_MAX_IV_BYTES];
486 char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
487 char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
488 struct hash_desc hash_desc;
489 struct scatterlist hash_sg;
493 * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
494 * @filename: NULL-terminated filename string
496 * This is the simplest mechanism for achieving filename encryption in
497 * eCryptfs. It encrypts the given filename with the mount-wide
498 * filename encryption key (FNEK) and stores it in a packet to @dest,
499 * which the callee will encode and write directly into the dentry
503 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
505 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
506 char *filename, size_t filename_size)
508 struct ecryptfs_write_tag_70_packet_silly_stack *s;
511 s = kmalloc(sizeof(*s), GFP_KERNEL);
513 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
514 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
517 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
519 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
521 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
523 printk(KERN_ERR "Internal error whilst attempting to get "
524 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
525 mount_crypt_stat->global_default_fn_cipher_name, rc);
528 mutex_lock(s->tfm_mutex);
529 s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
530 /* Plus one for the \0 separator between the random prefix
531 * and the plaintext filename */
532 s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
533 s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
534 if ((s->block_aligned_filename_size % s->block_size) != 0) {
535 s->num_rand_bytes += (s->block_size
536 - (s->block_aligned_filename_size
538 s->block_aligned_filename_size = (s->num_rand_bytes
541 /* Octet 0: Tag 70 identifier
542 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
543 * and block-aligned encrypted filename size)
544 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
545 * Octet N2-N3: Cipher identifier (1 octet)
546 * Octets N3-N4: Block-aligned encrypted filename
547 * - Consists of a minimum number of random characters, a \0
548 * separator, and then the filename */
549 s->max_packet_size = (1 /* Tag 70 identifier */
550 + 3 /* Max Tag 70 packet size */
551 + ECRYPTFS_SIG_SIZE /* FNEK sig */
552 + 1 /* Cipher identifier */
553 + s->block_aligned_filename_size);
555 (*packet_size) = s->max_packet_size;
558 if (s->max_packet_size > (*remaining_bytes)) {
559 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
560 "[%zd] available\n", __func__, s->max_packet_size,
565 s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
567 if (!s->block_aligned_filename) {
568 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
569 "kzalloc [%zd] bytes\n", __func__,
570 s->block_aligned_filename_size);
575 dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
576 rc = ecryptfs_write_packet_length(&dest[s->i],
578 + 1 /* Cipher code */
579 + s->block_aligned_filename_size),
580 &s->packet_size_len);
582 printk(KERN_ERR "%s: Error generating tag 70 packet "
583 "header; cannot generate packet length; rc = [%d]\n",
585 goto out_free_unlock;
587 s->i += s->packet_size_len;
588 ecryptfs_from_hex(&dest[s->i],
589 mount_crypt_stat->global_default_fnek_sig,
591 s->i += ECRYPTFS_SIG_SIZE;
592 s->cipher_code = ecryptfs_code_for_cipher_string(
593 mount_crypt_stat->global_default_fn_cipher_name,
594 mount_crypt_stat->global_default_fn_cipher_key_bytes);
595 if (s->cipher_code == 0) {
596 printk(KERN_WARNING "%s: Unable to generate code for "
597 "cipher [%s] with key bytes [%zd]\n", __func__,
598 mount_crypt_stat->global_default_fn_cipher_name,
599 mount_crypt_stat->global_default_fn_cipher_key_bytes);
601 goto out_free_unlock;
603 dest[s->i++] = s->cipher_code;
604 rc = ecryptfs_find_auth_tok_for_sig(
605 &s->auth_tok, mount_crypt_stat,
606 mount_crypt_stat->global_default_fnek_sig);
608 printk(KERN_ERR "%s: Error attempting to find auth tok for "
609 "fnek sig [%s]; rc = [%d]\n", __func__,
610 mount_crypt_stat->global_default_fnek_sig, rc);
611 goto out_free_unlock;
613 /* TODO: Support other key modules than passphrase for
614 * filename encryption */
615 BUG_ON(s->auth_tok->token_type != ECRYPTFS_PASSWORD);
618 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
619 s->auth_tok->token.password.session_key_encryption_key_bytes);
620 s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
621 s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
623 if (IS_ERR(s->hash_desc.tfm)) {
624 rc = PTR_ERR(s->hash_desc.tfm);
625 printk(KERN_ERR "%s: Error attempting to "
626 "allocate hash crypto context; rc = [%d]\n",
628 goto out_free_unlock;
630 rc = crypto_hash_init(&s->hash_desc);
633 "%s: Error initializing crypto hash; rc = [%d]\n",
635 goto out_release_free_unlock;
637 rc = crypto_hash_update(
638 &s->hash_desc, &s->hash_sg,
639 s->auth_tok->token.password.session_key_encryption_key_bytes);
642 "%s: Error updating crypto hash; rc = [%d]\n",
644 goto out_release_free_unlock;
646 rc = crypto_hash_final(&s->hash_desc, s->hash);
649 "%s: Error finalizing crypto hash; rc = [%d]\n",
651 goto out_release_free_unlock;
653 for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
654 s->block_aligned_filename[s->j] =
655 s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
656 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
657 == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
658 sg_init_one(&s->hash_sg, (u8 *)s->hash,
659 ECRYPTFS_TAG_70_DIGEST_SIZE);
660 rc = crypto_hash_init(&s->hash_desc);
663 "%s: Error initializing crypto hash; "
664 "rc = [%d]\n", __func__, rc);
665 goto out_release_free_unlock;
667 rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
668 ECRYPTFS_TAG_70_DIGEST_SIZE);
671 "%s: Error updating crypto hash; "
672 "rc = [%d]\n", __func__, rc);
673 goto out_release_free_unlock;
675 rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
678 "%s: Error finalizing crypto hash; "
679 "rc = [%d]\n", __func__, rc);
680 goto out_release_free_unlock;
682 memcpy(s->hash, s->tmp_hash,
683 ECRYPTFS_TAG_70_DIGEST_SIZE);
685 if (s->block_aligned_filename[s->j] == '\0')
686 s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
688 memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
690 rc = virt_to_scatterlist(s->block_aligned_filename,
691 s->block_aligned_filename_size, &s->src_sg, 1);
693 printk(KERN_ERR "%s: Internal error whilst attempting to "
694 "convert filename memory to scatterlist; "
695 "expected rc = 1; got rc = [%d]. "
696 "block_aligned_filename_size = [%zd]\n", __func__, rc,
697 s->block_aligned_filename_size);
698 goto out_release_free_unlock;
700 rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
703 printk(KERN_ERR "%s: Internal error whilst attempting to "
704 "convert encrypted filename memory to scatterlist; "
705 "expected rc = 1; got rc = [%d]. "
706 "block_aligned_filename_size = [%zd]\n", __func__, rc,
707 s->block_aligned_filename_size);
708 goto out_release_free_unlock;
710 /* The characters in the first block effectively do the job
711 * of the IV here, so we just use 0's for the IV. Note the
712 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
713 * >= ECRYPTFS_MAX_IV_BYTES. */
714 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
715 s->desc.info = s->iv;
716 rc = crypto_blkcipher_setkey(
