1/*
2 * ecryptfs_format.c: helper functions for the encrypted key type
3 *
4 * Copyright (C) 2006 International Business Machines Corp.
5 * Copyright (C) 2010 Politecnico di Torino, Italy
6 *                    TORSEC group -- http://security.polito.it
7 *
8 * Authors:
9 * Michael A. Halcrow <mahalcro@us.ibm.com>
10 * Tyler Hicks <tyhicks@ou.edu>
11 * Roberto Sassu <roberto.sassu@polito.it>
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation, version 2 of the License.
16 */
17
18#include <linux/module.h>
19#include "ecryptfs_format.h"
20
21u8 *ecryptfs_get_auth_tok_key(struct ecryptfs_auth_tok *auth_tok)
22{
23	return auth_tok->token.password.session_key_encryption_key;
24}
25EXPORT_SYMBOL(ecryptfs_get_auth_tok_key);
26
27/*
28 * ecryptfs_get_versions()
29 *
30 * Source code taken from the software 'ecryptfs-utils' version 83.
31 *
32 */
33void ecryptfs_get_versions(int *major, int *minor, int *file_version)
34{
35	*major = ECRYPTFS_VERSION_MAJOR;
36	*minor = ECRYPTFS_VERSION_MINOR;
37	if (file_version)
38		*file_version = ECRYPTFS_SUPPORTED_FILE_VERSION;
39}
40EXPORT_SYMBOL(ecryptfs_get_versions);
41
42/*
43 * ecryptfs_fill_auth_tok - fill the ecryptfs_auth_tok structure
44 *
45 * Fill the ecryptfs_auth_tok structure with required ecryptfs data.
46 * The source code is inspired to the original function generate_payload()
47 * shipped with the software 'ecryptfs-utils' version 83.
48 *
49 */
50int ecryptfs_fill_auth_tok(struct ecryptfs_auth_tok *auth_tok,
51			   const char *key_desc)
52{
53	int major, minor;
54
55	ecryptfs_get_versions(&major, &minor, NULL);
56	auth_tok->version = (((uint16_t)(major << 8) & 0xFF00)
57			     | ((uint16_t)minor & 0x00FF));
58	auth_tok->token_type = ECRYPTFS_PASSWORD;
59	strncpy((char *)auth_tok->token.password.signature, key_desc,
60		ECRYPTFS_PASSWORD_SIG_SIZE);
61	auth_tok->token.password.session_key_encryption_key_bytes =
62		ECRYPTFS_MAX_KEY_BYTES;
63	/*
64	 * Removed auth_tok->token.password.salt and
65	 * auth_tok->token.password.session_key_encryption_key
66	 * initialization from the original code
67	 */
68	/* TODO: Make the hash parameterizable via policy */
69	auth_tok->token.password.flags |=
70		ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET;
71	/* The kernel code will encrypt the session key. */
72	auth_tok->session_key.encrypted_key[0] = 0;
73	auth_tok->session_key.encrypted_key_size = 0;
74	/* Default; subject to change by kernel eCryptfs */
75	auth_tok->token.password.hash_algo = PGP_DIGEST_ALGO_SHA512;
76	auth_tok->token.password.flags &= ~(ECRYPTFS_PERSISTENT_PASSWORD);
77	return 0;
78}
79EXPORT_SYMBOL(ecryptfs_fill_auth_tok);
80
81MODULE_LICENSE("GPL");
82