KEYS: If install_session_keyring() is given a keyring, it should install it
[linux-3.10.git] / security / keys / ecryptfs_format.c
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
21 u8 *ecryptfs_get_auth_tok_key(struct ecryptfs_auth_tok *auth_tok)
22 {
23         return auth_tok->token.password.session_key_encryption_key;
24 }
25 EXPORT_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  */
33 void 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 }
40 EXPORT_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  */
50 int 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 }
79 EXPORT_SYMBOL(ecryptfs_fill_auth_tok);
80
81 MODULE_LICENSE("GPL");