718 s->auth_tok->token.password.session_key_encryption_key,
719 mount_crypt_stat->global_default_fn_cipher_key_bytes);
721 printk(KERN_ERR "%s: Error setting key for crypto context; "
722 "rc = [%d]. s->auth_tok->token.password.session_key_"
723 "encryption_key = [0x%p]; mount_crypt_stat->"
724 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
726 s->auth_tok->token.password.session_key_encryption_key,
727 mount_crypt_stat->global_default_fn_cipher_key_bytes);
728 goto out_release_free_unlock;
730 rc = crypto_blkcipher_encrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
731 s->block_aligned_filename_size);
733 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
734 "rc = [%d]\n", __func__, rc);
735 goto out_release_free_unlock;
737 s->i += s->block_aligned_filename_size;
738 (*packet_size) = s->i;
739 (*remaining_bytes) -= (*packet_size);
740 out_release_free_unlock:
741 crypto_free_hash(s->hash_desc.tfm);
743 kzfree(s->block_aligned_filename);
745 mutex_unlock(s->tfm_mutex);
751 struct ecryptfs_parse_tag_70_packet_silly_stack {
753 size_t max_packet_size;
754 size_t packet_size_len;
755 size_t parsed_tag_70_packet_size;
756 size_t block_aligned_filename_size;
759 struct mutex *tfm_mutex;
760 char *decrypted_filename;
761 struct ecryptfs_auth_tok *auth_tok;
762 struct scatterlist src_sg;
763 struct scatterlist dst_sg;
764 struct blkcipher_desc desc;
765 char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
766 char iv[ECRYPTFS_MAX_IV_BYTES];
767 char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
771 * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
772 * @filename: This function kmalloc's the memory for the filename
773 * @filename_size: This function sets this to the amount of memory
774 * kmalloc'd for the filename
775 * @packet_size: This function sets this to the the number of octets
776 * in the packet parsed
777 * @mount_crypt_stat: The mount-wide cryptographic context
778 * @data: The memory location containing the start of the tag 70
780 * @max_packet_size: The maximum legal size of the packet to be parsed
783 * Returns zero on success; non-zero otherwise
786 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
788 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
789 char *data, size_t max_packet_size)
791 struct ecryptfs_parse_tag_70_packet_silly_stack *s;
795 (*filename_size) = 0;
797 s = kmalloc(sizeof(*s), GFP_KERNEL);
799 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
800 "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
803 s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
804 if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
805 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
806 "at least [%d]\n", __func__, max_packet_size,
807 (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
811 /* Octet 0: Tag 70 identifier
812 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
813 * and block-aligned encrypted filename size)
814 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
815 * Octet N2-N3: Cipher identifier (1 octet)
816 * Octets N3-N4: Block-aligned encrypted filename
817 * - Consists of a minimum number of random numbers, a \0
818 * separator, and then the filename */
819 if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
820 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
821 "tag [0x%.2x]\n", __func__,
822 data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
826 rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
827 &s->parsed_tag_70_packet_size,
828 &s->packet_size_len);
830 printk(KERN_WARNING "%s: Error parsing packet length; "
831 "rc = [%d]\n", __func__, rc);
834 s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
835 - ECRYPTFS_SIG_SIZE - 1);
836 if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
838 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
839 "size is [%zd]\n", __func__, max_packet_size,
840 (1 + s->packet_size_len + 1
841 + s->block_aligned_filename_size));
845 (*packet_size) += s->packet_size_len;
846 ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
848 s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
849 (*packet_size) += ECRYPTFS_SIG_SIZE;
850 s->cipher_code = data[(*packet_size)++];
851 rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
853 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
854 __func__, s->cipher_code);
857 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
861 printk(KERN_ERR "Internal error whilst attempting to get "
862 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
863 s->cipher_string, rc);
866 mutex_lock(s->tfm_mutex);
867 rc = virt_to_scatterlist(&data[(*packet_size)],
868 s->block_aligned_filename_size, &s->src_sg, 1);
870 printk(KERN_ERR "%s: Internal error whilst attempting to "
871 "convert encrypted filename memory to scatterlist; "
872 "expected rc = 1; got rc = [%d]. "
873 "block_aligned_filename_size = [%zd]\n", __func__, rc,
874 s->block_aligned_filename_size);
877 (*packet_size) += s->block_aligned_filename_size;
878 s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
880 if (!s->decrypted_filename) {
881 printk(KERN_ERR "%s: Out of memory whilst attempting to "
882 "kmalloc [%zd] bytes\n", __func__,
883 s->block_aligned_filename_size);
887 rc = virt_to_scatterlist(s->decrypted_filename,
888 s->block_aligned_filename_size, &s->dst_sg, 1);
890 printk(KERN_ERR "%s: Internal error whilst attempting to "
891 "convert decrypted filename memory to scatterlist; "
892 "expected rc = 1; got rc = [%d]. "
893 "block_aligned_filename_size = [%zd]\n", __func__, rc,
894 s->block_aligned_filename_size);
895 goto out_free_unlock;
897 /* The characters in the first block effectively do the job of
898 * the IV here, so we just use 0's for the IV. Note the
899 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
900 * >= ECRYPTFS_MAX_IV_BYTES. */
901 memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
902 s->desc.info = s->iv;
903 rc = ecryptfs_find_auth_tok_for_sig(&s->auth_tok, mount_crypt_stat,
906 printk(KERN_ERR "%s: Error attempting to find auth tok for "
907 "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
909 goto out_free_unlock;
911 /* TODO: Support other key modules than passphrase for
912 * filename encryption */
913 BUG_ON(s->auth_tok->token_type != ECRYPTFS_PASSWORD);
914 rc = crypto_blkcipher_setkey(
916 s->auth_tok->token.password.session_key_encryption_key,
917 mount_crypt_stat->global_default_fn_cipher_key_bytes);
919 printk(KERN_ERR "%s: Error setting key for crypto context; "
920 "rc = [%d]. s->auth_tok->token.password.session_key_"
921 "encryption_key = [0x%p]; mount_crypt_stat->"
922 "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
924 s->auth_tok->token.password.session_key_encryption_key,
925 mount_crypt_stat->global_default_fn_cipher_key_bytes);
926 goto out_free_unlock;
928 rc = crypto_blkcipher_decrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
929 s->block_aligned_filename_size);
931 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
932 "rc = [%d]\n", __func__, rc);
933 goto out_free_unlock;
936 while (s->decrypted_filename[s->i] != '\0'
937 && s->i < s->block_aligned_filename_size)
939 if (s->i == s->block_aligned_filename_size) {
940 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
941 "find valid separator between random characters and "
942 "the filename\n", __func__);
944 goto out_free_unlock;
