2 * Copyright (C) 2010 IBM Corporation
5 * Mimi Zohar <zohar@us.ibm.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, version 2 of the License.
12 * - Used to signal when key is on keyring
13 * - Get the key and enable EVM
16 #include <linux/uaccess.h>
17 #include <linux/module.h>
20 static struct dentry *evm_init_tpm;
23 * evm_read_key - read() for <securityfs>/evm
25 * @filp: file pointer, not actually used
26 * @buf: where to put the result
27 * @count: maximum to send along
28 * @ppos: where to start
30 * Returns number of bytes read or error code, as appropriate
32 static ssize_t evm_read_key(struct file *filp, char __user *buf,
33 size_t count, loff_t *ppos)
41 sprintf(temp, "%d", evm_initialized);
42 rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
48 * evm_write_key - write() for <securityfs>/evm
49 * @file: file pointer, not actually used
50 * @buf: where to get the data from
52 * @ppos: where to start
54 * Used to signal that key is on the kernel key ring.
55 * - get the integrity hmac key from the kernel key ring
56 * - create list of hmac protected extended attributes
57 * Returns number of bytes written or error code, as appropriate
59 static ssize_t evm_write_key(struct file *file, const char __user *buf,
60 size_t count, loff_t *ppos)
65 if (!capable(CAP_SYS_ADMIN) || evm_initialized)
68 if (count >= sizeof(temp) || count == 0)
71 if (copy_from_user(temp, buf, count) != 0)
76 if ((sscanf(temp, "%d", &i) != 1) || (i != 1))
79 error = evm_init_key();
82 pr_info("EVM: initialized\n");
84 pr_err("EVM: initialization failed\n");
88 static const struct file_operations evm_key_ops = {
90 .write = evm_write_key,
93 int __init evm_init_secfs(void)
97 evm_init_tpm = securityfs_create_file("evm", S_IRUSR | S_IRGRP,
98 NULL, NULL, &evm_key_ops);
99 if (!evm_init_tpm || IS_ERR(evm_init_tpm))