linux/security/integrity/evm/evm_secfs.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2010 IBM Corporation
 *
 * Authors:
 * Mimi Zohar <[email protected]>
 *
 * File: evm_secfs.c
 *	- Used to signal when key is on keyring
 *	- Get the key and enable EVM
 */

#include <linux/audit.h>
#include <linux/uaccess.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include "evm.h"

static struct dentry *evm_dir;
static struct dentry *evm_init_tpm;
static struct dentry *evm_symlink;

#ifdef CONFIG_EVM_ADD_XATTRS
static struct dentry *evm_xattrs;
static DEFINE_MUTEX(xattr_list_mutex);
static int evm_xattrs_locked;
#endif

/**
 * evm_read_key - read() for <securityfs>/evm
 *
 * @filp: file pointer, not actually used
 * @buf: where to put the result
 * @count: maximum to send along
 * @ppos: where to start
 *
 * Returns number of bytes read or error code, as appropriate
 */
static ssize_t evm_read_key(struct file *filp, char __user *buf,
			    size_t count, loff_t *ppos)
{ … }

/**
 * evm_write_key - write() for <securityfs>/evm
 * @file: file pointer, not actually used
 * @buf: where to get the data from
 * @count: bytes sent
 * @ppos: where to start
 *
 * Used to signal that key is on the kernel key ring.
 * - get the integrity hmac key from the kernel key ring
 * - create list of hmac protected extended attributes
 * Returns number of bytes written or error code, as appropriate
 */
static ssize_t evm_write_key(struct file *file, const char __user *buf,
			     size_t count, loff_t *ppos)
{ … }

static const struct file_operations evm_key_ops = …;

#ifdef CONFIG_EVM_ADD_XATTRS
/**
 * evm_read_xattrs - read() for <securityfs>/evm_xattrs
 *
 * @filp: file pointer, not actually used
 * @buf: where to put the result
 * @count: maximum to send along
 * @ppos: where to start
 *
 * Returns number of bytes read or error code, as appropriate
 */
static ssize_t evm_read_xattrs(struct file *filp, char __user *buf,
			       size_t count, loff_t *ppos)
{ … }

/**
 * evm_write_xattrs - write() for <securityfs>/evm_xattrs
 * @file: file pointer, not actually used
 * @buf: where to get the data from
 * @count: bytes sent
 * @ppos: where to start
 *
 * Returns number of bytes written or error code, as appropriate
 */
static ssize_t evm_write_xattrs(struct file *file, const char __user *buf,
				size_t count, loff_t *ppos)
{ … }

static const struct file_operations evm_xattr_ops = …;

static int evm_init_xattrs(void)
{ … }
#else
static int evm_init_xattrs(void)
{
	return 0;
}
#endif

int __init evm_init_secfs(void)
{ … }