947 (*filename_size) = (s->block_aligned_filename_size - s->i);
948 if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
949 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
950 "invalid\n", __func__, (*filename_size));
952 goto out_free_unlock;
954 (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
956 printk(KERN_ERR "%s: Out of memory whilst attempting to "
957 "kmalloc [%zd] bytes\n", __func__,
958 ((*filename_size) + 1));
960 goto out_free_unlock;
962 memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
963 (*filename)[(*filename_size)] = '\0';
965 kfree(s->decrypted_filename);
967 mutex_unlock(s->tfm_mutex);
971 (*filename_size) = 0;
979 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
984 switch (auth_tok->token_type) {
985 case ECRYPTFS_PASSWORD:
986 (*sig) = auth_tok->token.password.signature;
988 case ECRYPTFS_PRIVATE_KEY:
989 (*sig) = auth_tok->token.private_key.signature;
992 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
993 auth_tok->token_type);
1000 * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1001 * @auth_tok: The key authentication token used to decrypt the session key
1002 * @crypt_stat: The cryptographic context
1004 * Returns zero on success; non-zero error otherwise.
1007 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1008 struct ecryptfs_crypt_stat *crypt_stat)
1011 struct ecryptfs_msg_ctx *msg_ctx;
1012 struct ecryptfs_message *msg = NULL;
1018 rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1020 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1021 auth_tok->token_type);
1024 rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1025 &payload, &payload_len);
1027 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1030 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1032 ecryptfs_printk(KERN_ERR, "Error sending message to "
1036 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1038 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1039 "from the user space daemon\n");
1043 rc = parse_tag_65_packet(&(auth_tok->session_key),
1046 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1050 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1051 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1052 auth_tok->session_key.decrypted_key_size);
1053 crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1054 rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1056 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1060 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1061 if (ecryptfs_verbosity > 0) {
1062 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1063 ecryptfs_dump_hex(crypt_stat->key,
1064 crypt_stat->key_size);
1072 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1074 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1075 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1077 list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1078 auth_tok_list_head, list) {
1079 list_del(&auth_tok_list_item->list);
1080 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1081 auth_tok_list_item);
1085 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1088 * parse_tag_1_packet
1089 * @crypt_stat: The cryptographic context to modify based on packet contents
1090 * @data: The raw bytes of the packet.
1091 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1092 * a new authentication token will be placed at the
1093 * end of this list for this packet.
1094 * @new_auth_tok: Pointer to a pointer to memory that this function
1095 * allocates; sets the memory address of the pointer to
1096 * NULL on error. This object is added to the
1098 * @packet_size: This function writes the size of the parsed packet
1099 * into this memory location; zero on error.
1100 * @max_packet_size: The maximum allowable packet size
1102 * Returns zero on success; non-zero on error.
1105 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1106 unsigned char *data, struct list_head *auth_tok_list,
1107 struct ecryptfs_auth_tok **new_auth_tok,
1108 size_t *packet_size, size_t max_packet_size)
1111 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1116 (*new_auth_tok) = NULL;
1118 * This format is inspired by OpenPGP; see RFC 2440
1121 * Tag 1 identifier (1 byte)
1122 * Max Tag 1 packet size (max 3 bytes)
1124 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1125 * Cipher identifier (1 byte)
1126 * Encrypted key size (arbitrary)
1128 * 12 bytes minimum packet size
1130 if (unlikely(max_packet_size < 12)) {
1131 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1135 if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1136 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1137 ECRYPTFS_TAG_1_PACKET_TYPE);
1141 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1142 * at end of function upon failure */
1143 auth_tok_list_item =
1144 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1146 if (!auth_tok_list_item) {
1147 printk(KERN_ERR "Unable to allocate memory\n");
1151 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1152 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1155 printk(KERN_WARNING "Error parsing packet length; "
1159 if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1160 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1164 (*packet_size) += length_size;
1165 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1166 printk(KERN_WARNING "Packet size exceeds max\n");
1170 if (unlikely(data[(*packet_size)++] != 0x03)) {
1171 printk(KERN_WARNING "Unknown version number [%d]\n",
1172 data[(*packet_size) - 1]);
1176 ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1177 &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1178 *packet_size += ECRYPTFS_SIG_SIZE;
1179 /* This byte is skipped because the kernel does not need to
1180 * know which public key encryption algorithm was used */
1182 (*new_auth_tok)->session_key.encrypted_key_size =
1183 body_size - (ECRYPTFS_SIG_SIZE + 2);
1184 if ((*new_auth_tok)->session_key.encrypted_key_size
1185 > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1186 printk(KERN_WARNING "Tag 1 packet contains key larger "
1187 "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1191 memcpy((*new_auth_tok)->session_key.encrypted_key,
1192 &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1193 (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1194 (*new_auth_tok)->session_key.flags &=
1195 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1196 (*new_auth_tok)->session_key.flags |=
1197 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1198 (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1199 (*new_auth_tok)->flags = 0;
1200 (*new_auth_tok)->session_key.flags &=
1201 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1202 (*new_auth_tok)->session_key.flags &=
1203 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1204 list_add(&auth_tok_list_item->list, auth_tok_list);
1207 (*new_auth_tok) = NULL;
1208 memset(auth_tok_list_item, 0,
1209 sizeof(struct ecryptfs_auth_tok_list_item));
1210 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1211 auth_tok_list_item);
1219 * parse_tag_3_packet
1220 * @crypt_stat: The cryptographic context to modify based on packet
1222 * @data: The raw bytes of the packet.
1223 * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1224 * a new authentication token will be placed at the end
1225 * of this list for this packet.
