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");
82