security/keys/encrypted-keys/masterkey_trusted.c

   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 #include <keys/encrypted-type.h>
  22 #include "encrypted.h"
  23
  24 /*
  25  * request_trusted_key - request the trusted key
  26  *
  27  * Trusted keys are sealed to PCRs and other metadata. Although userspace
  28  * manages both trusted/encrypted key-types, like the encrypted key type
  29  * data, trusted key type data is not visible decrypted from userspace.
  30  */
  31 struct key *request_trusted_key(const char *trusted_desc,
  32                                 u8 **master_key, size_t *master_keylen)
  33 {
  34         struct trusted_key_payload *tpayload;
  35         struct key *tkey;
  36
  37         tkey = request_key(&key_type_trusted, trusted_desc, NULL);
  38         if (IS_ERR(tkey))
  39                 goto error;
  40
  41         down_read(&tkey->sem);
  42         tpayload = rcu_dereference(tkey->payload.data);
  43         *master_key = tpayload->key;
  44         *master_keylen = tpayload->key_len;
  45 error:
  46         return tkey;
  47 }