1226 * @new_auth_tok: Pointer to a pointer to memory that this function
1227 * allocates; sets the memory address of the pointer to
1228 * NULL on error. This object is added to the
1230 * @packet_size: This function writes the size of the parsed packet
1231 * into this memory location; zero on error.
1232 * @max_packet_size: maximum number of bytes to parse
1234 * Returns zero on success; non-zero on error.
1237 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1238 unsigned char *data, struct list_head *auth_tok_list,
1239 struct ecryptfs_auth_tok **new_auth_tok,
1240 size_t *packet_size, size_t max_packet_size)
1243 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1248 (*new_auth_tok) = NULL;
1250 *This format is inspired by OpenPGP; see RFC 2440
1253 * Tag 3 identifier (1 byte)
1254 * Max Tag 3 packet size (max 3 bytes)
1256 * Cipher code (1 byte)
1257 * S2K specifier (1 byte)
1258 * Hash identifier (1 byte)
1259 * Salt (ECRYPTFS_SALT_SIZE)
1260 * Hash iterations (1 byte)
1261 * Encrypted key (arbitrary)
1263 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1265 if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1266 printk(KERN_ERR "Max packet size too large\n");
1270 if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1271 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1272 ECRYPTFS_TAG_3_PACKET_TYPE);
1276 /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1277 * at end of function upon failure */
1278 auth_tok_list_item =
1279 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1280 if (!auth_tok_list_item) {
1281 printk(KERN_ERR "Unable to allocate memory\n");
1285 (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1286 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1289 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1293 if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1294 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1298 (*packet_size) += length_size;
1299 if (unlikely((*packet_size) + body_size > max_packet_size)) {
1300 printk(KERN_ERR "Packet size exceeds max\n");
1304 (*new_auth_tok)->session_key.encrypted_key_size =
1305 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1306 if (unlikely(data[(*packet_size)++] != 0x04)) {
1307 printk(KERN_WARNING "Unknown version number [%d]\n",
1308 data[(*packet_size) - 1]);
1312 ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1313 (u16)data[(*packet_size)]);
1314 /* A little extra work to differentiate among the AES key
1315 * sizes; see RFC2440 */
1316 switch(data[(*packet_size)++]) {
1317 case RFC2440_CIPHER_AES_192:
1318 crypt_stat->key_size = 24;
1321 crypt_stat->key_size =
1322 (*new_auth_tok)->session_key.encrypted_key_size;
1324 ecryptfs_init_crypt_ctx(crypt_stat);
1325 if (unlikely(data[(*packet_size)++] != 0x03)) {
1326 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1330 /* TODO: finish the hash mapping */
1331 switch (data[(*packet_size)++]) {
1332 case 0x01: /* See RFC2440 for these numbers and their mappings */
1334 memcpy((*new_auth_tok)->token.password.salt,
1335 &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1336 (*packet_size) += ECRYPTFS_SALT_SIZE;
1337 /* This conversion was taken straight from RFC2440 */
1338 (*new_auth_tok)->token.password.hash_iterations =
1339 ((u32) 16 + (data[(*packet_size)] & 15))
1340 << ((data[(*packet_size)] >> 4) + 6);
1342 /* Friendly reminder:
1343 * (*new_auth_tok)->session_key.encrypted_key_size =
1344 * (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1345 memcpy((*new_auth_tok)->session_key.encrypted_key,
1346 &data[(*packet_size)],
1347 (*new_auth_tok)->session_key.encrypted_key_size);
1349 (*new_auth_tok)->session_key.encrypted_key_size;
1350 (*new_auth_tok)->session_key.flags &=
1351 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1352 (*new_auth_tok)->session_key.flags |=
1353 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1354 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1357 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1358 "[%d]\n", data[(*packet_size) - 1]);
1362 (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1363 /* TODO: Parametarize; we might actually want userspace to
1364 * decrypt the session key. */
1365 (*new_auth_tok)->session_key.flags &=
1366 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1367 (*new_auth_tok)->session_key.flags &=
1368 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1369 list_add(&auth_tok_list_item->list, auth_tok_list);
1372 (*new_auth_tok) = NULL;
1373 memset(auth_tok_list_item, 0,
1374 sizeof(struct ecryptfs_auth_tok_list_item));
1375 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1376 auth_tok_list_item);
1384 * parse_tag_11_packet
1385 * @data: The raw bytes of the packet
1386 * @contents: This function writes the data contents of the literal
1387 * packet into this memory location
1388 * @max_contents_bytes: The maximum number of bytes that this function
1389 * is allowed to write into contents
1390 * @tag_11_contents_size: This function writes the size of the parsed
1391 * contents into this memory location; zero on
1393 * @packet_size: This function writes the size of the parsed packet
1394 * into this memory location; zero on error
1395 * @max_packet_size: maximum number of bytes to parse
1397 * Returns zero on success; non-zero on error.
