masterkey_trusted.c

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/*
 * Copyright (C) 2010 IBM Corporation
 * Copyright (C) 2010 Politecnico di Torino, Italy
 *                    TORSEC group -- http://security.polito.it
 *
 * Authors:
 * Mimi Zohar <[email protected]>
 * Roberto Sassu <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 2 of the License.
 *
 * See Documentation/security/keys-trusted-encrypted.txt
 */

#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/err.h>
#include <keys/trusted-type.h>
#include <keys/encrypted-type.h>
#include "encrypted.h"

/*
 * request_trusted_key - request the trusted key
 *
 * Trusted keys are sealed to PCRs and other metadata. Although userspace
 * manages both trusted/encrypted key-types, like the encrypted key type
 * data, trusted key type data is not visible decrypted from userspace.
 */
struct key *request_trusted_key(const char *trusted_desc,
                u8 **master_key, size_t *master_keylen)
{
    struct trusted_key_payload *tpayload;
    struct key *tkey;

    tkey = request_key(&key_type_trusted, trusted_desc, NULL);
    if (IS_ERR(tkey))
        goto error;

    down_read(&tkey->sem);
    tpayload = tkey->payload.data;
    *master_key = tpayload->key;
    *master_keylen = tpayload->key_len;
error:
    return tkey;
}