/*
* AppArmor security module
*
* This file contains AppArmor /sys/kernel/security/apparmor interface functions
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
*
* 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.
*/
#include <linux/security.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/namei.h>
#include "include/apparmor.h"
#include "include/apparmorfs.h"
#include "include/audit.h"
#include "include/context.h"
#include "include/policy.h"
/**
* aa_simple_write_to_buffer - common routine for getting policy from user
* @op: operation doing the user buffer copy
* @userbuf: user buffer to copy data from (NOT NULL)
* @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size)
* @copy_size: size of data to copy from user buffer
* @pos: position write is at in the file (NOT NULL)
*
* Returns: kernel buffer containing copy of user buffer data or an
* ERR_PTR on failure.
*/
static char *aa_simple_write_to_buffer(int op, const char __user *userbuf,
size_t alloc_size, size_t copy_size,
loff_t *pos)
{
char *data;
BUG_ON(copy_size > alloc_size);
if (*pos != 0)
/* only writes from pos 0, that is complete writes */
return ERR_PTR(-ESPIPE);
/*
* Don't allow profile load/replace/remove from profiles that don't
* have CAP_MAC_ADMIN
*/
if (!aa_may_manage_policy(op))
return ERR_PTR(-EACCES);
/* freed by caller to simple_write_to_buffer */
data = kvmalloc(alloc_size);
if (data == NULL)
return ERR_PTR(-ENOMEM);
if (copy_from_user(data, userbuf, copy_size)) {
kvfree(data);
return ERR_PTR(-EFAULT);
}
return data;
}
/* .load file hook fn to load policy */
static ssize_t profile_load(struct file *f, const char __user *buf, size_t size,
loff_t *pos)
{
char *data;
ssize_t error;
data = aa_simple_write_to_buffer(OP_PROF_LOAD, buf, size, size, pos);
error = PTR_ERR(data);
if (!IS_ERR(data)) {
error = aa_replace_profiles(data, size, PROF_ADD);
kvfree(data);
}
return error;
}
static const struct file_operations aa_fs_profile_load = {
.write = profile_load,
.llseek = default_llseek,
};
/* .replace file hook fn to load and/or replace policy */
static ssize_t profile_replace(struct file *f, const char __user *buf,
size_t size, loff_t *pos)
{
char *data;
ssize_t error;
data = aa_simple_write_to_buffer(OP_PROF_REPL, buf, size, size, pos);
error = PTR_ERR(data);
if (!IS_ERR(data)) {
error = aa_replace_profiles(data, size, PROF_REPLACE);
kvfree(data);
}
return error;
}
static const struct file_operations aa_fs_profile_replace = {
.write = profile_replace,
.llseek = default_llseek,
};
/* .remove file hook fn to remove loaded policy */
static ssize_t profile_remove(struct file *f, const char __user *buf,
size_t size, loff_t *pos)
{
char *data;
ssize_t error;
/*
* aa_remove_profile needs a null terminated string so 1 extra
* byte is allocated and the copied data is null terminated.
*/
data = aa_simple_write_to_buffer(OP_PROF_RM, buf, size + 1, size, pos);
error = PTR_ERR(data);
if (!IS_ERR(data)) {
data[size] = 0;
error = aa_remove_profiles(data, size);
kvfree(data);
}
return error;
}
static const struct file_operations aa_fs_profile_remove = {
.write = profile_remove,
.llseek = default_llseek,
};
/** Base file system setup **/
static struct dentry *aa_fs_dentry __initdata;
static void __init aafs_remove(const char *name)
{
struct dentry *dentry;
dentry = lookup_one_len(name, aa_fs_dentry, strlen(name));
if (!IS_ERR(dentry)) {
securityfs_remove(dentry);
dput(dentry);
}
}
/**
* aafs_create - create an entry in the apparmor filesystem
* @name: name of the entry (NOT NULL)
* @mask: file permission mask of the file
* @fops: file operations for the file (NOT NULL)
*
* Used aafs_remove to remove entries created with this fn.
*/
static int __init aafs_create(const char *name, int mask,
const struct file_operations *fops)
{
struct dentry *dentry;
dentry = securityfs_create_file(name, S_IFREG | mask, aa_fs_dentry,
NULL, fops);
return IS_ERR(dentry) ? PTR_ERR(dentry) : 0;
}
/**
* aa_destroy_aafs - cleanup and free aafs
*
* releases dentries allocated by aa_create_aafs
*/
void __init aa_destroy_aafs(void)
{
if (aa_fs_dentry) {
aafs_remove(".remove");
aafs_remove(".replace");
aafs_remove(".load");
securityfs_remove(aa_fs_dentry);
aa_fs_dentry = NULL;
}
}
/**
* aa_create_aafs - create the apparmor security filesystem
*
* dentries created here are released by aa_destroy_aafs
*
* Returns: error on failure
*/
int __init aa_create_aafs(void)
{
int error;
if (!apparmor_initialized)
return 0;
if (aa_fs_dentry) {
AA_ERROR("%s: AppArmor securityfs already exists\n", __func__);
return -EEXIST;
}
aa_fs_dentry = securityfs_create_dir("apparmor", NULL);
if (IS_ERR(aa_fs_dentry)) {
error = PTR_ERR(aa_fs_dentry);
aa_fs_dentry = NULL;
goto error;
}
error = aafs_create(".load", 0640, &aa_fs_profile_load);
if (error)
goto error;
error = aafs_create(".replace", 0640, &aa_fs_profile_replace);
if (error)
goto error;
error = aafs_create(".remove", 0640, &aa_fs_profile_remove);
if (error)
goto error;
/* TODO: add support for apparmorfs_null and apparmorfs_mnt */
/* Report that AppArmor fs is enabled */
aa_info_message("AppArmor Filesystem Enabled");
return 0;
error:
aa_destroy_aafs();
AA_ERROR("Error creating AppArmor securityfs\n");
return error;
}
fs_initcall(aa_create_aafs);