1400 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1401 size_t max_contents_bytes, size_t *tag_11_contents_size,
1402 size_t *packet_size, size_t max_packet_size)
1409 (*tag_11_contents_size) = 0;
1410 /* This format is inspired by OpenPGP; see RFC 2440
1413 * Tag 11 identifier (1 byte)
1414 * Max Tag 11 packet size (max 3 bytes)
1415 * Binary format specifier (1 byte)
1416 * Filename length (1 byte)
1417 * Filename ("_CONSOLE") (8 bytes)
1418 * Modification date (4 bytes)
1419 * Literal data (arbitrary)
1421 * We need at least 16 bytes of data for the packet to even be
1424 if (max_packet_size < 16) {
1425 printk(KERN_ERR "Maximum packet size too small\n");
1429 if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1430 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1434 rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1437 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1440 if (body_size < 14) {
1441 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1445 (*packet_size) += length_size;
1446 (*tag_11_contents_size) = (body_size - 14);
1447 if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1448 printk(KERN_ERR "Packet size exceeds max\n");
1452 if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1453 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1458 if (data[(*packet_size)++] != 0x62) {
1459 printk(KERN_WARNING "Unrecognizable packet\n");
1463 if (data[(*packet_size)++] != 0x08) {
1464 printk(KERN_WARNING "Unrecognizable packet\n");
1468 (*packet_size) += 12; /* Ignore filename and modification date */
1469 memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1470 (*packet_size) += (*tag_11_contents_size);
1474 (*tag_11_contents_size) = 0;
1480 * ecryptfs_verify_version
1481 * @version: The version number to confirm
1483 * Returns zero on good version; non-zero otherwise
1485 static int ecryptfs_verify_version(u16 version)
1488 unsigned char major;
1489 unsigned char minor;
1491 major = ((version >> 8) & 0xFF);
1492 minor = (version & 0xFF);
1493 if (major != ECRYPTFS_VERSION_MAJOR) {
1494 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
1495 "Expected [%d]; got [%d]\n",
1496 ECRYPTFS_VERSION_MAJOR, major);
1500 if (minor != ECRYPTFS_VERSION_MINOR) {
1501 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
1502 "Expected [%d]; got [%d]\n",
1503 ECRYPTFS_VERSION_MINOR, minor);
1511 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1512 struct ecryptfs_auth_tok **auth_tok,
1517 (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1518 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1519 printk(KERN_ERR "Could not find key with description: [%s]\n",
1521 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1524 (*auth_tok) = ecryptfs_get_key_payload_data(*auth_tok_key);
1525 if (ecryptfs_verify_version((*auth_tok)->version)) {
1527 "Data structure version mismatch. "
1528 "Userspace tools must match eCryptfs "
1529 "kernel module with major version [%d] "
1530 "and minor version [%d]\n",
1531 ECRYPTFS_VERSION_MAJOR,
1532 ECRYPTFS_VERSION_MINOR);
1536 if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
1537 && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
1538 printk(KERN_ERR "Invalid auth_tok structure "
1539 "returned from key query\n");
1548 * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1549 * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1550 * @crypt_stat: The cryptographic context
1552 * Returns zero on success; non-zero error otherwise
1555 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1556 struct ecryptfs_crypt_stat *crypt_stat)
1558 struct scatterlist dst_sg[2];
1559 struct scatterlist src_sg[2];
1560 struct mutex *tfm_mutex;
1561 struct blkcipher_desc desc = {
1562 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1566 if (unlikely(ecryptfs_verbosity > 0)) {
1568 KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1569 auth_tok->token.password.session_key_encryption_key_bytes);
1571 auth_tok->token.password.session_key_encryption_key,
1572 auth_tok->token.password.session_key_encryption_key_bytes);
1574 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1575 crypt_stat->cipher);
1577 printk(KERN_ERR "Internal error whilst attempting to get "
1578 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1579 crypt_stat->cipher, rc);
1582 rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1583 auth_tok->session_key.encrypted_key_size,
1585 if (rc < 1 || rc > 2) {
1586 printk(KERN_ERR "Internal error whilst attempting to convert "
1587 "auth_tok->session_key.encrypted_key to scatterlist; "
1588 "expected rc = 1; got rc = [%d]. "
1589 "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1590 auth_tok->session_key.encrypted_key_size);
1593 auth_tok->session_key.decrypted_key_size =
1594 auth_tok->session_key.encrypted_key_size;
1595 rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1596 auth_tok->session_key.decrypted_key_size,
1598 if (rc < 1 || rc > 2) {
1599 printk(KERN_ERR "Internal error whilst attempting to convert "
1600 "auth_tok->session_key.decrypted_key to scatterlist; "
1601 "expected rc = 1; got rc = [%d]\n", rc);
1604 mutex_lock(tfm_mutex);
1605 rc = crypto_blkcipher_setkey(
1606 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1607 crypt_stat->key_size);
1608 if (unlikely(rc < 0)) {
1609 mutex_unlock(tfm_mutex);
1610 printk(KERN_ERR "Error setting key for crypto context\n");
1614 rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1615 auth_tok->session_key.encrypted_key_size);
1616 mutex_unlock(tfm_mutex);
1618 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1621 auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1622 memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1623 auth_tok->session_key.decrypted_key_size);
1624 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1625 if (unlikely(ecryptfs_verbosity > 0)) {
1626 ecryptfs_printk(KERN_DEBUG, "FEK of size [%d]:\n",
1627 crypt_stat->key_size);
1628 ecryptfs_dump_hex(crypt_stat->key,
1629 crypt_stat->key_size);
1636 * ecryptfs_parse_packet_set
1637 * @crypt_stat: The cryptographic context
1638 * @src: Virtual address of region of memory containing the packets
1639 * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1641 * Get crypt_stat to have the file's session key if the requisite key
1642 * is available to decrypt the session key.
1644 * Returns Zero if a valid authentication token was retrieved and
1645 * processed; negative value for file not encrypted or for error
1648 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1650 struct dentry *ecryptfs_dentry)
1653 size_t found_auth_tok;
1654 size_t next_packet_is_auth_tok_packet;
1655 struct list_head auth_tok_list;
1656 struct ecryptfs_auth_tok *matching_auth_tok;
1657 struct ecryptfs_auth_tok *candidate_auth_tok;
1658 char *candidate_auth_tok_sig;
1660 struct ecryptfs_auth_tok *new_auth_tok;
1661 unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1662 struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1663 size_t tag_11_contents_size;
1664 size_t tag_11_packet_size;
1667 INIT_LIST_HEAD(&auth_tok_list);
1668 /* Parse the header to find as many packets as we can; these will be
1669 * added the our &auth_tok_list */
1670 next_packet_is_auth_tok_packet = 1;
1671 while (next_packet_is_auth_tok_packet) {
1672 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1675 case ECRYPTFS_TAG_3_PACKET_TYPE:
1676 rc = parse_tag_3_packet(crypt_stat,
1677 (unsigned char *)&src[i],
1678 &auth_tok_list, &new_auth_tok,
1679 &packet_size, max_packet_size);
1681 ecryptfs_printk(KERN_ERR, "Error parsing "
1687 rc = parse_tag_11_packet((unsigned char *)&src[i],
1690 &tag_11_contents_size,
1691 &tag_11_packet_size,
1694 ecryptfs_printk(KERN_ERR, "No valid "
1695 "(ecryptfs-specific) literal "
1696 "packet containing "
1697 "authentication token "
1698 "signature found after "
1703 i += tag_11_packet_size;
1704 if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1705 ecryptfs_printk(KERN_ERR, "Expected "
1706 "signature of size [%d]; "
1709 tag_11_contents_size);
