security/keys/encrypted-keys/masterkey_trusted.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2010 IBM Corporation
   4  * Copyright (C) 2010 Politecnico di Torino, Italy
   5  *                    TORSEC group -- https://security.polito.it
   6  *
   7  * Authors:
   8  * Mimi Zohar <zohar@us.ibm.com>
   9  * Roberto Sassu <roberto.sassu@polito.it>
  10  *
  11  * See Documentation/security/keys/trusted-encrypted.rst
  12  */
  13
  14 #include <linux/uaccess.h>
  15 #include <linux/err.h>
  16 #include <keys/trusted-type.h>
  17 #include <keys/encrypted-type.h>
  18 #include "encrypted.h"
  19
  20 /*
  21  * request_trusted_key - request the trusted key
  22  *
  23  * Trusted keys are sealed to PCRs and other metadata. Although userspace
  24  * manages both trusted/encrypted key-types, like the encrypted key type
  25  * data, trusted key type data is not visible decrypted from userspace.
  26  */
  27 struct key *request_trusted_key(const char *trusted_desc,
  28                                 const u8 **master_key, size_t *master_keylen)
  29 {
  30         struct trusted_key_payload *tpayload;
  31         struct key *tkey;
  32
  33         tkey = request_key(&key_type_trusted, trusted_desc, NULL);
  34         if (IS_ERR(tkey))
  35                 goto error;
  36
  37         down_read(&tkey->sem);
  38         tpayload = tkey->payload.data[0];
  39         *master_key = tpayload->key;
  40         *master_keylen = tpayload->key_len;
  41 error:
  42         return tkey;
  43 }