1 /*
2  * Copyright (C) 2010 IBM Corporation
3  * Copyright (C) 2010 Politecnico di Torino, Italy
4  *                    TORSEC group -- http://security.polito.it
5  *
6  * Authors:
7  * Mimi Zohar <zohar@us.ibm.com>
8  * Roberto Sassu <roberto.sassu@polito.it>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation, version 2 of the License.
13  *
14  * See Documentation/security/keys-trusted-encrypted.txt
15  */
16 
17 #include <linux/uaccess.h>
18 #include <linux/module.h>
19 #include <linux/err.h>
20 #include <keys/trusted-type.h>
21 
22 /*
23  * request_trusted_key - request the trusted key
24  *
25  * Trusted keys are sealed to PCRs and other metadata. Although userspace
26  * manages both trusted/encrypted key-types, like the encrypted key type
27  * data, trusted key type data is not visible decrypted from userspace.
28  */
29 struct key *request_trusted_key(const char *trusted_desc,
30 				u8 **master_key, size_t *master_keylen)
31 {
32 	struct trusted_key_payload *tpayload;
33 	struct key *tkey;
34 
35 	tkey = request_key(&key_type_trusted, trusted_desc, NULL);
36 	if (IS_ERR(tkey))
37 		goto error;
38 
39 	down_read(&tkey->sem);
40 	tpayload = rcu_dereference(tkey->payload.data);
41 	*master_key = tpayload->key;
42 	*master_keylen = tpayload->key_len;
43 error:
44 	return tkey;
45 }
46