1713 ecryptfs_to_hex(new_auth_tok->token.password.signature,
1714 sig_tmp_space, tag_11_contents_size);
1715 new_auth_tok->token.password.signature[
1716 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1717 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1719 case ECRYPTFS_TAG_1_PACKET_TYPE:
1720 rc = parse_tag_1_packet(crypt_stat,
1721 (unsigned char *)&src[i],
1722 &auth_tok_list, &new_auth_tok,
1723 &packet_size, max_packet_size);
1725 ecryptfs_printk(KERN_ERR, "Error parsing "
1731 crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1733 case ECRYPTFS_TAG_11_PACKET_TYPE:
1734 ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1735 "(Tag 11 not allowed by itself)\n");
1740 ecryptfs_printk(KERN_DEBUG, "No packet at offset "
1741 "[%d] of the file header; hex value of "
1742 "character is [0x%.2x]\n", i, src[i]);
1743 next_packet_is_auth_tok_packet = 0;
1746 if (list_empty(&auth_tok_list)) {
1747 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1748 "eCryptfs file; this is not supported in this version "
1749 "of the eCryptfs kernel module\n");
1753 /* auth_tok_list contains the set of authentication tokens
1754 * parsed from the metadata. We need to find a matching
1755 * authentication token that has the secret component(s)
1756 * necessary to decrypt the EFEK in the auth_tok parsed from
1757 * the metadata. There may be several potential matches, but
1758 * just one will be sufficient to decrypt to get the FEK. */
1759 find_next_matching_auth_tok:
1761 list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1762 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1763 if (unlikely(ecryptfs_verbosity > 0)) {
1764 ecryptfs_printk(KERN_DEBUG,
1765 "Considering cadidate auth tok:\n");
1766 ecryptfs_dump_auth_tok(candidate_auth_tok);
1768 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1769 candidate_auth_tok);
1772 "Unrecognized candidate auth tok type: [%d]\n",
1773 candidate_auth_tok->token_type);
1777 ecryptfs_find_auth_tok_for_sig(&matching_auth_tok,
1778 crypt_stat->mount_crypt_stat,
1779 candidate_auth_tok_sig);
1780 if (matching_auth_tok) {
1782 goto found_matching_auth_tok;
1785 if (!found_auth_tok) {
1786 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1787 "authentication token\n");
1791 found_matching_auth_tok:
1792 if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1793 memcpy(&(candidate_auth_tok->token.private_key),
1794 &(matching_auth_tok->token.private_key),
1795 sizeof(struct ecryptfs_private_key));
1796 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1798 } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1799 memcpy(&(candidate_auth_tok->token.password),
1800 &(matching_auth_tok->token.password),
1801 sizeof(struct ecryptfs_password));
1802 rc = decrypt_passphrase_encrypted_session_key(
1803 candidate_auth_tok, crypt_stat);
1806 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1808 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1809 "session key for authentication token with sig "
1810 "[%.*s]; rc = [%d]. Removing auth tok "
1811 "candidate from the list and searching for "
1812 "the next match.\n", candidate_auth_tok_sig,
1813 ECRYPTFS_SIG_SIZE_HEX, rc);
1814 list_for_each_entry_safe(auth_tok_list_item,
1815 auth_tok_list_item_tmp,
1816 &auth_tok_list, list) {
1817 if (candidate_auth_tok
1818 == &auth_tok_list_item->auth_tok) {
1819 list_del(&auth_tok_list_item->list);
1821 ecryptfs_auth_tok_list_item_cache,
1822 auth_tok_list_item);
1823 goto find_next_matching_auth_tok;
1828 rc = ecryptfs_compute_root_iv(crypt_stat);
1830 ecryptfs_printk(KERN_ERR, "Error computing "
1834 rc = ecryptfs_init_crypt_ctx(crypt_stat);
1836 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1837 "context for cipher [%s]; rc = [%d]\n",
1838 crypt_stat->cipher, rc);
1841 wipe_auth_tok_list(&auth_tok_list);
1847 pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
1848 struct ecryptfs_crypt_stat *crypt_stat,
1849 struct ecryptfs_key_record *key_rec)
1851 struct ecryptfs_msg_ctx *msg_ctx = NULL;
1852 char *payload = NULL;
1854 struct ecryptfs_message *msg;
1857 rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1858 ecryptfs_code_for_cipher_string(
1860 crypt_stat->key_size),
1861 crypt_stat, &payload, &payload_len);
1863 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1866 rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1868 ecryptfs_printk(KERN_ERR, "Error sending message to "
1872 rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1874 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1875 "from the user space daemon\n");
1879 rc = parse_tag_67_packet(key_rec, msg);
1881 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
1888 * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1889 * @dest: Buffer into which to write the packet
1890 * @remaining_bytes: Maximum number of bytes that can be writtn
1891 * @auth_tok: The authentication token used for generating the tag 1 packet
1892 * @crypt_stat: The cryptographic context
1893 * @key_rec: The key record struct for the tag 1 packet
1894 * @packet_size: This function will write the number of bytes that end
1895 * up constituting the packet; set to zero on error
1897 * Returns zero on success; non-zero on error.
1900 write_tag_1_packet(char *dest, size_t *remaining_bytes,
1901 struct ecryptfs_auth_tok *auth_tok,
1902 struct ecryptfs_crypt_stat *crypt_stat,
1903 struct ecryptfs_key_record *key_rec, size_t *packet_size)
1906 size_t encrypted_session_key_valid = 0;
1907 size_t packet_size_length;
1908 size_t max_packet_size;
1912 ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
1914 encrypted_session_key_valid = 0;
1915 for (i = 0; i < crypt_stat->key_size; i++)
1916 encrypted_session_key_valid |=
1917 auth_tok->session_key.encrypted_key[i];
1918 if (encrypted_session_key_valid) {
1919 memcpy(key_rec->enc_key,
1920 auth_tok->session_key.encrypted_key,
1921 auth_tok->session_key.encrypted_key_size);
1922 goto encrypted_session_key_set;
1924 if (auth_tok->session_key.encrypted_key_size == 0)
1925 auth_tok->session_key.encrypted_key_size =
1926 auth_tok->token.private_key.key_size;
1927 rc = pki_encrypt_session_key(auth_tok, crypt_stat, key_rec);
1929 printk(KERN_ERR "Failed to encrypt session key via a key "
1930 "module; rc = [%d]\n", rc);
1933 if (ecryptfs_verbosity > 0) {
1934 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
1935 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
1937 encrypted_session_key_set:
1938 /* This format is inspired by OpenPGP; see RFC 2440
1940 max_packet_size = (1 /* Tag 1 identifier */
1941 + 3 /* Max Tag 1 packet size */
1943 + ECRYPTFS_SIG_SIZE /* Key identifier */
1944 + 1 /* Cipher identifier */
1945 + key_rec->enc_key_size); /* Encrypted key size */
1946 if (max_packet_size > (*remaining_bytes)) {
1947 printk(KERN_ERR "Packet length larger than maximum allowable; "
1948 "need up to [%td] bytes, but there are only [%td] "
1949 "available\n", max_packet_size, (*remaining_bytes));
1953 dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
1954 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
1955 (max_packet_size - 4),
1956 &packet_size_length);
1958 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
1959 "header; cannot generate packet length\n");
1962 (*packet_size) += packet_size_length;
1963 dest[(*packet_size)++] = 0x03; /* version 3 */
1964 memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
1965 (*packet_size) += ECRYPTFS_SIG_SIZE;
1966 dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
1967 memcpy(&dest[(*packet_size)], key_rec->enc_key,
1968 key_rec->enc_key_size);
1969 (*packet_size) += key_rec->enc_key_size;
1974 (*remaining_bytes) -= (*packet_size);
1979 * write_tag_11_packet
1980 * @dest: Target into which Tag 11 packet is to be written
1981 * @remaining_bytes: Maximum packet length
1982 * @contents: Byte array of contents to copy in
1983 * @contents_length: Number of bytes in contents
1984 * @packet_length: Length of the Tag 11 packet written; zero on error
1986 * Returns zero on success; non-zero on error.
1989 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
1990 size_t contents_length, size_t *packet_length)
1992 size_t packet_size_length;
1993 size_t max_packet_size;
1996 (*packet_length) = 0;
1997 /* This format is inspired by OpenPGP; see RFC 2440
1999 max_packet_size = (1 /* Tag 11 identifier */
2000 + 3 /* Max Tag 11 packet size */
2001 + 1 /* Binary format specifier */
2002 + 1 /* Filename length */
2003 + 8 /* Filename ("_CONSOLE") */
2004 + 4 /* Modification date */
2005 + contents_length); /* Literal data */
2006 if (max_packet_size > (*remaining_bytes)) {
2007 printk(KERN_ERR "Packet length larger than maximum allowable; "
2008 "need up to [%td] bytes, but there are only [%td] "
2009 "available\n", max_packet_size, (*remaining_bytes));
2013 dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2014 rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2015 (max_packet_size - 4),
2016 &packet_size_length);
2018 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2019 "generate packet length. rc = [%d]\n", rc);
2022 (*packet_length) += packet_size_length;
2023 dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2024 dest[(*packet_length)++] = 8;
2025 memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2026 (*packet_length) += 8;
2027 memset(&dest[(*packet_length)], 0x00, 4);
2028 (*packet_length) += 4;
2029 memcpy(&dest[(*packet_length)], contents, contents_length);
2030 (*packet_length) += contents_length;
2033 (*packet_length) = 0;
2035 (*remaining_bytes) -= (*packet_length);
2040 * write_tag_3_packet
2041 * @dest: Buffer into which to write the packet
2042 * @remaining_bytes: Maximum number of bytes that can be written
2043 * @auth_tok: Authentication token
2044 * @crypt_stat: The cryptographic context
2045 * @key_rec: encrypted key
2046 * @packet_size: This function will write the number of bytes that end
2047 * up constituting the packet; set to zero on error
2049 * Returns zero on success; non-zero on error.
2052 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2053 struct ecryptfs_auth_tok *auth_tok,
2054 struct ecryptfs_crypt_stat *crypt_stat,
2055 struct ecryptfs_key_record *key_rec, size_t *packet_size)
2058 size_t encrypted_session_key_valid = 0;
2059 char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2060 struct scatterlist dst_sg[2];
2061 struct scatterlist src_sg[2];
2062 struct mutex *tfm_mutex = NULL;
2064 size_t packet_size_length;
2065 size_t max_packet_size;
2066 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2067 crypt_stat->mount_crypt_stat;
2068 struct blkcipher_desc desc = {
2070 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2075 ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2077 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2078 crypt_stat->cipher);
2080 printk(KERN_ERR "Internal error whilst attempting to get "
2081 "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2082 crypt_stat->cipher, rc);
2085 if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2086 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2088 printk(KERN_WARNING "No key size specified at mount; "
2089 "defaulting to [%d]\n", alg->max_keysize);
2090 mount_crypt_stat->global_default_cipher_key_size =
2093 if (crypt_stat->key_size == 0)
2094 crypt_stat->key_size =
2095 mount_crypt_stat->global_default_cipher_key_size;
2096 if (auth_tok->session_key.encrypted_key_size == 0)
2097 auth_tok->session_key.encrypted_key_size =
2098 crypt_stat->key_size;
2099 if (crypt_stat->key_size == 24
2100 && strcmp("aes", crypt_stat->cipher) == 0) {
2101 memset((crypt_stat->key + 24), 0, 8);
2102 auth_tok->session_key.encrypted_key_size = 32;
2104 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2105 key_rec->enc_key_size =
2106 auth_tok->session_key.encrypted_key_size;
2107 encrypted_session_key_valid = 0;
2108 for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2109 encrypted_session_key_valid |=
2110 auth_tok->session_key.encrypted_key[i];
2111 if (encrypted_session_key_valid) {
2112 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2113 "using auth_tok->session_key.encrypted_key, "
2114 "where key_rec->enc_key_size = [%d]\n",
2115 key_rec->enc_key_size);
2116 memcpy(key_rec->enc_key,
2117 auth_tok->session_key.encrypted_key,
2118 key_rec->enc_key_size);
2119 goto encrypted_session_key_set;
2121 if (auth_tok->token.password.flags &
2122 ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2123 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2124 "session key encryption key of size [%d]\n",
2125 auth_tok->token.password.
2126 session_key_encryption_key_bytes);
2127 memcpy(session_key_encryption_key,
2128 auth_tok->token.password.session_key_encryption_key,
2129 crypt_stat->key_size);
2130 ecryptfs_printk(KERN_DEBUG,
2131 "Cached session key " "encryption key: \n");
2132 if (ecryptfs_verbosity > 0)
2133 ecryptfs_dump_hex(session_key_encryption_key, 16);
2135 if (unlikely(ecryptfs_verbosity > 0)) {
2136 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2137 ecryptfs_dump_hex(session_key_encryption_key, 16);
2139 rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2141 if (rc < 1 || rc > 2) {
2142 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2143 "for crypt_stat session key; expected rc = 1; "
2144 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
2145 rc, key_rec->enc_key_size);
2149 rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2151 if (rc < 1 || rc > 2) {
2152 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2153 "for crypt_stat encrypted session key; "
2154 "expected rc = 1; got rc = [%d]. "
2155 "key_rec->enc_key_size = [%d]\n", rc,
2156 key_rec->enc_key_size);
2160 mutex_lock(tfm_mutex);
2161 rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2162 crypt_stat->key_size);
2164 mutex_unlock(tfm_mutex);
2165 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2166 "context; rc = [%d]\n", rc);
2170 ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n",
2171 crypt_stat->key_size);
2172 rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2173 (*key_rec).enc_key_size);
2174 mutex_unlock(tfm_mutex);
2176 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2179 ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2180 if (ecryptfs_verbosity > 0) {
2181 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%d]:\n",
2182 key_rec->enc_key_size);
2183 ecryptfs_dump_hex(key_rec->enc_key,
2184 key_rec->enc_key_size);
2186 encrypted_session_key_set:
2187 /* This format is inspired by OpenPGP; see RFC 2440
2189 max_packet_size = (1 /* Tag 3 identifier */
2190 + 3 /* Max Tag 3 packet size */
2192 + 1 /* Cipher code */
2193 + 1 /* S2K specifier */
2194 + 1 /* Hash identifier */
2195 + ECRYPTFS_SALT_SIZE /* Salt */
2196 + 1 /* Hash iterations */
2197 + key_rec->enc_key_size); /* Encrypted key size */
2198 if (max_packet_size > (*remaining_bytes)) {
2199 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2200 "there are only [%td] available\n", max_packet_size,
2201 (*remaining_bytes));
2205 dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2206 /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2207 * to get the number of octets in the actual Tag 3 packet */
2208 rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2209 (max_packet_size - 4),
2210 &packet_size_length);
2212 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2213 "generate packet length. rc = [%d]\n", rc);
2216 (*packet_size) += packet_size_length;
2217 dest[(*packet_size)++] = 0x04; /* version 4 */
2218 /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2219 * specified with strings */
2220 cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2221 crypt_stat->key_size);
2222 if (cipher_code == 0) {
2223 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2224 "cipher [%s]\n", crypt_stat->cipher);
2228 dest[(*packet_size)++] = cipher_code;
2229 dest[(*packet_size)++] = 0x03; /* S2K */
2230 dest[(*packet_size)++] = 0x01; /* MD5 (TODO: parameterize) */
2231 memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2232 ECRYPTFS_SALT_SIZE);
2233 (*packet_size) += ECRYPTFS_SALT_SIZE; /* salt */
2234 dest[(*packet_size)++] = 0x60; /* hash iterations (65536) */
2235 memcpy(&dest[(*packet_size)], key_rec->enc_key,
2236 key_rec->enc_key_size);
2237 (*packet_size) += key_rec->enc_key_size;
2242 (*remaining_bytes) -= (*packet_size);
2246 struct kmem_cache *ecryptfs_key_record_cache;
2249 * ecryptfs_generate_key_packet_set
2250 * @dest_base: Virtual address from which to write the key record set
2251 * @crypt_stat: The cryptographic context from which the
2252 * authentication tokens will be retrieved
2253 * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2254 * for the global parameters
2255 * @len: The amount written
2256 * @max: The maximum amount of data allowed to be written
2258 * Generates a key packet set and writes it to the virtual address
2261 * Returns zero on success; non-zero on error.
2264 ecryptfs_generate_key_packet_set(char *dest_base,
2265 struct ecryptfs_crypt_stat *crypt_stat,
2266 struct dentry *ecryptfs_dentry, size_t *len,
2269 struct ecryptfs_auth_tok *auth_tok;
2270 struct ecryptfs_global_auth_tok *global_auth_tok;
2271 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2272 &ecryptfs_superblock_to_private(
2273 ecryptfs_dentry->d_sb)->mount_crypt_stat;
2275 struct ecryptfs_key_record *key_rec;
2276 struct ecryptfs_key_sig *key_sig;
2280 mutex_lock(&crypt_stat->keysig_list_mutex);
2281 key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2286 list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2288 memset(key_rec, 0, sizeof(*key_rec));
2289 rc = ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
2293 printk(KERN_ERR "Error attempting to get the global "
2294 "auth_tok; rc = [%d]\n", rc);
2297 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID) {
2299 "Skipping invalid auth tok with sig = [%s]\n",
2300 global_auth_tok->sig);
2303 auth_tok = global_auth_tok->global_auth_tok;
2304 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2305 rc = write_tag_3_packet((dest_base + (*len)),
2307 crypt_stat, key_rec,
2310 ecryptfs_printk(KERN_WARNING, "Error "
2311 "writing tag 3 packet\n");
2315 /* Write auth tok signature packet */
2316 rc = write_tag_11_packet((dest_base + (*len)), &max,
2318 ECRYPTFS_SIG_SIZE, &written);
2320 ecryptfs_printk(KERN_ERR, "Error writing "
2321 "auth tok signature packet\n");
2325 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2326 rc = write_tag_1_packet(dest_base + (*len),
2328 crypt_stat, key_rec, &written);
2330 ecryptfs_printk(KERN_WARNING, "Error "
2331 "writing tag 1 packet\n");
2336 ecryptfs_printk(KERN_WARNING, "Unsupported "
2337 "authentication token type\n");
2342 if (likely(max > 0)) {
2343 dest_base[(*len)] = 0x00;
2345 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2349 kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2353 mutex_unlock(&crypt_stat->keysig_list_mutex);
2357 struct kmem_cache *ecryptfs_key_sig_cache;
2359 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2361 struct ecryptfs_key_sig *new_key_sig;
2364 new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2368 "Error allocating from ecryptfs_key_sig_cache\n");
2371 memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2372 mutex_lock(&crypt_stat->keysig_list_mutex);
2373 list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2374 mutex_unlock(&crypt_stat->keysig_list_mutex);
2379 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2382 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2383 char *sig, u32 global_auth_tok_flags)
2385 struct ecryptfs_global_auth_tok *new_auth_tok;
2388 new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2390 if (!new_auth_tok) {
2392 printk(KERN_ERR "Error allocating from "
2393 "ecryptfs_global_auth_tok_cache\n");
2396 memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2397 new_auth_tok->flags = global_auth_tok_flags;
2398 new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2399 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2400 list_add(&new_auth_tok->mount_crypt_stat_list,
2401 &mount_crypt_stat->global_auth_tok_list);
2402 mount_crypt_stat->num_global_auth_toks++;
2403 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);